Anyone familiar with hay fever understands that the weather has an impact on respiratory symptoms. However, many of the effects of weather on respiratory function remain uncertain. One unanswered question is the extent to which storms affect people with chronic lung disease, particularly the type affecting the way air enters and leaves the lungs. These “obstructive lung diseases” are characterized by problems with narrowing of the airways. The most common obstructive pulmonary diseases are asthma and chronic obstructive pulmonary disease (COPD). The two main types of COPD are chronic bronchitis and emphysema.
Obstructive pulmonary disease affects about 10% of the American population and accounts for a disproportionate share of hospitalizations and deaths. Indeed, COPD is the fourth most common cause of death in American adults.
A study looked at the relationship between thunderstorms and COPD, asthma symptoms
In one recent article Posted in JAMA Internal Medicine, the researchers analyzed Medicare claims from 1999 to 2012 to determine whether storms led to an increase in emergency room visits related to respiratory illnesses in patients with obstructive pulmonary disease. The study included 46,581,214 patients over 65 years of age who had 22,118,934 emergency room visits due to respiratory problems. Obstructive pulmonary disease was a diagnosis in 43.6% of patients and included asthma (10.5%), COPD (26.5%) and combined asthma and COPD (6.6%).
The researchers used weather data from the United States’ National Oceanic and Atmospheric Administration (NOAA) to identify the dates of the thunderstorms. The NOAA database covers the continental United States and includes data specifically related to storms: wind speed, lightning, precipitation, and temperature. It also includes information on pollen and common air pollutants, including small particles (less than 10 millimeters in diameter), nitrogen dioxide, sulfur dioxide, ozone, and carbon monoxide.
The analysis showed that emergency room visits for people with obstructive pulmonary disease were more frequent during thunderstorms, especially the day before a thunderstorm. Interestingly, there was no difference between the different types of obstructive pulmonary disease. Compared to the usual number of emergency room visits, people with asthma experienced a 1.1% increase, while patients with COPD and combined COPD and asthma showed a 1.2% increase the day before the storm. The researchers calculated that for every million Medicare beneficiaries, there were between 22 and 34 additional emergency room visits for patients with obstructive pulmonary disease during the three days before and after the storms. This translated into 52,000 additional emergency room visits.
Why might symptoms get worse with stormy weather?
The authors looked for possible reasons why symptoms worsened in stormy weather. They found that a higher concentration of fine particles before storms correlated with an increase in emergency room visits. The levels of pollen and other air pollutants did not change until after the storms passed, making it less likely that these factors were responsible for an increase in respiratory symptoms.
These results differ from other reports examining the effects of storms on asthma and COPD, which found that the effects of drafts and rain on pollen could increase symptoms in patients whose lung disease is affected by allergies (which are for most asthmatics). Again other studies identified changes in sulfur dioxide as a major factor in the increase in COPD symptoms during storms. At this point, it is still unclear which of these possible factors has the greatest effect on the increase in respiratory symptoms.
This makes it very difficult to know how, or even if, patients could avoid lung disease problems during storms. However, since the authors identified increases in all groups of patients with obstructive pulmonary disease, it is reasonable for people with COPD, asthma, or COPD and asthma to know that their symptoms can flare up for as long as possible. the storms.
The study methods had advantages and limitations
Using the large Medicare database allowed these researchers to identify small, but potentially clinically important, effects that would be missed with smaller patient groups. The Medicare database also provided access to actual patient data.
However, this study had important limitations. The patients were all over 65 and may not be representative of most asthma patients, who are generally much younger. Additionally, the use of diagnoses identified by hospital bills did not allow researchers to study a uniform group of patients with a narrowly defined diagnosis. Having very different patients in the same diagnostic group would make it more difficult to clearly correlate specific factors with an increase in symptoms. In addition, this study did not examine whether patients with non-obstructive lung disease such as idiopathic pulmonary fibrosis and hypersensitivity pneumonitis were also affected by storms.
Climate change may portend more symptom flares in people with asthma and COPD
One of the effects of climate change is an increase in the number and severity of storms. As the climate changes, patients with lung disease are likely to have more frequent and severe worsening of symptoms requiring emergency room visits. This would increase both the burden of disease in these patients and the stress on our healthcare system.