Table 3.
Association of cigarette exposure with depression
| Cigarette exposure | OR (95% CI) | |||
|---|---|---|---|---|
| Total | Male | Female | P modification | |
| Smoking status | 0.668 | |||
| Never | 1 (ref.) | 1 (ref.) | 1 (ref.) | |
| Former | 1.334 (1.003, 1.773) * | 1.364 (0.799, 2.328) | 1.281 (0.804, 2.043) | |
| Current | 2.525 (1.936, 3.293) ***§§§ | 2.258 (1.424, 3.582) **§ | 2.660 (1.946, 3.637) ***§§§ | |
| Pack-years of smoking | 1.007 (1.002, 1.012) * | 1.004 (0.997, 1.011) | 1.012 (1.004, 1.020) ** | 0.154 |
| Never-smokers | 1 (ref.) | 1 (ref.) | 1 (ref.) | |
| Q1 | 1.755 (1.121, 2.747) * | 2.029 (1.112, 3.701) * | 1.586 (0.974, 2.582) | |
| Q2 | 1.530 (1.091, 2.144) * | 1.532 (0.738, 3.181) | 1.491 (0.913, 2.435) | |
| Q3 | 2.062 (1.466, 2.902) *** | 1.740 (1.027, 2.949) * | 2.051 (1.256, 3.349) ** | |
| Q4 | 2.424 (1.624, 3.615) *** | 1.793 (1.124, 2.862) * | 2.675 (1.556, 4.599) ** | |
| Ptrend | < 0.001 | 0.011 | < 0.001 | |
| Cigarettes per day now | 1.044 (1.029, 1.058) *** | 1.021 (0.998, 1.044) | 1.067 (1.044, 1.092) *** | 0.011 |
| Non-smokers | 1 (ref.) | 1 (ref.) | 1 (ref.) | |
| Q1 | 1.798 (1.054, 3.068) * | 1.908 (0.835, 4.356) | 1.567 (0.870, 2.824) | |
| Q2 | 1.869 (1.188, 2.940) * | 2.321 (1.366, 3.945) ** | 1.633 (1.040, 2.562) * | |
| Q3 | 2.032 (1.384, 2.981) ** | 2.373 (1.189, 4.736) * | 2.027 (1.339, 3.069) ** | |
| Q4 | 3.025 (2.188, 4.181) *** | 1.494 (0.807, 2.766) | 4.020 (2.603, 6.207) *** | |
| Ptrend | < 0.001 | 0.008 | < 0.001 | |
Models were adjusted for age, gender, BMI, race, educational qualification, physical activity, alcohol consumption, ratio of family income to poverty, regular periods, and batch (survey cycle). Ptrend was tested by including never-/non-smokers, Q1, Q2, Q3, and Q4 as 1, 2, 3, 4, 5 (continuous variable) in models, respectively. *P < 0.05, **P < 0.01, ***P < 0.001. §former smokers were as a reference. §P < 0.05, §§P < 0.01, §§§P < 0.001