Low serum vitamin D levels increase the mortality of cardiovascular disease in older adults: A dose-response meta-analysis of prospective studies

Abstract

Lower circulating vitamin D is common in older adults and may be a potential reversible risk factor for cardiovascular disease (CVD) in older adults, however, presented controversial results.Database was searched update to February 2018. Key data were extracted from eligible studies. Dose-response meta-analysis were conducted for synthesizing data from eligible studies.A total of 13 eligible studies involving 21,079 participants were included in this meta-analysis. Person with lower 25-hydroxyvitamin D status (25 (OH)D level <50 nmol/L) appeared to have higher mortality of CVD in older adults (RR = 1.54, 95% CI 1.24-1.91). Furthermore, a significantly higher mortality of CVD in older adults was observed for the deficient (<25 nmol/L; RR = 1.47, 95% CI 1.15-1.81) and insufficient (25-50 nmol/L; RR = 1.16, 95% CI 1.04-1.27) categories of 25 (OH)D, compared to the reference category of >75 nmol/L. Additionally, decrease of 10 nmol/L 25-hydroxyvitamin D was associated with a 7% incremental in the risk of CVD mortality in older adults.Considering these promising results, circulating vitamin D is associated with CVD mortality increment in older adults.

Figure 1

Flow diagram of the study selection process.

Figure 2

Forest plot showing the pooled effects of serum 25-hydroxyvitamin D on the risk of cardiovascular disease mortality in older adults. Solid diamonds and horizontal lines represent RRs (95% CIs) for the outcome of interest. Solid circles and horizontal lines represent RRs (95% CIs); the gray boxes reflect the statistical weight of the study. The dotted vertical line denotes the point estimate for the pooled RRs and the solid vertical line indicates the line of no effect. The open diamond represents the pooled RR with its 95% CI. CI = confidence interval; RRs = relevant risks.

Figure 3

Dose–response analysis between serum 25-hydroxyvitamin D and the relative risk of cardiovascular disease mortality in older adults. The solid line represents point estimates of the association of serum 25-hydroxyvitamin D and cardiovascular disease risk with the use of a restricted cubic splines model, and the dashed lines indicate 95% CIs. CI = confidence interval; RRs = relevant risks.

Figure 4

A funnel plot for the meta-analysis between serum 25-hydroxyvitamin D and the relative risk of cardiovascular disease mortality in older adults.