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 .
Serum 25-Hydroxyvitamin D Levels Are Strongly Related to Systolic Blood Pressure But Do Not Predict Future Hypertension
Vitamin D receptors have been detected in vascular smooth muscle cells , and 1,25-dihydroxyvitamin D inhibits the renin mRNA expression . Epidemiological studies show an inverse relation between serum 25-hydoxyvitamin D levels and blood pressure , and low serum 25-hydoxyvitamin D levels are reported to be predictors of future development of hypertension . This may indicate an important role for vitamin D in blood pressure regulation . In the present study , 25-hydoxyvitamin D was measured in sera collected in 1994 from 4125 subjects who did not use blood pressure medication , and thereafter measurement was repeated in 2008 for 2385 of these subjects . In sera from 1994 there was a significant decrease in age , body mass index , and systolic blood pressure and a significant increase in physical activity score across increasing 25-hydoxyvitamin D quartiles . After adjusting for sex , age , body mass index , and physical activity , the difference in systolic blood pressure between the lowest and highest serum 25-hydoxyvitamin D quartiles was 3.6 mm Hg . After adjustment for confounders , serum 25-hydoxyvitamin D from 1994 did not predict future hypertension or increase in blood pressure , nor was there any significant association between change in serum 25-hydoxyvitamin D from 1994 to 2008 and change in blood pressure . Our results do not support a causal role for vitamin D in blood pressure regulation , and large r and omized clinical trials , preferably including subjects with hypertension and /or low serum 25-hydoxyvitamin D levels , are greatly needed to clarify whether vitamin D supplementation affects the blood pressure
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 .