Vitamin D, Parathyroid Hormone, and Cardiovascular Mortality in Older Adults: The Rancho Bernardo Study

Jan 19, 2011
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Authors:
Jassal SK, Chonchol M, von Mühlen D, Smits G, Barrett-Connor E.
Citation:
Am J Med 2010;123:1114-1120.
Summary By:
Elizabeth A. Jackson, MD, FACC

Study Questions:

Is vitamin D and parathyroid hormone (PTH) associated with cardiovascular disease (CVD) mortality among older adults?

Methods:

Data from the Rancho Bernardo study, a prospective cohort of community-dwelling older adults, were used for the present study. Serum samples from 1997-1999 were used to measure serum levels of 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH]2D), and intact PTH. Glomerular filtration rate was calculated for all participants included in this study. Participants were followed up to 10.4 (mean 6.4) years.

Results:

A total of 1,073 adults, mean age 74 years, who completed the evaluation in 1997-1999, were included. During follow-up, 111 deaths due to CVD occurred. Vitamin D deficiency, defined as 25(OH)D of 30 ng/ml or less, was present in 14% of the cohort. Mean levels of vitamin D were 42 ng/ml for serum levels of 25(OH)D, and median 29 pg/ml for 1,25(OH)2D. Median levels of intact PTH were median 46 pg/ml. Mean estimated glomerular filtration rate was 74 ml/min/1.73 m2. In unadjusted models, higher levels of 1,25(OH)2D were protective against cardiovascular mortality, whereas higher levels of intact PTH predicted increased risk of cardiovascular death. After adjusting for age and multiple covariates, there was no significant association between 25(OH)D, 1,25(OH)2D, or intact PTH and cardiovascular mortality. The results did not differ by an estimated glomerular filtration rate ≥60 ml/min/1.73 m2 or <60 ml/min/1.73 m2.

Conclusions:

The authors concluded that among middle-income, community-dwelling older Caucasian adults residing in a temperate climate, serum levels of 25(OH)D, 1,25(OH)2D, and intact PTH were not independently associated with cardiovascular mortality.

Perspective:

These data add to a growing number of studies which have not observed a significant cardiovascular benefit associated with vitamin D levels. Further information from randomized clinical trials will inform clinicians regarding vitamin D supplementations and risk for a variety of outcomes including CVD.

Keywords: Climate, Follow-Up Studies, Vitamin D Deficiency, Dietary Supplements, Cardiovascular Diseases, Glomerular Filtration Rate, Parathyroid Hormone, Vitamin D, Dihydroxycholecalciferols


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