Background: Epidemiologic studies have suggested associations between vitamin D status and coronary heart disease (CHD) risk. The purpose of this work was to determine if vitamin D status was predictive of CHD risk assessed by Framingham risk score (FRS) in overweight, Caucasian, postmenopausal women, using the baseline data collected in a clinical trial.
Methods: The study comprised 178 women aged 42-67 years (mean±standard deviation [SD] 55.7±4.3). Fasting serum was used to analyze blood lipids and vitamin D. The status of the latter was determined based on serum 25-hydroxyvitamin D [25(OH)D], with inadequacy defined as serum 25(OH)D <75 nmol/L (or <50.0 nmol/L, per new Institute of Medicine recommendations). Usual dietary intake and activity were assessed using 3-day food and 2-day activity records, respectively. Education, medical history, blood pressure, and anthropometric measures were obtained as well. Season was determined based on date of blood draw.
Results: Mean serum 25(OH)D concentration was 65.3±27.5 nmol/L (range 7.0-147.6 nmol/L); 66% (n=118) and 32% (n=57) of subjects were vitamin D insufficient [25(OH)D <75 nmol/L or <50 nmol/L, respectively] of which 14% (n=25) were vitamin D deficient [25(OH)D <37.5 nmol/L]. Body mass index (BMI) was a significant negative and dietary vitamin D positive predictor of 25(OH)D. In hierarchical regression, FRS was predicted by education level only. No association was observed between 25(OH)D and FRS (p=0.981).
Conclusions: Serum 25(OH)D concentrations were inversely associated with BMI, but no relationship with FRS was found. Given the physiologic importance of vitamin D, further investigations aimed at determining the effects of obesity and heart disease on vitamin D requirements are warranted.