Objective: In earlier analyses of nonHispanic White women we found a stronger relation between abuse history and midpregnancy elevated depressive symptoms in women with the serotonin transporter (5-HTTLPR) S/S genotype. Here, we focus on African–American women (N=698). Our inquiry is motivated by racial differences in depression diagnosis/treatment, stressors, and frequency of major 5-HTTLPR alleles (S, LA, LG).
Materials and methods: Stressful life events (lifetime) and depressive symptoms (current) were ascertained at 15–27 weeks gestation. A Center for Epidemiological Studies Depression Score of more than or equal to 18 was considered ‘elevated’. Life events were scored together and separated into six subconstructs. 5-HTTLPR genotypes were grouped as follows: (i) L and S alleles, (ii) S-LG equivalence (‘triallelic to biallelic’), and (iii) LA/LA, all others, S/S (‘high/intermediate/low’). Odds ratios (OR) for ‘elevated’ depressive symptoms-life events (total and subconstructs) relations were calculated for each genotype grouping.
Results: The prevalence of ‘elevated’ depressive symptoms did not vary by genotype. The relation between stressful life events and ‘elevated’ depressive symptoms was stronger in S/S compared with LA/LA genotype (interaction P=0.11). Of the six subconstructs, only abuse showed a statistically significant gene–environment interaction. The OR for the abuse-‘elevated’ depressive symptoms association was greater for S/S vs. LA/LA genotype (interaction P=0.03) and in the ‘triallelic to biallelic’ grouping (interaction P=0.04). In the ‘high/intermediate/low’ grouping, ‘low’ (S/S) had a higher OR (5.5) than both ‘intermediate’ and ‘high’ (ORs≤2.3) (interaction P=0.10).
Conclusions: These results show the importance of examining racial groups, specific stressful events, and different 5-HTTLPR genotype groupings when exploring gene–environment interactions in depression.
aDepartments of Psychiatry
dPediatrics and Human Development
eMicrobiology and Molecular Genetics
fStatistics and Probability, Michigan State University, East Lansing, Michigan, USA
Correspondence to Jeanette M. Scheid, MD, PhD, Associate Professor of Psychiatry, B107B West Fee Hall, Michigan State University, East Lansing, MI 48824, USA Tel: +1 517 432 4215; fax: +1 517 432 3603; e-mail: firstname.lastname@example.org
Received June 17, 2010
Accepted February 18, 2011