SERUM 25-HYDROXYVITAMIN D LEVEL AND RISK FOR INCIDENT STROKE IN CHINESE COMMUNITY-DWELLING OLDER MEN
R. Chan, D. Chan, J. Leung, J. Woo, C. Ohlsson, D. Mellström, P. Leung, T. Kwok
J Aging Res Clin Practice 2012;1(3):202-208
Objective: This study examined the association of serum vitamin D level and stroke incidence in older Chinese men. Design: Prospective cohort study. Setting: Hong Kong, China. Participants: 939 community-dwelling Chinese men aged 65 and older. Measurements: Baseline serum 25-hydroxyvitamin D (25OHD) level was measured using a competitive radioimmunoassay kit. Data on stroke incidence between 2001 and 2008 were retrieved from territory-wide hospital database. Cox regression analyses were performed with adjustments for age, body mass index, serum parathyroid hormone level, education, season of blood sampling, self-reported history of stroke and diabetes, hypertension status, and lifestyle factors. Results: Seventy nine (8.4%) men had incident stroke. In either crude or adjusted models, serum 25OHD level was not associated with stroke incidence. Results remained unchanged when serum 25OHD level was divided into quartiles or dichotomized into low (<50 nmol/L) and adequate (>=50 nmol/L) levels for analyses. Subjects with increasing age [adjusted HR (95% CI), 1.08 (1.03-1.13)], higher serum PTH level [2.58 (1.49-4.45)] and self-reported history of stroke [5.40 (3.01-9.71)] were associated with higher stroke incidence (p<0.001). Conclusions: The findings show no association between serum 25OHD level and risk of stroke in older Chinese men. The lack of association may possibly be due to the relatively high serum 25OHD level of the study ample. The implication of the positive association of serum PTH level with stroke incidence was limited by the lack of renal function measurements in this study.