Bone mineral density in an urban and a rural children population-A comparative, population-based study in Enugu State, Nigeria.

ABSTRACT

INTRODUCTION: Osteoporosis is one of the non-communicable diseases linked to urbanisation. The foundation of osteoporotic fractures stems from childhood. Therefore, studies that promote maximising peak bone mass are strongly advocated. Studies have shown that there are differences in the incidence of osteoporotic fractures in rural and urban communities. No study has investigated urban-rural differences in BMD of Nigerian children. This study, therefore, aimed to investigate urban-rural differences in BMD of Nigerian children and the association with physical activity, demographic and anthropometric variables. METHODS: In a cross-sectional, study in Enugu, Nigeria, estimated bone mineral density (eBMD) was measured at the calcaneum using the QUS densitometer, Hologic Sahara, in 457 urban (Enugu metropolis) and 559 rural (Nsukka community) children aged 6-14 years. Height, weight and physical activity were measured. Independent sample t-test was used for comparative analysis while Pearson correlation coefficients and multiple regression models were used to examine the relationship between the eBMD and the other parameters. RESULTS: The mean (S.D) eBMD of the urban children [0.52(0.09) g/cm2] were significantly higher (p < 0.05) than their age- and gender-matched counterparts in the rural areas [0.51(0.08) g/cm2]. Age and weight predicted (p < 0.05) the eBMD in the urban subjects while only age was the predictor (p < 0.05) in the rural subjects. The physical activity pattern had no relationship with eBMD in both urban and rural children in Enugu, Nigeria. CONCLUSIONS: The eBMD of rural children is lower than that of their age- and gender-matched urban counterparts.