A nested case-control study on association between self-reported occupational sulfur dioxide exposure and hypertension

Abstract

BackgroundCurrent evidence on whether occupational sulfur dioxide (SO2) exposure affects the risk of hypertension is still limited, and the research results of the effect of environmental SO2 exposure on risk of hypertension remain inconsistent.ObjectiveTo analyze the association between self-reported occupational exposure to SO2 and the risk of hypertension, and the potential dose-response relationship between the years of exposure to SO2 and the risk of hypertension.MethodsBased on the Jinchang cohort, a nested case-control study design was adopted. A total of 841 newly diagnosed hypertension patients were followed up as the case group, and the control group was selected with 1∶1 individual matching based on non-occupational factors and occupational factors, respectively. The former matching conditions included age ±2 years old, same gender, working age ±2 years, and home address in the same sub-district. The latter was limited to working in the same workshop on the basis of the former conditions. Finally, the former included 717 controls and the latter included 488 controls. A unified questionnaire was used to collect general demographic characteristics, lifestyle habits, history of diabetes, family history of hypertension, and information on occupational exposure to SO2 (self-reported history of occupational exposure to SO2 and years of exposure to SO2). Conditional logistic regression model was used to analyze the association between occupational exposure to SO2 and hypertension, and the dose-response relationship between the years of SO2 exposure and the risk of hypertension.ResultsIn the nested case-control study matching with the non-occupational factors, the OR of hypertension in workers with self-reported occupational exposure to SO2 was 2.39 (95%CI: 1.68-3.39); while when matching with the occupational factors, the OR of hypertension in workers with self-reported occupational exposure to SO2 was 1.48 (95%CI: 1.04-2.12). The results of the dose-response relationship showed that as the SO2 exposure years increased from 1-9 years, 10-19 years, 20-29 years, and 30 years and above, in the nested case-control study matching with non-occupational factors, the ORs of hypertension were 1.85 (95%CI: 0.68-5.08), 1.46 (95%CI: 0.58-3.67), 1.64 (95%CI: 1.00-2.67), and 4.95 (95%CI: 2.63-9.31), respectively; in the nested case-control study matching with occupational factors, the ORs of hypertension were 0.98 (95%CI: 0.40-2.41), 1.84 (95%CI: 0.72-4.70), 1.37 (95%CI: 0.82-2.29), and 2.44 (95%CI: 1.37-4.35), respectively. The two dose-response relationships were positive by χ2 trend test (Ptrend<0.05).ConclusionSelf-reported occupational exposure to SO2 is associated with the risk of hypertension in the study population, and the hypertension risk increases with the increase of SO2 exposure years.

Keywords

• hypertension
• sulfur dioxide
• self-reported occupational exposure
• nested case-control study
• jinchang cohort