Purpose: To compare the mortality risk of smoking and overall occupational exposure in Guangzhou, China.
Methods: Baseline data on smoking and occupational exposure of 82159 workers aged 30+ were retrieved from medical records established in 1988-92. Vital status and causes of death were followed through 1998.
Results: During follow-up 1584 workers had died. Adjusted relative risks (RR) with 95% confidence intervals (95%CI) for ever-smoking in men was 1.23 (1.07-1.41) for total deaths, 1.43 (1.17-1.74) for all cancer, 3.77 (2.31-6.14) for lung cancer and 2.54 (1.09-5.92) for stomach cancer (all showing significant linear trends with amount and duration of smoking). The RR in women of 1.10 (0.59-2.06) for total deaths and 1.60 (0.65-3.92) for all cancer were positive but not significant. No significant excess mortality risk was observed for occupational exposure in each gender. In both genders combined, the RR for total deaths was 1.23 (1.08-1.40) for smoking and 1.07 (0.96-1.19) for occupational exposure. If the relationships were causal, 12% of all deaths could be attributed to smoking but only 3% to occupational exposure.
Conclusion: Smoking was more predictive of premature deaths than overall occupational exposures in middle aged workers. Smoking cessation should be a top priority in occupational health practice.