Table 1.
Subject characteristics
| Characteristics | Menthol | Non-menthol | P-value |
|---|---|---|---|
| Number | 3758 | 1941 | — |
| General characteristics | |||
| Age (year) | 54.4 ± 6.9 | 58.2 ± 8.0 | <0.001 |
| Gender | 0.281 | ||
| Male (%) | 54.7 | 56.2 | |
| Female (%) | 45.3 | 43.8 | |
| Race | <0.001 | ||
| White (%) | 33.7 | 82.6 | |
| African-American (%) | 66.3 | 17.4 | |
| Smoking history (pack-years) | 41.1 ± 22.3 | 46.5 ± 24.7 | <0.001 |
| Age smoked first cigarette | 16.7 ± 5.2 | 17.0 ± 4.9 | <0.001 |
| BMI (kg/m2) | 28.7 ± 6.5 | 27.9 ± 5.8 | <0.001 |
| Pulmonary variables | |||
| FEV1 (% of predicted value) | 82.5 ± 21.8 | 77.1 ± 23.4 | <0.001 |
| FVC (% of predicted value) | 89.8 ± 17.6 | 87.5 ± 17.8 | <0.001 |
| FEV1/FVC (%) | 0.72 ± 0.13 | 0.67 ± 0.14 | <0.001 |
| COPD defined by spirometry (%) | 32.1 | 45.8 | <0.001 |
| 6MWT (ft) | 1325.7 ± 369.2 | 1389.2 ± 379.0 | <0.001 |
| mMRC score | 1.4 ± 1.5 | 1.3 ± 1.4 | 0.012 |
| SGRQ total score | 28.2 ± 22.7 | 27.8 ± 23.2 | 0.303 |
| BODE index | 1.3 ± 1.6 | 1.3 ± 1.7 | 0.181 |
| Respiratory symptoms | |||
| Chronic cough (%) | 39.5 | 46.3 | <0.001 |
| Chronic sputum (%) | 35.5 | 40.1 | <0.001 |
| Current medication use (%) | 30.6 | 34.5 | 0.011 |
Data are presented as mean ± standard deviation or %.
BMI, body mass index; BODE, BMI, airflow obstruction, dyspnoea, exercise capacity; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; mMRC, modified Medical Research Council; SGRQ, St George’s Respiratory Questionnaire; 6MWT, 6-min walk test.