Psychological Medicine



Gender differences in heritability of depressive symptoms in the elderly


M. JANSSON a1c1, M. GATZ a1, S. BERG a1, B. JOHANSSON a1, B. MALMBERG a1, G. E. McCLEARN a1, M. SCHALLING a1 and N. L. PEDERSEN a1c1
a1 Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; Department of Psychology, University of Southern California, Los Angeles, USA; Institute of Gerontology, Jönköping University, Jönköping, Sweden; Department of Psychology, Göteborg University, Göteborg, Sweden; Center for Developmental and Health Genetics, Pennsylvania State University, USA; Department of Molecular Medicine, Karolinska Institutet and Karolinska Sjukhuset, Stockholm, Sweden

Article author query
jansson m   [PubMed][Google Scholar] 
gatz m   [PubMed][Google Scholar] 
berg s   [PubMed][Google Scholar] 
johansson b   [PubMed][Google Scholar] 
malmberg b   [PubMed][Google Scholar] 
mcclearn g   [PubMed][Google Scholar] 
schalling m   [PubMed][Google Scholar] 
pedersen n   [PubMed][Google Scholar] 

Abstract

Background. The present study aimed to investigate the relative importance of genetic and environmental influences on depressive symptoms in the elderly.

Methods. Depressive symptoms were assessed through the Center for Epidemiological Studies – Depression (CES-D) scale. The CES-D scale was administered to 959 twin pairs (123 female MZs, 90 male MZs, 207 same-sex female DZs, 109 same-sex male DZs and 430 opposite-sex DZs) aged 50 years or older (mean age 72 years). A dichotomous depressed state variable was constructed based on CES-D cut-offs and self-reported use of antidepressant medication. Structural equation models were fitted to the data to dissect genetic and environmental variance components.

Results. The sex-specific heritability estimates for depressive symptoms were 14% for males and 29% for females and 23% when constrained to be equal for men and women. The prevalence of clinically significant depressive symptoms was 16% for men and 24% for women. Heritability estimates for the dichotomous depressed state measure were 7% for males and 49% for females in the full model and 33% when constrained to be equal.

Conclusion. Our results suggest that depressive symptoms in the elderly are moderately heritable, with a higher heritability for women than men, although differences in heritability estimates were not statistically significant.


Correspondence:
c1 Nancy Pedersen/Mårten Jansson, Department of Medical Epidemiology and Biostatistics (MEB), Box 281, Karolinska Institutet, S-171 77 Stockholm, Sweden. (Email: Nancy.Pedersen@mep.ki.se or martja@ki.se)


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