Shared genetic factors in the co-occurrence of symptoms of depression and cardiovascular risk factors.

BACKGROUND: We aim to investigate the extent to which shared genetic and shared environmental factors play a role in the co-occurrence of symptoms of depression and cardiovascular risk factors. METHODS: The analyses included 2383 individuals from a genetically isolated population in the Netherlands (mean age 48.7 years (standard deviation 15.1), percentage of women 56.9%). Symptoms of depression were assessed using the Center for Epidemiology Studies Depression Scale (CES-D) and the Depression subscale of the Hospital Anxiety and Depression Scale (HADS-D). Assessment of cardiovascular risk factors included systolic and diastolic blood pressure, plasma, glucose levels, high and low density lipoprotein (HDL, LDL) and total cholesterol levels. RESULTS: Overall, we found that HADS-D was significantly correlated to total cholesterol levels (correlation coefficient [rho]=0.05), and inversely associated to HDL (rho=-0.06). Statistically significant genetic correlations (rho(G)) were found between CES-D scores and total plasma cholesterol (rho(G)=0.30), LDL (rho(G)=0.31) and total cholesterol/HDL ratios (rho(G)=0.25). For HADS-D scores, a significant genetic correlation was found with total cholesterol/HDL ratios (rho(G)=0.27). Environmental correlations (rho(E)) with an opposite direction were found between CES-D and both total cholesterol (rho(E)=-0.16) and LDL (rho(E)=-0.15). LIMITATION: By adjusting for sibship, we are taking into account environmental effects, however we cannot exclude dominance variance. CONCLUSIONS: Our study shows that there is evidence for shared genetic factors contributing to the co-occurrence of symptoms of depression and lipid levels. This finding suggests a joint genetic pathogenesis. Future research is encouraged to assess susceptibility genes for mood disorders to be studied for cardiovascular disorders and vice versa.