Obesity enhanced respiratory health effects of ambient air pollution in Chinese children: the Seven Northeastern Cities study

Abstract

OBJECTIVE: Experimental data suggest that obesity enhances the effects of ambient air pollutants on exacerbation of asthma; however, there is little supporting epidemiological evidence. The aim of present study is to evaluate whether obesity modifies the association between ambient air pollution and respiratory symptoms and asthma in children. METHODS: In Northeast China, 30 056 children aged 2-14 years were selected from 25 districts of seven cities. Parents of the children completed questionnaires that characterized the children's histories of respiratory symptoms and illness, and associated risk factors. Overweight and obesity were calculated with an age and sex-specific body mass index (BMI, kg m À 2 ), with BMIs of greater than the 85th and 95th percentiles defining overweight and obesity, respectively. Average annual ambient exposure to particulate matter with an aerodynamic diameter p10 mm (PM 10 ), sulfur dioxide (SO 2 ), nitrogen dioxides (NO 2 ) and ozone (O 3 ) was estimated from data collected at monitoring stations in each of the 25 study districts. RESULTS: We observed consistent and significant interactions between exposure and obesity on respiratory symptoms and asthma. The associations between each pollutant's yearly concentrations and respiratory symptoms and asthma were consistently larger for overweight/obese children than for normal-weight children, with odds ratios (ORs) ranging from 1.17 per 31 mg m À 3 for PM 10 on wheeze (95% confidence interval (CI): 1.01, 1.36) to 1.50 per 10 mg m À 3 for NO 2 on phlegm (95% CI: 1.21, 1.87) and cough (95% CI: 1.24, 1.81). CONCLUSION: These results showed that overweight/obesity enhanced respiratory health effects of air pollution in the study children.

Mechanisms of Asthma in Obesity. Pleiotropic Aspects of Obesity Produce Distinct Asthma Phenotypes

“…Obese people have increased airway reactivity and respiratory symptoms in response to ozone (71,72), and increases in IL-1b in induced sputum in response to ozone are directly correlated with BMI (73). Increased responses to ozone are also reported in different models of obese mice (19,74,75).…”

Abdominal adiposity intensifies the negative effects of ambient air pollution on lung function in Korean men

“…They reported significant interactions between a change in PM 10 concentration and BMI; after a decrease in PM 10 concentration, the annual rates of decline in lung function were smaller in the groups with low or normal BMI compared with those defined as obese according to BMI. Dong et al 13 found that the risks for asthma and respiratory symptoms including cough were greater in obese children than in normal weight children. In particular, the interaction effects with obesity on cough and phlegm were significant for NO 2 and PM 10 concentrations.…”

“…Although previous reports have shown significant synergistic effects of obesity and exposure to ambient air pollutants such as nitrogen dioxide (NO 2 ) and PM 10 content on lung function using an indirect measurement of obesity including body mass index (BMI), 6,13,14 accurate quantitative measurement of adipose tissue mass by computed tomography (CT) is needed to understand the plausible mechanisms between adipose tissue and air pollution in lung function. However, to our knowledge, no studies have investigated whether there is an additive effect of fat accumulation in adipose tissue on the relationship between ambient air pollution and lung function.…”

Sex-specific difference of the association between ambient air pollution and the prevalence of obesity in Chinese adults from a high pollution range area: 33 Communities Chinese Health Study

“…Thus, measured concentrations were more likely to reflect the background pollution level in a city rather than those from local sources. In line with prior research (Dong et al, 2013a(Dong et al, , 2013b, these measurements were used as proxies for long-term exposure for the participants. Measurements adhered closely to the methodological standards outlined by the State Environmental Protection Administration of China.…”

“…We have reported air pollution data collection elsewhere (Dong et al, 2013a(Dong et al, , 2013b. Briefly, during the investigation, each district had only one municipal air monitoring station.…”