Air Pollution Associated Hypertension and Increased Blood Pressure May Be Reduced by Breastfeeding in Chinese Children: The Seven Northeastern Cities Chinese Children's Study

Int J Cardiol. 2014 Oct 20;176(3):956-61. doi: 10.1016/j.ijcard.2014.08.099. Epub 2014 Aug 26.

Abstract

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 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 O3 (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 O3 (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 O3 (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.

Keywords: Air pollution; Blood pressure; Breastfeeding; Hypertension; Interaction effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Air Pollutants / analysis
  • Air Pollution / adverse effects*
  • Air Pollution / analysis
  • Blood Pressure
  • Body Height
  • Body Weight
  • Breast Feeding*
  • Carbon Monoxide / analysis
  • Child
  • Child, Preschool
  • China
  • Cities
  • Cross-Sectional Studies
  • Female
  • Humans
  • Hypertension / epidemiology*
  • Hypertension / prevention & control
  • Male
  • Nitrogen Dioxide / analysis
  • Ozone / analysis
  • Prevalence
  • Sulfur Dioxide / analysis

Substances

  • Air Pollutants
  • Sulfur Dioxide
  • Ozone
  • Carbon Monoxide
  • Nitrogen Dioxide