Association between serum cotinine in non-smokers (≥5 years since quitting) or active smokers and cardiovascular disease risk factors in men and women (mean (SD) or %(n))*
| Risk factors | Non-smokers (serum cotinine ng/ml) | Smokers | p(trend)† | p(difference)† | ||||
| N | ≤0.05 | 0.06–0.19 | 0.20–0.70 | 0.71–15 | 1–9 Cigarettes/day (n=306) | In non-smokers | Cotinine ≤0.05 vs smokers | |
| (n=2256) | (n=1248) | (n=1184) | (n=686) | |||||
| Cotinine (ng/ml)‡ | 5680 | 0.05 | 0.14 | 0.34 | 1.69 | 104.57 | – | – |
| Age (years) | 5680 | 69.3 (5.5) | 68.4 (5.5) | 68.2 (5.5) | 68.1 (5.4) | 69.1 (5.3) | <0.001 | 0.526 |
| Men % (n) | 5680 | 38.3 (865) | 45.1 (563) | 51.6 (611) | 55.5 (381) | 39.4 (121) | <0.001 | 0.516 |
| Southern region of residence, % | 5680 | 43.4 (981) | 32.2 (402) | 27.4 (324) | 20.7 (142) | 30.4 (93) | <0.001 | 0.001 |
| Manual occupational class, % | 5345 | 41.0 (880) | 45.5 (539) | 56.5 (626) | 65.7 (418) | 55.3 (147) | <0.001 | <0.001 |
| Never/occasional alcohol use, % | 5397 | 52.1 (1128) | 48.0 (571) | 41.7 (475) | 40.1 (256) | 54.5 (145) | <0.001 | 0.589 |
| >43 Alcohol units/week, % | 5397 | 0.4 (9) | 0.3(4) | 1.6 (18) | 4.2 (27) | 0.8 (2) | <0.001 | 0.518 |
| Never-smokers, % | 5680 | 56.7 (1278) | 54.1 (675) | 46.6 (552) | 40.5 (278) | – | <0.001 | – |
| Low level of physical activity, % (<3 h moderate/vigorous /week) | 5645 | 62.9 (1377) | 59.6 (721) | 61.2 (698) | 62.4 (406) | 74.6 (206) | 0.002 | <0.001 |
| Pre-existing diabetes, % | 5680 | 10.2 (230) | 8.5 (106) | 11.5 (136) | 10.5 (72) | 9.8 (30) | 0.762 | 0.791 |
| Body mass index (kg/m2) | 5647 | 26.9 (4.3) | 27.4 (4.1) | 27.8 (4.5) | 27.8 (4.5) | 25.8 (3.9) | <0.001 | <0.001 |
| Systolic Blood Pressure (mm Hg)§ | 5646 | 149.5 (24.3) | 147.7 (24.5) | 147.6 (24.1) | 150.3 (24.1) | 146.1 (25.4) | 0.690 | 0.018 |
| Diastolic Blood Pressure (mm Hg)§ | 5646 | 82.3 (11.5) | 82.0 (11.4) | 82.7 (12.1) | 84.1 (11.9) | 80.8 (11.6) | 0.096 | 0.030 |
| Total cholesterol (mmol/l) | 5648 | 6.5 (1.2) | 6.4 (1.2) | 6.3 (1.1) | 6.3 (1.2) | 6.4 (1.2) | 0.131 | 0.353 |
| HDL cholesterol (mmol/l) | 5629 | 1.6 (0.4) | 1.5 (0.4) | 1.5 (0.4) | 1.5 (0.4) | 1.5 (0.5) | 0.160 | 0.151 |
| Triglyceride (mmol/l)ঠ| 5495 | 1.6 | 1.6 | 1.6 | 1.6 | 1.7 | 0.100 | 0.016 |
| C-reactive protein (mg/l)‡ | 5601 | 1.5 | 1.5 | 1.7 | 1.9 | 2.3 | <0.001 | <0.001 |
| IL-6 (pg/ml)‡ | 5640 | 2.2 | 2.2 | 2.3 | 2.5 | 3.1 | <0.001 | <0.001 |
| White cell count (×109/l)‡¶ | 5418 | 6.6 | 6.7 | 6.7 | 6.7 | 7.8 | 0.062 | <0.001 |
| FEV1§** | 5680 | 2.3 (0.5) | 2.3 (0.5) | 2.3 (0.5) | 2.2 (0.6) | 2.0 (0.6) | <0.001 | <0.001 |
↵* Non-smoker sample excludes (i) current cigarette, pipe or cigar smokers, (ii) ex-smokers who quit <5 years ago, (iii) pre-existing myocardial infarction or stroke. Means are adjusted for age, gender and region;
↵† p(trend) from linear regression models of ln(cotinine) in non-smokers, p(difference) from linear regression models contrasting cotinine<0.05 with 1–9/day smokers. Models adjusted for age, gender and region;
↵‡ geometric mean;
↵§ adjusted for interobserver variation;
↵¶ Adjusted for time of day;
↵** adjusted for height squared and age.
FEV1, forced expiratory volume in 1 s; HDL, high-density lipoprotein; IL, interleukin.