Hot weather appears to be triggering more frequent hospital visits for children with asthma.

Symptoms of the lung condition, such as breathlessness and wheezing, are more commonly associated with cold weather. To better understand the impact of hot temperatures, at the University of California, San Francisco (UCSF), and her colleagues studied electronic health data from UCSF Benioff Children’s Hospitals.

The data included records on asthma hospitalisations and the patients’ addresses. The researchers used information from PRISM Climate Group at Oregon State University to obtain temperature records at the patients’ homes every day from June to September between 2017 and 2020.

The researchers defined heatwaves in 18 different ways. By looking at the range of temperatures that occurred over these periods, they considered it a heatwave if it fell in the top 1 per cent of these temperatures, or the top 2.5 per cent, or the top 5 per cent, and so on.

Presenting their results at the American Thoracic Society conference in San Diego, California, this week, the researchers found that across all of the heatwave definitions, these temperatures were associated with 19 per cent higher odds, on average, of a child with asthma being admitted to hospital, compared with when there wasn’t a heatwave.

While further research is required, hot weather can contribute to smog and ozone pollution, which may inflame or irritate the airways, says Ye.

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“As we continue to see global temperatures rise due to human-generated climate change, we can expect a rise in health-related issues as we observe longer, more frequent and severe heatwaves,” she says.

Children are particularly vulnerable to extreme heat, says at the UCSF’s Western States Pediatric Environmental Health Specialty Unit. Speaking of the researchers’ approach to defining heatwaves, she says: “The fact that their results were robust to different definitions of extreme heat is powerful.”

Treating gum disease after a procedure to correct an irregular and abnormally fast heart rate may lower the risk of the cardiac condition reoccurring.

The disorder, known as atrial fibrillation, involves an irregular heartbeat and can increase the risk of stroke and even heart failure. In advanced cases, it can be treated via catheter ablation, a procedure that very carefully destroys a damaged area of the heart that is interrupting its electrical circuits.

Now, at Hiroshima University in Japan and his colleagues have shown that gum disease may be a risk factor for atrial fibrillation.

The team enrolled 288 people who all had gum disease and underwent ablation to treat atrial fibrillation. Of these, 97 received treatment for their gum disease up to three months later.

In a follow-up period lasting up to two years, 24 per cent of the participants experienced atrial fibrillation again, but this was 61 per cent less likely to occur among those whose gum disease was treated after ablation.

The risk of developing atrial fibrillation again was higher if the person’s gum disease was more severe.

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If gum tissue is inflamed or even ulcerated, bacteria and inflammatory immune proteins can enter the bloodstream, which may affect the heart, says Miyauchi.

The researchers also measured levels of inflammatory proteins in the participants’ blood before they underwent ablation, finding that these were elevated in those with severe gum disease. Higher levels of antibodies for gum disease-related bacteria were also linked to greater atrial fibrillation reoccurrence, says Miyauchi.

The team encourages people with atrial fibrillation to seek treatment for gum disease if necessary. It can be prevented by brushing with a fluoride toothpaste at least twice a day, flossing or using interdental sticks every day and regularly seeing a dentist.

at NYU Grossman School of Medicine in New York points out that the study was relatively small, with just 97 participants receiving treatment for gum disease. “Although many attempts have been made to show the link between gum disease and heart disease, this study does not show a definitive link between atrial fibrillation recurrence.” Nevertheless, “it does set the groundwork for future studies in this area”.