Clinical trial NCT05256212: Occupational Exposure of Firefighters to Environmental Pollutants
Official title: Occupational Exposure of Firefighters to Environmental Pollutants
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Healthy
Lead sponsor: Assaf-Harofeh Medical Center
Sponsor class: OTHER_GOV
Collaborators: name: Ben-Gurion University of the Negev
First posted: 2022-02-25
Enrollment: 108
Sex: MALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Firefighters

Brief summary: The aim of the current trial is to assess the exposure of firefighters (FF) to environmental pollutants emitted from fires, to explore the association of exposure with their health status and to compare these data with those of non-FF participants

Detailed description: Occupational exposure of firefighters to environmental contaminants Background Firefighters (FF) are exposed during their firefighting activities to a vast array of contaminants and toxic gases vapors that are released into the environment as results of combustion. Between those materials, there are heavy metals, brominated flame retardants (Polybrominated diphenyl ethers, PBDEs) and Volatile organic Compounds (VOC) that include between others Benzene, Toluene, Ethylbenzene and Xylene (BTEX).In the last decade a concern for negative health impact for all these contaminants appeared.

There is a vast use of these materials in the production of cars, furniture, electrical appliances, mattresses, paints, etc. These materials are released into the environment and absorbed by the human body.

There are some groups with increased exposure to these materials in comparison to the general population, as results of occupational exposure. Some of these groups include FF, workers who recycle electronic equipment and furniture manufacture workers.

Purposes:

1. to measure the levels of PBDEs, heavy metals and BTEX metabolites in the blood and urine of FF who are exposed to fires during their work
2. to evaluate the association between the levels of these materials and the health status of the participants. This will be done using a health questionnaire and the results of blood tests showing liver, renal and thyroid functions.
3. to compare their exposure levels and health status with those of general population

This is a prospective observational trial in a FF group. Exposure data from the activity log for each of the FF will also be collected.

Bromide flame retardants PBDEs

These materials are added during the manufacture process to many products such as: plastic, textile, furnitures, mattresses and electric equipment in order to reduce their flammability.

There are 5 main groups of flame retardants and more than 75 different kinds. BSEF (2006) reported the highest consumption of decaBDE at 65.7 kt in 2002, The wide manufacture and use of PBDEs increases their release and their accumulation in the environment with time.

Although PBDEs increase the safety of products in times of fire, they can release unwanted byproducts such as: dibenzene dioxinbromide and dibenzenofuran bromide.

During the last years, there is an increasing concern re. the nocive effects of these materials when they accumulate in the body.

Earlier animal studies show toxic effects of flame retardants: developmental neurotoxicity, hormonal effects and morphological renal and liver changes.

Additional studies show effects on sex hormones, ano-genital distance, puberty onset and spermatogenesis.

VOC-BTEX: these are aromatic hydrocarbon compounds, widely used in industry. They are a significant part of the air pollutants.

They have low boiling point and their main way of exposure is via the air. Humans are exposed to them from different sources: cleaning products, paints, solvents, cosmetics, car exhaust gases and cigarettes smoking.

Exposure to VOC can increase risk of congenital malformations, neuro-cognitive impairment, asthma and cancer.

During combustion, VOC are released into the environment. They may harm many systems in the body: neural, respiratory, reproductive. They also harm the liver and are mutagenic and immunotoxic.

Heavy metals (HM)

Humans are exposed to HM via the air, water or food. At high levels, all HM can harm the lungs. Some of the HM are more harmful than others:

Lead -Pb is known for neurological and cognitive harmful effects. Can also harm red blood cells, aminoacids metabolism and other metabolic systems.

Mercury -Hg can harm CNS, kidneys and embryos. Short exposure at high levels may harm: lungs, blood tension and heartbeat, digestive system, skin and eyes.

Cadmium- Cd causes abortion and preterm deliveries and can cause acidosis. Chromium-Cr: hexavalent chromium may cause skin, eyes and respiratory problems. Chronic exposure can cause cancer.

Study Plan

1. Trial population

   FF will be recruited (200). Exposure levels will be assessed for each participant by means of a detailed questionnaire. Levels of HM, PBDEs and BTEX found in blood and urine will be evaluated against health parameters such as: liver, renal and thyroid function, considering demographical , occupational and health variables (age, tenure, known diseases, eating habits, smoking and drinking.
2. Data and specimen collection

   From each FF, urine and blood (30 cc) samples will be collected and keep refrigerated till arrival into the lab. Samples will be separated and the ones for pollutants analysis will be kept in deep freezer (-80C) till analyzed.
3. Questionnaires FF will fill up specific questionnaires regarding demography, life-style, life habits during non-working hours. Basic health status, chronic diseases related to thyroid, fertility, psychological problems, both prescription and non-prescription drugs use.
4. Occupational data General data is routinely collected at the FF station such as work procedures, drills, number of calls.

   In addition, personal data will be collected for each FF: tenure, shifts/year, fire calls or other calls/year, task at the station , etc.
5. Lab tests:

Thyroid function: the following will be tested: 4-FT4; TSH; TPO-Ab Tg-Ab at Shamir MC central Lab using SOP Renal function: creatinine and GFR will be measured. Liver function: AST and ALT will be measured

PBDEs will be measured by GC-MS BTEX metabolites will be measured by LC-MS/MS Heavy Metals will be measured by ICP-MS

As a control group, samples collected in 12/12 trial (NCT03084445) that were not yet analyzed will be used. These samples were collected from men arriving to Shamir MC delivery room with their spouses.

Eligibility criteria: Inclusion Criteria:

\* active firefighters

Exclusion Criteria:

\* Women

firefighters with known liver, renal or thyroid problems

Primary outcomes:
measure: PBDEs levels, measured in serum by GC-MS
timeFrame: Day 1- day of recruitment
measure: BTEX levels, measured in urine by LC-MS/MS
timeFrame: Day 1- day of recruitment
measure: Heavy metals (Pb, Hg, Cd) levels, measured in urine by ICP-MS
timeFrame: Day 1- day of recruitment
Secondary outcomes:
measure: Liver enzymes levels (x2 of Upper Limit of Normal), measured in serum
timeFrame: Day 1- day of recruitment
measure: renal function (eGFR<60), by creatinine level measured in serum
timeFrame: Day 1- day of recruitment
measure: Thyroid function (TSH or FT4 out of lab reference values) measured in serum
timeFrame: Day 1- day of recruitment
Other outcomes:
Locations:
city: Zerifin
country: Israel
facility: Assaf Harofeh Medical Center
Study officials:
affiliation: Shamir MC
name: Matityahu Berkovitch, Prof
role: PRINCIPAL_INVESTIGATOR
References: