January 09, 2024
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Key takeaways:
- A higher 7-day moving average for precipitation resulted in greater fractional exhaled nitric oxide.
- Adolescents with vs. without asthma had more airway inflammation with increases in average rain/snowfall.
Among adolescents, increases in average rain or snowfall over a week resulted in heightened fractional exhaled nitric oxide, signaling airway inflammation, according to results published in Annals of the American Thoracic Society.
Among adolescents, increases in average rain or snowfall over a week resulted in heightened fractional exhaled nitric oxide, signaling airway inflammation, according to results published in Annals of the American Thoracic Society. Image: Adobe Stock
Nassikas and colleagues analyzed 1,019 (mean age, 13.2 years; 49.7% girls; 64.4% white) early adolescents from the northeast U.S. in a prospective prebirth cohort study to find out if 1-, 2-, 3- and 7-day moving averages of precipitation the week before an assessment impacted lung function or airway inflammation, measured by fractional exhaled nitric oxide (FeNO). They also tested to see if asthma changed these findings.
Researchers looked for links between the two factors through linear regression models that accounted for sex, race/ethnicity, diagnosis of ever asthma, age, height, weight, maternal education and household income, prevalence of household smoking, date, season and moving averages for mean daily temperature.
Primary finding
During the time span before the assessment, researchers observed a median daily precipitation of 2 mm.
For all precipitation moving averages, researchers did not find any significant links between these averages and measures of lung function (FEV1 and FVC). In contrast, FeNO went up by 2.1% (95% CI, 0.2%-4%) when the 3-day moving precipitation average increased by 2 mm per day and by 4% (95% CI, 1.1%-6.9%) when the 7-day moving average was heightened by 2 mm per day.
Additional adjustment for air pollutants and relative humidity did not change this finding, according to researchers.
Secondary findings
Among those with an asthma diagnosis (26.1%), researchers found that each 2 mm increase in average 3-day moving precipitation resulted in a greater percentage of FeNO than those without an asthma diagnosis (5.8%; 95% CI, 1.8%-9.9% vs. 1%; 95% CI, –1.2% to 3.2%; P = .04).
In terms of lung function, adolescents with vs. without asthma had poorer FEV1 with every 2 mm per day increase in 2-day (–12.2 mL; 95% CI, –29.4 to 4.9 vs. 8.4 mL; 95% CI, –1.8 to 18.6; P = .04) and 3-day (–13 mL; 95% CI, –33.5 to 7.5 vs. 8.8 mL; 95% CI, –2.7 to 20.2) moving precipitation averages.
Researchers observed comparable findings when evaluating FVC, with asthmatics having decreased FVC with every 2 mm per day rise in 1-day (–15.6 mL; 95% CI, –28.1 to –3.1 vs. 7.2 mL; 95% CI, –0.7 to 15.1; P < .01), 2-day (–16.2 mL; 95% CI, –34.3 to 1.9 vs. 9.7 mL; 95% CI, –1.1 to 20.5; P = .02) and 3-day (–16.6 mL; 95% CI, –38.3 to 5 vs. 8.2 mL; 95% CI, –4 to 20.3) precipitation moving averages compared with those without asthma.
Aeroallergen sensitization (immunoglobulin E [IgE] > 0.35 IU/mL) was found in 58% of those who had this measurement (n = 638). Notably, those with vs. without outdoor aeroallergen sensitization (IgE against common ragweed, oak, ryegrass or silver birch) had a greater percentage of FeNO when the 3-day precipitation moving average was heightened by 2 mm per day (5.1%; 95% CI, 0.9-9.5 vs. 0.7%; 95% CI, –1.9 to 3.4).
Researchers also observed that girls had higher FeNO (6.9%; 95% CI, 2.7-11.3) with every 2 mm per day rise in the 7-day moving average of precipitation vs. boys (1.4%; 95% CI, –2.5 to 5.3).
“In the Northeast, increases in annual total precipitation and extreme precipitation events are expected in the future as a result of climate change,” Nassikas and colleagues wrote. “Determining if differences in exposure to precipitation are associated with acute changes in lung function and airway inflammation, especially in higher-risk groups such as asthma, will inform public health measures and may provide valuable information for counseling families about the risks of environmental exposures.”
Implications
Reference:
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Disclosures:
Nassikas reports receiving the following grants: UG3OD02328, P30-ES000002, R01HD023286 and Harvard-NIEHS Center/NIH grant P30ES000002. He also reports receiving consulting fees from Industrial Economics Inc. (subcontract from U.S. Environmental Protection Agency), receiving honorarium from Columbia University and being a co-chair of an American Thoracic Society sponsored workshop with funding from Rocky Mountain Institute. Please see the study for all other authors’ relevant financial disclosures. Pavelack reports receiving an NIH training grant and an NYU pilot grant. McCormack reports receiving funding from the NIH; consulting fees from Aridis, Boehringer Ingelheim, GlaxoSmithKline, MCG Diagnostics and NDD Medical Technologies; authorship and editorial work for pulmonary function testing from UpToDate; and payment from Talem Health for medical education for asthma and COPD.
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