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 .
Oral vitamin D3 and calcium for secondary prevention of low-trauma fractures in elderly people (Randomised Evaluation of Calcium Or vitamin D, RECORD): a randomised placebo-controlled trial.
BACKGROUND Elderly people who have a fracture are at high risk of another . Vitamin D and calcium supplements are often recommended for fracture prevention . We aim ed to assess whether vitamin D3 and calcium , either alone or in combination , were effective in prevention of secondary fractures . METHODS In a factorial- design trial , 5292 people aged 70 years or older ( 4481 [ 85 % ] of whom were women ) who were mobile before developing a low-trauma fracture were r and omly assigned 800 IU daily oral vitamin D3 , 1000 mg calcium , oral vitamin D3 ( 800 IU per day ) combined with calcium ( 1000 mg per day ) , or placebo .  Participants who were recruited in 21 UK hospitals were followed up for between 24 months and 62 months . Analysis was by intention-to-treat and the primary outcome was new low-energy fractures . FINDINGS 698 ( 13 % ) of 5292 participants had a new low-trauma fracture , 183 ( 26 % ) of which were of the hip . The incidence of new , low-trauma fractures did not differ significantly between participants allocated calcium and those who were not ( 331 [ 12.6 % ] of 2617 vs 367 [ 13.7 % ] of 2675 ; hazard ratio ( HR ) 0.94 [ 95 % CI 0.81 - 1.09 ] ) ; between participants allocated vitamin D3 and those who were not ( 353 [ 13.3 % ] of 2649 vs 345 [ 13.1 % ] of 2643 ; 1.02 [ 0.88 - 1.19 ] ) ; or between those allocated combination treatment and those assigned placebo ( 165 [ 12.6 % ] of 1306 vs 179 [ 13.4 % ] of 1332 ; HR for interaction term 1.01 [ 0.75 - 1.36 ] ) . The groups did not differ in the incidence of all-new fractures , fractures confirmed by radiography , hip fractures , death , number of falls , or quality of life . By 24 months , 2886 ( 54.5 % ) of 5292 were still taking tablets , 451 ( 8.5 % ) had died , 58 ( 1.1 % ) had withdrawn , and 1897 ( 35.8 % ) had stopped taking tablets but were still providing data for at least the main outcomes . Compliance with tablets containing calcium was significantly lower ( difference : 9.4 % [ 95 % CI 6.6 - 12.2 ] ) , partly because of gastrointestinal symptoms . However , potentially serious adverse events were rare and did not differ between groups . INTERPRETATION The findings do not support routine oral supplementation with calcium and vitamin D3 , either alone or in combination , for the prevention of further fractures in previously mobile elderly people
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 .