Vitamin d, parathyroid hormone, and cardiovascular mortality in older adults: the Rancho Bernardo study.

Background: recent systematic reviews have cast doubt on the association between vitamin D and cardiovascular disease. No prior studies have investigated the association between 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH](2)D), or intact parathyroid hormone and cardiovascular mortality in a temperate climate.

Methods: a total of 1073 community-dwelling older adults were evaluated in 1997-1999; serum levels of 25(OH)D (mean 42 ng/mL), 1,25(OH)(2)D (median 29 pg/mL), and intact parathyroid hormone (median 46 pg/mL) were measured; mean estimated glomerular filtration rate was 74 mL/min/1.73 m(2). Participants were followed up to 10.4 (mean 6.4) years with 111 cardiovascular deaths.

Results: in unadjusted Cox proportional hazards models, higher levels of 1,25(OH)(2)D were protective against cardiovascular mortality, whereas higher levels of intact parathyroid hormone predicted increased risk of cardiovascular death. After adjusting for age alone or multiple covariates, there was no significant association between 25(OH)D, 1,25(OH)(2)D, or intact parathyroid hormone and cardiovascular mortality; results did not differ by an estimated glomerular filtration rate ≥ 60 mL/min/1.73 m(2) or<60 mL/min/1.73 m(2).

Conclusion: in this prospective study of Caucasian, middle-income, community-dwelling older adults living in sunny southern California, serum levels of 25(OH)D, 1,25(OH)(2)D, and intact parathyroid hormone were not independently associated with cardiovascular mortality.