Ambient formaldehyde exposure a risk factor for hypertension, angina pectoris

Individuals with long-term exposure to ambient formaldehyde are at increased risk of hypertension and angina pectoris symptoms, with the risk modified by several factors such as age and smoking status, among others, according to a study.

Researchers used data from the World Health Organization Study on Global Aging and Adult Health (WHO SAGE) study.  They looked at 9,341 participants, of which 36.10 percent were >65 years of age, 51.75 percent were men, 56.55 percent resided in rural areas, 61.07 percent lived in Southern China, and 45.09 percent used unclean fuel as their primary household cooking fuel.

Cox proportional hazards regression model was used to examine the associations of formaldehyde with hypertension and angina pectoris symptoms. Mediating effect analysis was also performed to assess the mediating effect of hypertension between formaldehyde exposure and angina pectoris symptoms.

Over a mean follow-up of 6.6 years, 439 (5.30 percent) participants reported angina pectoris symptoms and 1,543 (42.63 percent) reported hypertension. A total of 3,619 participants were included in the analysis of formaldehyde and hypertension, and 8,270 were included in the analysis of formaldehyde and angina pectoris symptoms.

Results showed a positive association between long‐term exposure to formaldehyde and the outcomes. Each 3.33 x 10¹⁵ molecules/cm² increment of formaldehyde was associated with a 66-percent increase in the risk of angina pectoris symptoms (hazard ratio [HR], 1.66, 95 percent confidence interval [CI], 1.29–2.13), while each 3.34, 10¹⁵ molecules/cm² increment was associated with a 17-percent higher risk of hypertension (HR, 1.17, 95 percent CI, 1.02–1.34).

The association between formaldehyde and angina pectoris symptoms was pronounced among older participants (≥65 years: HR, 1.90, 95 percent CI, 1.29–2.80) and those living in rural areas (HR, 2.71, 95 percent CI, 1.54–4.77). On the other hand, the association between formaldehyde and hypertension was stronger among male participants (HR, 1.27, 95 percent CI, 1.02–1.58), those living in rural areas (HR, 1.22, 95 percent CI, 0.94–1.59), and those who were smokers or had a smoking history (HR, 1.33, 95 percent CI, 1.02–1.72).

In mediation analysis, hypertension mediated 18.44 percent of the association between formaldehyde exposure and angina pectoris symptoms.