Table 3. Regression coefficients of tertiles of cotinine level and body mass index for hearing threshold.
| Variables | Tertile of serum cotinine level (ng/mL) | High-PTA |
Low-PTA |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Normal weight |
Overweight |
Obesity |
Normal weight |
Overweight |
Obesity |
||||||||
| β (95%CI) | P value | β (95%CI) | P value | β (95%CI) | P value | β (95%CI) | P value | β (95%CI) | P value | β (95%CI) | P value | ||
| Model 1 | Tertile 1 | Reference | — | Reference | — | Reference | — | Reference | — | Reference | — | Reference | — |
| Tertile 2 | −0.031 (−0.086,0.025) | 0.280 | 0.014 (−0.040,0.069) | 0.607 | 0.038 (−0.016,0.092) | 0.173 | −0.039 (−0.095,0.016) | 0.167 | −0.024 (−0.077,0.029) | 0.378 | 0.024 (−0.034,0.083) | 0.417 | |
| Tertile 3 | 0.031 (−0.030,0.093) | 0.314 | 0.022 (−0.032,0.075) | 0.432 | 0.076 (0.024,0.128) | 0.004 | 0.002 (−0.059,0.064) | 0.944 | 0.039 (−0.013,0.092) | 0.143 | 0.071 (0.015,0.127) | 0.014 | |
| P for trend | 0.388 | 0.433 | 0.004 | 0.955 | 0.137 | 0.013 | |||||||
| Model 2 | Tertile 1 | Reference | — | Reference | — | Reference | — | Reference | — | Reference | — | Reference | — |
| Tertile 2 | −0.26 (−0.082,0.030) | 0.356 | 0.023 (−0.031,0.077) | 0.403 | 0.038 (−0.016,0.092) | 0.168 | −0.037 (−0.094,0.019) | 0.192 | −0.018 (−0.072,0.035) | 0.498 | 0.023 (−0.035,0.082) | 0.434 | |
| Tertile 3 | 0.033 (−0.028,0.095) | 0.289 | 0.037 (−0.017,0.091) | 0.176 | 0.077 (0.025,0.129) | 0.004 | 0.003 (−0.059,0.064) | 0.932 | 0.049 (−0.004,0.102) | 0.067 | 0.068 (0.012,0.125) | 0.018 | |
| P for trend | 0.352 | 0.177 | 0.004 | 0.973 | 0.064 | 0.016 | |||||||
| Model 3 | Tertile 1 | Reference | — | Reference | — | Reference | — | Reference | — | Reference | — | Reference | — |
| Tertile 2 | −0.024 (−0.080,0.032) | 0.409 | 0.024 (−0.030,0.078) | 0.389 | 0.042 (−0.012,0.097) | 0.127 | −0.032 (−0.088,0.024) | 0.265 | −0.015 (−0.067,0.038) | 0.583 | 0.028 (−0.031,0.087) | 0.356 | |
| Tertile 3 | 0.034 (−0.028,0.095) | 0.282 | 0.040 (−0.014,0.094) | 0.143 | 0.076 (0.024,0.128) | 0.004 | 0.009 (−0.053,0.071) | 0.776 | 0.053 (0.001,0.105) | 0.047 | 0.068 (0.011,0.124) | 0.019 | |
| P for trend | 0.340 | 0.144 | 0.005 | 0.861 | 0.044 | 0.017 | |||||||
Adjusted covariates:
Model 1 = age, sex, race.
Model 2 = Model 1 + (BMI, HDL-C, uric acid, waist circumference).
Model 3 = Model 2 + (abnormal otoscopy, abnormal tympanometry, present used of ototoxic agents, history of stroke, diabetes, heart disease).
Definition of abbreviations: High-PTA = Pure tone average at high frequencies, Low-PTA = Pure tone average at low frequencies, BMI = body mass index, HDL-C = high-density lipoprotein cholesterol.
Definition: Normal weight (BMI 18.5 to <25); overweight (BMI 25 to <30); obesity (BMI ≧ 30).