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 Supplementation in Pregnancy: A Controlled Trial of Two Methods
& NA ; A r and omized study was conducted to evaluate the effects of single‐dose and daily vitamin D supplementation in pregnant women during the last trimester of a winter pregnancy in the Northwest of France . The women were divided into three r and omized groups : one ( N = 21 ) was given a vitamin D2 supplement of 1000 IU/day during the last three months of pregnancy , one ( N = 27 ) was given a single oral dose of 5 mg at the seventh month of pregnancy , and one ( N = 29 ) acted as a control . Venous plasma sample s were obtained at delivery from the women and from cord blood , and levels of calcium , 25‐OHD , and 1,25(OH)2D were determined . No significant difference in plasma calcium concentration was found among the three groups , but within each group plasma calcium concentrations were higher in the cord sample s than in the respective maternal sample s. The levels of the two metabolites measured were consistently lower in the cord sample s than in the respective maternal sample s. Cord 25‐OHD concentrations correlated with those of maternal plasma . No significant modification of maternal calciuria or of the birth weight of term infants was observed . 25‐OHD concentrations were greater in maternal and cord plasma from treated mothers , but only a slight difference was observed between the supplemented groups . 1,25(OH)2D concentrations were not significantly different in the three groups . A single 5‐mg dose of vitamin D given orally at the seventh month of pregnancy provides effective prophylaxis in the authors ’ region . ( Obstet Gynecol 68:300 , 1986
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 .