Asthma Morbidity, Mortality Linked to Extreme Weather Events, Study Finds

The effects of extreme weather events have been linked to increased asthma morbidity and mortality, especially among women and children. This adds context to the severity of climate change as a critical concern for managing and controlling asthma.

“The novelty of this study is that we investigated the effects of extreme weather events on asthma-related outcomes,” wrote the researchers of the study. “Our results suggest that climate change and extreme weather events could increase the risk of asthma morbidity and mortality.”

The full findings from this systemic review and meta-analysis are published in European Respiratory Review.

Climate change’s impact on the frequency and intensity of extreme weather events is known to pose a threat to respiratory health, including asthma which is the most common chronic and lung disease in children and adolescents. In the current study, the researchers aimed to evaluate the associations between extreme weather events and asthma-related outcomes.

Using the PubMed, EMBASE, Web of Science, and ProQuest databases, the researchers gathered studies that identified a connection between extreme weather events and the following asthma-related outcomes: hospital admission, ED visits, outpatient visits, asthma mortality, asthma symptoms, and asthma diagnoses up to October 20, 2022.

The extreme weather events identified included: floods, hurricanes, dust storms, cold spells, blizzards, ice storms, thunderstorms, typhoons, and heat waves.

The main outcome was a diagnosis of asthma as defined by the International Classification of Diseases or national/local definitions.

The researchers defined asthma events as a worsening of asthma which required an unexpected hospital visit, ED visit, hospitalization, or occurrence of asthma symptoms. Additionally, subgroup analyses were performed for gender, age, region, and type of extreme weather event.

A total of 6910 studies were identified, in which 165 full-text studies were eligible for evaluation. Furthermore, 31 of these studies were included in the study analyses.

The results of the study showed that extreme weather events were associated with an increasing risk of general asthma outcomes, with a 1.18-fold relative risk for asthma events (95% CI, 1.13-1.24), 1.10-fold for asthma symptoms (95% CI, 1.03-1.18), and 1.09-fold for asthma diagnoses (95% CI, 1.00-1.19).

Furthermore, extreme weather events were associated with an increased risk for acute asthma exacerbations:

• Emergency department visits (1.25-fold; 95% CI, 1.14-1.37)
• Hospital admissions (1.1-fold; 95% CI, 1.04-1.17)
• Outpatient visits (1.19-fold; 95% CI, 1.06-1.34)
• Mortality (2.10-fold; 95% CI, 1.35-3.27)

Lastly, extreme weather events were found to increase the risk of asthma events in females 1.29-fold (95% CI, 0.98-1.69) and children (1.19-fold; 95% CI, 1.08-1.32), respectively, with thunderstorms increasing the risk by 1.24-fold (95% CI, 1.13-1.36).

However, the researchers acknowledge there were some limitations to their study. First, due to a lack of specific data, not all asthma-related outcomes were evaluated in the analyses. Furthermore, most of the exposure assessments were recorded using meteorological station or remote sensing data, resulting in incomplete exposure information.

Despite limitations, the researchers believe that the results of this study suggest how increasing extreme weather events as a repercussion of climate change poses a serious threat to asthma morbidity and mortality, especially among women and children.

“In conclusion, exposure to extreme weather events was associated with asthma morbidity and mortality,” wrote the researchers. “Our findings suggested that patients with asthma may be more susceptible to poorer outcomes in extreme weather events.”

Results

Makrufardi F, Manullang A, Rusmawatiningtyas D, Chung KF, Lin SC, Chuang HC. Extreme weather and asthma: a systematic review and meta-analysis. Eur Respir Rev. 2023;32(168):230019. doi:10.1183/16000617.0019-2023