Estimated net endogenous acid production and intake of bone health-related nutrients in Hong Kong Chinese adolescents.

BACKGROUND/OBJECTIVES: To examine the daily intake of bone health-related nutrients and to explore the association between diet composition and estimated net endogenous acid production (estimated NEAP) in Hong Kong Chinese adolescents. SUBJECT/METHODS: In total, 171 boys and 180 girls aged 10-12 years of Chinese origin from nine primary schools from the Hong Kong Adolescent Bone Health Cohort Study. The study design used food frequency questionnaire. Mean daily intakes of foods and selected nutrients were estimated. Mean percentage of nutrient intake contributed by different food groups was presented. Frassetto's method was used to calculate the estimated NEAP from the diet's protein to potassium ratio. RESULTS: There was no significant difference in the energy-adjusted intakes of most nutrients between boys and girls, except for intakes of vitamins C and D. Mean protein, sodium and potassium intakes were higher than the Chinese dietary reference intake (DRI), whereas mean intakes of magnesium, calcium and vitamin D were lower than the DRI. Boys had significantly higher estimated NEAP than girls (P=0.0051). Estimated NEAP was significantly positively correlated with meat intake and negatively associated with the consumption of fruits, vegetables, legumes, beverages and dairy products. CONCLUSIONS: The results highlight the importance of considering whole diet quality when interpreting the effects of single nutrient or diet's net acid load on bone. The effect on high protein intake and low fruit and vegetable intake on the long-term bone health of Hong Kong Chinese adolescents warrants attention.

Relationship between grip strength and bone mineral density in healthy Hong Kong adolescents.

UNLABELLED: This study evaluated the magnitude of the correlations among grip strength, bone mineral density (BMD) and bone mineral content (BMC), after controlling for weight, height, pubertal development, weight-bearing activities and calcium intake. The results lead to the conclusion that grip strength is an independent predictor of bone mass in both sexes. The relationship between muscle strength and bone mass is systemic. INTRODUCTION: Previous studies had shown a site-specific relationship between muscle strength and bone in pubertal children. This study evaluated the magnitude of the correlations among grip strength, bone mineral density (BMD) and bone mineral content (BMC) at distant bone. METHODS: Cross-sectional data of 169 11- to 12-year-old boys and 173 10- to 11-year-old girls came from the baseline result of a cohort study. Grip strength, BMD, BMC, weight, height, pubertal development, weight-bearing activities and calcium intake were measured. Pearson correlations and multiple regressions were used to calculate univariate and adjusted associations among grip strength and bone mass at distant bone. RESULTS: Significant correlations were shown between grip strength and bone mass at hip, spine and whole body (boys: BMC:0.72-0.74, BMD:0.38-0.60; girls: BMC:0.71-0.72, BMD:0.44-0.63; p<0.0001). Multiple regressions with all covariates showed that about 70% and 50%, respectively, of the variations in BMC and BMD could be explained but not for whole body BMD. Grip strength was an independent predictor of bone mass, except hip BMD in boys and whole body BMD in girls. Stepwise regression showed that grip strength was a robust predictor in both sexes. Prediction models by grip strength and weight explained about 60% and 40% of the variations in BMC of different sites and in BMD of hip and spine, respectively. CONCLUSIONS: We found that grip strength is an independent predictor of bone mass in both sexes. The relationship between muscle strength and bone mass is systemic.