March 21, 2011 -- Asthma may increase your risk of developing diabetes and heart disease, shows new research presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology in San Francisco.
The common denominator between these conditions appears to be inflammation, according to researchers led by Young J. Juhn, MD, MPH, of the Mayo Clinic in Rochester, Minn.
Juhn and colleagues followed 2,392 people with asthma and 4,784 people without asthma from 1964 to 1983. People with asthma were at higher risk for developing diabetes and heart disease, but not inflammatory bowel disease or rheumatoid arthritis, the study showed.
Specifically, the diabetes rate in people without asthma was 104 per 100,000 people compared to 138.4 per 100,000 people among those with asthma. For heart disease, the rate in people without asthma was 134 per 100,000 people vs. 188.6 per 100,000 among those participants with asthma.
“While it’s important for clinicians to be aware of the increased risks of coronary artery disease and diabetes in asthmatics, these findings should be interpreted cautiously given the preliminary nature,” Juhn says in a news release. “Given the significant proportion of people affected by asthma, we need to continue to carefully monitor the potential impact of asthma epidemiology on the epidemiology of other chronic diseases.”
The Role of Inflammation
“There is an abundance of literature linking diabetes prevalence and chronic obstructive pulmonary disease [COPD],” says Neil Schachter, MD, professor of pulmonary medicine at Mount Sinai School of Medicine in New York City. COPD is an umbrella term for a group of progressive lung diseases including emphysema and chronic bronchitis that make it harder to breathe.
A link between asthma and diabetes is “plausible,” he says.
“The link with COPD and diabetes is bolstered by a link between smoking and diabetes and a theoretical link between the concept that an underlying systemic inflammation leads to both COPD and diabetes,” he says.
What’s more, “the extensive use of corticosteroids in COPD may unmask early or unsuspected diabetes,” he says.
These factors may also play a role in the proposed asthma-diabetes link he says, adding that the rate of smoking among people with asthma is higher than one would anticipate.
“There is a link between obesity and asthma and certainly a link between obesity and type 2 diabetes,” he says.
“More epidemiologic data is necessary before considering this a strong association,” Schachter says.
Jerome V. Tolbert, MD, PhD, director of outreach program at Friedman Diabetes Institute of Beth Israel Medical Center in New York City, says the new link makes sense.
While Tolbert says he would like to see the findings reproduced in larger studies of more diverse populations, he says that “we know that diseases like diabetes are pro-inflammatory disease and we do see these links between autoimmune diseases and diabetes.”
“Heart disease and diabetes can go hand in hand, and most [people with diabetes] die of heart disease,” he says. “There may be something here.”
Ninety-eight percent of the new study participants were white, but asthma rates are higher among African-Americans, he says.
Asthma is an inflammatory condition as well. “We treat asthma with steroids because of inflammation and people get better,” he says.
Steroids used to treat asthma may also increase diabetes risk, he says, “Sometimes steroids throw people into diabetic state.”
Given the high rates of prediabetes and undiagnosed diabetes, Tolbert urges all people with asthma to get screened to see if they are at risk for diabetes.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.