BMC Public Health 2009, 9:340 http://www.biomedcentral.com/1471-2458/9/340 Table 3: Odds ratio for reporting acne with mental distress, diet, lifestyle factors and socio-demographic variables among 1316 and 1647 late adolescent boys and girls in Oslo, Norway. Mental distress Diet Soft drinks with sugar Raw vegetables Fat fish Chocolate/sweets Potato chips Lifestyle Cigarette smoking Alcohol intake Socio-demographic factors Ethnicity Income No Yes Often Seldom Often Seldom Seldom Often Seldom Often Seldom Often Yes, daily Yes, but has quit or sometimes No, never Often Seldom Western Non-Western >1.0 million NOK 0.5-1.0 million NOK < 0.5 million NOK Acne Crude OR Males 1.0 1.22 (0.84-1.77) 1.0 1.26 (0.91-1.74) 1.0 1.49 (0.81-2.67) 1.0 1.40 (1.01-1.94) 1.0 1.54 (1.03-2.29) 1.0 1.06 (0.65-1.74) 1.14 (0.73-1.78) 1.0 1.31 (0.95-1.79) 1.0 1.02 (0.69-1.51) 1.0 1.09 (0.68-1.73) 1.10 (0.76-1.61) 1.0 1.63 (1.08-2.44) 1.0 2.16 (1.61-2.90) 1.0 1.68 (1.10-2.57) 1.0 2.04 (1.50-2.77) Females Adjusted OR Males Females 1.0 0.88 (0.53-1.46) 1.0 1.41 (1.05-1.90) 1.0 1.47 (0.81-2.67) 1.0 1.29 (0.95-1.74) 1.0 1.07 (0.67-1.70) 1.0 1.12 (0.73-1.73) 1.09 (0.73-1.61) 1.0 1.22 (0.90-1.66) 1.0 1.77 (1.27-2.45) 1.0 1.55 (1.02-2.34) 2.14 (1.36-3.35) 1.0 1.04 (0.95-2.08) 1.0 1.30 (0.93-1.82) 1.0 1.57 (0.86-2.86) 1.0 1.26 (0.84-1.88) 1.0 1.45 (0.88-2.40) 1.0 1.16 (0.70-1.92) 1.19 (0.73-1.93) 1.0 1.33 (0.93-1.89) 1.0 0.79 (0.48-1.31) 1.0 1.0 (0.57-1.74) 1.06 (0.72-1.57) 1.0 1.11 (0.64-1.92) 1.0 1.38 (1.01-1.88) 1.0 1.32 (0.70-2.47) 1.0 1.26 (0.84-1.88) 1.0 1.45 (0.88-2.40) 1.0 1.25 (0.80-1.95) 1.18 (0.77-1.82) 1.0 1.01 (0.71-1.43) 1.0 1.53 (0.95-2.16) 1.0 1.33 (0.87-2.04) 1.48 (0.88-2.48) 95% confidence interval Adjusted OR for reporting acne with mental distress, adjusted for all other factors in the table among 1316 and 1647 late adolescent boys and girls in Oslo Norway. and mental distress in any direction. No collinearity was identified between the variables. We also tested for inter- action, and no statistical interaction was identified between gender and mental distress or between ethnicity and mental distress. Discussion In this population-based study of a general adolescent population, the strongest and most consistent finding is the significant association between acne and mental dis- tress which is found among both boys and girls in the crude and the adjusted model. Another result from our study that supports a link between acne and mental dis- tress is the increase in mental distress when the severity of acne increases. These two findings have to our knowledge never been seen before in the same study. Previous studies have also shown an association between mental problems and acne. In a large study in New Zea- land of 9567 adolescents of 12-18 years of age, a signifi- cant odds ratio of 2.04 was seen between self-reported acne and depressive symptoms measured using Reynolds Adolescent Depression Scale [15]. In Australia, Kilkenny et al found an association (OR = 1.61) between self- reported severe acne and psychiatric symptoms measured using the Clinical Interview Schedule among 2491 stu- dents [17]. From the United Kingdom, Smithard et al found among 317 pupils aged 14-16 a significant odds ratio of 1.86 between acne which was objectively assessed by a researcher and psychological morbidity, measured by Strength and Difficulties Questionnaire [16]. These studies are in contrast to a recent Finnish study of 165 male conscripts with acne who did not suffer more depressive symptoms than patients with knee symptoms [22]. The Leeds acne grading scale was used to objectively measure acne, and mental problems were measured with the General Health Questionnaire and the Beck Depres- sion Inventory. In yet another study of 2657 students aged 14 to 20 from Turkey, no association between acne and Page 5 of 8 (page number not for citation purposes)