People with celiac disease have higher rates of many other conditions, most of which don't involve their gastrointestinal tracts. For example, it's common to see thyroid disease and type 1 diabetes in people who also have celiac disease.

Asthma may represent another of these conditions that often appear in concert with celiac disease. The common respiratory ailment, which affects nearly 8 percent of the U.S. population, occurs more frequently in celiacs than it does in the general population.

This elevated risk of asthma may not be limited to diagnosed celiacs: there's some anecdotal evidence that asthma may represent one symptom of non-celiac gluten sensitivity. A few people I know have seen improvement in their asthma after adopting the gluten-free diet, even though they're not diagnosed celiacs. However, medical research has not yet borne out this possible link.

Finally, it's possible that someone who reacts with wheezing and difficulty breathing to wheat ingestion might have a wheat allergy, which is a completely different condition.

There's no evidence that celiac disease actually causes asthma. It's possible that nutritional deficiencies occurring due to celiac may help incite asthma, and it's also possible that common genetic or environmental factors may contribute to your risk for both asthma and celiac disease.

Allergies, Cigarette Smoke Raise Asthma Risk

Asthma, a chronic lung disease that makes it difficult for you to breathe, occurs in both adults and children. In fact, asthma is a leading cause of hospitalizations for children.

When you have asthma, your airways constrict, become inflamed, and sometimes clog with mucus, and the muscles you use to breathe tighten. As a result, you wheeze, cough, and feel as if you cannot take a deep breath.

There are several different types of asthma, including allergic asthma (i.e., asthma induced by allergies), exercise-induced asthma, asthma that occurs as a result of irritants in your workplace, and nocturnal asthma. If you have a family history that includes asthma, a personal history of allergies, or if you're exposed to cigarette smoke on a regular basis, you're at higher risk for asthma.

Celiac Disease Another Possible Risk for Asthma

You likely can add celiac disease to the list of conditions predisposing you to asthma: Several studies indicate a higher risk of asthma in people with celiac disease.

For example, researchers from Sweden performed a large study looking at more than 28,000 individuals with celiac disease — confirmed by biopsy — and more than 140,000 people in the general population over the course of nearly 40 years.

They found a 1.6-fold higher risk of asthma in people with celiac disease and noted that the risk remained five years after the person's celiac disease diagnosis. Even after the researchers adjusted for three known risk factors — smoking, high body mass index and being born via cesarean section — they still found that celiac disease raised people's risk of asthma.

People who had celiac disease also faced a 1.7-fold increased risk of allergic conjunctivitis, allergic rhinitis, and eczema.

Asthma was diagnosed slightly earlier in people with celiac disease, as well — at age 15, compared with age 16 in people without celiac, the study found.

Asthma, Autoimmune Conditions Linked

Two other studies have linked asthma with autoimmune diseases, including celiac disease.

One study looked at patients hospitalized for asthma and found they had a high risk of eventually being diagnosed with 11 autoimmune conditions, including celiac disease. Patients of all ages had a higher risk of the autoimmune conditions Addison's disease, which involves the adrenal glands, and Crohn's disease, which affects your intestinal tract. Children with asthma, meanwhile, had a higher risk of celiac disease and immune thrombocytopenic purpura, a bleeding disorder.

That study suggests asthma and autoimmune conditions such as celiac may share genetic roots or environmental triggers.

Meanwhile, a third study found a very high incidence of asthma — nearly 25 percent — in children with celiac disease. The study authors said there could be "a common environmental denominator behind the disease processes."

Will Asthma Clear Up Gluten-Free?

If you have asthma, can you expect it to improve or even clear up once you've been diagnosed with celiac disease and have begun to follow the gluten-free diet?

Unfortunately, there's no solid medical evidence indicating that your asthma will improve gluten-free. However, it's definitely possible — anecdotally, I've seen it happen several times.

One possible reason for an improvement in your asthma might be an improvement in your vitamin D levels.

Most celiacs are deficient in vitamin D at diagnosis, and many continue to be deficient well after diagnosis. Vitamin D deficiency has been linked to the development of asthma, although it's not clear if the deficiency actually causes asthma. Nonetheless, it's possible that if your vitamin D levels improve — either because your intestinal lining has healed and you're absorbing nutrients better, or because you're supplementing to reverse a deficiency — you may find that your asthma improves, as well.

Some of the studies involving celiac disease and asthma suggest that generalized inflammation — a result of the autoimmune process — also could contribute to asthma. Therefore, if you remain diligent on the gluten-free diet, you may see your asthma calm down, as well.