Table 3.

Selected models and odds of low BMD

	Variables in model	OR (95% CI) per 1-SD increase of predictive model score	P
Traditional model	Age, sex, BMI, centres, and CTX-I	1.17 (1.01-1.38)	0.04
Full model	Age, sex, BMI, centres, CTX-I, and selected metabolites	5.94 (4.54-7.95), among which 4.45 (3.50-5.77) was attributed to the selected metabolites	<0.001

The predictive model scores were calculated as the weighted sum of all covariates with weights equal to the regression coefficients from the predictive models built by the logistic regression model or the elastic net regression models.

BMD, bone mineral density; BMI, body mass index; CTX-I, C-terminal telopeptide of type I collagen; OR, odds ratio; CI, confidence interval; and SD, standard deviation.