Table 3 Noise, shift work, and physical workload as a predictor of coronary heart disease (CHD) risk among industrially employed men for different follow ups (FU).
| n/CHD cases | Unadjusted | Age adjusted | SBP–TotC–Smo–BMI adjusted | Gemfibrozil adjusted | Adjusted‡ | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | RR | 95% CI | RR | 95% CI | RR | 95% CI | RR | 95% CI | |||
| Continuous and/or impulse noise | ||||||||||||
| FU –91 | No | 940/48 | 1 | 1 | 1 | 1 | 1 | |||||
| Continuous | 680/51 | 1.48 | (1.00–2.19) | 1.47 | (0.99–2.18) | 1.39 | (0.93–2.06) | 1.47 | (0.99–2.18) | 1.29 | (0.85–1.96) | |
| Both | 184/12 | 1.28 | (0.68–2.41) | 1.28 | (0.68–2.40) | 1.16 | (0.61–2.18) | 1.25 | (0.66–2.34) | 1.12 | (0.58–2.14) | |
| FU –95 | No | 940/99 | 1 | 1 | 1 | 1 | 1 | |||||
| Continuous | 680/90 | 1.27 | (0.96–1.70) | 1.27 | (0.95–1.69) | 1.21 | (0.91–1.61) | 1.27 | (0.96–1.69) | 1.16 | (0.86–1.57) | |
| Both | 184/27 | 1.42 | (0.93–2.17) | 1.42 | (0.93–2.17) | 1.29 | (0.84–1.98) | 1.39 | (0.91–2.13) | 1.28 | (0.83–1.99) | |
| FU –99 | No | 940/162 | 1 | 1 | 1 | 1 | 1 | |||||
| Continuous | 680/134 | 1.16 | (0.93–1.46) | 1.16 | (0.92–1.45) | 1.11 | (0.89–1.40) | 1.16 | (0.92–1.46) | 1.07 | (0.84–1.37) | |
| Both | 184/48 | 1.58 | (1.15–2.18)** | 1.59 | (1.15–2.19)** | 1.46 | (1.06–2.02)* | 1.56 | (1.13–2.16)** | 1.45 | (1.04–2.02)* | |
| Day or shift work | ||||||||||||
| FU –91 | Day | 1140/58 | 1 | 1 | 1 | 1 | 1 | |||||
| Shift | 664/53 | 1.59 | (1.10–2.31)* | 1.63 | (1.12–2.37)* | 1.49 | (1.02–2.17)* | 1.57 | (1.08–2.28)* | 1.47 | (0.98–2.19) | |
| FU –95 | Day | 1140/120 | 1 | 1 | 1 | 1 | 1 | |||||
| Shift | 664/96 | 1.41 | (1.08–1.84)* | 1.44 | (1.10–1.88)** | 1.33 | (1.01–1.74)* | 1.39 | (1.07–1.82)* | 1.32 | (0.99–1.76) | |
| FU –99 | Day | 1140/196 | 1 | 1 | 1 | 1 | 1 | |||||
| Shift | 664/148 | 1.34 | (1.08–1.66)** | 1.37 | (1.11–1.70)** | 1.30 | (1.04–1.61)* | 1.33 | (1.08–1.65)** | 1.27 | (1.01–1.60)* | |
| Physical workload† | ||||||||||||
| FU –91 | 1 tertile | 787/45 | 1 | 1 | 1 | 1 | 1 | |||||
| 2 tertile | 409/25 | 1.07 | (0.66–1.74) | 1.07 | (0.66–1.74) | 0.99 | (0.61–1.62) | 1.07 | (0.66–1.74) | 0.85 | (0.50–1.42) | |
| 3 tertile | 608/41 | 1.18 | (0.77–1.80) | 1.17 | (0.76–1.78) | 1.10 | (0.72–1.69) | 1.17 | (0.77–1.79) | 1.10 | (0.71–1.68) | |
| FU –95 | 1 tertile | 787/89 | 1 | 1 | 1 | 1 | 1 | |||||
| 2 tertile | 409/47 | 1.01 | (0.71–1.44) | 1.01 | (0.71–1.44) | 0.95 | (0.67–1.36) | 1.02 | (0.72–1.45) | 0.85 | (0.58–1.24) | |
| 3 tertile | 608/80 | 1.17 | (0.87–1.59) | 1.16 | (0.86–1.57) | 1.11 | (0.82–1.50) | 1.17 | (0.86–1.58) | 1.11 | (0.82–1.50) | |
| FU –99 | 1 tertile | 787/134 | 1 | 1 | 1 | 1 | 1 | |||||
| 2 tertile | 409/77 | 1.11 | (0.83–1.46) | 1.10 | (0.83–1.46) | 1.07 | (0.80–1.41) | 1.12 | (0.84–1.48) | 0.96 | (0.71–1.29) | |
| 3 tertile | 608/133 | 1.31 | (1.03–1.67)* | 1.29 | (1.02–1.64)* | 1.27 | (0.99–1.61) | 1.32 | (1.03–1.67)* | 1.26 | (0.99–1.60) | |
The relative risks (RR) with 95% confidence intervals (95% CI) and p value were derived using Cox proportional hazards models with different covariates.
SBP, systolic blood pressure; TotC, total serum cholesterol; Smo, smoking; BMI, body mass index.
*p<0.05; **p<0.01.
†Product of proportion of exposed (prevalence P) and mean level of exposure among the exposed (level L).
‡Noise adjusted for day/shift work, day/shift work adjusted for noise, physical workload adjusted for day/shift work.