ESPE Abstracts

Objective: The aim of this study was to reveal the increase of BMI during later infant related to skeletal maturation in prepubertal obese boys.

Subjects and Methods: The subjects were 63 Japanese 10-years old obese boys. Height and weight were measured. Bone age (BA) of left hand-wrist radiographs was assessed using RUS score of the Japanese-standardized Tanner-Whitehouse 2 method. Weight and length or height at birth, 1.5, 3 and 6 years old were obtained from maternal and child health handbook or school health check-up card. We analyzed the relationship between relative BA (bone-chronological age) and BMI at each age, ΔBMI (1.5–3 years old), ΔBMI (3–6 years old), ΔBMI (6–10 years old) using simple linear regression analyses. We analyzed the relation independent variables to relative BA using multiple linear regression analyses. Independent variables were model 1 as BMI at birth, 1.5, 3, 6 and 10 years old, model 2 as ΔBMI (1.5–3 years old), ΔBMI (3–6 years old), ΔBMI (6–10 years old). Odd’s ratio of relative bone age ≥2 years old was analyzed using multiple logistics regression analysis.

Results: The mean of height was 141.4±6.2 cm, weight was 51.6±6.3 kg, body mass index (BMI) was 25.8±2.1 kg/m², BA and relative BA were, 11.7±1.4 and 1.7±1.3 years old. Simple regression analysis revealed relative BA had positively correlated with BMI at 6 and 10 years old, ΔBMI (1.5–3 years old), ΔBMI (3–6 years old) significantly. Multiple regression analysis revealed relative BA had significantly positively correlated with BMI at 6 old at model 1, ΔBMI (1.5–3 years old), ΔBMI (3–6 years old) at model 2. Multiple logistics regression analysis using independent variables as ΔBMI (1.5–3 years old)≥0, ΔBMI (3–6 years old)≥2 and BMI at 6 years old≥20 revealed odd’s ratio of relative bone age ≥2 years old was 1.99 (1.18–3.40) at ΔBMI (3–6 years old) ≥2.

Conclusions: Rapid BMI gain and high BMI at later infant period accelerates skeletal maturation in prepubertal obese children. This disorders of bone growth in prepubertal obese children will lead to suboptimal final height and affect their quality of life.