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Identification of a mechanism for increased cardiovascular risk among individuals with low vitamin D concentrations

Schnatz, Peter F. DO, FACOG, FACP, NCMP1,2,3,4; Nudy, Matthew1; O'Sullivan, David M. PhD1; Ethun, Kelly DVM5; Appt, Susan E. DVM5; Clarkson, Thomas B. DVM5

doi: 10.1097/gme.0b013e318212539d
Original Articles

Objective: The aim of this study was to investigate the plasma concentrations of vitamin D and its association with plasma lipid profiles.

Methods: Plasma vitamin D3 and lipid concentrations were measured in 119 female cynomolgus monkeys (premenopausal, n = 49; ovariectomized, n = 70) consuming approximately 1,000 IU per day of vitamin D3. In a subset of the ovariectomized monkeys (n = 23), vitamin D3 was remeasured after 6 months. The concentrations of vitamin D3 were analyzed as a continuous variable and were divided at the median into high (≥48 ng/mL) versus low (<48 ng/mL) groupings.

Results: Among the 119 monkeys, the range of vitamin D3 concentrations was 24.0 to 95.2 ng/mL (mean ± SD, 48.5 ± 12.7 ng/mL). Plasma vitamin D3 concentration was positively associated with high-density lipoprotein cholesterol (HDL-C; P = 0.003). Monkeys in the high vitamin D3 group had a significantly greater plasma HDL-C concentration (57.9 mg/dL) than did those in the low vitamin D3 group (47.1 mg/dL; P = 0.001). Although the difference was not significant (P = 0.120), the monkeys in the high vitamin D3 group had a decreased total plasma cholesterol-to-HDL-C ratio compared with those in the low vitamin D3 group (5.4 and 6.2, respectively), potentially putting them at lower risk of atherosclerosis development.

Conclusions: Given that the monkeys all consumed a diet replete in vitamin D3, it seems that individual differences in vitamin D absorption or metabolism may have determined whether the monkeys had high or low concentrations of vitamin D3. Lower vitamin D3 was associated with a more atherogenic lipid profile, a major risk factor for progressing to coronary artery atherosclerosis in monkeys and human beings.

Low concentrations of vitamin D3 were associated with lower HDL-C concentrations and a worsening lipid profile when monkeys were fed a moderately atherogenic diet.

From the Departments of 1ObGyn and 2Internal Medicine, The Reading Hospital and Medical Center, Reading, PA; Departments of 3ObGyn and 4Internal Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA; and 5Department of Pathology/Comparative Medicine, Wake Forest University, Winston-Salem, NC.

Received December 3, 2010; revised and accepted January 25, 2011.

The data from this study were presented in oral abstract form at The North American Menopause Society 21st Annual Meeting in Chicago, IL, on October 8, 2010. These data and results, however, have not been published in manuscript form and have not been submitted previously to another journal.

Funding/support: This study was supported in part by the research budget of The Reading Hospital and Medical Center and the National Institute on Aging 2R01 AG027847 (SEA).

Financial disclosure/conflicts of interest: None reported.

Address correspondence to: Peter F. Schnatz, DO, FACOG, FACP, NCMP, Department of ObGyn-R1, The Reading Hospital and Medical Center, PO Box 16052, Reading, PA 19612-6052. E-mail: schnatzp@readinghospital.org

©2011The North American Menopause Society