The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels
Background A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D ( 25OHD ) levels on non-skeletal outcomes .
We performed a systematic quantitative review on characteristics of r and omized clinical trials ( RCTs ) included in meta-analyses ( MAs ) on non-skeletal effects of vitamin D supplementation .
Prevalence of cardiovascular risk factors and the serum levels of 25-hydroxyvitamin D in the United States: data from the Third National Health and Nutrition Examination Survey.
BACKGROUND Results of several epidemiologic and clinical studies have suggested that there is an excess risk of hypertension and diabetes mellitus in persons with suboptimal intake of vitamin D.  METHODS We examined the association between serum levels of  25-hydroxyvitamin D ( 25[OH]D )  and select cardiovascular disease risk factors in US adults . A secondary analysis was performed with data from the Third National Health and Nutrition Examination Survey , a national probability survey conducted by the National Center for Health Statistics between January 1 , 1988 , and December 31 , 1994 , with oversampling of persons 60 years and older , non-Hispanic black individuals , and Mexican American individuals . RESULTS There were 7186 male and 7902 female adults 20 years and older with available data in the Third National Health and Nutrition Examination Survey . The mean 25(OH)D level in the overall sample was 30 ng/mL ( 75 nmol/L ) . The 25(OH)D levels were lower in women , elderly persons ( > or=60 years ) , racial/ethnic minorities , and participants with obesity , hypertension , and diabetes mellitus . The adjusted prevalence of hypertension ( odds ratio [ OR ] , 1.30 ) , diabetes mellitus ( OR , 1.98 ) , obesity ( OR , 2.29 ) , and high serum triglyceride levels ( OR , 1.47 ) was significantly higher in the first than in the fourth quartile of serum 25(OH)D levels ( P<.001 for all ) . CONCLUSIONS Serum 25(OH)D levels are associated with important cardiovascular disease risk factors in US adults . Prospect i ve studies to assess a direct benefit of cholecalciferol ( vitamin D ) supplementation on cardiovascular disease risk factors are warranted
The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels
Background A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D ( 25OHD ) levels on non-skeletal outcomes .
We performed a systematic quantitative review on characteristics of r and omized clinical trials ( RCTs ) included in meta-analyses ( MAs ) on non-skeletal effects of vitamin D supplementation .