Obesity and the metabolic syndrome also affect the lungs

Published Online: March 4, 2015

It is widely recognized that obesity and the metabolic syndrome (central obesity, high blood pressure, and abnormal changes in blood sugar and lipid levels) may precede cardiovascular disease and diabetes, or predispose patients to these diseases. Now, Dr. E. Forno and colleagues report that the metabolic syndrome and insulin resistance (a condition in which the body no longer responds to insulin normally, and may lead to higher blood sugar levels and diabetes) are also associated with lower lung function in adolescents.

In their study, recently published in The Journal of Allergy and Clinical Immunology, the authors looked at data from 1,429 adolescents aged 12 to 17 years who participated in the 2007-2010 National Health and Nutrition Examination Survey (NHANES), a sample representative of the US population. They found that adolescents with insulin resistance had lower FEV1 and FVC, two important measures of lung function. These results were mainly seen among overweight or obese adolescents.

At the same time, adolescents with metabolic syndrome had lower FEV1/FVC, a lung function measure that may signal airway obstruction similar to that found in asthma; this decrease was also more pronounced among overweight or obese participants. Furthermore, having metabolic syndrome and asthma combined led to an even more negative effect on lung function: compared to healthy adolescents, FEV1/FVC was ~2% lower in adolescents with metabolic syndrome, ~5% lower in those with asthma, and ~10% lower in those with both conditions—even after taking into account their obesity. Their average FEV1/FVC was ~74.8-76.8%, well below the normal limit of 80%.

In summary, this study shows that obesity, insulin resistance, and the metabolic syndrome may lead to worsened lung function in adolescents with and without asthma. Management of these conditions should be part of the treatment of obese asthmatic children and adolescents. Further research will be needed to understand the underlying causes of these associations.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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