Abstract
BACKGROUND: We aimed to investigate the associations of long-term exposure to ambient formaldehyde with hypertension and angina pectoris symptoms in Chinese adults. METHODS AND RESULTS: Participants' information was obtained from the WHO SAGE (World Health Organization Study on Global Aging and Adult Health) study. The Cox proportional hazards regression model was applied to estimate the associations of formaldehyde with hypertension and angina pectoris symptoms. Mediating effect analysis was used to investigate the mediating effect of hypertension between formaldehyde exposure and angina pectoris symptoms. Long-term exposure to formaldehyde was positively associated with the risk of angina pectoris symptoms (hazard ratio [HR], 1.66 [95% CI, 1.29-2.13], per interquartile range [IQR], 3.33, 10(15) molecules/cm(2)) and hypertension (HR, 1.17 [95% CI, 1.02-1.34], per IQR, 3.34, 10(15) molecules/cm(2)). The associations between formaldehyde and angina pectoris symptoms were greater in participants aged ≥65 years (HR, 1.90 [95% CI, 1.29-2.80]) and in rural areas (HR, 2.71 [95% CI, 1.54-4.77]), whereas the associations of formaldehyde with hypertension were stronger in men (HR, 1.27 [95% CI, 1.02-1.58]), rural areas (HR, 1.22 [95% CI, 0.94-1.59]), and in ever smokers (HR, 1.33 [95% CI, 1.02-1.72]). The mediation effect analysis indicated that 18.44% (95% CI, 2.17-37.65) of the association between formaldehyde exposure and angina pectoris symptoms was mediated by hypertension. CONCLUSIONS: Long-term exposure to ambient formaldehyde was positively associated with hypertension and angina pectoris symptoms. The effects of formaldehyde may be modified by age, sex, urbanicity, and smoking status. Hypertension might play a mediating effect in formaldehyde-induced angina pectoris symptoms.