The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels
Background A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D ( 25OHD ) levels on non-skeletal outcomes .
We performed a systematic quantitative review on characteristics of r and omized clinical trials ( RCTs ) included in meta-analyses ( MAs ) on non-skeletal effects of vitamin D supplementation .
Independent association of low serum 25-hydroxyvitamin d and 1,25-dihydroxyvitamin d levels with all-cause and cardiovascular mortality.
BACKGROUND In cross-sectional studies , low serum levels of 25-hydroxyvitamin D are associated with higher prevalence of cardiovascular risk factors and disease . This study aim ed to determine whether endogenous 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are related to all-cause and cardiovascular mortality . METHODS Prospect i ve cohort study of 3258 consecutive male and female patients ( mean [ SD ] age , 62 [ 10 ] years ) scheduled for coronary angiography at a single tertiary center . We formed quartiles according to 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels within each month of blood drawings . The main outcome measures were all-cause and cardiovascular deaths . RESULTS During a median follow-up period of 7.7 years , 737 patients ( 22.6 % ) died , including 463 deaths from cardiovascular causes . Multivariate-adjusted hazard ratios ( HRs ) for patients in the lower two 25-hydroxyvitamin D quartiles ( median , 7.6 and 13.3 ng/mL [ to convert 25-hydroxyvitamin D levels to nanomoles per liter , multiply by 2.496 ] ) were higher for all-cause mortality ( HR , 2.08 ; 95 % confidence interval [ CI ] , 1.60 - 2.70 ; and HR , 1.53 ; 95 % CI , 1.17 - 2.01 ; respectively ) and for cardiovascular mortality ( HR , 2.22 ; 95 % CI , 1.57 - 3.13 ; and HR , 1.82 ; 95 % CI , 1.29 - 2.58 ; respectively ) compared with patients in the highest 25-hydroxyvitamin D quartile ( median , 28.4 ng/mL ) . Similar results were obtained for patients in the lowest 1,25-dihydroxyvitamin D quartile . These effects were independent of coronary artery disease , physical activity level , Charlson Comorbidity Index , variables of mineral metabolism , and New York Heart Association functional class . Low 25-hydroxyvitamin D levels were significantly correlated with variables of inflammation ( C-reactive protein and interleukin 6 levels ) , oxidative burden ( serum phospholipid and glutathione levels ) , and cell adhesion ( vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 levels ) . CONCLUSIONS Low 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are independently associated with all-cause and cardiovascular mortality . A causal relationship has yet to be proved by intervention trials using vitamin
The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels
Background A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D ( 25OHD ) levels on non-skeletal outcomes .
We performed a systematic quantitative review on characteristics of r and omized clinical trials ( RCTs ) included in meta-analyses ( MAs ) on non-skeletal effects of vitamin D supplementation .