Table 2.
Strength of the evidence for the relationship between current smoking and the 36 health outcomes analyzed
| Risk–outcome pair | Risk unit | Mean risk at different exposure levels | 85th percentile risk level | Mean risk at 85th percentile risk level | ROSs | Average BPRF | Average increased risk (%) | Star rating | Pub. bias | No. of studies | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 10 | 20 | 40 | ||||||||||
| Laryngeal cancer | Pack-years | 2.30 (1.88, 2.84) | 3.77 (2.73, 5.30) | 7.25 (4.48, 12.05) | 14.62 (7.62, 29.11) | 50.50 | 17.73 (8.82, 37.07) | 1.56 | 4.75 | 374.95 | 5 | 0 | 5 |
| Aortic aneurism (ref. age: 55–59 years) | Cigarettes per day | 2.52 (1.79, 3.60) | 3.78 (2.31, 6.33) | 5.39 (2.89, 10.36) | 6.22 (3.17, 12.64) | 30.00 | 6.08 (3.13, 12.27) | 0.92 | 2.50 | 149.73 | 5 | 0 | 14 |
| Peripheral artery disease (ref. age: 60–64 years) | Cigarettes per day | 2.52 (1.67, 3.90) | 3.80 (2.10, 7.14) | 5.69 (2.62, 12.94) | 7.82 (3.13, 20.68) | 31.25 | 7.16 (2.98, 18.16) | 0.86 | 2.37 | 136.53 | 5 | 0 | 6 |
| Lung cancer | Pack-years | 1.58 (1.19, 2.15) | 2.48 (1.40, 4.53) | 5.11 (1.84, 14.99) | 11.62 (2.49, 58.73) | 50.88 | 13.42 (2.63, 74.59) | 0.73 | 2.07 | 106.66 | 5 | 1 | 78 |
| Other pharynx cancer | Pack-years | 1.65 (1.30, 2.13) | 2.20 (1.51, 3.30) | 3.02 (1.77, 5.30) | 3.89 (2.02, 7.78) | 63.75 | 4.72 (2.24, 10.45) | 0.65 | 1.92 | 92.26 | 5 | 0 | 8 |
| COPD | Pack-years | 1.61 (1.21, 2.17) | 2.16 (1.37, 3.51) | 3.17 (1.60, 6.55) | 5.05 (1.94, 13.97) | 49.75 | 6.01 (2.08, 18.58) | 0.54 | 1.72 | 72.11 | 4 | 1 | 13 |
| Lower respiratory infection | Cigarettes per day | 1.46 (1.23, 1.76) | 1.83 (1.38, 2.46) | 2.63 (1.68, 4.23) | 2.97 (1.79, 5.06) | 31.25 | 2.97 (1.79, 5.06) | 0.43 | 1.54 | 54.45 | 4 | 0 | 7 |
| Pancreatic cancer | Pack-years | 1.26 (1.22, 1.31) | 1.47 (1.38, 1.57) | 1.72 (1.57, 1.88) | 1.80 (1.63, 1.98) | 51.25 | 1.87 (1.69, 2.08) | 0.42 | 1.52 | 51.66 | 4 | 0 | 19 |
| Bladder cancer | Pack-years | 1.21 (1.08, 1.36) | 1.43 (1.16, 1.77) | 1.90 (1.31, 2.81) | 2.92 (1.57, 5.63) | 50.65 | 3.29 (1.65, 6.83) | 0.34 | 1.40 | 40.18 | 3 | 1 | 30 |
| Tuberculosis | Cigarettes per day | 1.46 (1.13, 1.92) | 1.88 (1.22, 2.97) | 2.71 (1.38, 5.56) | 3.47 (1.49, 8.50) | 26.56 | 3.24 (1.46, 7.56) | 0.27 | 1.31 | 31.04 | 3 | 0 | 19 |
| Esophageal cancer | Pack-years | 1.24 (1.06, 1.46) | 1.48 (1.11, 2.00) | 1.96 (1.20, 3.32) | 3.12 (1.36, 7.57) | 50.00 | 4.79 (1.53, 16.26) | 0.26 | 1.29 | 29.36 | 3 | 1 | 14 |
| Cervical cancer | Pack-years | 1.60 (1.12, 2.35) | 1.99 (1.18, 3.48) | 2.37 (1.23, 4.79) | 2.62 (1.26, 5.72) | 25.50 | 2.53 (1.25, 5.36) | 0.21 | 1.24 | 23.53 | 3 | 0 | 4 |
| Multiple sclerosis | Cigarettes per day | 1.14 (1.10, 1.17) | 1.31 (1.23, 1.40) | 1.78 (1.55, 2.06) | 2.77 (2.17, 3.60) | 20.00 | 1.78 (1.55, 2.06) | 0.21 | 1.23 | 23.36 | 3 | 0 | 6 |
| Rheumatoid arthritis | Cigarettes per day | 1.20 (1.10, 1.31) | 1.40 (1.20, 1.66) | 1.67 (1.31, 2.14) | 1.73 (1.34, 2.26) | 26.25 | 1.72 (1.34, 2.25) | 0.21 | 1.23 | 23.32 | 3 | 1 | 6 |
| Lower back pain | Cigarettes per day | 1.58 (1.11, 2.28) | 1.96 (1.16, 3.39) | 2.26 (1.20, 4.40) | 2.29 (1.21, 4.50) | 26.25 | 2.29 (1.21, 4.49) | 0.20 | 1.22 | 21.84 | 3 | 0 | 6 |
|
Ischemic heart disease (ref. age: 55–59 years) |
Cigarettes per day | 1.66 (1.09, 2.57) | 2.12 (1.14, 4.1) | 2.43 (1.17, 5.27) | 4.20 (1.28, 14.77) | 31.25 | 3.13 (1.22, 8.50) | 0.19 | 1.20 | 20.39 | 3 | 1 | 60 |
| Peptic ulcer | Cigarettes per day | 1.47 (1.11, 1.97) | 1.79 (1.17, 2.80) | 2.10 (1.22, 3.73) | 2.16 (1.23, 3.92) | 21.94 | 2.12 (1.22, 3.80) | 0.18 | 1.20 | 19.84 | 3 | 0 | 7 |
| Macular degeneration | Cigarettes per day | 1.33 (1.07, 1.69) | 1.67 (1.12, 2.54) | 2.23 (1.20, 4.31) | 2.42 (1.22, 5.01) | 27.50 | 2.41 (1.22, 4.99) | 0.18 | 1.19 | 19.44 | 3 | 0 | 2 |
|
Parkinson's disease (protective risk) |
Cigarettes per day | 0.79 (0.66, 0.93) | 0.65 (0.47, 0.88) | 0.54 (0.34, 0.84) | 0.49 (0.29, 0.81) | 26.25 | 0.51 (0.31, 0.83) | 0.16 | 0.85 | −14.88 | 3 | 1 | 14 |
| Stomach cancer | Pack-years | 1.10 (1.06, 1.15) | 1.18 (1.10, 1.27) | 1.29 (1.16, 1.44) | 1.39 (1.22, 1.60) | 51.13 | 1.61 (1.32, 1.97) | 0.16 | 1.17 | 17.39 | 3 | 1 | 13 |
|
Stroke (ref. age: 55–59) |
Cigarettes per day | 1.40 (1.07, 1.88) | 1.75 (1.11, 2.82) | 2.23 (1.16, 4.45) | 2.43 (1.18, 5.22) | 29.50 | 2.42 (1.18, 5.19) | 0.16 | 1.17 | 16.89 | 3 | 0 | 67 |
| Type 2 diabetes | Cigarettes per day | 1.23 (1.09, 1.39) | 1.38 (1.15, 1.68) | 1.49 (1.18, 1.90) | 1.67 (1.24, 2.29) | 26.25 | 1.54 (1.20, 2.01) | 0.15 | 1.16 | 15.76 | 3 | 1 | 28 |
| Cataracts | Cigarettes per day | 1.10 (1.08, 1.12) | 1.16 (1.13, 1.19) | 1.29 (1.23, 1.35) | 1.70 (1.54, 1.88) | 25.00 | 1.43 (1.34, 1.53) | 0.14 | 1.15 | 15.47 | 3 | 0 | 10 |
| Nasopharyngeal cancer | Pack-years | 1.16 (1.04, 1.31) | 1.28 (1.06, 1.56) | 1.39 (1.08, 1.83) | 1.97 (1.17, 3.43) | 50.00 | 2.67 (1.26, 5.94) | 0.13 | 1.14 | 14.29 | 2 | 1 | 12 |
| Alzheimer’s and other dementia | Cigarettes per day | 1.16 (1.04, 1.30) | 1.29 (1.06, 1.58) | 1.46 (1.10, 1.96) | 1.74 (1.14, 2.70) | 30.00 | 1.54 (1.11, 2.18) | 0.09 | 1.10 | 9.70 | 2 | 1 | 8 |
| Gallbladder diseases | Cigarettes per day | 1.15 (1.03, 1.30) | 1.24 (1.05, 1.49) | 1.29 (1.05, 1.61) | 1.51 (1.09, 2.14) | 27.93 | 1.41 (1.07, 1.88) | 0.06 | 1.06 | 6.34 | 2 | 0 | 4 |
|
Atrial fibrillation and flutter (ref. age: 55–59 years) |
Cigarettes per day | 1.34 (1.03, 1.78) | 1.40 (1.03, 1.93) | 1.40 (1.03, 1.93) | 1.40 (1.03, 1.93) | 25.00 | 1.40 (1.03, 1.93) | 0.06 | 1.06 | 5.67 | 2 | 0 | 5 |
| Lip and oral cavity cancer | Pack-years | 1.15 (1.00, 1.34) | 1.37 (0.99, 1.94) | 2.05 (0.98, 4.50) | 3.50 (0.97, 13.93) | 49.68 | 3.91 (0.96, 17.56) | 0.05 | 1.05 | 4.81 | 2 | 0 | 10 |
| Breast cancer | Pack-years | 1.08 (1.02, 1.14) | 1.13 (1.04, 1.24) | 1.17 (1.04, 1.31) | 1.17 (1.04, 1.31) | 34.10 | 1.17 (1.04, 1.31) | 0.04 | 1.04 | 4.46 | 2 | 0 | 23 |
| Colon and rectum cancer | Pack-years | 1.07 (0.99, 1.16) | 1.12 (0.98, 1.29) | 1.19 (0.97, 1.46) | 1.20 (0.97,1.50) | 50.00 | 1.20 (0.97, 1.50) | −0.01 | 0.99 | N/A | 1 | 0 | 16 |
| Kidney cancer | Pack-years | 1.01 (1.00, 1.02) | 1.04 (0.99, 1.09) | 1.15 (0.98, 1.36) | 1.52 (0.94, 2.53) | 45.86 | 1.59 (0.93, 2.79) | −0.01 | 0.99 | N/A | 1 | 1 | 18 |
| Leukemia | Pack-years | 1.04 (0.98, 1.11) | 1.07 (0.97, 1.19) | 1.10 (0.95, 1.29) | 1.62 (0.79, 3.47) | 37.50 | 1.50 (0.82, 2.80) | −0.04 | 0.96 | N/A | 1 | 0 | 7 |
| Fracture | Binary | N/A | N/A | N/A | N/A | 1 (binary) | 1.34 (0.84, 1.97) | −0.05 | 0.95 | N/A | 1 | 0 | 59 |
| Prostate cancer | Cigarettes per day | 1.03 (0.98, 1.10) | 1.07 (0.95, 1.21) | 1.16 (0.89, 1.53) | 1.30 (0.82, 2.10) | 29.73 | 1.25 (0.85, 1.89) | −0.06 | 0.94 | N/A | 1 | 1 | 22 |
| Liver cancer | Pack-years | 1.15 (0.84, 1.59) | 1.26 (0.75, 2.19) | 1.39 (0.65, 3.10) | 1.42 (0.64, 3.30) | 62.50 | 1.42 (0.64, 3.30) | −0.32 | 0.72 | N/A | 1 | 0 | 11 |
| Asthma | Cigarettes per day | 1.41 (0.54, 3.96) | 1.59 (0.43, 6.39) | 1.61 (0.42, 6.74) | 1.64 (0.41, 7.23) | 26.25 | 1.63 (0.41, 7.04) | −0.64 | 0.53 | N/A | 1 | 0 | 7 |
The ROS represents the signed value of the log(BPRF) averaged across the 15th–85th percentiles of exposure. The BPRF corresponds to the lower (if harmful) or higher (if protective) UI—inclusive of between-study heterogeneity—for each risk–outcome pair’s RR curve. ROSs are directly comparable across outcomes and each risk–outcome pair receives an ROS based on the final formulation of the risk curve. For Parkinson’s disease, the ROS reflects a protective effect of smoking, whereas for the other outcomes it reflects a harmful effect. Negative ROSs indicate that a conservative interpretation of the available evidence suggests that there may be no association between risk and outcome. For ease of interpretation, we have transformed the ROS and BPRF into a star rating (1–5), with a higher rating representing a larger effect and stronger evidence. Average BPRF, which is the exponential ROS for harmful effects (or exponential negative ROS for protective effects), is the conservative exposure-averaged RR consistent with all the available data. Average increased risk, which equates to (average BPRF − 1) × 100% for harmful effects or (1 − average BPRF) × 100% for protective effects, refers to the percentage increase in RR based on a conservative interpretation of the evidence. For harmful risks, this percentage is positive and, for protective risks, negative, indicating the percentage decrease in RR. The average increased risk is not applicable for pairs with negative ROSs. N/A, not available; Pub., Publication; ref., reference.