Association between Serum Cotinine Levels and Bone Mineral Density: An Analysis of the National Health and Nutrition Examination Survey (NHANES)

Table 2

The association between serum cotinine (ng/mL) and lumbar bone mineral density (mg/cm²).

	Model 1	Model 2	Model 3
	β (95% CI) value	β (95% CI) value	β (95% CI) value
Serum cotinine (mg/dL)	−0.037 (−0.068, −0.005) 0.026	−0.061 (−0.092, −0.029) <0.001	−0.046 (−0.078, −0.014) 0.005
Serum cotinine categories
Q1	Reference	Reference	Reference
Q2	−7.505 (−19.196, 4.187) 0.204	−9.279 (−20.975, 2.417) 0.118	−8.712 (−20.455, 3.019) 0.142
Q3	−4.270 (−16.707, 8.167) 0.495	−13.305 (−26.378, −0.232) 0.046	−13.238 (−26.281, −0.194) 0.047
Q4	−15.595 (−28.402, −2.787) 0.018	−26.983 (−40.266, −13.700) <0.001	−22.771 (−35.842, −9.700) 0.001
Subgroup analysis stratified by sex
Men	−0.018 (−0.055, 0.020) 0.355	−0.040 (−0.079, − 0.002) 0.038	−0.020 (−0.059, 0.018) 0.297
Women	−0.072 (−0.132, −0.012) 0.019	−0.099 (−0.156, −0.042) <0.001	−0.089 (−0.146, −0.033) 0.002
Subgroup analysis stratified by race/ethnicity
Mexican American	0.045 (−0.106, 0.196) 0.550	0.062 (−0.090, 0.214) 0.413	0.072 (−0.076, 0.220) 0.331
Non-Hispanic black	−0.018 (−0.084, 0.047) 0.573	−0.030 (−0.094, 0.034) 0.346	−0.013 (−0.075, 0.04) 0.667
Non-Hispanic white	−0.084 (−0.124, −0.043) <0.001	−0.082 (−0.123, −0.041) <0.001	−0.066 (−0.107, −0.061) 0.002
Other race/ethnicity	0.047 (−0.027, 0.121) 0.210	0.039 (−0.036, 0.115) 0.304	0.044 (−0.034, 0.121) 0.265

Model 1: no covariates were adjusted. Model 2: age, gender, and race/ethnicity were adjusted. Model 3: age, gender, race/ethnicity, education, body mass index, physical activity, serum albumin, blood urea nitrogen, serum uric acid, serum calcium, and serum phosphorus were adjusted. In the subgroup analysis stratified by sex and race/ethnicity, the model is not adjusted for sex and race/ethnicity, respectively.