Table 3. Adjusted hazard ratios (95% CI) for incidence diabetes according to baseline smoking intensity 1 .
n | Cases | Incidence | Age-adjusted incidence | Attributable risk 2 | Model 1 3 | Model 2 4 | |
---|---|---|---|---|---|---|---|
Total | 36756 | ||||||
Never smoker | 19324 | 707 | 10.4 | 11.2 | - | 1.00 | 1.00 |
Current smoker (cigarettes smoked/d) | |||||||
1–10 | 3880 | 154 | 11.7 | 13.5 | 2.3 | 1.23 (1.03–1.46) | 1.31 (1.10–1.58) |
11–20 | 11604 | 660 | 15.7 | 16.9 | 5.7 | 1.37 (1.22–1.53) | 1.36 (1.22–1.52) |
21+ | 1948 | 149 | 21.5 | 20.8 | 9.6 | 1.51 (1.26–1.81) | 1.50 (1.25–1.80) |
P for trend | <0.001 | <0.001 | |||||
BMI <23 kg/m2 | 23432 | 617 | |||||
Never smoker | 10739 | 194 | 5.1 | 5.7 | - | 1.00 | 1.00 |
Current smoker (cigarettes smoked/d) | |||||||
1–10 | 2163 | 47 | 6.3 | 7.7 | 2.0 | 1.33 (0.96–1.84) | 1.35 (0.98–1.87) |
11–20 | 5807 | 204 | 9.6 | 10.5 | 4.8 | 1.50 (1.22–1.85) | 1.49 (1.21–1.83) |
21+ | 851 | 42 | 13.7 | 12.4 | 6.7 | 1.74 (1.24–2.46) | 1.74(1.23–2.45) |
P for trend | <0.001 | <0.001 | |||||
BMI ≥23 kg/m2 | 21971 | 1566 | |||||
Never smoker | 8585 | 513 | 17.0 | 17.8 | - | 1.00 | 1.00 |
Current smoker (cigarettes smoked/d) | |||||||
1–10 | 1717 | 107 | 18.9 | 20.9 | 3.1 | 1.26 (1.02–1.56) | 1.28 (1.03–1.58) |
11–20 | 5797 | 456 | 21.8 | 23.9 | 6.1 | 1.28 (1.12–1.45) | 1.28(1.12–1.45) |
21+ | 1097 | 107 | 27.7 | 28.4 | 10.6 | 1.49 (1.20–1.84) | 1.39 (1.12–1.72) |
P for trend | <0.001 | <0.001 | |||||
5 P for interaction | 0.07 |
CI, confidence interval; BMI, body mass index.
1Analyses excluded former smoker (n = 8647).
2Difference in age-adjusted incidence rate per 1000 person-years between never smoker and current smoker.
3Adjusted for age (years), sex, and worksite.
4Adjusted for all factors in model 1 plus BMI (kg/m2), waist circumference (cm), and hypertension (yes or no).
5P for interaction for dichotomized variable of BMI (<23 or ≥23 kg/m2) on the association between smoking and type 2 diabetes was based on model 2 and was examined using the likelihood ratio test