Rate of trabecular bone area in 3-6-year-old children and relation to intrauterine growth.

Background: The aim of the present study was to investigate bone mass using rate of trabecular bone area (RTBA) in Japanese children to determine its relationship with indices of growth such as height and weight from before birth through childhood.

Methods:   A cross-sectional study was conducted. The sample consisted of Japanese boys (n= 716) and girls (n= 586) aged 3-6 years. RTBA was measured using quantitative ultrasound (ultrasonic bone densitometer, Benus III; Ishikawa Seisakusho, Kanazawa, Japan). The relation between RTBA and height and weight during childhood and also at birth was assessed.

Results: The average RTBA in boys was 27.7 ± 1.59% (mean ± SD) and that in girls was 27.9 ± 1.59%. RTBA significantly correlated with weight both in boys (P= 0.013) and girls (P= 0.016). Significant correlation was demonstrated between RTBA and height, especially in girls (P= 0.045). Statistical significance was shown between RTBA and birth length in boys (P= 0.015) and girls (P= 0.007), and weight at birth in boys (P= 0.014). On multiple regression analysis RTBA correlated significantly with birthweight for boys (standardized coefficient β= 0.093, P= 0.028) and birth length for girls (β= 0.122, P= 0.007).

Conclusion: Augmentation of bone mass is related not only to weight and height during childhood but also to prenatal factors such as growth, and possibly with nutrition in utero.