Air pollution-associated blood pressure may be modified by diet among children in Guangzhou, China

To assess the associations between long-term air pollution exposure and blood pressure in children, and to explore the modifying effects of diet on prehypertension and hypertension.

We evaluated 7225 primary school children aged 6-12 years from Guangzhou, China, in 2017. The blood pressure was measured objectively. The individual 1-year average concentration of particles with an aerodynamic diameter of 2.5 μm or less or 10 μm or less (PM2.5, PM10), sulfur dioxide (SO2), and ozone (O3) before each blood pressure measurement were calculated by inverse distance weighting interpolation according to each home address. Generalized linear mixed-effects models were used to examine the health effects and potential effect modifications by diet factors after adjusting for covariates.

The results showed that the estimated increase in mean SBP was 0.92 mmHg (95% CI 0.05-1.79) per interquartile range increase in O3. An interquartile range increase in the 1-year mean of SO2 and O3 was associated with odds ratios of 1.26 (95% CI 1.04-1.52) and 1.20 (95% CI 1.06-1.35) for prehypertension, respectively. In addition, an interquartile range increase in PM2.5, SO2, and O3 exposure was positively associated with hypertension, with odds ratios of 1.33 (95% CI 1.11-1.61), 1.70 (95% CI 1.33-2.16), and 1.48 (95% CI 1.20-1.83), respectively. Stronger effect estimates between PM2.5, SO2, and O3 concentration on prehypertension were exhibited among subgroups of children with a higher intake of sugar-sweetened beverages.

Long-term exposure to PM2.5, SO2, and O3 were associated with higher blood pressure levels in children, and dietary intake might modify these associations.