Table 3. Incidence rates and hazard ratios for impaired insulin secretion and insulin resistance according to smoking status.
| Never‐smokers | Ex‐smokers | Current smokers | |
|---|---|---|---|
| n | 353 | 583 | 263 |
| Impaired insulin secretion | |||
| Cases (n)/person‐years | 122/1,009 | 213/1,703 | 114/691 |
| Incidence rate (per 1,000 person‐years) | 120.9 | 125.1 | 165.0 |
| HR (95% CI) | |||
| Model 1 | 1.0 | 1.00 (0.80–1.25) | 1.38 (1.07–1.79) |
| Model 2 | 1.0 | 1.03 (0.82–1.29) | 1.51 (1.16–1.97) |
| Model 3 | 1.0 | 1.06 (0.84–1.32) | 1.55 (1.18–2.02) |
| Model 4 | 1.0 | 1.04 (0.83–1.30) | 1.54 (1.16–2.03) |
| Model 5 | 1.0 | 1.02 (0.82–1.29) | 1.89 (1.42–2.51) |
| Model 6 | 1.0 | 1.06 (0.84–1.33) | 1.95 (1.44–2.63) |
| Model 7* | 1.0 | 1.02 (0.81–1.29) | 1.94 (1.42–2.65) |
| Insulin resistance | |||
| Cases (n)/person‐years | 22/1,216 | 44/2,011 | 33/865 |
| Incidence rate (per 1,000 person‐years) | 18.1 | 21.9 | 38.2 |
| HR (95% CI) | |||
| Model 1 | 1.0 | 1.19 (0.71–1.99) | 2.15 (1.25–3.69) |
| Model 2 | 1.0 | 1.04 (0.62–1.75) | 1.93 (1.10–3.38) |
| Model 3 | 1.0 | 0.92 (0.54–1.57) | 1.59 (0.91–2.78) |
| Model 4 | 1.0 | 1.00 (0.59–1.69) | 1.59 (0.88–2.85) |
| Model 5 | 1.0 | 1.03 (0.61–1.74) | 1.42 (0.74–2.72) |
| Model 6 | 1.0 | 0.95 (0.56–1.61) | 1.11 (0.67–1.79) |
| Model 7† | 1.0 | 0.94 (0.43–2.06) | 1.06 (0.58–1.72) |
Model 1: Adjusted for age. Model 2: Adjusted for age, familial history of diabetes (yes or no), alcohol consumption (0, 1–139 or ≥140 g/week), exercise (0, 1–119 or ≥120 min/week), systolic blood pressure, log‐transformed triglyceride and log‐transformed γ‐glutamyltransferase. Model 3: Adjusted for all factors in model 2 plus waist circumference. Model 4: Adjusted for all factors in model 2 plus leukocyte count. Model 5: Adjusted for all factors in model 2 plus changes in smoking status between the baseline and final examinations (no change, started smoking or quit smoking) and Δ waist circumference (Δ = final examination–baseline examination). Model 6: Adjusted for all factors in model 2 plus waist circumference, leukocyte count, changes in smoking status and Δ waist circumference.
Model 7: *Adjusted for all factors in model 6 among 1,100 men excluding 99 men who developed insulin resistance. †Adjusted for all factors in model 6 among 750 men excluding 449 men who developed impaired insulin secretion.
CI, confidence interval; HR, hazard ratio.