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 .
Does Vitamin D Strengthen the Increase in Femoral Neck BMD in Osteoporotic Women Treated with Estrogen?
Abstract . The long-term effects on bone of estrogen therapy ( HRT ) combined with vitamin D3 supplementation were evaluated and compared with the effects of HRT without vitamin D3 supplementation in a 4-year prospect i ve , partly r and omized study among 60 osteoporotic women ( mean age 55.4 years ; range 49.7–59.4 years ) . The women studied were a subgroup of the population -based Kuopio Osteoporosis Risk Factor and Prevention Study ( OSTPRE ) ( n = 13100 ) . The bone mineral densities ( BMD ) of the lumbar spine and femoral neck were determined by dual-energy X-ray absorptiometry ( DXA ) in 3236 perimenopausal women . Those 106 women with baseline BMD more than 2 SDs less than the mean value in this population , either at the lumbar spine ( BMD < 0.826 g/cm2 ) and /or femoral neck ( BMD < 0.684 g/cm2 ) , were offered treatment for osteoporosis . After exclusions , 60 women were included in the analyses . Group allocation was : HRT ( estradiol valerate ( 2 mg ) plus cyproterone acetate , 1 mg , sequentially : ClimenR ) ( n = 21 ) ; HRT + Vit D : Climen + vitamin D3 ( cholecalciferol , 300 IU/day , no intake during June – August ) ( n = 23 ) ; controls :  16 women who refused all treatment served as a non-r and omized control group . In the HRT group , the highly significant increase in lumbar BMD was 5.4 % , 5.3 % , 4.7 % and 4.0 % after 1 , 2 , 3 and 4 years of treatment , respectively , all compared with the baseline values and with the control group . The increase in femoral neck BMD was statistically insignificant ( 1.4 % , 2.2 % , 1.9 % and 2.1 % , respectively ; p > 0.05 ) . In the HRT + Vit D group , the lumbar BMD increased by 3.7 % , 4.9 % , 4.9 % and 4.9 % ( p < 0.001 ) , whereas the 5.8 % increase in femoral neck BMD reached significance at 4 years ( p < 0.01 ) when compared with the control group as well as with the baseline values . However , there were no statistically significant differences in lumbar or femoral BMD changes between the two HRT groups . In conclusion , estrogen  can substantially increase lumbar bone mass in patients with postmenopausal osteoporosis . In addition , the combination of HRT and vitamin D3 may increase femoral neck BMD in osteoporotic women more than estrogen alone
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 .