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 .
Alfacalcidol reduces accelerated bone turnover in elderly women with osteoporosis
To evaluate the effects of alfacalcidol on bone turnover in elderly women with osteoporosis , an open-label , prospect i ve , calcium-controlled study was conducted . A total of 80 patients with osteoporosis were divided into two groups : the control group , group C ( mean age , 78.0 years ) , in which patients were given calcium , and group D ( mean age , 77.4 years ) , in which the patients were given alfacalcidol 1 µg/day together with calcium for 6 months . Calcium regulation , lumbar bone mineral density ( LBMD ) , and markers for bone turnover were assessed . A significant increase in urinary calcium/creatinine ratio ( 90 % increase from baseline at 3 months ; P = 0.0083 , and 60 % at 6 months ; P = 0.0091 ) and a significant decrease in serum parathyroid hormone ( 30 % decrease from baseline at 6 months ; P < 0.0001 ) was observed in group D compared with the corresponding changes in group C. Significant decreases of bone resorption markers ( deoxypyridinoline and N-telopeptide ) at 6 months ( about 15 % decrease from the baseline values ) were observed in group D compared with the corresponding changes in group C. The changes in bone formation markers ( bone-derived alkaline phosphatase and osteocalcin ) in group D were significantly different at 6 months ( −21.5 % ; P = 0.0047 and −13.4 % ; P = 0.0032 , respectively ) from the values in group C. The magnitudes of the decrease in bone turnover markers were highly correlated with the corresponding baseline values , suggesting that alfacalcidol treatment effectively reduces bone turnover in patients with high bone turnover rates . The LBMD in group D increased by 1.7 % and that in group C decreased by 1.6 % ( P = 0.0384 ) . The changes in calcium metabolism and LBMD were in good agreement with those in previous reports . Although the changes in bone turnover markers in group D were slight , significant reduction in bone turnover with alfacalcidol treatment , together with the change in calcium metabolism , may account for the effects of alfacalcidol on BMD and on fracture prevention reported previously . In conclusion , alfacalcidol reduces bone turnover  in elderly women with high-bone-turnover osteoporosis , and it may have beneficial effects on bone
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 .