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 comparison of the effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on biochemical responses and the wellbeing of patients
Background For adults , vitamin D intake of 100 mcg ( 4000 IU)/day is physiologic and safe . The adequate intake ( AI ) for older adults is 15 mcg ( 600 IU)/day , but there has been no report focusing on use of this dose . Methods We compared effects of these doses on biochemical responses and sense of wellbeing in a blinded , r and omized trial . In Study 1 , 64 out patients ( recruited if summer 2001 25(OH)D < 61 nmol/L ) were given 15 or 100 mcg/day vitamin D in December 2001 . Biochemical responses were followed at subsequent visits that were part of clinical care ; 37 patients completed a wellbeing question naire in December 2001 and February 2002 . Subjects for Study 2 were recruited if their 25(OH)D was < 51 nmol/L in summer 2001 . 66 out patients were given vitamin D ;  51 completed a wellbeing question naire in both December 2002 and February 2003 . Results In Study 1 , basal summer 25-hydroxyvitamin D [ 25(OH)D ] averaged 48 ± 9 ( SD ) nmol/L. Supplementation for more than 6 months produced mean 25(OH)D levels of 79 ± 30 nmol/L for the 15 mcg/day group , and 112 ± 41 nmol/L for the 100 mcg/day group . Both doses lowered plasma parathyroid hormone with no effect on plasma calcium . Between December and February , wellbeing score improved more for the 100-mcg/day group than for the lower-dosed group ( 1-tail Mann-Whitney p = 0.036 ) . In Study 2 , 25(OH)D averaged 39 ± 9 nmol/L , and winter wellbeing scores improved with both doses of vitamin D ( two-tail p < 0.001 ) . Conclusion The highest AI for vitamin D  brought summertime 25(OH)D to > 40 nmol/L , lowered PTH , and its use was associated with improved wellbeing . The 100 mcg/day dose produced greater responses . Since it was ethically necessary to provide a meaningful dose of vitamin D to these insufficient patients , we can not rule out a placebo wellbeing response , particularly for those on the lower dose . This work confirms the safety and efficacy of both 15 and 100 mcg/day vitamin D3 in patients who needed additional 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 .