April 27, 2000 -- If you have seasonal allergies or know someone who does, you know the misery associated with a high pollen count: sneezing, itchy eyes, and increased asthma problems. Even if you felt like dying, you probably wouldn't think of these pollen-heavy days as deadly.
Think again, say Dutch investigators who found more death due to heart disease and certain respiratory conditions on days with high pollen counts.
"Pollen is a well-known trigger of allergies, especially hay fever and asthma," the authors write. "However, deaths related to these conditions are extremely rare, and cannot account for the associations seen in this study." They likened the association to the one between air pollution and death, noting that a 5% to 10% increase in death is seen on high-pollution days. The new study was published in the journal The Lancet.
"The association is a bit like the link between [death] and very warm or very cold weather, which are also known to increase [death]," lead author Bert Brunekreef, PhD, tells WebMD. "Similar findings have been reported repeatedly for air pollution." Brunekreef is an epidemiologist in the Netherlands.
The authors looked for relationships between pollen counts and death due to heart disease, pneumonia, and chronic obstructive pulmonary disease (COPD), a chronic lung disease. They obtained statistics for the total number of daily deaths from the Netherlands' Central Bureau of Statistics over an eight-year period. The investigators then related these statistics to corresponding data for airborne pollen concentrations.
During this period, there was an average of more than 330 deaths per day. Of these, there was an average of about 140 deaths per day due to cardiovascular disease, 16 for COPD, and 10 for pneumonia.
When the researchers looked at the number and rate of deaths and the amount of Poacae, a common pollen found in the Netherlands, they found that the days with the highest pollen counts were associated with an increase of about 6% in death from heart disease, 15% in death from COPD, and 17% in death from pneumonia.
The authors write that, in other research, certain indicators of allergies are linked to increased death due to heart disease and COPD, and that their study seems to support pollen's contribution to the death rate. They caution, though, that their findings should be replicated in other studies before this link can be confirmed.
People with COPD should be less worried about the pollen outdoors than they are about the smoke indoors, according to a respiratory disease expert. "We have no proof that any of the people who died were allergic. The vast majority of patients with COPD, for example, do not have allergies," Eric Schenkel, MD, tells WebMD.
"There's no evidence whatsoever that inhalation of pollution causes cardiac problems, though." Schenkel is an allergist who focuses on COPD and is the director of Valley Clinical Research Center in Easton, Pa. He is also a clinical assistant professor of medicine at MCP/Hahnemann University School of Medicine in Philadelphia.
The study was funded by the Ministry of the Environment in the Netherlands.
- A new study shows that people are more likely to die from heart disease and certain respiratory conditions on days with high pollen counts.
- Pollen is known to trigger allergies, but deaths related to this are extremely rare and unable to account for the findings.
- Other studies have shown a similar increase in the death rate related to air pollution, very warm weather, and very cold weather.