I used to think asthma was a condition you either had or didn’t, and that it was typically diagnosed in childhood.

That changed when I was diagnosed with asthma in my 50s.

I’m not alone. In the United States, 21 million adults (8.4 percent of adults) have asthma, compared with 4.2 million children (5.8 percent). More than half of U.S. women over age 40 with asthma were diagnosed as adults.

Asthma can range from being a hassle to life-threatening — it causes one’s airways to constrict and can make breathing uncomfortable, laborious and sometimes impossible.

Experts are still trying to pin down why there are so many cases of adult-onset asthma today.

Hormones, gender, puberty

Rates of asthma increased steeply from the 1960s to the turn of the 21st century, perhaps thanks to greater awareness and recognition of the condition. The rise slowed in the early 2000s, and prevalence has been steady or decreasing slightly since then, which may reflect better treatments for controlling asthma.

While what causes asthma — in childhood or adulthood — remains murky, research indicates that a family history of the condition, allergies, environmental factors and childhood respiratory infections put people at higher risk for it. Doctors also have identified characteristics of the disease based on the person’s age when breathing troubles begin.

“In children, asthma tends to be more benign,” says Sally Wenzel, a pulmonologist and the Rachel Carson chair in Environmental Health at the University of Pittsburgh. “In adults, it’s more unpredictable.”

The albuterol shortage is about to get worse

There are other key contrasts.

Before puberty, asthma affects more boys than girls; in adulthood, the gender disparity is flipped, and more women have asthma than men.

A majority of children’s asthma cases are related to allergies, but a minority of adult-onset cases have that link. There are theories about these differences, such as the potential role of hormones in the gender switch after puberty, but much is still unknown.

Race, climate change risks

Race also plays a role. Black Americans, Puerto Ricans (but not other Hispanic groups) and Native Americans/Alaska Natives have the highest rates of asthma, and Black Americans die of the condition in disproportionate numbers, according to the Office of Minority Health in the Department of Health and Human Services.

Six things you should know about asthma

The reasons are as complex as the disease itself. Officials of the Asthma and Allergy Foundation of America say environmental inequities, such as those involving air pollution and housing, and health-care disparities play a greater role than genetics in the differences.

Aspects of climate change have also contributed to increased plant allergens. Greater frequency and intensity of thunderstorms — another consequence of climate change — have also been linked to the rise of thunderstorm asthma triggered by atmospheric pressure changes and storms lifting allergens into the air. After a thunderstorm event in Melbourne, Australia, in 2016, for example, experts estimated that at least 9,000 more people sought medical attention for asthma than usual over three days.

Managing symptoms, avoiding misdiagnosis

What experts do know is that getting appropriate treatment when breathing troubles begin — at any age — is crucial.

The strategies to manage asthma include avoiding triggers — whether those are allergens, cold air, exercise or respiratory viruses — and using medications, which fall into two general categories.

Treatments that turn down the volume on airway hypersensitivity include corticosteroid inhalers (including Alvesco, Pulmicort and Flovent) and pills (such as Singulair), all of which target inflammatory mediators. The second category includes rescue inhalers (such as Proventil, Ventolin and ProAir) that can interrupt an asthma attack in progress.

Shawn Aaron, a respirologist at the Ottawa Hospital Research Institute, noticed that many patients who had been referred to him weren’t responding to treatment, which led him to wonder whether their diagnoses were correct.

“There are so many conditions that can mimic asthma — anything that results in shortness of breath, coughing and wheeze,” Aaron says.

He designed a study to reassess the status of 613 adults who were diagnosed with asthma by a physician in the previous five years. He used the gold-standard lung function test, called spirometry, and found that 1 in 3 study subjects did not meet the diagnostic criteria for asthma. “And 50 percent of them never had lung function tests,” he adds.

Spirometry measures how much air you forcibly exhale after a deep breath. For asthma assessment, you do the test twice, the second time after using an inhaler that delivers bronchodilator medicine to open up the airways.

“That’s the problem in asthma — you can breathe in, but not out,” says Wenzel, calling it “air trapping.” If a patient improves their exhalation after the bronchodilator, “then it’s asthma,” she says. “The hallmark criterion is an obstruction when blowing out air.”

General practitioners often make the diagnosis based on symptoms alone, Aaron says. Spirometry is not complicated. “It’s easy, cheap and takes 15 [to] 30 minutes,” he adds — but it is not done by many labs and may be harder to access than other lab-based tests such as blood draws.

The subjects in Aaron’s study who were recategorized as not having asthma were subsequently diagnosed with other conditions that affected their breathing, including allergies, reflux, anxiety or chronic obstructive pulmonary disorder. Twelve patients had serious cardiorespiratory conditions that had been misdiagnosed as asthma.

Misdiagnosis is a common problem, one that doctors are working to address with more objective measures, such as spirometry, and careful ruling out of other contributing factors or conditions.

Aaron’s study also found that some people who had been diagnosed appropriately — that is, with spirometry — no longer had asthma. Their condition had remitted.

Remission is less likely to occur in adults than in children, but that doesn’t mean it never happens. Treatment guidelines suggest tapering asthma medications in people who have had good control for at least three months because the condition can wax and wane.

Allergies, pneumonia, other triggers

A 2011 study found that many asthma cases were associated with a recent respiratory infection. Adults with newly diagnosed asthma were roughly seven times more likely than those without a diagnosis to have had an infection of their lower airways — bronchitis or pneumonia — in the previous year, and roughly twice as likely to have had an upper respiratory illness such as a cold or sinus infection.

A more recent study evaluated preceding health events in 200 adults with newly diagnosed asthma. New allergies were identified in 11 percent of participants, pneumonia in 8 percent and upper respiratory symptoms in 22 percent.

This explains my situation. Several months after recovering from pneumonia, I would still have bouts of rather disturbing shortness of breath. I followed up with a pulmonologist and was diagnosed with asthma.

Researchers speculate that respiratory infections may cause lingering damage to airways or trigger hypersensitive immune and inflammatory processes, although — as with so many aspects of asthma — those hypotheses await further evidence and understanding.

Source link