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 .
Vitamin D Intake and Risk of Incident Hypertension: Results From Three Large Prospective Cohort Studies
Emerging evidence suggests an inverse relation between vitamin D and  blood pressure . We examined the independent association between intake of vitamin D and the risk of incident hypertension among participants of 3 large and independent prospect i ve cohorts : Nurses Health Study I ( NHS I ; n=77 436 ) , NHS II ( n=93 803 ) , and Health Professionals ’ Follow-up Study ( HPFS ; n=38 074 ) .  Relative risks and 95 % confidence intervals for incident hypertension were computed according to quintiles of vitamin D intake using Cox proportional hazards regression and adjusted for relevant covariates . Each cohort was followed for ≥8 years . Vitamin D intake was not associated with the risk of developing hypertension . The multivariable relative risk estimates for the highest compared with lowest quintile of intake were 0.98 ( 0.93 to 1.04 ) in NHS I , 1.13 ( 0.99 to 1.29 ) in NHS II , and 1.03 ( 0.93 to 1.15 ) in HPFS . When we compared participants who consumed ≥1600 to < 400 IU per day and those who consumed ≥1000 to < 200 IU per day , no association was found . We conclude that higher intake of vitamin D is not associated with a lower risk of incident hypertension
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 .