Muscle fitness and its association with body mass index in children and adolescents aged 7–18 years in China: a cross-sectional study

Table 3 The association between BMI and hand grip strength, vertical jump and sit-and-reach in children and adolescents aged 7–18 in China, 2014

Hand grip strength	Model 1^a					Model 2
Hand grip strength	B	SE	95% CI		p	B	SE	95% CI		p
Age	2.253	0.038	2.178	2.328	< 0.001	2.275	0.038	2.200	2.350	< 0.001
Sex (ref = girls)	6.546	0.239	6.077	7.015	< 0.001	6.580	0.236	6.117	7.043	< 0.001
Residential areas (ref = rural)	0.196	0.255	−0.304	0.695	0.442	0.203	0.256	−0.704	0.298	0.427
Shaanxi (ref = Hainan)	0.822	0.270	0.293	1.352	0.002	0.467	0.272	−0.065	0.999	0.086
Thinness (ref = normal weight)	–	–	–	–	–	−2.997	0.355	−3.693	−2.301	< 0.001
Overweight/obesity (ref = normal weight)	–	–	–	–	–	1.220	0.477	0.285	2.155	0.011
Vertical jump
Age	0.475	0.046	0.385	0.564	< 0.001	0.442	0.046	0.351	0.532	< 0.001
Sex (ref = girls)	5.107	0.267	4.584	5.631	< 0.001	5.179	0.267	4.656	5.701	< 0.001
Residential areas (ref = rural)	−0.145	0.304	−0.740	0.450	0.632	0.109	0.309	−0.496	0.715	0.723
Thinness (ref = normal weight)	–	–	–	–	–	0.230	0.385	−0.524	0.985	0.550
Overweight/obesity (ref = normal weight)	–	–	–	–	–	−2.681	0.655	−3.965	−1.397	< 0.001
Sit-and-reach
Age	0.998	0.056	0.888	1.108	< 0.001	0.981	0.057	0.870	1.092	< 0.001
Sex (ref = girls)	−3.193	0.327	−3.834	−2.553	< 0.001	− 3.114	0.327	− 3.754	− 2.473	< 0.001
Residential areas (ref = rural)	0.180	0.371	−0.907	0.548	0.628	−0.177	0.379	−0.921	0.566	0.640
Thinness (ref = normal weight)	–	–	–	–	–	−1.313	0.467	−2.228	−0.399	0.005
Overweight/obesity (ref = normal weight)	–	–	–	–	–	−1.623	0.813	−3.216	−0.030	0.046

BMI body mass index (kg/m²), B regression coefficient, SE standard error of regression coefficient, CI confidence interval
^aModel 1: adjusted for age, sex, residential areas and study sites; Model 2: adjusted for age, sex, residential areas, study sites (if applicable) and BMI. Age was analyzed as continuous data; sex, BMI, residential areas and study sites were set as dummy variables

ISSN: 1471-2431