27.In this study a consistent association between acne and mental problems has been shown for both genders in a model which also includes diet, lifestyle factors and socio-demographic variables.The strength of the study is the non-healthcare-seeking sample with a relatively high rate of participation (80%), the use of validated instruments to measure acne and mental distress [35,36] and the inclusion of possible confounders in the multivariate analyses which are lacking in similar studies [15-17,21,22].Interestingly the protective effect of a high intake of vegetables and low intake of chocolate/sweets and potato chips in the present study is in coherence with the hypothesis that a low-glycemic diet is beneficial to arrest the development of acne.Regarding smoking our results are in correspondence with a study from Denmark among girls [50], but in contrast to studies showing both increased [11] and decreased prevalence of acne in smokers [12].In the adjusted analyses, the association between the socio-demographic variables and acne is no longer significant.In the present study an association between acne and a low intake of raw vegetables and a high intake of chocolate/sweets and potato chips has been found, but in the adjusted model the association with raw vegetables remains significant only among girls.Unfortunately we did not have data on the intake of milk in this study, and theoretically milk could have been a confounder in the exploration of the association between acne and mental distress.In the study we have found an almost doubled prevalence of self-reported acne among girls with a non-Western background compared to the reference population.Therefore we would suggest that measuring psychological parameters should be included in future studies on acne, especially in studies with a longitudinal design.This study shows that both dietary factors and mental health problems are candidates as causative factors in the development of acne among adolescents in a Western country.A small randomized controlled study has shown that a low glycaemic diet decreases the number of acne lesions after 12 weeks [23].This has never been shown before.28.29.30.Conclusion
31.