[Association between body mass index and calcaneus bone mineral density in adults in a cross-sectional study in Tongxiang, Zhejiang Province].

Objective

To evaluate the association between body mass index (BMI) and bone mineral density of calcaneus in adults.

Methods

Data of the second resurvey of China Kadoorie Biobank study from Tongxiang of Zhejiang Province were used. A total of 2 896 participants aged 44-84 years were included in the final analysis. Overweight was defined as 23.0 kg/m2≤BMI<25.0 kg/m2, and obesity was defined as BMI ≥25.0 kg/m2 based on the criteria recommended by WHO/West Pacific Region. Multiple linear regression model was used to evaluate the association between BMI and calcaneus bone mineral density. Restricted cubic splines were used to investigate the dose-response relationship between BMI and calcaneus bone mineral density.

Results

The calcaneus bone mineral density in the study subjects were as follow (x±SE): the broadband ultrasound attenuation was (109.4±12.1) dB/MHz, the speed of ultrasound was (1 545.9±33.8) m/s, and the stiffness index was 85.7±15.8. After adjusting for socio-demographic factors, lifestyle, waist circumference, diabetes and hypertension prevalence, BMI was positively associated with calcaneus stiffness index in non-overweight and non-obese adults, with β of 2.30 (95%CI: 1.11-3.49) for men (P<0.001) and 1.08 (95%CI: 0.38-1.78) for women (P=0.003), respectively. In addition, BMI was positively associated with calcaneus stiffness index in overweight and obese women (β=0.90, 95%CI: 0.38-1.42) (P<0.001), and null association was found in overweight and obese men (β=0.06, 95%CI: -0.92-1.04) (P=0.900). Restricted cubic spline model showed a nonlinear dose-response relationship between BMI and calcaneus stiffness index.

Conclusion

Non-linear association was found between BMI with calcaneus bone mineral density in adults.