Systematic evaluation of the environmental effect on depressive symptoms in late adolescence and early adulthood: exposome-wide association study and twin modeling

Abstract

The exposome represents the totality of environmental effects, but systematic evaluation between it and depressive symptoms is scant. We sought to comprehensively identify the association of the exposome with depressive symptoms in late adolescence and early adulthood and determine genetic and environmental covariances between them. Based on the population-based FinnTwin12 cohort (3025 participants in young adulthood and 4127 at age 17), the exposome-wide association study (ExWAS) design was used to identify significant exposures from 12 domains. Bivariate Cholesky twin models were fitted to an exposome score and depressive symptoms. In ExWASes, 29 and 46 exposures were significantly associated with depressive symptoms in young adulthood and at age 17, respectively, and family-related exposures were the most influential. Twin models indicated considerable genetic and environmental covariances between the exposome score and depressive symptoms. The findings underscore the systematic approach of the exposome and the consideration of relevant genetic effects.