RESULTS The meta- analysis of observational studies showed a weaker slope of dose-response relations than the meta- analysis of RCTs .
The obtained dose-response estimate between vitamin B-12 intake and status provides complementary evidence to underpin recommendations for a vitamin B-12 intake of population
BACKGROUND Many r and omized controlled trials ( RCTs ) and observational studies have provided information on the association between vitamin B-12 intake and biomarkers .
The use of these data to estimate dose-response relations provides a useful means to summarize the body of evidence .
OBJECTIVE We systematic ally review ed studies that investigated vitamin B-12 intake and biomarkers of vitamin B-12  status and estimated dose-response relations with the use of a meta- analysis .
Low serum vitamin B-12 levels are associated with increased hip bone loss in older women: a prospective study.
The purpose of this study was to test whether low serum vitamin B-12 levels are associated with more rapid bone loss in elderly women . We archived sera and measured calcaneal bone  mineral density ( BMD ) in community-dwelling white women , aged 65 yr and over , who participated in the Study of Osteoporotic Fractures . BMD of the hip and subregions was measured 2 yr later . Repeat measurements of calcaneal and hip BMD were obtained after 5.9 and 3.5 yr of follow-up , respectively .  Serum vitamin B-12 assays  were performed in 83 r and omly selected participants with initial and repeat measurements of BMD who were not taking estrogen replacement therapy at baseline . After adjusting for age , weight , and clinic site , women with vitamin B-12 levels at or below 280 pg/ml ( 207.2 pmol/liter ; lowest quintile ) experienced an annual change of -1.6 % ( 95 % confidence interval , -2.4 % to -0.8 % ) in total hip BMD , compared with -0.2 % ( -0.5 % to 0.2 % ) in women with levels above 280 pg/ml ( P = 0.003 ) . Results were similar when subregions of the hip were analyzed separately . Serum vitamin B-12 levels were not significantly associated with calcaneal bone loss . We conclude that low serum vitamin B-12 levels are associated with increased rates of hip , but not calcaneal , bone loss in older women
RESULTS The meta- analysis of observational studies showed a weaker slope of dose-response relations than the meta- analysis of RCTs .
The obtained dose-response estimate between vitamin B-12 intake and status provides complementary evidence to underpin recommendations for a vitamin B-12 intake of population
BACKGROUND Many r and omized controlled trials ( RCTs ) and observational studies have provided information on the association between vitamin B-12 intake and biomarkers .
The use of these data to estimate dose-response relations provides a useful means to summarize the body of evidence .
OBJECTIVE We systematic ally review ed studies that investigated vitamin B-12 intake and biomarkers of vitamin B-12  status and estimated dose-response relations with the use of a meta- analysis .