25(OH)D3 and Cardiovascular Risk Factors in Female Nonhuman Primates

Objective: To determine if interindividual differences in plasma concentrations of 25-hydroxyvitamin D-3 (25(OH)D-3) have pathophysiologic significance, we evaluated a cohort of female monkeys, seeking to identify associations with clinically relevant cardiovascular risk factors, including age, abdominal obesity (waist circumference), and high-density lipoprotein cholesterol (HDL-C). Methods: One hundred fifty-five female vervet monkeys (Chlorocebus aethiops sabaeus) aged 3-25 years consumed a typical western diet for 7-8 weeks that provided a woman's equivalent of approximately 1000 IU/day of vitamin D-3. Measurements of vitamin D-3 and HDL-C concentrations, as well as waist circumference, were obtained. Results: Among young monkeys (aged 3-5 years), compared to older monkeys (aged 16-25 years), the mean plasma 25(OH)D-3 concentrations were 82.3 +/- 3.2 ng/mL and 58.6 +/- 2.9 ng/mL (p < 0.0001), respectively. Plasma 25(OH)D-3 concentrations had a range of 19.6-142.0 ng/mL (mean +/- standard error [SE] 66.4 +/- 1.7 ng/mL). 25(OH)D-3 concentrations were inversely associated with age (p < 0.0001) and waist circumference (p = 0.016) and were positively correlated with HDL-C (p = 0.01). However, when statistically controlling for age, none of these relationships remained significant. Conclusions: Higher plasma concentrations of 25(OH)D-3 were associated with more favorable cardiovascular risk factors, with inverse associations observed between 25(OH)D-3 and abdominal obesity, HDL-C, and age. These associations were no longer significant when controlling for age.