Bone mineral density in Chinese elderly female vegetarians, vegans, lacto-vegetarians and omnivores.

OBJECTIVES: To compare the bone mineral density and dietary intake of elderly Chinese vegetarian women with omnivores, to compare the bone mineral density of Chinese 'vegans' and 'lactovegetarians', and to study the relationship between nutrient intake and BMD in vegetarians.

DESIGN: A cross-sectional survey.

SETTING AND SUBJECTS: A community-based study. The vegetarian women (aged 70-89 y) (n = 76) were non-institutionalized subjects. All of them were Buddhists. Their bone mineral density were compared to normal elderly volunteers (aged 70-89 y) (n = 109) who were recruited to establish normal BMD ranges. Their dietary intake was compared to omnivorous subjects from a previous dietary survey (n = 250).

METHODS: Dietary assessment was by the 24 h recall method, and bone mineral density was measured by dual-X-ray-densitometry. The analysis of co-variance was used to compare the BMD between vegetarians and omnivores, with adjustment for potential confounders. The BMD in 'vegans' and 'lactovegetarians' were compared by similar methods. The t-test was used to compare dietary intake between omnivores and vegetarians. The relationship between nutrient intake and BMD was studied by correlation and multiple regression.

RESULTS: The dietary calorie, protein and fat intake were much lower, but the sodium/creatinine ratio was much higher in vegetarians than omnivores. The BMD at the spine was similar between vegetarians and omnivores. However, the BMD at the hip was significantly lower in vegetarians at some sites (P < 0.05). There was no significant difference in BMD between 'vegans' and 'lactovegetarians'. BMD in vegetarians appeared to be positively correlated with energy, protein and calcium intake; and negatively associated with urinary sodium/creatinine levels.

CONCLUSIONS: There is a relationship between diet and BMD. The BMD at the hip was lower in vegetarians than omnivores, but no difference was observed between 'vegans' and 'lactovegetarians'. There is a complex relationship between the intake of various nutrient and BMD in vegetarians.