Blood Pressure Responses to Air Pollution in Chinese Children: Effect Modification by Obesity

Abstract

PURPOSE: To assess effect modification by obesity on the association between pollutants and blood pressure (BP) in Chinese children. METHODS: We investigated 26,039 Chinese children, aged 6-18 years old, from 50 elementary schools and 44 middle schools from seven provinces in China in 2014. The weight, height, waist circumferences, and BP were measured. Total seven and half months concentrations of particulates with an aerodynamic diameter < 2.5 and ≤10 μm (PM2.5 and PM10), ozone (O3) sulfur dioxide (SO2), nitrogen dioxides (NO2), and carbon monoxide (CO) were assessed based on the measurement from national monitoring stations and the personal short-term inhalation rate. Two-level regression analysis was used to examine the effects, controlling for sex, age, early life factors, physical activity, screen time, socioeconomic status, passive smoking exposure, and family history of hypertension. RESULTS: The results showed that associations existed between elevated BP and pollutants. The increase in systolic BP ranged from 0.21 mmHg per 62.2 mg/m3 increase for CO (95%CI: 0.03-0.40 mmHg) to 1.49 mmHg per 1320.4 μg/m3 increase for PM10 (95%CI: 1.21-1.86 mmHg). The increases in mean diastolic BP ranged from 0.42 mmHg per 368.6 μg/m3 increase for NO2 (95%CI: 0.22-0.62 mmHg) to 0.82 mmHg per 1320.4 μg/m3 increase for PM10 (95%CI: 0.54-1.10 mmHg). Compared to children with normal weight or non-abdominal obesity, underweight, overweight, obese, or abdominally obese children exhibited consistently stronger effects. CONCLUSIONS: Study findings indicate that high levels of PM2.5, PM10, SO2, NO2, O3, and CO are associated with increased BP among Chinese children. Underweight, overweight, obesity, and abdominal obesity may increase the risk.