The association between high plasma homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet

BACKGROUND: A long-term vegetarian diet is generally poor in vitamin B group. The lack of vitamin B(12) together with vitamin B(6) and folate deficiency is closely related to homocysteine metabolism. Hyperhomocysteinemia was found to be associated with increased bone turnover markers and increased fracture risk. Thus, hyperhomocysteinemia, vitamin B(12) and folate deficiency may be regarded as novel risk factors for micronutrient deficiency-related osteoporosis. AIM OF THE STUDY: To assess the possible impact of a vegetarian diet on bone mineral density in cohort of Slovak vegetarian women. METHODS: Fasting serum glucose, albumin, calcium, phosphorous and creatinine as well as bone markers, serum vitamin B(12), folate and plasma levels of total homocysteine were assessed in two nutritional groups (vegetarians vs. nonvegetarians) of apparently healthy women (age range 20-70 years). Bone mineral density of the femoral neck, trochanter, total femur and lumbar spine was measured in all subjects. RESULTS: Vegetarians had a significantly lower weight (p < 0.05), higher PTH (p < 0.01) and homocysteine (p < 0.001). Vitamin B(12) was significantly higher in nonvegetarians (p < 0.001). No differences were observed in folate levels. Univariate analysis showed significant association between homocysteine and B(12) (p < 0.01), folate (p < 0.001), creatinine (p < 0.001), total proteins (p < 0.049), age (p < 0.001) and vegetarian food intake (p < 0.001). Vegetarians had a significantly lower TrFBMD (p < 0.05) and ToFBMD (p < 0.05). Age and CTx were significant predictors in all sites of measured BMD and PTH. A strong correlation between homocysteine and FNBMD (r = -0.2009, p < 0.002), TrFBMD (r = -0.1810, p < 0.004) and ToFBMD (r = -0.2225, p