Adipose tissue stimulates bone growth in prepubertal children

Abstract

Context: Fat mass represents a positive influence on bone mass in adults, independently of other factors such as lean mass, but whether a similar action occurs in children is unclear.

Objective: Our objective was to examine the relationship between fat mass and bone mass in children.

Design and setting: We conducted combined cross-sectional and prospective analyses at university research clinics.

Participants: Participants included children aged 9.9 yr from a large population-based birth cohort in southwest England.

Outcomes: Relationships between total body fat mass were measured by dual-energy x-ray absorptiometry at age 9.9 yr, and 1) total-body-less-head bone mass and area at age 9.9 and 2) increase in bone mass and area over the following 2 yr.

Results: There was a strong positive relationship between total body fat mass and total-body-less-head bone mass and area, even after adjustment for height and/or lean mass (P < 0.001). There was a similar positive association between total body fat mass and increase in bone mass and area over the following 2 yr in boys and Tanner stage 1 girls. In contrast, no association was present between fat mass and gain in bone mass and size in Tanner stage 2 girls, whereas a negative association was seen in Tanner stage 3 girls (puberty-fat mass interaction, P < 0.001).

Conclusions: In prepubertal children, fat mass is a positive independent determinant of bone mass and size and of increases in these parameters over the following 2 yr, suggesting that adipose tissue acts to stimulate bone growth. However, this relationship is attenuated by puberty.

Figures

Fig. 1

Recruitment pattern of the study sample used to analyze associations between fat mass and bone area.

Fig. 2

Effect of total-body fat mass on skeletal area adjusted for age at DXA scan, gender, ethnic group, and socioeconomic status. Results show mean ± 95% confidence interval of skeletal area for TBLH (A), spine (B), upper limbs, (C) and lower limbs (D), according to quartile of total-body fat mass in 3082 boys and girls undergoing DXA scans at age 9.9 yr. Test for trend showed statistically significant (P < 0.001) association between fat mass quartile and skeletal area at all four sites.

Fig. 3

Effect of total-body fat mass on skeletal area adjusted for height, total body lean mass, age at DXA scan, gender, ethnic group, and socioeconomic status. Results show mean ± 95% confidence interval of skeletal area for TBLH (A), spine (B), upper limbs, (C) and lower limbs (D), according to quartile of total-body fat mass in 3082 boys and girls undergoing DXA scans at age 9.9 yr. Test for trend showed statistically significant (P < 0.001) association between fat mass quartile and skeletal area at all four sites.