Outdoor pollen exposure may make asthma attacks worse

Is pollen a risk factor? asthma Worse? In one study, the association between pollen sensitization and asthma suggests how precautions for asthma management should consider pollen exposure and climate change.

“To the best of our knowledge, this is the first systematic review and meta-analysis to comprehensively summarize the relationship between pollen exposure and asthma exacerbation, assessed through a range of respiratory outcomes,” said this study. Researcher writes.

The results of this systemic review are: allergy.

Pollen is a known risk factor for allergic rhinitis and was recently identified as a risk factor for asthma. However, few studies have evaluated the association between pollen exposure and asthma exacerbations. Furthermore, increased pollen concentrations due to climate change may contribute to exacerbation of allergic symptoms in patients with moderate to severe asthma.

In this study, 3244 records were identified from electronic databases, of which 270 full texts were evaluated and 73 studies were included in the final analysis. Studies used in the review shared the same study design, population, age range and lag (measured in days) between pollen assessment and asthma exacerbation.

Although meta-analyses could not be performed for all outcomes, the investigators investigated .grass pollen, tree pollen, cypress, and ragweed exposure.

Most of these studies reported a strong association between worsening asthma-related hospitalizations and increased pollen concentrations. Among children under 18 years of age, the strongest association was found between asthma attacks and asthma-related emergency department (ED) admissions or admissions and increased grass pollen concentrations in the previous 2 days.

An analysis of five studies observed a significant association between severe asthma exacerbations (odds ratio). [OR]1.00; 95% CI, 1.00-1.01) and increasing grass pollen concentration from 0 to 50 pollen grains/m³ Patients under the age of 18 have a time lag of 0-2 days.

In addition, two studies confirmed an association between asthma-related ED visits and tree pollen with a one-day delay. Additionally, with a delay of 2 days, one study reported a positive association of 100 grains/m2.³ Increase in individuals under 18 between lags 0 and 2. However, a second study, a case-crossover study, reported no associations. At 3 days and his 4 days lag, two studies reported a positive association, but it was not clear.

Although no meta-analysis was performed in these two studies, a positive association was found when tree pollen concentrations increased from 0 to 50 grains/m2.³ Between lags 0 and 2 (OR, 1.19; 95% CI, 1.17-1.21 and OR, 1.02; 95% CI, 0.99-1.04), respectively.Finally, when tree pollen concentrations increased above 50 grains/m³no association was observed in the meta-analysis (OR, 1.00, 95% CI, 0.99-1.02).

Although inconsistent, results suggest that tree pollen may increase asthma-related ED visits or delay hospitalization by up to 7 days overall in individuals under 18 years of age. doing.

Despite some unclear associations, researchers believe that outdoor pollen exposure may influence asthma attacks and asthma-related hospitalizations, although these potential effects are This association needs careful consideration, as more research is needed to determine.

“The current evidence suggesting an impact of pollen on asthma exacerbations prompts us to propose recommendations and precautions to protect individuals during pollen season,” the researchers concluded. Further research is urgently needed to assess whether they are effective.”

reference

Annesi-Maesano I, Cecchi L, Benedetta B, et al. Is pollen exposure a risk factor for moderate and severe asthma exacerbations? allergyMarch 2023 doi:10.1111/all.15724