Asthma is a chronic inflammatory disorder affecting millions of people worldwide. Around 300 million people suffer from asthma throughout the world.

Obesity is another health condition that has gained epidemic proportion worldwide. A person is said to be obese when his body mass index (BMI) is between 25 to 30 kg/m2. According to the WHO statistics, more than 1 billion adults are overweight. Of these, at least 200 million men and nearly 300 million women are obese.

Studies have increasingly confirmed a modern link between obesity and asthma. Obesity and breathing problems coexist in both obese adults and children.

Obesity not only causes asthma but also worsens the asthma symptoms and makes management difficult. This leads to the use of more medications and even more hospitalization among the obese.


Doctors often find that the overweight or obese people complain of asthma more often than normal weighing people do, after taking into consideration lifestyle habits such as and physical activity. Wheezing is a common complaint among obese people.

Seven percent of adults with normal BMI suffer from asthma while 11 percent of adults with an obese BMI have asthma. Among the female gender, about 15 percent of women who are obese suffer from asthma.

Obese adults with asthma are nearly five times more likely to be hospitalized for asthma symptoms than non-obese asthmatics.

Even among teenagers and children, asthma is more prevalent among the overweight and obese. They are twice more likely to suffer from asthma than normal weighing children. Roughly, 21 percent of American children between the ages of 12 and 19 years old are obese.

In obese people, the symptoms are more severe and they are more difficult to manage. Hospitalization is also more common among the obese.

Obesity and asthma link: Possible pathophysiology

Obesity does make it hard for the obese to breathe easily. The risk of asthma is more than tripled in obese people as compared to people with normal weight.

The reason for obesity and the asthma link is not yet certain but some experts suggest low-grade inflammation associated with obesity as the reason while others suggest insulin resistance as the cause. As you know, bronchial asthma is a chronic inflammatory condition of the airways.

Secondly, fat poses a load on the respiratory organs as the excess fat in the chest wall presses on the lungs restricting their expansion during breathing. As a result, obese people are shallow breathers, which leads to bronchial asthma. It is called respiratory laziness.

Besides bronchial asthma, other lung complications of obesity include bronchitis, obesity hypoventilation syndrome ( a condition in which poor breathing leads to low oxygen and high carbon dioxide levels in the blood) and respiratory insufficiency.

Again, obesity is associated with other health problems such as depression and sleep apnea. People suffering from these conditions have more severe asthma symptoms than people without these comorbidities.

In a Norwegian study, 135,000 men and women were studied with regards to the obesity and asthma prevalence. It was found that with every single unit increase in BMI, the risk of bronchial asthma increased by 10% in men. In women, the risk increased by 7 %.

According to American Lung Association Airways Clinical Research Centers Network (ACRC),  people with asthma and a BMI over 30 do not respond to medications in the way people with a lower BMI do.

Obesity and asthma: the role of environmental pollutants

Environmental pollution is a known risk factor for causing lung problems such as bronchial asthma. There is growing evidence now, which suggests that environmental pollution can also contribute to the development of obesity.

According to a study conducted by the American Diabetes Association, exposure to high levels of persistent organic pollutants (POP) may exert an obesogenic effect.

While it is important to consider other critical factors such as smoking and allergies, losing weight brings about a considerable improvement in the overall picture.