The study led by NAMS Board of Trustees member Peter F. Schnatz, DO, NCMP, is helping to settle those questions because it looked both at how a calcium and vitamin D supplement changed cholesterol levels and how it affected blood levels of vitamin D in postmenopausal women.
Daily, the women in the WHI CaD trial took either a supplement containing 1,000 mg of calcium and 400 IU of vitamin D3 or a placebo.
This analysis looked at the relationship between taking supplements and levels of vitamin D and cholesterol in some 600 of the women who had both their cholesterol levels and their vitamin D levels measured.
The women who took the supplement were more than twice as likely to have vitamin D levels of at least 30 ng/mL (normal according to the Institute of Medicine) as were the women who took the placebo. Supplement users also had low-density lipoprotein (LDL—the "bad" cholesterol) levels that were between 4 and 5 points lower.
The investigators discovered, in addition, that among supplement users, those with higher blood levels of vitamin D had higher levels of high-density lipoprotein (HDL—the "good" cholesterol) and lower levels of triglycerides (although for triglycerides to be lower, blood levels of vitamin D had to reach a threshold of about 15 ng/mL).
The study has been published in the journal of The North American Menopause Society (NAMS).