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 .
Long-term vitamin D3 supplementation may have adverse effects on serum lipids during postmenopausal hormone replacement therapy.
OBJECTIVE The positive short-term effects of postmenopausal hormone replacement therapy ( HRT ) on serum lipids are well known , but it has been suggested that they vanish with time . Cholecalciferol ( vitamin D3 ) is widely used to prevent postmenopausal osteoporosis but the influence of vitamin D3 on serum lipids is poorly known . The long-term effects of HRT and vitamin D3 on the concentrations of serum lipids were studied in a population -based prospect i ve 3-year study . DESIGN AND METHODS 464 women were r and omized into four treatment groups : ( i ) HRT ( sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate ) , ( ii ) Vit D3 ( vitamin D3 300 IU/day ) , ( iii ) HRT+Vit D3 ( both as above ) , ( iv ) placebo ( calcium lactate 500 mg/day ) . RESULTS 320 women completed the study . After three years of treatment , serum concentrations of low density lipoprotein ( LDL ) cholesterol decreased in the HRT group ( 10.1 % , P<0.001 ) and the HRT+Vit D3 group ( 5.9 % , P=0.005 ) , increased in the Vit D3 group ( 4.1 % , P=0.035 ) but remained unchanged in the placebo group . The concentrations of total cholesterol decreased by 5.8 % in the HRT group ( P<0.001 ) and by 3.3 % in the HRT+Vit D3 group ( P=0.023 ) , but did not change in the other two groups . Serum concentrations of high density lipoprotein ( HDL ) cholesterol decreased in the Vit D3 group ( 5.2 % , P=0.001 ) , HRT+Vit D3 group ( 3.7 % , P=0.046 ) , and the placebo group ( 4.5 % , P=0.006 ) but did not change significantly in the HRT group . The HDL/LDL ratio increased in the HRT group ( 10.5 % , P=0.006 ) and decreased in the Vit D3 group ( 10.5 % , P<0.001 ) whereas no changes occurred in the other two groups . In addition , serum triglycerides increased similarly in all groups ( 14.0 - 18.8 % , P<0.05 - 0.001 ) . CONCLUSIONS Our results confirm the positive long-term effect of HRT with sequential estradiol valerate and cyproterone acetate on serum lipid concentrations . In addition , the results suggest that vitamin D3 supplementation may have unfavorable effects on lipids in postmenopausal women .  Pure vitamin D3 treatment was associated with increased serum LDL cholesterol . Furthermore , the beneficial effects of HRT on serum LDL cholesterol content were reduced when estradiol valerate was combined with vitamin D3 . However , the relevance of these associations to cardiovascular morbidity remains to be established
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 .