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Bone mineral content of two populations of Chinese children with different calcium intakes
1Department of Paediatrics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin.
Insights
Children in Hong Kong had higher bone mineral content (BMC) than those in Jiangmen, China. This difference may stem from long-term calcium intake and physical activity variations.
Area of Science:
- Pediatric Nutrition
- Bone Health
- Anthropometry
Background:
- Bone mineral content (BMC) is a critical indicator of skeletal health in children.
- Regional disparities in childhood BMC may be influenced by environmental and lifestyle factors.
- Understanding these disparities is crucial for developing targeted health interventions.
Purpose of the Study:
- To compare the bone mineral content (BMC) of 5-year-old children in Jiangmen, China, and Hong Kong.
- To investigate the factors contributing to observed regional differences in childhood BMC.
- To explore the potential roles of calcium intake and physical activity in BMC variations.
Main Methods:
- Single-photon absorptiometry was used to measure BMC at the distal 1/3 radius in 115 children from Jiangmen and 128 from Hong Kong.
- Calcium intake, weight, and height were recorded for all participants.
- Multiple regression analysis was employed to identify predictors of BMC and adjust for confounding variables.
Main Results:
- Jiangmen children exhibited significantly lower mean BMC (14%), weight (10%), and height (4%) compared to Hong Kong children (P < 0.001).
- Bone width, weight, and regional location explained 62% of the variance in BMC (P < 0.0001).
- Even after adjusting for bone width, weight, and other confounders, a significant regional difference in BMC persisted (P < 0.0001), particularly in subgroups with similar low calcium intake.
Conclusions:
- A significant regional disparity in bone mineral content exists between children in Jiangmen and Hong Kong.
- Long-term habitual calcium intake and physical activity levels are suggested as primary contributors to this discrepancy.
- Further research into habitual lifestyle factors is warranted to elucidate the causes of regional BMC differences in children.
Abstract:
Bone mineral content (BMC) of 5-year-old Chinese children (115 children in Jiangmen, China and 128 children in Hong Kong) was evaluated by single-photon absorptiometry at the distal 1/3 radius. The mean (S.D.) calcium intakes of children of Jiangmen and Hong Kong were 244 (46) and 542 (332) mg/day, respectively. The mean BMC, weight and height of Jiangmen children were significantly less than Hong Kong children by 14%, 10% and 4%, respectively (P < 0.001). Multiple regression analysis showed that 62% of the variance in BMC was explained by bone width (BW), weight and regional location (P < 0.0001). A regional difference in BMC of 0.0303 g/cm (P < 0.0001) still remained after adjusting for BW and weight by multiple regression analysis. When comparing sub-groups of children in the two regions with comparable low current calcium intake at 5 years, the BMC of Jiangmen children was still significantly lower than Hong Kong children even when potential confounders were adjusted (P < 0.003). The study suggests that the regional discrepancy in BMC might be explained by long-term habitual calcium intake and physical activity.