The role of socioregional factors in moderating genetic influences on early adolescent behavior problems and alcohol use

Abstract

Background: Twin and family studies have demonstrated that adolescent alcohol use and behavior problems are influenced by a combination of genetic and environmental factors. More recently, studies have begun to investigate how genetic and environmental influences may interact, with efforts underway to identify specific environmental variables that moderate the expression of genetic predispositions. Previously, we have reported that community-level factors, including urban/rural residency, migration rates, and prevalence of young adults, moderate the importance of genetic effects on alcohol use in late adolescence (ages 16 to 18). Here, we extend these findings to test for moderating effects of these socioregional factors on alcohol use and behavior problems assessed in a younger sample of adolescent Finnish twins.

Methods: Using data from the population-based Finnish twin study, FinnTwin12, biometric twin models were fit to data on >1,400 twin pairs to examine the significance of each of the socioregional moderating variables on alcohol use measured at age 14, and behavior problems, measured at age 12.

Results: We find no evidence of a moderating role of these socioregional variables on alcohol use; however, there was significant moderation of genetic influences on behavior problems, with effects limited to girls. Genetic influences assumed greater importance in urban settings, communities with greater migration, and communities with a higher percentage of slightly older adolescents.

Conclusions: The moderation effects observed on behavior problems in early adolescence paralleled the effects found on alcohol use late in adolescence in an independent sample, providing further support for the idea that behavior problems may represent an earlier manifestation of the predisposition to subsequent alcohol problems. Our findings also support the growing body of evidence suggesting that females may be more susceptible to a variety of environmental influences than males.

Fig. 1

Moderation model. The latent variable A, represented in a circle, indicates additive genetic influences on the trait (T) of interest. C represents common (shared) environmental influences on a trait, and latent E represents unique environmental influences, which are uncorrelated between the twins. The triangle indicates the mean/thresholds for T and is necessary when modeling raw data. The standard paths a, c, and e, indicating the magnitude of effect of each latent variable on the trait, each include a β term, which indicates the significance of a measured moderator variable M on each of these genetic and environmental influences.

Fig. 2

Changing variance in additive genetic effects, common environmental effects, and unique environmental effects on age 12 behavior problems in girls across increasing levels of percentage of older adolescents in the neighborhood.