Elevated depressive symptoms and compositional changes in LDL particles in middle-aged men.

Depression and cardiovascular disease (CVD) are closely associated, but the mechanisms underlying this connection are unclear. Regardless of the low cholesterol levels observed in depression, a small particle size of low-density lipoproteins (LDL), as well as elevated apolipoprotein B (ApoB) levels, are related to increased CVD risk, even when levels of LDL cholesterol are low. We examined the association between elevated depressive symptoms and compositional changes in serum LDL particles in a sample of 2,456 middle-aged Finnish men. Depressive symptoms were assessed with the 18-item Human Population Laboratory Depression Scale, and the study population was divided into two groups (elevated depressive symptoms, n = 269; non-depressed, n = 2,187). The levels of serum total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C, HDL-C), triglycerides (TG), and ApoB were determined. The LDL-C/ApoB ratio, a marker of compositional changes in LDL particle size, was calculated. The group with elevated depressive symptoms had lowered levels of serum TC (P = 0.028) and LDL-C (P = 0.008). No differences were observed in the LDL-C/ApoB ratio. The likelihood for belonging to the group with elevated depressive symptoms increased 10% for each 0.5 mmol/l decrease in the levels of TC (P = 0.002) or LDL-C (P = 0.001) in regression models adjusted for age, examination years, marital and socioeconomic status, energy expenditure, body mass index, CVD history, alcohol consumption, smoking, and the use of lipid-lowering, antidepressant and antipsychotic medications. Our findings suggest that greater small-particle LDL levels are not associated with depression, and are thus unlikely to underlie the association between cardiovascular risk and depression.