Seasonal variation of serum high density lipoprotein cholesterol levels in men.

To determine if there are seasonal variations in serum high density lipoprotein cholesterol (HDL-C), the concentration of HDL-C was measured monthly for 12 consecutive months in 31 healthy men and 24 male inpatients with schizophrenia. In addition to HDL-C, total cholesterol (TC) and triglyceride (TG) concentrations in serum were assayed, and low density lipoprotein cholesterol (LDL-C) was estimated by calculation. Mean serum HDL-C levels of schizophrenic patients were significantly low compared with those of healthy controls, 35 +/- 12 and 49 +/- 11 mg/dl, respectively. The TC levels of schizophrenic patients were significantly higher in January and March as compared with August. The HDL-C levels in summer and autumn were significantly lower than those in winter and spring in both healthy men and schizophrenic patients. The concentration of LDL-C was significantly high in September and October as compared with April in healthy men. In patients with schizophrenia, LDL-C level seemed higher in January and March as compared with August.