Air pollution associated hypertension and increased blood pressure may be reduced by breastfeeding in Chinese children: The Seven Northeastern Cities Chinese Children's Study

Methods Nine thousand three hundred fifty-four Chinese children, ages 5-17 years old, from 24 elementary schools and 24 middle schools in the Seven Northeastern Cities during 2012-2013 were evaluated. The weight, height, and BP were measured. Four-year average concentrations of particles with an aerodynamic diameter of ≤10 μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxides (NO₂), ozone (O₃), and carbon monoxide (CO) were calculated from monitoring stations. Two-level regression analysis was used to examine the effects, controlling for covariates.

Results The results showed that associations existed between hypertension and pollutants. The odds ratios for hypertension ranged from 1.12 per 46.3 μg/m³ increase for O₂ (95% confidence interval [CI], 1.10-1.13) to 1.68 per 30.6 μg/m³ increase for PM₁₀ (95% CI, 1.53-1.86). The increases in mean diastolic BP ranged from 0.58 mm Hg per 46.3 μg/m³ increase for O₂ (95% CI, 0.52-0.63 mm Hg) to 2.89 mm Hg per 563.4 μg/m³ increase for CO (95% CI: 2.53-3.24 mm Hg). The increase in systolic BP ranged from 0.50 mm Hg per 46.3 μg/m³ increase for O₂ (95% CI: 0.43-0.57 mm Hg) to 2.10 mm Hg per 30.6 μg/m³ increase for PM₁₀ (95% CI, 1.73-2.47 mm Hg). Compared with children who had been breastfed, non-breastfed children exhibited consistently stronger effects. Conclusion Study findings indicate that high levels of PM₁₀, SO₂, NO₂, O₃, and CO are associated with increased arterial BP and hypertension among the children. Breastfeeding may reduce the risk.

Background Little is known about the association between air pollution and hypertension among children, and no studies report whether breastfeeding modifies this association in children.