Background

Sparse data address the effects of nitrogen dioxide (NO₂) exposure in inner-city schools on obese students with asthma.

Objective

We sought to evaluate relationships between classroom NO₂ exposure and asthma symptoms and morbidity by body mass index (BMI) category.

Methods

The School Inner-City Asthma Study enrolled students aged 4 to 13 years with asthma from 37 inner-city schools. Students had baseline determination of BMI percentile. Asthma symptoms, morbidity, pulmonary inflammation, and lung function were monitored throughout the subsequent academic year. Classroom NO₂ data, linked to enrolled students, were collected twice per year. We determined the relationship between classroom NO₂ levels and asthma outcomes by BMI stratification.

Results

A total of 271 predominantly black (35%) or Hispanic students (35%) were included in analyses. Fifty percent were normal weight (5-84th BMI percentile), 15% overweight (≥85-94th BMI percentile), and 35% obese (≥95th BMI percentile). For each 10-parts per billion increase in NO₂, obese students had a significant increase in the odds of having an asthma symptom day (odds ratio [OR], 1.86; 95% CI, 1.15-3.02) and in days caregiver changed plans (OR, 4.24; 95% CI, 2.33-7.70), which was significantly different than normal weight students who exhibited no relationship between NO₂ exposure and symptom days (OR, 0.90; 95% CI, 0.57-1.42; pairwise interaction P = .03) and change in caregiver plans (OR, 1.37; 95% CI, 0.67-2.82; pairwise interaction P = .02). Relationships between NO₂ levels and lung function and fractional exhaled nitric oxide did not differ by BMI category. If we applied a conservative Holm-Bonferroni correction for 16 comparisons (obese vs normal weight and overweight vs normal weight for 8 outcomes), these findings would not meet statistical significance (all P > .003).

Conclusions

Obese BMI status appears to increase susceptibility to classroom NO₂ exposure effects on asthma symptoms in inner-city children. Environmental interventions targeting indoor school NO₂ levels may improve asthma health for obese children. Although our findings would not remain statistically significant after adjustment for multiple comparisons, the large effect sizes warrant future study of the interaction of obesity and pollution in pediatric asthma.

中文翻译：

---

肥胖可能会加剧城市学校中 NO2 暴露对儿童哮喘症状的不利影响。

背景

稀疏数据解决了市中心学校中二氧化氮 (NO ₂ ) 暴露对患有哮喘的肥胖学生的影响。

客观的

我们试图通过体重指数 (BMI) 类别评估课堂 NO ₂暴露与哮喘症状和发病率之间的关系。

方法

学校内城哮喘研究招募了来自 37 所内城学校的 4 至 13 岁哮喘学生。学生有基线确定的 BMI 百分位数。在随后的学年中监测哮喘症状、发病率、肺部炎症和肺功能。与注册学生相关的第₂课堂数据每年收集两次。我们通过 BMI 分层确定课堂 NO ₂水平与哮喘结果之间的关系。

结果

共有 271 名主要是黑人 (35%) 或西班牙裔学生 (35%) 被纳入分析。50% 为正常体重（第 5-84 BMI 百分位数），15% 超重（≥ 85-94th BMI 百分位数）和 35% 肥胖（≥ 95th BMI 百分位数）。NO ₂每增加十亿分之一，肥胖学生出现哮喘症状日的几率显着增加（比值比 [OR]，1.86；95% CI，1.15-3.02），并且照顾者改变计划的天数(OR, 4.24; 95% CI, 2.33-7.70)，这与正常体重学生显着不同，他们在 NO ₂暴露与症状天数之间没有关系（OR，0.90；95% CI，0.57-1.42；成对相互作用P  = .03) 和照料者计划的变化（OR，1.37；95% CI，0.67-2.82；成对交互P = .02）。NO ₂水平与肺功能和呼出气一氧化氮分数之间的关系没有因 BMI 类别而异。如果我们对 16 项比较（8 项结果的肥胖与正常体重和超重与正常体重）应用保守的 Holm-Bonferroni 校正，这些结果将不具有统计学意义（所有P  > .003）。

结论

肥胖的 BMI 状态似乎会增加课堂 NO ₂暴露对市中心儿童哮喘症状的敏感性。针对室内学校 NO ₂水平的环境干预可能会改善肥胖儿童的哮喘健康。尽管我们的研究结果在对多重比较进行调整后不会保持统计显着性，但较大的效应量值得未来对儿童哮喘中肥胖和污染的相互作用进行研究。