Background – Nutrition is known to have an important influence on bone mass accretion during puberty.
Objective – To assess, in a longitudinal study, the effect of differences in food intake on total body bone mass accretion in Chinese girls during puberty, using a mixed model analysis.
Design – Subjects were 377 Chinese girls who had participated in a two-year milk supplementation trial and a three year follow-up study from the ages of 10 to 15 yr. Total body bone mass was measured by dual energy x-ray absorptiometry at baseline and then at 12, 24, 48 and 60 m later. Food intake was estimated from a 7-d food record at baseline and then subsequently from a 3-d food record over two weekdays and one weekend day. The quantity of cereals, vegetables and fruit, legumes and nuts, meat, eggs, dairy products, and “other” foods consumed was estimated from these records.
Outcomes – After adjusting for age, total body bone mineral content (tBMC) from baseline to the end of the follow- up study was positively associated with the quantity of dairy products (β=0.043, P=0.01) and eggs (β=0.172, P=0.03) consumed for all subjects, with or without milk supplementation. In contrast, when tBMC of the control group (representing typical girls in China at puberty) was analysed separately, the only dietary association was with consumption of dairy products (β=0.075, P=0.02). For all subjects, the foods associated with tBMC were dairy products and eggs during the intervention study (P≤0.05). However, during the 3 yr follow-up study positive associations were found with the intake of dairy products (P=0.05). The effect of dietary variation on total body bone mineral density (tBMD) differed slightly from that on total body BMC in the intervention trial and the follow- up study. In general, tBMD was positively associated with the consumption of eggs (P<0.05).
Conclusions – The quantity of dairy products consumed was the most significant dietary factor related to total body BMC in Chinese girls at puberty. The quantity of eggs consumed might also be related to bone mass accretion in these subjects.
Acknowledgement –This study was funded by Dairy Australia, Danone-China and the Nestle Foundation