Table 4 Joint effects of shift work (SW), noise, and physical workload (PW) on risk of coronary heart disease (CHD) risk among industrially employed men for different follow ups.
| n/CHD cases | Unadjusted | Age adjusted | SBP–TotC–Smo–BMI adjusted | Blue‐/white‐collar adjusted | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | RR | 95% CI | RR | 95% CI | RR | 95% CI | |||
| Shift work + noise | ||||||||||
| Fu –95 | SW−, no | 746/72 | 1 | 1 | 1 | 1 | ||||
| SW−, continuous | 310/34 | 1.13 | (0.75–1.71) | 1.10 | (0.73–1.65) | 1.08 | (0.72–1.63) | 1.05 | (0.65–1.70) | |
| SW−, both | 84/14 | 1.78 | (1.01–3.16)* | 1.72 | (0.97–3.05) | 1.60 | (0.90–2.83) | 1.65 | (0.88–3.09) | |
| SW+, no | 194/27 | 1.47 | (0.94–2.28) | 1.45 | (0.93–2.26) | 1.31 | (0.84–2.04) | 1.40 | (0.87–2.24) | |
| SW+, continuous | 370/56 | 1.62 | (1.14–2.30)** | 1.65 | (1.16–2.34)** | 1.46 | (1.03–2.08)* | 1.50 | (0.97–2.32) | |
| SW+, both | 100/13 | 1.36 | (0.76–2.46) | 1.40 | (0.78–2.53) | 1.21 | (0.67–2.18) | 1.26 | (0.66–2.40) | |
| Fu –99 | SW−, no | 746/121 | 1 | 1 | 1 | 1 | ||||
| SW−, continuous | 310/52 | 1.04 | (0.75–1.43) | 0.99 | (0.72–1.37) | 1.00 | (0.72–1.39) | 0.88 | (0.60–1.28) | |
| SW−, both | 84/23 | 1.82 | (1.16–2.84)** | 1.74 | (1.11–2.72)* | 1.67 | (1.07–2.60)* | 1.54 | (0.95–2.50) | |
| SW+, no | 194/41 | 1.34 | (0.94–1.92) | 1.33 | (0.93–1.89) | 1.23 | (0.87–1.76) | 1.21 | (0.83–1.76) | |
| SW+, continuous | 370/82 | 1.43 | (1.08–1.89)* | 1.45 | (1.10–1.93)** | 1.31 | (0.99–1.74) | 1.21 | (0.86–1.70) | |
| SW+, both | 100/25 | 1.59 | (1.03–2.44)* | 1.65 | (1.07–2.54)* | 1.43 | (0.93–2.21) | 1.35 | (0.84–2.16) | |
| Shift work + physical workload† | ||||||||||
| Fu –95 | SW−, PW− | 748/35 | 1 | 1 | 1 | 1 | ||||
| SW−, PW+ | 392/23 | 1.20 | (0.83–1.73) | 1.17 | (0.81–1.70) | 1.11 | (0.77–1.60) | 1.08 | (0.69–1.68) | |
| SW+, PW− | 448/35 | 1.43 | (1.02–2.01)* | 1.45 | (1.04–2.03)* | 1.26 | (0.90–1.77) | 1.31 | (0.88–1.95) | |
| SW+, PW+ | 216/18 | 1.65 | (1.10–2.47)* | 1.67 | (1.12–2.51)* | 1.50 | (1.00–2.26)* | 1.49 | (0.92–2.39) | |
| Fu –99 | SW−, PW− | 748/117 | 1 | 1 | 1 | 1 | ||||
| SW−, PW+ | 392/79 | 1.32 | (0.99–1.76) | 1.29 | (0.97–1.71) | 1.25 | (0.94–1.67) | 1.18 | (0.83–1.67) | |
| SW+, PW− | 448/94 | 1.39 | (1.06–1.82)* | 1.41 | (1.08–1.85)* | 1.26 | (0.96–1.65) | 1.26 | (0.92–1.73) | |
| SW+, PW+ | 216/54 | 1.69 | (1.22–2.33)** | 1.72 | (1.25–2.38)*** | 1.58 | (1.14–2.18)** | 1.51 | (1.03–2.20)* | |
| Noise + physical workload† | ||||||||||
| Fu –95 | No, PW− | 820/39 | 1 | 1 | 1 | 1 | ||||
| Continuous, PW− | 376/31 | 1.43 | (1.01–2.02)* | 1.43 | (1.01–2.02)* | 1.30 | (0.92–1.83) | 1.29 | (0.84–2.00) | |
| No, PW+ | 120/9 | 1.36 | (0.80–2.32) | 1.34 | (0.78–2.28) | 1.24 | (0.72–2.11) | 1.23 | (0.68–2.23) | |
| Continuous, PW+ | 304/20 | 1.21 | (0.82–1.79) | 1.20 | (0.81–1.76) | 1.18 | (0.80–1.74) | 1.10 | (0.69–1.76) | |
| Both, PW+ | 184/12 | 1.48 | (0.96–2.29) | 1.48 | (0.96–2.28) | 1.33 | (0.86–2.06) | 1.34 | (0.81–2.23) | |
| Fu –99 | No, PW− | 820/134 | 1 | 1 | 1 | 1 | ||||
| Continuous, PW− | 376/77 | 1.29 | (0.98–1.71) | 1.29 | (0.98–1.71) | 1.19 | (0.90–1.58) | 1.11 | (0.79–1.57) | |
| No, PW+ | 120/28 | 1.50 | (1.00–2.25) | 1.47 | (0.98–2.21) | 1.40 | (0.93–2.11) | 1.29 | (0.82–2.03) | |
| Continuous, PW+ | 304/57 | 1.17 | (0.85–1.59) | 1.14 | (0.83–1.55) | 1.15 | (0.84–1.57) | 1.00 | (0.69–1.45) | |
| Both, PW+ | 184/48 | 1.68 | (1.21–2.33)** | 1.68 | (1.21–2.34)** | 1.54 | (1.10–2.14)* | 1.44 | (0.98–2.12) | |
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; ***p<0.001.
†PW+ when product of prevalence (P) and level (L) is in 3 tertile.