There is currently no firm evidence that vitamin D supplementation decreases or increases cancer occurrence in predominantly elderly community-dwelling women .
Vitamin D₃ supplementation  decreased cancer mortality  and vitamin D supplementation  decreased all-cause mortality , but these estimates are at risk of type I errors due to the fact that too few participants were examined , and to risks of attrition bias originating from substantial dropout of participants .
Combined vitamin D₃ and calcium supplements  increased nephrolithiasis , whereas it remains unclear from the included trials whether vitamin D₃ , calcium , or both were responsible for this effect .
BACKGROUND The evidence on whether vitamin D supplementation is effective in decreasing cancers is contradictory .
OBJECTIVES To assess the beneficial and harmful effects of vitamin D supplementation for prevention of cancer in adults .
Short and long-term variations in serum calciotropic hormones after a single very large dose of ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) in the elderly.
CONTEXT In humans , few studies have compared the potencies of ergocalciferol and cholecalciferol in improving and maintaining vitamin D status . OBJECTIVE Our objective was to evaluate the effects of a single very large dose of both calciferols on serum changes of 25-hydroxyvitamin D [ 25(OH)D ] , 1,25-dihydroxyvitamin D [ 1,25(OH)(2)D ] , ionized calcium , and parathyroid hormone ( PTH ) at baseline , and at 3 , 7 , 30 , and 60 d. DESIGN This was a prospect i ve r and omized intervention study . SETTING The study was performed in a nursing home residence . PARTICIPANTS A total of 32 elderly female patients ( age range 66 - 97 yr ) , with vitamin D deficiency was included in the study . INTERVENTION Participants were r and omized into four groups of eight to receive a single dose of 300,000 IU ergocalciferol or cholecalciferol by oral ( os ) or i m route . RESULTS 25(OH)D levels sharply increased at d 3 only when vitamins were given os . The 30-d basal difference in serum 25(OH)D was significantly greater after cholecalciferol os administration ( 47.8 + /- 7.3 ng/ml ) compared with other forms ( D(3 ) i m : 15.9 + /- 11.3 ; D(2 ) os : 17.3 + /- 4.7 ; D(2 ) i m : 5 + /- 4.4 ; all P < 0.001 ) . The area under the curve ( AUC ) of the serum 25(OH)D against time ( AUC(60 ) ) was : D(3 ) os , 3193 + /- 759 ng x d/ml vs. D(2 ) os , 1820 + /- 512 , P < 0.001 ; and D(3 ) i m , 1361 + /- 492 vs. D(2 ) i m , 728 + /- 195 , P < 0.01 . 25(OH)D significantly influences PTH levels at 3 ( P < 0.03 ) , 7 ( P < 0.01 ) , 30 ( P < 0.01 ) , and 60 d ( P < 0.05 ) . At 60 d , the form of vitamin ( cholecalciferol ) significantly lowers PTH levels ( P = 0.037 ) . CONCLUSIONS Cholecalciferol is almost twice as potent as ergocalciferol in increasing serum 25(OH)D , when administered either by mouth or i m . 25(OH)D plays a role in modulating serum PTH
There is currently no firm evidence that vitamin D supplementation decreases or increases cancer occurrence in predominantly elderly community-dwelling women .
Vitamin D₃ supplementation  decreased cancer mortality  and vitamin D supplementation  decreased all-cause mortality , but these estimates are at risk of type I errors due to the fact that too few participants were examined , and to risks of attrition bias originating from substantial dropout of participants .
Combined vitamin D₃ and calcium supplements  increased nephrolithiasis , whereas it remains unclear from the included trials whether vitamin D₃ , calcium , or both were responsible for this effect .
BACKGROUND The evidence on whether vitamin D supplementation is effective in decreasing cancers is contradictory .
OBJECTIVES To assess the beneficial and harmful effects of vitamin D supplementation for prevention of cancer in adults .