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

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. 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 mu m(PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), ozone (O-3), 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 mu g/m(3) increase for O-3 (95% confidence interval [CI], 1.10-1.13) to 1.68 per 30.6 mu g/m(3) increase for PM10 (95% CI, 1.53-1.86). The increases in mean diastolic BP ranged from 0.58 mm Hg per 46.3 mu g/m(3) increase for O-3 (95% CI, 0.52-0.63 mm Hg) to 2.89 mm Hg per 563.4 mu g/m(3) 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 mu g/m(3) increase for O-3 (95% CI: 0.43-0.57mm Hg) to 2.10mm Hg per 30.6 mu g/m(3) increase for PM10 (95% CI, 1.73-2.47mm 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, O-3, and CO are associated with increased arterial BP and hypertension among the children. Breastfeeding may reduce the risk. (C) 2014 Elsevier Ireland Ltd. All rights reserved.