Associations of serum 25-hydroxycholecalciferol and parathyroid hormone with serum lipids differ by sex and vitamin D status.

Objective: Although emerging evidence indicates an association between vitamin D and serum lipids, the data are still inconsistent. The purpose of the present study was to investigate whether 25-hydroxycholecalciferol (25-hydroxyvitamin D3; 25(OH)D3) or intact parathyroid hormone (iPTH) was independently related to serum lipids in elderly women and men.

Methods: Cross-sectional study. Fasting serum levels of 25(OH)D3, iPTH, TAG, total cholesterol (TC), HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) were assessed. Body composition was measured by bioelectrical impedance analysis. Lifestyle factors, such as nutrient intake, time spent outdoors, physical activity, smoking, supplement intake and medication, were assessed by questionnaires. Multiple regression analyses were performed to examine associations of 25(OH)D3 and iPTH with serum lipids. Methods: Giessen, Germany. Methods: One hundred and ninety-three well-functioning German elderly aged 66-96 years.

Results: After adjusting for age, body fat, physical activity, smoking, alcohol intake, lipid-modifying drugs and either iPTH or 25(OH)D3, 25(OH)D3 was a predictor of TAG (standardised coefficient beta (β)=-0.180), HDL-C (β=0.197), LDL-C:HDL-C (β=-0.298) and TC:HDL-C (β=-0.302) in women, whereas iPTH was a predictor of HDL-C (β=-0.297) in men. In sub-analysis, associations between 25(OH)D3 and TC (β=-0.252), HDL-C (β=0.230), LDL-C (β=-0.324), LDL-C:HDL-C (β=-0.412) and TC:HDL-C (β=-0.380) were found in women with 25(OH)D3 concentrations above or equal the median vitamin D status (62.3 nmol/l), but not in women with lower 25(OH)D3 concentrations.

Conclusions: In the elderly, associations of 25(OH)D3 and iPTH with serum lipids may differ by sex and may require a vitamin D status above 62 nmol/l.