B vitamins, homocysteine and their relation with bone mineral density, falls and hip fracture among older persons

High homocysteine concentration is associated with increased hip fracture risk among elders, yet here is little evidence that homocysteine affects bone. Homocysteine concentration is determined by the B vitamins folate, B12 and B6, and deficiencies in these nutrients may influence bone strength. Thus, B vitamins may be responsible for the observed effect of homocysteine on hip fracture risk. This dissertation explores the associations of folate, vitamin b12 and vitamin B6 with hip fracture, bone mineral density (BMD) and falls among elderly men and women in the Framingham Study Original Cohort.; Baseline (1987--1990) plasma concentrations of folate, vitamin B12, vitamin B6 and homocysteine were obtained from 1,256 men and women (mean age 76 years). Categories of vitamins (normal, low, deficient) and homocysteine (normal, high) were defined based on clinical cutoffs. Participants were followed from baseline for fifteen-year hip fracture risk, four-year BMD change, and one-year falls rate.; Women with deficient folate had twice the risk of hip fracture compared to women with normal concentrations, and folate was directly associated with baseline femoral neck BMD among men. Although vitamin B12 was not associated with hip fracture in either men or women, B12 was directly associated with baseline hip BMD in men and women, and with spine BMD in men. Women with deficient B12 had more rapid bone loss versus women with lower B12. Deficient vitamin B6 among women was associated with a two-fold increased hip fracture risk. B6 was directly associated with baseline hip BMD in men and women, and inversely associated with four-year femoral neck bone loss among men. None of the three B vitamins, or homocysteine, was associated with the rate of falling. The observed associations of B vitamins with hip fracture and BMD were similar after adjustment for each of the other plasma measures, suggesting that these B vitamins may have independent effects on hip fracture and BMD.; This work provides a better understanding of potentially modifiable factors for hip fracture, which may have tremendous public health implications both for interventions aimed at preventing fractures and for the diets of many men and women.