The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health .
Inflammatory processes involved in disease occurrence and clinical course would reduce 25(OH)D , which would explain why low vitamin D status is reported in a wide range of disorders .
In elderly people , restoration of vitamin D deficits due to ageing and lifestyle changes induced by ill health could explain why low-dose supplementation leads to slight gains in survival
Low serum concentrations of 25-hydroxyvitamin D ( 25[OH]D ) have been associated with many non-skeletal disorders .
However , whether low 25(OH)D is the cause or result of ill health is not known .
Calcium plus vitamin D supplementation and mortality in postmenopausal women: the Women's Health Initiative calcium-vitamin D randomized controlled trial.
BACKGROUND Calcium and vitamin D ( CaD ) supplementation trials including the Women 's Health Initiative ( WHI ) trial of CaD have shown nonsignificant reductions in total mortality . This report examines intervention effects on total and cause-specific mortality by age and adherence . METHODS The WHI CaD trial was a r and omized , double-blind , placebo-controlled trial that enrolled 36,282 postmenopausal women aged 51 - 82 years from 40 U.S. clinical centers . Women were assigned to 1,000 mg of elemental calcium carbonate and 400 IU of vitamin D(3 ) daily or placebo with average follow-up of 7.0 years . RESULTS The hazard ratio ( HR ) for total mortality was 0.91 ( 95 % confidence interval [ CI ] , 0.83 - 1.01 ) with 744 deaths in women r and omized to CaD versus 807 deaths in the placebo group . HRs were in the direction of reduced risk but nonsignificant for stroke and cancer mortality , but near unity for coronary heart disease and other causes of death . HRs for total mortality were 0.89 in the 29,942 women younger than 70 years ( 95 % CI , 0.79 - 1.01 ) and 0.95 in the 6,340 women aged 70 and older ( 95 % CI , 0.80 - 1.12 ; p value for age interaction = .10 ) . No statistically significant interactions were observed for any baseline characteristics . Treatment effects did not vary significantly by season . CONCLUSIONS In the WHI CaD trial , supplementation did not have a statistically significant effect on mortality rates but the findings support the possibility that these supplements may reduce mortality rates in postmenopausal women . These data can neither support nor refute recommendations for higher dose vitamin D supplementation to reduce cancer or total mortality
The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health .
Inflammatory processes involved in disease occurrence and clinical course would reduce 25(OH)D , which would explain why low vitamin D status is reported in a wide range of disorders .
In elderly people , restoration of vitamin D deficits due to ageing and lifestyle changes induced by ill health could explain why low-dose supplementation leads to slight gains in survival
Low serum concentrations of 25-hydroxyvitamin D ( 25[OH]D ) have been associated with many non-skeletal disorders .
However , whether low 25(OH)D is the cause or result of ill health is not known .