Physical, Mental Toll of Wild Fires May Have Been Underestimated

By Linda Carroll

October 21, 2021

NEW YORK (Reuters Health) - Nearly all people surveyed during bushfires in Australia reported one or more physical symptoms that they attributed to smoke from the fires, a new study shows.

Online survey responses from 2,084 adult Australians during the 2019-20 bushfire season revealed that 97% reported at least one symptom tied to smoke, most commonly eye or throat irritation or cough, while more than 55% reported symptoms of anxiety or depression related to the smoke, researchers report in Frontiers in Public Health.

"Prolonged exposure to bushfire smoke itself - that is, not to the fires directly - had health effects for just about everyone in our study," said Dr. Ian Walker, a professor and director of the Research School of Psychology at Australian National University, in Canberra. "Those effects were on physical health and on mental health and wellbeing. They were worse for women than men, and worse for people who previously experienced bushfires."

"The effects are likely to fade with time, but are also likely to persist for some people," Dr. Walker told Reuters Health email. "Exposure to bushfire smoke has direct effects on health; it also has indirect effects through disruptions to sleep and exercise which in turn have their own negative effects on health."

"Climate scientists predict that bushfires are likely to become more frequent and more intense," he noted.

To take a closer look at the impact of wildfires, one that went beyond statistics based on admissions to the health system, Dr. Walker and his team asked survey respondents about their experiences from December 15, 2019, to February 15, 2020, when levels of bushfire-smoke air pollution affecting the Canberra region were highest.

They reached out to adult residents of the Australian Capital Territory (ACT) and immediately adjacent regions of New South Wales. They used three methods to recruit participants: invitation by letter, a representative population sample recruited by an external company and a convenience sample recruited via social media, radio ads and word of mouth. Each method yielded between 31% and 39% of the total sample.

The response rate for the mailed invitations was only 6%. Forty percent of the overall sample was male; the mean age of the volunteers was 45 years.

The most common symptoms reported were eye irritation or watery eyes (73%), throat irritation or dry throat (70%) and cough (51%). Many also reported headaches (38%), breathlessness (22%) sneezing (21%) or wheeze/whistling chest (20%).

Women had almost three times the odds of men of experiencing a greater number of physical health conditions as a result of smoke.

More than 55% of volunteers reported symptoms of anxiety (45%) and/or feeling depressed (21%) as a result of the smoke. Women were significantly more likely than men to report negative mental-health outcomes (odds ratio, 1.99). Half of the volunteers reported poorer sleep, defined as either disrupted or poor sleep (37%) and/or fatigue or feeling tired (33%).

About 17% of people said they had sought advice from a health professional or medical facility for their smoke-related symptoms.

"My primary advice for the average person would be to follow health advice about wearing protective masks, staying indoors, and using air filters, especially if they have any underlying or chronic health issues that might be exacerbated by the smoke," Dr. Walker said. "For situations likely to last several days, pay attention to alerts from health authorities or others about air quality (in Australia there are apps that report local air quality, updated hourly). Tend to others' needs. Be reassured that for most people, any health effects are likely to be short-lived."

Dr. Walker's advice for mental health clinicians is to "prepare for a surge in presentations, especially in people with heightened anxiety, but also in people experiencing distress because of changes to sleep patterns, inability to get to work or school, and changes to exercise and other physical routines.

The study "goes beyond the normal type of data that is usually collected around wildfire exposures," which is usually hospital data, said Dr. Cecelia Sorensen, an associate professor of environmental health sciences at Columbia University's Mailman School of Public Health and an associate professor of emergency medicine at the Columbia-Irving Medical Center, in New York City.

"Some people have no access to healthcare and some don't seek treatment. This is a slice of the experiences of people we don't normally see after a wild fire," Dr. Sorensen said.

"I am very concerned and a little surprised at how many people reported symptoms," she said. "It's really concerning that 97% reported symptoms. This is a public-health crisis that is not being addressed."

Moreover, Dr. Sorensen said, "we know that wildfire smoke is potentially more hazardous than normal PM pollution because it actually has a worse composition."

SOURCE: Frontiers in Public Health, online October 14, 2021.