To compare the access to and effective use of health services available among international migrants and Chileans.Caracterización Socioeconómica Nacional ), version 2017. Indicators of access to the health system  and effective use of health services  were described in immigrants and local population, self-reported. Gaps by immigrant status were estimated using logistic regressions, with complex samples. Secondary analysis of the National Socioeconomic Characterization Survey , coverage (OR: 2.7 95%CI: 2.0–3.7) and unsatisfied need. The difference between immigrants and locals was not statistically significant in barriers to health care access (α = 0.005). Disadvantages persist regarding the access to and use of health services by immigrants as opposed to Chileans compared with information from previous years. It is necessary to reduce the gaps between immigrants and people born in Chile, especially in terms of health system access. This is the first barrier to effective use of services. The generation of concrete strategies and health policies that consider an approach of social participation of the immigrant community is suggested to bring the health system closer to this population. It was recognized globally by most countries in the treaty adopted by the United Nations General Assembly in 1966 and came into force in 1976. In 2002, Latin American countries and the Caribbean agreed to initiate efforts to extend social health protection. It also appears as one of the eight Areas of Action defined in the Health Agenda for the Americas 2008–2017. In this agenda, all the Ministers of Health from Ibero-America committed themselves to combating health exclusion and building integrated social protection systems with the signing of the Iquique Declaration in July 20072 . Each dimension is essential for a State to provide and guarantee the right to health in its fundamental aspects. Vertical coverage includes the indicator of effective use of health services or benefits5 , of special relevance for the identification of gaps in health access by the general population and vulnerable groups7 . Differences in the effective use of health benefits between social groups, in the face of the same perceived need, correspond to unjust and preventable differences  that require constant attention and reparation. The indicator of effective use of health services or benefits can be disaggregated into the chain of health need and demand: (i) perceived health need, (ii) expressed and unexpressed demand, (iii) satisfied and unsatisfied demand8 .Social health protection is a concrete safeguard measure of the human right to health. It is developed through three main and complementary dimensions: (i) horizontal coverage ; (ii) vertical coverage (access to benefits); and (iii) financial protection9 . This country has a mixed health system, with a public component (close to 70.0% of the population) that protects the sickest and the poorest, a private component (close to 25.0% of the population) that protects the youngest and wealthiest, and a minor component of the armed forces and public order (5.0%). The Constitution of Chile indicates that free and equal access to health should be provided, but this premise has failed by demonstrating profound health inequalities among social groups, to the detriment of the least advantaged in their socioeconomic position. International migrant population has the right to use the public or private health system if they have a valid residence visa, selecting the type of provision according to co-payment capacity. For migrants going through a visa application process, an opportunity for health access on an equal footing with other migrants and Chileans was created if they document a situation of lack of resources to a witness of faith, usually a social worker, in the same health system .In Chile, there is still a debate about repositioning social health protection as a human right for the entire population residing in our territory, regardless of their sex, ethnicity, socioeconomic level or migratory status10 . Human displacement in all its forms is one of humanity’s greatest challenges. Migration is also recognized as a social determinant of health in the world. The process of migration itself, as well as factors associated with it when some degree of vulnerability or lack of protection of universal rights is experienced, have the potential to affect the physical, mental and emotional health of migrants and their families12 .Health protection for international migrants is a global concern. In ancient times and in modern life, moving from one place to another has always offered the opportunity to improve well-being. International migration represents an issue of global attention, reflecting international processes of social inequality and development, conflict and international stratification of labor, and processes of population ageing, to name only some of its dimensions. Added to this, in the globalization era, and given the ease access to information, the advance in communications and the reduced time and cost of moving from one place to another is faster and less costly today than in the past10 . On the other hand, risks associated with displacement, such as psychosocial disorders, reproductive health problems, increased neonatal mortality, drug abuse, nutritional disorders, alcoholism and exposure to violence have also been described12 . One of the aspects of growing interest on a global scale concerns the continuity of care in the transnational setting. This is due to the risks of health care interruption, mainly due to lack of health access in the receiving country12 .The health of migrants is affected when they are not adequately protected. Accidents, hypothermia, burns, cardiovascular accidents, complications in pregnancy and childbirth, diabetes and hypertension are the conditions most frequently mentioned by the World Health Organization12 . The migratory experience can have a negative impact on all social strata. However, health problems tend to concentrate on those migrants who experience poverty, exclusion and discrimination14 .The most recent estimate from the Department of Foreigners and Migration of the Ministry of Interior and Public Security in Chile, from April 2018, indicated there would be a 6.6% international migrant population, corresponding to a marked increase from 2012 census statistics that estimated 2.5-3.0%. The majority of international migrants come from countries of the Southern Cone , especially Argentina, Colombia, Venezuela, Ecuador, Bolivia and Haiti (2017 Short Census). It is important to recognize the great socioeconomic variability that the international migrant population presents in Chile and in the world. Just as there are migrants of high social hierarchy, there are also those of medium and low socioeconomic levels15 reported that the immigrant population would underutilize healthy child control compared with the local population, would use Pap smears screening similarly to the national one, and would use more prenatal and gynecological care services than locals. In addition, a clear socioeconomic gradient is observed in most of these services.In both Chile and the region as a whole, the evidence for the use of health services by international migrants is limited. Studies conducted by Cabieses et al.The aim of this study was to compare the effective use of the health services available among international and Chilean migrants. This comparison enables us to identify inequality gaps in the use of services, which are potentially modifiable, can have a negative impact on the health of migrants and run counter to the universal goal of social health protection.16 . This survey allows us to observe general patterns of the population that self-reports as an immigrant (born abroad) and to compare it with the Chilean population (born in Chile).Cross-sectional observational study. Secondary analysis of the National Socioeconomic Characterization Survey , version 201716 .The CASEN survey is developed periodically by the Ministry of Social Development. It is an instrument for diagnosis, evaluation and targeting, with the objective of knowing the socioeconomic conditions of the country’s households, especially those groups defined as priorities by social policies. This anonymous and free survey uses a complex probabilistic sample, allowing the representation of individuals in private residences of 324 towns of the 16 regions of the country, excluding towns with difficult access and institutionalized peopleCASEN had 70,948 households in 2017, considering a non-response rate of 26.6%. This survey contains information of 216,439 people residing in private households, of which 207,603  were Chilean and 6,811  immigrants. Thus, 94.6% of the population represented was Chilean and 4.4%, immigrant; 0.94% of the individuals did not report their migratory status, and therefore were excluded from the analysis. Data collection was carried out by a structured direct interview with habitual residents or an adult of the family, able to answer for the other members of the household.The study variables were:1.Access to the health systemAffiliation of a health insurance system [yes/no].Type of health insurance [public/private/other].Both were created by recoding the question “Which health insurance system do you use? .”2.Indicators of effective use of health services17: Self-reports constructed from the variables available in the CASEN 201716 survey   .Perceived need for health: Short-term  and long-term .Demand expressed and not expressed: have consulted the Chilean health system, or not, for those who reported having had some short-term health need [yes/no]; and to be covered or not by the AUGE-GES system in the case of long-term needs.Satisfied and unsatisfied demand: (yes) Appointment or coverage of the perceived health need in short or long term, respectively, or no appointment or coverage for voluntary reasons. (No) no appointment or coverage for involuntary reasons.Reasons for not having an appointment  or coverage .Barriers to health care: Presence of problems during the appointment due to short-term need [yes/no]. Indicator constructed from the questions: When you had an appointment, did you have any of the following problems? a) arriving for the appointment, hospital, clinic, etc. b) to get an appointment/health care (slot). c) to be attended at the establishment  d) paying for care due to cost e) delivery of medications at the healthcare establishment or access to them because of the costs.In cases of short and long-term perceived health need, a higher indicator value reflected a worse health condition. On the other hand, a higher value in the indicators: no access to a health insurance system, demand not expressed, no appointment, no coverage, no appointment or no coverage for involuntary reasons, unsatisfied need and presence of barriers to access, indicated a worse access to health services.3.Sociodemographic control variables: age, sex, area of residence [urban/rural], educational level [no education/basic/high/technical or professional], activity status [employed/unemployed/active], autonomous quintile of total household income.2 with second-order Rao-Scott correction (statistic F).The indicators of access to the health system and effective use of health services were analyzed descriptively for immigrants and people born in Chile, in totality and stratified according to sociodemographic variables. The independence between migratory status and indicators of effective use of health services and access to the health system was analyzed through Pearson’s test χLogistic regression models were performed, adjusted for sociodemographic variables, considering the use of a health insurance system, Demand satisfied in the short and long-term and Barriers to care, as dependent variables, and immigrant status as an independent variable. This is for the total population and for people over 14 years old (adults), additionally considering the activity condition variable.Database management and data analysis was performed using STATA 14 (StataCorp) software, considering the complex design of the survey (conglomerate stratum and expansion factor) and an estimate of variance by linearization by Taylor series. A significance of 0.05 and 95% confidence was considered for all analyses.The total of 16.3% of the country’s immigrants affirmed that they did not use a health insurance system, a value seven times higher compared with the Chileans (2.3%).Immigrants showed significantly less perceived health need than those born in Chile in both short and long-term. In the short-term, in immigrants, 15.1% of the total population reported illness or accident in the three months prior to the survey (vs. 20.2% in Chileans); of these, 9.3% did not have an appointment and 1.7 of every 100 people did not meet their health need by not having an appointment for reasons beyond their control. For Chileans, these values will correspond to 6.1% and 0.7 out of 100, respectively, significantly lower than in immigrants. On the contrary, immigrants and Chileans reported a similar proportion of problems during the appointment (access barriers): approximately 25.0% of consultants for short-term needs . In the long term, 9.6% of the immigrants were in medical treatment for some illness during the year prior to the survey (vs. 26.2% in Chileans), of which 44.4% were for another health condition different from the 20 main AUGE-GES pathologies treated. This percentage corresponded to 27.2% in Chileans. Immigrants significantly reported a higher proportion of no coverage  and unsatisfied needs , being specifically 2.9 and 4.7 times higher in immigrants than in Chileans, respectively   . In terAfter adjusting for socio-demographic variables, immigrants have 7.5 times more chances of not having health insurance than Chileans. The odds were 6.2 times greater in immigrants than in Chileans over 15 years old and considering the activity condition .Sex, having secondary or higher education compared with no schooling, and belonging to the richest income quintile were significant factors in the lack of health provision, disadvantageous to women, people with no schooling and lower income for the total population. In people over 15 years old, in addition, age and unemployment in reference to occupation will turn out to be significant. On the other hand, having a high school education in relation to no schooling ceased to be significant   .Among the 632,770 immigrants with health insurance, 80.0% used the public system, 18.0% from the private system and 2.0% from the armed forces (FF.AA.) or other, while in Chileans these percentages were 82.1%, 15.0% and 2.9%, respectively. The proportion of men and women using the private health system was higher in both immigrants and Chileans. 15.2% (95%CI:12.26–18.79%) of women with pensions used the public system, while in men, 21.0% (95%CI:16.78–26.03%) were immigrants. [Results not presented in the table]The immigrant population presented 21.0% (OR = 0.79) less odds of having short-term health needs (illnesses or accidents) than Chileans. However, their odds of not getting an appointment were 1.7 times higher because of this need and the odds of not satisfying this need or not getting an appointment for involuntary reasons were 3.1 higher. All this after adjusting for sociodemographic variables. This situation was maintained for people older than 15 years. Sex, age, schooling and belonging to the richest quintile were significant variables in non-expression of demand. Education ceased to be significant in individuals over 15 years old, and the rest of the income quintiles (with the exception of the III) and the activity condition became significant   .Immigrants had 2.0% (OR = 0.98) times less chance of presenting access barriers than Chileans. After adjusting for socio-demographic variables, this situation was reversed. Immigrants had a greater chance of presenting access barriers both for the entire population and for those aged 15 years or older. It was not significant for none of the cases   .For long-term needs (treatment of some diseases), immigrants had greater odds of not having their treatment covered despite having a lesser chance of receiving treatment. Specifically, adjusting for sociodemographic variables, immigrants had 53.0% (OR = 0.47) times less odds of being in treatment for some disease than Chileans and 37.0% (OR = 0.63) times less odds that this disease was an AUGE-GES pathology. Among those with AUGE-GES pathologies, the immigrant population had 2.7 times more odds of not being covered and 3.3 times more odds of not satisfying this necessity for coverage than Chileans. Immigrants older than 15 years had a greater chance of not being covered by AUGE-GES and not satisfying their long-term need compared with Chileans. With the exception of sex and basic education in contrast to no schooling, all variables considered were significant in no coverage and no satisfaction. In people over 15 years old, it was also not significant to have a secondary education in contrast to having no schooling   .When analyzing the models of indicators of effective use of health services stratified with and without health provision, the presence of long-term needs and coverage of this immigrant status variable was significant   .The results of this study indicate that immigrants are still at a disadvantage in terms of access and use of health services compared with Chileans. Immigrants presented 7.5 times more chances of not having health insurance than Chileans and a lower perceived need but less appointment, coverage or need satisfaction in the short and long-term. Immigrants were 1.7 times more likely to get an appointment in case of an illness or accident and 3.1 times more likely to not satisfy their need by not attending the appointment for reasons out of their control than people born in Chile. On the other hand, the immigrant population were 2.7 times more likely to not have their treatment covered by AUGE-GES and 3.3 times more likely to not satisfy this need for coverage than Chileans.17 .Many countries have been challenged by the global increase in international migrants recently. This brings a series of challenges for diverse sectors, education, health and social protection, just to name a few, which become more complex to face when this population is in conditions of social vulnerability. Health protection in international migrants is a global concern, and access to health services is a fundamental aspect of this work18 . On the other hand, it has been reported that a significant proportion of them live in conditions of social vulnerability. Because they are in an irregular situation, poverty, inadequate housing conditions, unemployment or informal employment and processes of discrimination and abuse or because of the difficulty in obtaining official residence identity document in the country, which, in matters of health access, is essential in order to use the health pension system19 . The number of 15.7% immigrants were not affiliated to any health system in 2015, a value 5.8 times greater than that compared with people born in Chile. The immigrant population was at a disadvantage as to the local population in other indicators of health access, such as the medical care rate for health problems and the issue with health care access18 .The percentage of first-generation immigrants present in the country increased 0.7% in Chile between 2013 and 2015, and it represents 110,738 immigrants17 . Even more worrying is that some of these indicators have increased between 2013 and 2017. 15.6% of immigrants had no health insurance in 2013, while it was 16.3% in 2017; 8.9% of those with short-term needs did not had an appointment because of this need in 2013, while it was 9.4% in 2017. 27.9% of those in treatment for an AUGE-GES disease were not covered by it in 2013, while this value was 44.6% in 2017.The same problems are observed in previous years by Cabieses et al. regarding the effective use of health services for short and long-term needs and access to the health system17 . Even more so in Chile, where according to the CASEN survey (2015), 18.5% of 12 years old or older immigrants participated or participate in some organization or group18 . The CASEN survey in all its versions is nationally representative and allows a diagnosis of the situation of the immigrant population in the country with respect to various socioeconomic conditions. In this specific case of health, it provides information about health conditions , access to the system, health services, health insurance, use of these and associated payments, which in turn may be associated with each other and with a wide range of demographic, cultural and socioeconomic factors17 . Despite this, the sample selection process of the survey does not seek to represent the international migrant population in particular and the country of birth  has non-response percentages (responds “does not know”) of 0.9% in 2017. On the other hand, the CASEN survey only allows the analysis of residents in homes, leaving out of the scenario the number of immigrants in street situations, which, according to local media, are increasing20 . The analyses carried out from this survey are limited to the variables present in it. Some of the cultural challenges such as differences in perceptions, traditions and lifestyles, among others, represented as barriers to integration and therefore into obstacles and challenges in access to health systems and services19 cannot be analyzed directly. It is therefore widely useful in the future to complement the analyses presented in this manuscript.It is necessary to reduce inequality gaps in health access and use of health services by the migrant population. To this end, concrete health strategies and policies are necessary, allowing, by social determinants of health, to protect the health and well-being of migrants, from the appearance of short and long-term health problems, and factors that may favor them, to their effective resolution. Interventions that consider a social participation approach of the international migrant community and that bring the Chilean health system closer to this population are widely recommendedThis study indicates that disadvantages persist in access to health services and their use among immigrants compared with those born in Chile. It is necessary to reduce the gaps between immigrants and Chileans, especially in terms of affiliation to a health system. This is the first barrier to the effective use of services. We suggest the generation of concrete strategies and health policies that consider a social participation approach of the immigrant community and, additionally, bring the health system closer to this population.Demand model (short-term): N=3,415,253Df=1,289 F=10.64. Model Satisfaction requirement (short-term): N=3,393,049 Df=1,289 F=6.91. Model Barriers: N=3,146. Df=1,288 F=17.78. Adult demand model (short-term): N=2,797,755 Df=1,288 F=6.54. F=6,08. Model Satisfaction of needs in adults (short-term): N=2,778,419 Df=1,288 F=3.72. Model Obstacles in adults: N=2,563,952 Df=1,287 F=13.76. Model Coverage: N=2,974,923 Df=1,295 F=118.55. Model Coverage in adults: N=2,840,844Df=1,295 F=25.94. Model Satisfaction (long-term): N=2,853,809 Df=1,295 F=100.76. Model Adult satisfaction (long-term): N=2,727,317 Df=1,295 F=21.8 1 .El derecho a la salud es un derecho humano universal e inalienable. Fue reconocido de forma global por la mayoría de los países del mundo en el tratado adoptado por la Asamblea General de las Naciones Unidas en 1966 y puesto en vigor en 1976. En 2002, países de América Latina y el Caribe acordaron iniciar esfuerzos para extender la protección social en salud. Esta aparece también como una de las ocho Áreas de Acción definidas en la Agenda de Salud de las Américas 2008–2017. En dicha agenda, todos los Ministros de Salud de Iberoamérica se comprometieron a combatir la exclusión en salud y construir sistemas integrados de protección social con la firma de la declaración de Iquique en Julio 20072 Cada dimensión es esencial para que un Estado otorgue y garantice el derecho a la salud en sus aspectos fundamentales. Dentro de la cobertura vertical está el indicador de uso/utilización efectiva de servicios o prestaciones de salud5 , de especial relevancia para la identificación de brechas de acceso a salud por parte de población general y grupos vulnerables7 . Diferencias de uso efectivo de prestaciones de salud entre grupos sociales, ante igual necesidad sentida, corresponde a diferencias injustas y prevenibles  que requieren de constante atención y reparación. El indicador de uso/utilización efectiva de servicios o prestaciones de salud puede desagregarse en la cadena de necesidad y demanda en salud: (i) necesidad sentida de salud, (ii) demanda expresada y no expresada, (iii) demanda satisfecha y no satisfecha8 .La protección social en salud es una medida concreta de garantía del derecho humano en salud. Se desarrolla a través de tres dimensiones principales y complementarias entre sí: (i) cobertura horizontal ; (ii) cobertura vertical (acceso a prestaciones); y (iii) protección financiera9 . Este país cuenta con un sistema de salud mixto, con componente público  que protege a los más enfermos y a los más pobres, componente privado  que protege a los más jóvenes y adinerados, y componente menor de fuerzas armadas y del orden público . La Constitución de Chile indica que se debe brindar acceso libre e igualitario a la salud, pero esta premisa ha fallado al demostrarse profundas desigualdades en salud entre grupos sociales, en desmedro de los menos aventajados en su posición socioeconómica. La población migrante internacional cuenta con derecho a uso del sistema de salud público o privado si tiene su visa de residencia vigente, seleccionando el tipo de previsión según capacidad de copago. Para migrantes con visa en trámite, se creó la oportunidad de acceso a salud en igualdad de condición que los demás migrantes y chilenos si es que documentan situación de carencia de recursos a un testigo de fe, habitualmente trabajador social, en el mismo sistema de salud .En Chile, aún está presente el debate de reposicionar la protección social en salud como un derecho humano para toda la población residente en nuestro territorio, independientemente de su condición de género, etnia, nivel socioeconómico o estatus migratorio10 . El desplazamiento humano en todas sus formas es uno de los mayores desafíos de la humanidad. La migración es además un reconocido determinante social de la salud en el mundo. El proceso de migrar en sí mismo, así como factores asociados a este cuando se experimenta algún grado de vulnerabilidad o falta de protección a derechos universales, tienen el potencial de afectar la salud física, mental y emocional de las personas migrantes y sus familias12 .La protección de la salud por parte de migrantes internacionales es de preocupación global. En tiempos antiguos y en la vida moderna, el desplazamiento de un lugar a otro siempre ha ofrecido la oportunidad de mejor bienestar. La migración internacional representa un tema de atención mundial, al ser reflejo de procesos internacionales de desigualdad social y de desarrollo, de conflicto y de estratificación internacional del trabajo, y de procesos de envejecimiento poblacional, por mencionar algunas de sus dimensiones. Sumado a esto, en la era de la globalización, y dadas las facilidades de acceso a información, el avance en las comunicaciones y el menor tiempo y costo de los traslados, el llegar de un lugar a otro resulta hoy en día más rápido y menos costoso que en el pasado10 . Por otra parte, riesgos derivados de los desplazamientos, tales como trastornos psicosociales, problemas de salud reproductiva, mayor mortalidad neonatal, uso indebido de drogas, trastornos nutricionales, alcoholismo y exposición a la violencia, también han sido descritos12 . Uno de los aspectos de creciente interés a escala global tiene relación con la continuidad del cuidado en el escenario transnacional. Esto por los riesgos en salud de la interrupción de la atención, fundamentalmente por falta de acceso a ella en el país receptor12 .La salud de personas migrantes puede verse afectada cuando no cuentan con adecuada protección. Accidentes, hipotermia, quemaduras, accidentes cardiovasculares, complicaciones del embarazo y el parto, diabetes e hipertensión, son las afecciones más mencionadas por la Organización Mundial de la Salud12 . La experiencia migratoria puede impactar negativamente en todos los estratos sociales; sin embargo, los problemas de salud tienden a concentrarse en aquellos migrantes que experimentan pobreza, exclusión y discriminación14 .La más reciente estimación del Departamento de Extranjería y Migración del Ministerio del Interior y Seguridad Pública en Chile en abril del 2018 indicaba que existiría un 6,6% de población migrante internacional, correspondiendo a un marcado aumento desde estadísticas censales del 2012 que estimaban un 2,5-3,0%. La mayoría de los migrantes internacionales provienen de países del cono sur (el llamado patrón migratorio “sur-sur” propio de la región de Latinoamérica), en especial Argentina, Colombia, Venezuela, Ecuador, Bolivia y Haití (Censo abreviado del 2017). Es relevante reconocer la gran variabilidad socioeconómica que la población migrante internacional presenta en Chile y el mundo. Así como existen migrantes de alta jerarquía social, también los hay de nivel socioeconómico medio y bajo15 han reportado que la población inmigrante sub-utilizaría el control de niño sano comparado con la población local, utilizaría en forma similar el screening de Papanicolaou a la nacional, y utilizaría más servicios de atención prenatal y ginecológica que la local. Además, se ha observado un claro gradiente socioeconómico en la mayoría de estas prestaciones.Tanto en Chile como en la región en su conjunto, existe evidencia limitada del uso de servicios de salud por parte de población migrante internacional. Estudios realizados por Cabieses y colaboradoresEl objetivo de este estudio fue comparar el uso efectivo de servicios de salud disponibles entre migrantes internacionales y chilenos. Dicha comparación permite identificar brechas de desigualdad en uso de servicios, que son potencialmente modificables, que pueden impactar negativamente en la salud de los migrantes y que van en contra de la meta universal de protección social en salud.16 . Esta encuesta permite observar patrones generales de población que se autorreporta como inmigrante (nacida en el extranjero) y compararla con la chilena (nacida en Chile).Estudio observacional de corte transversal. Análisis secundario de encuesta de Caracterización Socioeconómica Nacional (CASEN), versión 201716 .La encuesta CASEN es desarrollada periódicamente por el Ministerio de Desarrollo Social. Es un instrumento de diagnóstico, evaluación y focalización, con el objetivo de conocer condiciones socioeconómicas de los hogares del país, especialmente aquellos grupos definidos como prioritarios por las políticas sociales. Esta encuesta, anónima y de libre disposición, utiliza un muestreo probabilístico de naturaleza compleja, permitiendo la representatividad de residentes en viviendas particulares de 324 comunas de las 16 regiones del país, excluyendo comunas de difícil acceso y personas institucionalizadasCASEN contó con 70.948 hogares en 2017, considerando una tasa de no respuesta del 26,6%. Esta encuesta contiene información de 216.439 personas residentes en hogares particulares, de las cuales 207.603 (representativos de 16.843.471) eran chilenas y 6.811 (representativas de 777.407) inmigrantes. Así, el 94,6% de la población representada era chilena y 4,4% inmigrante; 0,94% de los individuos no reportaron su estatus migratorio, y por ende fueron excluidos del análisis. La recolección de datos se realizó mediante entrevista estructurada directa a residentes habituales o un adulto de la familia, teniendo la facultad de responder por otros miembros del hogar.Las variables del estudio fueron:1.Acceso al sistema de saludPertenencia a un sistema de previsional de salud [sí/no].Tipo de previsión de salud [pública/privada/otra].Ambos creados a partir de la recodificación de la pregunta “¿A qué sistema previsional de salud pertenece usted? ”17 : Autorreportes construidos a partir de las variables disponibles en encuesta CASEN 201716  y a largo plazo (Durante los últimos 12 meses ¿ha estado en tratamiento médico? [sí/no]).Demanda expresada y no expresada: Haber consultado o no al sistema de salud chileno, para aquellos que reportaron haber tenido alguna necesidad de salud de corto plazo [sí/no]. Y encontrarse cubierto o no el tratamiento por el sistema AUGE-GES en el caso de las necesidades a largo plazo.Demanda satisfecha y no satisfecha: (sí) Consulta o cobertura de la necesidad sentida en salud a corto o largo plazo, respectivamente, o no consulta o cobertura por motivos voluntarios. (no) no consulta o cobertura por motivos involuntarios.Razones de no consulta (¿Por qué no tuvo consulta ni atención?) o cobertura (¿Por qué este tratamiento médico no fue cubierto por el sistema AUGE-GES?).Barreras de atención: Presencia de problemas durante la consulta por necesidad a corto plazo [sí/no]. Indicador construido a partir de las preguntas: Cuando consultó, ¿se le presentó alguno de los siguientes problemas? a) llegar a la consulta, hospital, consultorio, etc. b) conseguir una cita/atención (hora). c) ser atendido en el establecimiento  d) pagar por la atención debido al costo e) entrega de medicamentos en el establecimiento de salud o acceso a ellos por su costo.En los casos de necesidad sentida de salud a corto y largo plazo, un mayor valor del indicador reflejaba una peor condición de salud. Por otro lado, un mayor valor en los indicadores de: no pertenencia a un sistema previsional de salud, demanda no expresada, no consulta, no cobertura, no consulta o no cobertura por motivos involuntarios, necesidad no satisfecha y presencia de barreras de acceso, indicaba un peor acceso a servicios de salud.3.Variables sociodemográficas de control: edad, sexo, zona de residencia [urbano/rural], nivel educacional [sin educación/primaria/secundaria/técnica o profesional], condición de actividad [ocupados/desocupados/inactivos], quintil autónomo del ingreso total del hogar.Los indicadores de acceso al sistema de salud y uso efectivo de servicios de salud fueron analizados descriptivamente para inmigrantes y nacidos en Chile, en su totalidad y estratificados según variables sociodemográficas. Se analizó la independencia entre la condición migratoria e indicadores de uso efectivo de servicios de salud y acceso al sistema de salud mediante el test de Pearson con corrección de segundo orden Rao y Scott (estadístico F).Se realizaron modelos de regresión logística, ajustados por variables sociodemográficas, considerando Pertenencia a un sistema de previsional de salud, Demanda satisfecha a corto y largo plazo y Barreras de atención, como variables dependientes, y condición de inmigrante como variable independiente. Esto para el total de la población y para mayores de 14 años (adultos) considerando adicionalmente la variable condición de actividad.El manejo de base de datos y análisis de estos se realizó mediante el software STATA 14 (StataCorp), considerando el diseño complejo de la encuesta (estrato conglomerado y factor de expansión) y una estimación de varianza por linealización por series de Taylor. Se consideró una significancia de 0,05 y confianza del 95% para todos los análisis.Un 16,3% de los inmigrantes del país afirmaban no pertenecer a un sistema previsional de salud, valor siete veces mayor en comparación con los nacidos en Chile .Los inmigrantes presentaron significativamente una menor necesidad sentida en salud que los nacidos en Chile tanto a largo como a corto plazo. A corto plazo, en inmigrantes, un 15,1% del total de la población reportó enfermedad o accidente en los tres meses previos a la encuesta ; de estos, el 9,3% no consultaron y 1,7 de cada 100 no logró satisfacer su necesidad en salud al no consultar por motivos ajenos a su voluntad. En chilenos, estos valores corresponderán a 6,1% y 0,7 de cada 100, respectivamente, significativamente menores que en inmigrantes. Por el contrario, inmigrantes y chilenos reportaron una proporción similar de presencia de problemas durante la consulta (barreras de acceso): aproximadamente un 25,0% del total de consultantes por necesidades a corto plazo . A largo plazo, un 9,6% de los inmigrantes se encontraba en tratamiento médico por alguna enfermedad durante el año previo a la encuesta , de los cuales el 44,4% eran por otra condición de salud distinta a las 20 principales patologías AUGE-GES consultadas; este porcentaje correspondió al 27,2% en chilenos. Los inmigrantes reportaron significativamente una mayor proporción de no cobertura  y necesidades no satisfechas , siendo específicamente 2,9 y 4,7 veces mayor en inmigrantes que en chilenos, respectivamente   . En térTras ajustar por variables sociodemográficas, los inmigrantes presentan 7,5 veces más chances de no tener previsión de salud que los chilenos. Este chance fue 6,2 veces mayor en inmigrantes que en chilenos en mayores de 15 años y considerando la condición de actividad .El sexo, el tener educación media o superior en comparación con no tener educación, y el pertenecer el quintil de ingreso más rico en comparación con el más pobre, resultaron ser factores significativos en la falta de previsión de salud, en desventaja de las mujeres, personas sin educación y de menores ingresos para el total de la población. En mayores de 15 años, adicionalmente, la edad y desocupación en referencia a la ocupación resultaran ser significativas. Por otro lado, el tener educación media en referencia a no tener educación dejó de ser significativa   .Dentro de los 632.770 inmigrantes con previsión de salud, el 80,0% pertenecía al sistema público, el 18,0% al privado y el 2,0% fuerzas armadas (FF.AA.) u otro, mientras que en chilenos estos porcentajes fueron 82,1%, 15,0% y 2,9% respectivamente. La proporción de pertenecientes al sistema privado de salud en hombres que en mujeres fue mayor tanto en inmigrantes como en nacidos en Chile. El 15,2%  de las mujeres con previsión pertenecían al sistema público, mientras que en hombres un 21,0%  en inmigrantes. [Resultados no presentados en tabla]La población inmigrante presentó significativamente 21,0%  menos chance de tener necesidades a corto plazo en salud (enfermedades o accidentes) que los chilenos. Sin embargo, tuvieron 1,7 veces más chance de no consultar ante esta necesidad y 3,1 veces más chance de no satisfacer esta, es decir, no haber consultado por motivos involuntarios. Todo esto tras ajustar por variables sociodemográficas. Esta situación se mantuvo en mayores de 15 años. Sexo, edad, educación y pertenecer al quintil más rico en contraste con el más pobre fueron variables significativas en la no expresión de la demanda. La educación dejó de ser significativa en mayores de 15 años, y el resto de los quintiles de ingreso (a excepción del III) y la condición de actividad pasaron a serlo   .De manera cruda, los inmigrantes tenían 2,0%  veces menos chance de presentar barreras de acceso que los chilenos. Tras ajustar por variables sociodemográficas, esta situación se invirtió. Los inmigrantes presentaran una mayor chance de presentar barreras de acceso tanto para el total de la población como para los de 15 años o más. Para ninguno de los casos esto fue significativo   .Para las necesidades a largo plazo  de manera significativa, los inmigrantes tuvieron un mayor chance de no tener su tratamiento cubierto pese a presentar un menor chance de estar en tratamiento. Específicamente, ajustando por variables sociodemográficas, los inmigrantes tenían 53,0%  veces menos chance de estar en tratamiento por alguna enfermedad que los chilenos y 37,0%  veces menos chance de que esta enfermedad fuera una patología AUGE-GES. Entre aquellos con patologías AUGE-GES, la población inmigrante tenía 2,7 veces más chance de no estar cubierta y 3,3 veces más chance de no satisfacer esta necesidad de cobertura que los chilenos. En mayores de 15 años, los inmigrantes tuvieron mayor chance de no estar cubiertos por el AUGE-GES y no satisfacer su necesidad a largo plazo que los chilenos. A excepción del sexo y el tener educación básica en contraste con el no tener educación, todas las variables consideradas fueron significativas en la no cobertura y no satisfacción. En mayores de 15 años tampoco fue significativo el tener educación media en contraste con no tener educación   .Al analizar los modelos de indicadores de uso efectivo de servicios de salud estratificados por con y sin previsión de salud, la presencia de necesidades a largo plazo y cobertura de esta la variable condición de inmigrante fue significativa   .Los resultados de este estudio indican que los inmigrantes aún se encuentran en desventaja en términos de acceso y uso a servicios de salud en comparación con los nacidos en Chile. Los inmigrantes presentaron 7,5 veces más chances de no tener previsión de salud que los chilenos y una menor necesidad sentida pero una menor consulta, cobertura o satisfacción de estas necesidades a corto y a largo plazo. Los inmigrantes tenían 1,7 veces más chance de no consultar ante una enfermedad o accidente y 3,1 veces más chance de no satisfacer su necesidad, al no consultar por motivos ajenos a su voluntad, que los nacidos en Chile. Por otro lado, la población inmigrante tenía 2,7 veces más chance de no tener cubierto su tratamiento por el AUGE-GES y 3,3 veces más chance de no satisfacer esta necesidad de cobertura que los chilenos.17 .Muchos países se han visto desafiados por el aumento global de población migrante internacional en los últimos años. Esto trae consigo una seria de desafíos para diversos sectores, educación, salud y protección social, solo por nombrar algunos, los cuales se vuelven más complejos de enfrentar cuando esta población se encuentra en condiciones de vulnerabilidad social. La protección de la salud en migrantes internacionales es de preocupación global, y el acceso a servicios de salud una arista fundamental para esta labor18 . Por otro lado, se ha reportado que una proporción significativa de estos viven en condiciones de vulnerabilidad social, ya sea por encontrarse en situación irregular, pobreza, malas condiciones de vivienda, desempleo o empleo informal y procesos de discriminación y abuso o la dificultada para obtener documentación oficial de identidad de residencia en el país, lo cual en temas de acceso a salud es esencial para poder pertenecer al sistema previsional de salud19 . Para el año 2015, un 15,7% de los inmigrantes no se encontraba afiliado a ningún sistema de salud, valor 5,8 veces mayor que en nacidos en Chile. La población inmigrante se encontraba en situación de desventaja respecto a la población local también en otros indicadores de acceso a salud, como tasa de atención médica ante problema de salud y problema de acceso a atención18 .El porcentaje de inmigrantes de primera generación presentes en el país aumentó en 0,7% en Chile, entre el 2013 y 2015, lo cual se traduce en 110.738 inmigrantes17 . Más preocupante aun es que algunos de estos indicadores han aumentado entre 2013 y 2017. Un 15,6% de los inmigrantes no tenían previsión de salud en 2013, mientras que fueron un 16,3% en 2017; un 8,9% de los que tenían necesidades a corto plazo no consultaron por esta necesidad en 2013, mientras que fue un 9,4% en 2017. Un 27,9% de los que se encontraban en tratamiento por una enfermedad AUGE-GES no se encontraban cubiertos por el mismo en 2013, mientras que este valor fue de 44,6% en 2017.Se observan las mismas falencias que en años anteriores por Cabieses y cols. en cuanto al uso efectivo de servicios de salud por necesidades a corto y largo plazo y acceso al sistema de salud17 ; más aún en Chile, en donde según la encuesta CASEN (2015), un 18,5% de los inmigrantes de 12 años o más han participado o participan en alguna organización o grupo organizado18 . La encuesta CASEN en todas sus versiones es de representación nacional y permite obtener un diagnóstico de la situación de la población inmigrante en el país respecto a diversas condiciones socioeconómicas. En este caso específico de la salud, esta permite conocer: condiciones de salud , acceso al sistema, servicios de salud, seguros de salud, uso de estos y pagos asociados, las cuales a su vez pueden asociarse entre ellas y entre una amplia diversidad de factores demográficos, culturales y socioeconómicos17 . Pese a esto, el proceso de selección muestral de la encuesta no busca representar a la población migrante internacional en particular y la variable de país de nacimiento (que permite la estratificación entre inmigrante y chileno) cuenta con porcentajes no respuesta (responde “no sabe”) en 2017 del 0,9%. Por otro lado, la encuesta CASEN solo permite el análisis de residentes en viviendas, dejando fuera del panorama a aquellos inmigrantes en situación de calle, los cuales según medios locales se encuentran en incremento20 . Los análisis realizados a partir de esta encuesta se encuentran limitados a las variables presentes en ella. Algunos de los desafíos culturales como diferencias en visiones, tradiciones y estilos de vida, entre otros, que se traducen en barreras de integración y por ende en barreras y desafíos en el acceso a sistemas y servicios de salud19 no pueden ser analizados directamente. Es, por tanto, de amplia utilidad a futuro complementar los análisis presentados en este manuscrito.Es necesario reducir brechas de desigualdad en acceso y uso de servicios de salud por parte de población migrante. Para eso, son necesarias estrategias concretas en salud y políticas que permitan, a través los determinantes sociales de la salud, proteger la salud y bienestar de migrantes, desde la aparición de problemas de salud de corto y largo plazo, y factores que puedan favorecer estos, hasta su efectiva resolución. Intervenciones que consideren un enfoque de participación social de la comunidad migrante internacional y que acerquen el sistema de salud chileno a esta población son ampliamente recomendadasEl presente estudio indica que persisten las desventajas en acceso y uso a servicios de salud en inmigrantes en comparación con los nacidos en Chile. Es necesario reducir las brechas entre inmigrantes y nacidos en Chile, sobre todo en cuanto a pertenencia a un sistema de salud. Esta es la primera barrera para un uso efectivo de servicios. Se sugiere generar estrategias concretas y políticas en salud que consideren un enfoque de participación social de la comunidad inmigrante y, adicionalmente, acerquen al sistema de salud a esta población.Modelo Demanda (corto plazo): N=3.415.253Df=1.289 F=10,64. Modelo Satisfacción necesidad (corto plazo): N=3.393.049 Df=1.289 F=6,91. Modelo Barreras: N=3.146. Df=1.288 F=17,78. Modelo Demanda en adultos (corto plazo): N=2.797.755 Df=1.288 F=6,54. F=6,08. Modelo Satisfacción necesidad en adultos (corto plazo): N=2.778.419 Df=1.288 F=3,72. Modelo barreras en adultos: N=2.563.952 Df=1.287 F=13,76. Modelo Cobertura: N=2.974.923 Df=1.295 F=118,55. Modelo Cobertura en adultos: N=2.840.844Df=1.295 F=25,94. Modelo Satisfacción necesidad (largo plazo): N=2.853.809 Df=1.295 F=100,76. Modelo Satisfacción necesidad en adultos (largo plazo): N=2.727.317 Df=1.295 F=21,8


Background: Foundry workers are occupationally exposed to hazardous substances such as silicadusts and toxic gases. The aim of this study was to examine the effects of simultaneous exposure tocomplex mixtures of silica dust, formaldehyde, and triethylamine on lung function parameters.Study design: A cross-sectional study.Methods: This study was conducted on 55 male workers of core making unit of a foundry plant (thecase group) and 55 workers in a food industry were enrolled as a control group in 2015. Workers weremonitored for personal exposure to crystalline silica respirable dust, according the NIOSH methodNo.7602. The concentrations of formaldehyde and triethylamine were measured using a PIDinstrument. Lung function tests were performed according to the ERS/ATS standards.Results: The mean concentrations of personal exposure to silica dust, formaldehyde, andtriethylamine in the core making workers were 0.23 mg/m3, 2.85 ppm, and 5.55 ppm and respectiveexposures of control subjects were less than the LOD (limit of detection). There were significantassociations between exposure to silica dust and decreases in FVC  values(P<0.05). The findings showed a statistically significant synergistic effect of silica dust andtriethylamine on FVC values (P<0.05).Conclusions: The mean exposure of all studied substances was higher than occupational exposurelimits. Synergistic effects of exposure to silica dust and triethylamine on some lung functionparameters were observed. Simultaneous exposure of foundry workers to silica dust and triethylaminecould impair lung function. Exposure to silica dust in foundry workers has been described previously3. Exposure to crystalline silica has caused silicosis, lung cancer, pulmonary tuberculosis, chronic bronchitis, and chronic obstructive pulmonary disease6. International Agency for Research on Cancer (IARC) classified inhaled crystalline silica as a group 1 carcinogen8.Workers in many workplace settings are occupationally exposed to a number of hazardous substances, associated with a wide range of adverse health effects9conducted a case-control study in a cohort of 5016 foundry workers employed for at least one year in the studied aluminum foundries in Sweden including 31 cases of lung cancer. Their results indicate the odds ratio of lung cancer of cumulative quartz exposures in the range of 0.001–1.0 mg/m3-yr at a value of 1.6 . The geometric mean value for occupational exposure to crystalline silica aerosols in 20 studied foundry workers in the east zone of Tehran was 0.343 mg per cubic meter10. The concentration of respirable crystalline silica dust in aluminum foundry workers was 0.10 mg per cubic meter11. The air concentrations of respirable silica dust in the studied stone crushing units in Iran exceeded the threshold limit value (TLV) in industrial units of Azandarian12.Westberg and Bellander13 studied the effect of exposure to silica dust on lung function tests of 209 male foundry workers and 239 office workers selected as a control group. Geometric mean concentration of the quartz in molding and core making units were 0.051 mg/m3 and 0.023 mg/m3, respectively. All ventilation parameters except FVC were significantly lower in foundry workers than those in the control group were. The reduction in the FVC and FEV1 values of workers exposed to respirable crystalline silica dust was reported14.Several attempts have been made to measure pulmonary function among foundry workers. Koo et al. 15. Exposed workers were reported to suffer from irritation of the upper respiratory system, change in pulmonary function parameters such as decline in the FEV1, and sensitization effects17. IARC classified formaldehyde as human carcinogens that cause nasopharyngeal cancer in humans19. Reversible changes in the lung function parameters have been observed at 2.4 mg/m3 exposure level20.Formaldehyde as a highly reactive carbonyl compound may cause irritation and health symptoms21. The general effects of tertiary amines include irritation, headache, nausea, anxiety, faintness and corrosive effects to the skin, mucous membrane, eye, nose, throat, respiratory distress, cough, and corneal edema22.Tertiary amines such as triethylamine are used in the core making processesGiven the importance of adverse health effects of workers' exposure, there has been little discussion on the effects of simultaneous exposure to complex mixtures of silica dust, formaldehyde, and triethylamine on the respiratory system of foundry workers abroad and in Iran.Therefore, the objective of this study was to examine the effects of simultaneous exposure to complex mixtures of silica dust, formaldehyde, and triethylamine on the respiratory system of core making workers at a foundry located in the greater Tehran, Iran.-five male subjects of a food manufacturing plant without active exposure to any dusts or gases from similar socioeconomic class participated as a control group as well. Workers and controls were matched for gender and the number of participants. The demographic features such as age, work experience, body mass index (BMI) of workers, and cigarette smoking habit in the case and control groups were obtained prior to survey. None of the exposed workers used personal protective equipment.Census procedure was used to determine the sample size and all 55 male workers of core making unit of a foundry plant , located in Tehran, Iran with inclusion criteria of one year of work experience and willing to participate in the research were enrolled in this cross-sectional analytical study in 2015 (the case group). FiftyAll subjects signed consent forms and the study was approved by local Ethics Committee.Since, the concentration of air pollutants is affected by indoor climate parameters, indoor climate factors, including relative humidity, air pressure level, and wind speed were measured in core making environment.24. Each set was comprised of a calibrated SKC sampling pump  equipped with mixed cellulose ester (MCE) filters  and a 10-mm nylon cyclone (SKC) at a flow rate of 1.7 L/min. Quartz purchased from Merck (Germany) was used for the preparation of standard samples in the range of 20-200 µg per sample. After personal sampling, 200 mg potassium bromide purchased from Merck Co. was added to MCE filters. All filters were placed in the muffle furnace at 600 °C for 2 h. Subsequently, all samples were transferred to a mortar for complete mixing and homogenizing. Finally, each sample was pressed under 20 mega-pascal for 2 min for manufacturing 13 mm pellets. Each pellet was analyzed for crystalline silica by WQF-510A FT-IR spectrometer (China) in a range from 400 to 4000 cm-1 or 710-825 nm24.Workers' exposure to crystalline silica dust was monitored according to an improved method of National Institute for Occupational Safety and Health (NIOSH) 760225. The intra- and inter-day coefficients of variation were considered for the precision of the method and accuracy was examined as percentage of recovery of standards. The coefficient of variation less than 10% and recovery efficiency in the range of 80% to 100% was considered as acceptable26. The LOD and LOQ (limit of quantification) values for analysis of crystalline silica dust were calculated according to equation No. 1 and No. 2, respectively.The validity of silica dust measurements was determined as wellLOD = Xbi + 3Sbi Eq. 1LOQ = Xbi + 10Sbi Eq. 2i was the mean concentration of the blank and Sbi was the standard deviation (SD) of the blank27.Where Xb28. PhoCheck Tiger PID was used to measure some compounds in previous work such as the toluene concentration at the inlet and outlet of the oxidation reactor29. The instrument was calibrated using the contamination-free air in the range of 0.4 to 14 ppm prepared in Tedlar bags . Atmospheric stock gas standards were prepared through static injection of known amounts of volatile liquid (using micro syringe Hamilton Company) into a 1L Tedlar bag containing contamination-free air. Hamilton gas tight syringe (0-500 µl) was used to transfer known amount of gas volume into 10 L Tedlar bags and filling them with known volume of contamination-free air by setting the proper flow and time parameters. Contamination-free atmosphere gases in the range of 0.4 to 14 and 0.4 to 12 as ppm for formaldehyde and trimethylamine respectively were prepared for calibration of PID.The concentrations of formaldehyde and triethylamine were measured using a photoionization detector (PID) apparatus . The usual mechanism of action of PID instrument as a real-time analyzer is ionization using ultraviolet radiation-7 a.m.) and after shift (during 4-5 p.m.). The workers' state of respiratory health was classified according to ATS/ERS guidelines for spirometric patterns of normal, obstructed, restricted, or mixed obstructed and restricted32. The subjects rested for 5 min before performing pulmonary-function tests. Spirometry was performed in standing positions of subjects and at least three acceptable maneuvers were obtained. Spirometric values were corrected for age, height, weight, and smoking habitLung function tests were performed using a spirometer . Pulmonary function parameters such as FVC, FEV1, FEV1/FVC, peak expiratory flow (PEF), and mid forced expiratory flow (FEF 25–75%) were considered. Lung function tests were measured according to the ERS/ATS standards before shift . The normality of the data was determined using Kolmogorov–Smirnov test. The independent 2, respectively. Among core making workers, 32.7% smoked cigarettes. The average (SD) number of cigarettes smoked per day was 11.56 (7) during 10.81 (7.33) yr on average. The average (SD) regarding age, work experience, and BMI of workers in the control group were 37.15 (7.96) yr, 10.72 (6.84) yr, and 25.24 (3.77) kg/m2, respectively. Among subjects in the control group, 14.5% smoked cigarettes. The average (SD) number of cigarettes smoked per day was 7.50 (5.34) during 8.38 (5.29) yr on average. The independent samples t-test indicated significant differences in age and work experience of workers in the case and control groups (P<0.001). The chi-square test revealed that the numbers of current smokers were significantly higher (P=0.025) in the case group than in the control group. Because the spirometric values were based on subjects' age in the case and control groups, no adjustment was applied to this variable. The results were adjusted for work experience and the number of cigarette smokers. However, no statistical significant differences were found for other demographic variables.The average (SD) regarding age, work experience, and BMI of core making workers was 31.98 (6.90) yr, 5.32 (4.59) yr, and 25.11 (3.82) kg/m-IR spectroscopy method was 2.57 and 3.61%, respectively. The efficiency of recovery for silica dust samples was 100%. The LOD and LOQ for silica dust samples were 5.04 μg/sample and 3.82μg/sample, respectively.Measured indoor air parameters in the core-making unit of a foundry plant are presented in 34.The results obtained from the monitoring of occupational exposure to crystalline silica, formaldehyde, and triethylamine in the core-making unit are shown in t-test showed significant decreases (P <0.05) in the mean values of some lung function parameters including FVC, FEV1, and FEV1/FVC values in the exposed group compared to control group for before and after work shifts. Linear regression  indicated significant differences (P<0.05) in FVC and FEV1 values between exposed and control subjects before and after work shifts.Results of lung function tests for exposed and control groups were compared . However-Whitney tests revealed that differences in the spirometric patterns of workers between the exposed and control groups before starting a work shift (P=0.001) and after the work shift (P=0.007) were significant  denotes that increases for exposure to silica dust and triethylamine were associated with decreases in FEV1 and FVC values . No signP=0.034; β=-0.301) and after shift . There were significant associations between exposure to silica dust and FEV1 values only after shift .The association of lung function parameters with exposures to silica dust was determined after adjusting for exposures to formaldehyde, and triethylamine. The multiple regression analysis of data revealed that there were significant associations between exposure to silica dust and FVC values before shift (P=0.025) and after (P=0.029) work shifts. In addition, the results indicated a statistically significant synergistic effect of silica dust and triethylamine on FEV1 (P=0.010) and PEF (P=0.009) before and after work shifts FEV1 (P=0.001); PEF (P=0.003). The statistically significant synergistic effect of exposures to formaldehyde and smoking habits on FEF 25–75% values before (P=0.036) and after (P=0.028) work shifts were noticed.he synergistic effects of simultaneous exposures to silica dust, formaldehyde, and triethylamine were investigated using linear regression analysis. The findings showed a statistically significant synergistic effect of silica dust and triethylamine on FVC values before (*years of work) data indicated that there were significant associations between exposure to silica dust and FVC, FEV1, and FEF 25–75% values before and after work shifts (P<0.05).The simple regression analysis of cumulative exposure  reported on 19 workers in 3 foundries36.The occupational exposure of foundry workers in this study (0.41-6.47 ppm) to formaldehyde was approximately in the same range as the formaldehyde concentrations in the breathing zone in a steel foundry (2-4 ppm)35who found lower mean values of FVC among steel foundry workers. This finding also is in agreement with those of Johnson et al. 37who found significantly lower mean values of FEV1 among workers in an iron and steel foundry than control subjects did. In addition, our results are consistent with those of other findings and suggest that there was no difference in spirometric values of smokers and non-smokers in the case group13.This finding supports previous research, which stated the prime role of silica dust exposure in reducing ventilator capacity of the foundry workers13.We found that FVC and FEV1 values were significantly lower in foundry workers than in control subjects. Our findings are consistent with those of Low and Mitchell38. Although extensive research has been carried out to examine the synergistic effects of exposure to toxic agents40, to the best of our knowledge, too little attention has been paid to determine the combined effects of respirable silica dust, formaldehyde, and triethylamine on lung function parameters in literature.The results of this study revealed that combined exposure to silica dust and triethylamine had synergistic effects with some lung function parameters. This was accompanied by significant decreases in the values of FVC and FEV1. The phenomenon of simultaneous exposure of foundry workers to dust and fumes impaired their lung function parameters. In another study, combined occupational exposures to airborne dusts, gases, and fumes were associated with a reduction in peak expiratory flow rate (PEF)Prevalence of obstructive, restrictive, and mixed ventilatory impairments were significantly higher among our foundry workers than among control subjects. Although there were no statistically significant correlation between formaldehyde exposure and lung function parameters, the cumulative exposure of formaldehyde of our foundry workers was significantly correlated with FEF 25–75 after work shifts. This phenomenon signifies short and long-term effects of formaldehyde as irritant gas.41, more stringent of control measures, and health promotion programs are recommended for foundry workers.Results of combined exposure to silica dust and irritant gases on lung function parameters of foundry workers in this study, has raised serious concerns about their respiratory health. Therefore, more thorough examinations of their occupational exposures and health surveillance, including radiographic assessments of workers' lung conditions, according to Steenland and Ward (2014)The mean concentrations of silica dust, formaldehyde, and triethylamine in the breathing- zone air of study foundry workers were higher than proposed occupational exposure limits. Some lung function parameters such as FVC and FEV1 values were significantly lower in foundry workers than in control subjects. The findings showed a statistically significant synergistic effect of silica dust and triethylamine on FVC values. Synergistic effects of exposure to formaldehyde and smoking habits on FEF 25–75 values were observed.This study was done as a partial fulfillment of Master of Science degree in Occupational Health Engineering. The authors also appreciate the workers and management of the foundry plant for their sincere supports and corporations.The authors have declared no conflict of interest.This project was financially supported by the Safety Promotion and Injury Prevention Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.The air concentrations of silica dust, formaldehyde, and triethylamine exceeded the respective threshold limit values.Lower values for some lung function parameters were observed in foundry workers compared to the control subjects. Synergistic effects of combined exposure to silica dust and triethylamine on FVC values were reported.