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 .
Randomized placebo-controlled trial of high-dose prenatal third-trimester vitamin D3 supplementation in Bangladesh: the AViDD trial
Background Antenatal vitamin D status may be associated with the risk of adverse pregnancy and neonatal outcomes ; however , the benefits of vitamin D supplementation during pregnancy remain unknown . Methods We conducted a double-blind placebo-controlled r and omized trial to evaluate the effect of high-dose prenatal 3rd trimester vitamin D3 supplementation on maternal and neonatal ( cord blood ) serum 25-hydroxyvitamin D ( 25(OH)D ) concentration ( primary biochemical efficacy outcome ) and maternal serum calcium concentration ( primary safety measure ) . Eligibility criteria were pregnant women aged 18 to < 35 years , at 26 to 29 weeks gestation , and residing in Dhaka , Bangladesh . 160 women were r and omized by 1:1 allocation to one of two parallel intervention groups ; placebo ( n = 80 ) or 35,000 IU/week of vitamin D3 ( n = 80 ) until delivery . All participants , study personnel and study investigators were blind to treatment allocation . Results Mean maternal 25(OH)D concentration was similar in the vitamin D and placebo groups at baseline ( 45 vs. 44 nmol/L ; p = 0.66 ) , but was significantly higher in the vitamin D group vs. placebo group among mothers at delivery ( 134 vs. 38 nmol/L ; p < 0.001 ) and newborns ( cord blood : 103 vs. 39 ; p < 0.001 ) . In the vitamin D group , 95 % of neonates and 100 % of mothers attained 25(OH)D > 50 nmol/L , versus 21 % mothers and 19 % of neonates in the placebo group . No participants met criteria for hypercalcemia , there were no known supplement-related adverse events , and major pregnancy outcomes were similar between groups . Conclusions Antenatal 3rd-trimester vitamin D3 supplementation ( 35,000 IU/week ) significantly raised maternal and cord serum 25(OH)D concentrations above 50 nmol/L in almost all participants without inducing hypercalcemia or other observed safety concerns . Doses up to 35,000 IU/week may be cautiously used in further research aim ed at establishing the clinical effects and safety of vitamin D3 supplementation in pregnancy . Trial registration This trial was registered at Clinical Trials.gov ( NCT01126528 )
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 .