Intake of B vitamins and carotenoids in relation to risk of hip fracture in elderly Chinese

Experimental evidence has implicated that homocysteine and oxidative stress may be involved in the pathogenesis of osteoporosis. In accord, observational studies among Caucasian populations have also suggested that homocysteine-related B vitamins (vitamins B2, B6, B12, and folate) and carotenoids with antioxidant functions may be beneficial to bone health and therefore protect against osteoporotic fractures. Incidence of hip fracture is rising in Asia, but there is paucity among Asian populations on dietary factors. We prospectively examined the associations of dietary intakes of B vitamins and carotenoids with hip fracture risk among elderly Chinese in the Singapore Chinese Health Study. Cox proportional hazards model was applied to determine the strength of association after adjusting for potential confounders. Our results showed a dose-dependent inverse relationship between vitamin B6 intake and hip fracture risk among women (p for trend = 0.002). Conversely, no protective association was found in men. Dietary intakes of vitamins B2, B12, and folate were not related to hip fracture risk in either gender. Vegetables are main sources of carotenoid intake in this population. In men, we found a dose-dependent inverse relationship between consumption of total vegetables and hip fracture risk (p for trend = 0.004). Similarly, higher intakes of total carotenoids, α- and β-carotene, were associated with lower hip fracture risk in men (all p for trend <0.05). Consumption of vegetables or carotenoids did not show an association with hip fracture risk in women. The gender-specific results in the protective roles of dietary B vitamins and carotenoids suggest that the mechanistic pathway for osteoporosis may be different between men and women.