Some 24 million Americans now suffer from asthma, a chronic lung disease that inflames and narrows the airways. When exposed to a trigger like pollen, pet dander, cigarette smoke, or exercise, these passages constrict even more or fill up with mucus, severely hindering breathing. This often causes wheezing, panting, coughing, or burning chest followed by dizziness and full-body exhaustion. But even though we understand more about asthma and its causes than we did 20 years ago, many mysteries remain.
“We know more about risk factors associated with asthma, but we don’t have the complete story on why one person gets it and another doesn’t,” says Doug Brugge, professor of public health and community medicine at Tufts University School of Medicine. “We know there are environmental exposures like tobacco smoke and air pollution. We know asthma runs in families, so genetics play a role. But there’s still much more to be learned.”
What has become evident in recent years is that asthma likely isn’t a single disease. Rather, it’s a cluster of conditions, which could explain why it comes on for most people during childhood but not until adulthood for others — and why different triggers exacerbate asthma in different people. It’s also clear that asthma rates have been increasing sharply since the early 1980s. Nobody knows exactly why, but there are several solid theories. Our soaring obesity rate may have something to do with it. Asthma is much more common among people with body-mass indexes of 30 or up, and 36 percent of Americans now fit that bill.
Also, allergies, a frequent asthma trigger, have become much more widespread in the last 30 years. “Asthma is increasing right alongside with allergies, although not quite as dramatically since not all cases are related to allergies,” says Dr. Sally Wenzel, director of the University of Pittsburgh Asthma Institute. “There are also environmental exposures we don’t fully understand yet. But we do know that if you’re exposed to industrial chemicals or hairspray on a regular basis, you’re more likely to have respiratory problems.”
There’s also the hygiene hypothesis — the idea that today’s sanitary environment cheats our immune system out of developing defenses against viruses and pathogens. “In my opinion, one of the biggest possible drivers of asthma rates may be how our immune systems develop in utero and as young children,” Brugge says. “Our microbiome used to be exposed to a more natural environment in which it encountered more biological agents. That allowed the immune system to develop in a way that was protective against developing asthma.” However, other experts dismiss the hygiene hypothesis, since rates are also increasing in less-than-sanitary urban conditions and developing nations.
Brugge suspects Americans’ low vitamin D levels may also play a role in asthma’s uptick. “The populations with low prevalence of asthma and poor sanitary conditions also tend to get more sunlight exposure,” he says. “They live closer to the equator and wear less clothing. The hygiene and vitamin D theories are not mutually exclusive, but it’s not unreasonable to think something may be going on here.”
Although there are more legitimate asthma cases today, this condition is also wildly misdiagnosed. “More doctors are diagnosing based on clinical symptoms instead of actually conducting a breath test,” Wenzel says. “Doctors have less time with patients than they used to, and since they don’t want to miss asthma, many people are being misdiagnosed.” A recent study in JAMA found that one third of adults diagnosed with asthma probably didn’t have it.
A misdiagnosis can be quite problematic. For one, you might start avoiding exercise or staying indoors unnecessarily in an attempt to thwart attacks. “Additionally, when people who don’t have asthma are treated with medication, they obviously won’t respond to the drugs,” Wenzel says. “Then treatment is often increased, and they get more and more side effects without any benefit.”
On the flip side, many people who do have asthma don’t bother seeking a diagnosis or treatment. “Since asthma is so common, it’s often viewed as no big deal, a simple disease, not very scary,” says Wenzel. "One of my pet peeves is how asthma is portrayed in movies and on TV. It’s always a whiny kid or nerdy adult who has to puff on an inhaler whenever they get anxious. That’s sending a terrible message. People don’t seek help or they get embarrassed to use their inhalers.”
But undetected or unmanaged asthma can cause permanent lung damage — or worse. “You can die,” says Wenzel. “Between 3,000 and 4,000 people die of asthma each year, most of whom didn’t realize they had it.”
If you suspect you have asthma, see your doctor immediately and insist on a breathing test. “Many primary care doctors have a spirometer in their office, although it may be collecting dust,” Wenzel says. “A spirometry test should be conducted before and after you take a few puffs of albuterol. Generally, an asthma diagnosis means your breathing got better after taking albuterol.” She says some general practitioners aren’t well-versed in asthma, and you may need to see a specialist — but if you’re having problems, don’t wait. Starting with a GP is fine.
Once you’ve been diagnosed, “understand your asthma — when it’s bad and not so bad — and be prepared with the appropriate medications,” Brugge says. “I’ve lived in the same place for a long time, so I know exactly what allergies to expect in early spring, and I know I’ll begin having asthma symptoms by late May. Identify your triggers, whether dust mites, pollen, cats, or cigarette smoke, and do your best to avoid them.”