Childhood Obesity and Asthma

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Obesity and asthma have become two of the most common chronic diseases in children, and there may be a link between the two. For decades, researchers have been uncovering associations between asthma and obesity in adults; now, studies appear to show that there are associations between obesity and asthma in children as well. While a cause-effect relationship has not been definitively established, studies point to a number of ways in which obesity and asthma seem to interact in children.

Prevalence of Asthma and Obesity

According to asthma surveillance data from the Centers for Disease Control and Prevention (CDC), as recently as 2012, the prevalence of asthma in children in the United States was 9.3%. Also according to the CDC, based on data from the National Health and Nutrition Examination Survey (NHANES), the prevalence of obesity in youth was nearly 17%.

Researchers have found that the incidence and prevalence rates of childhood asthma increase in the presence of childhood obesity. And longitudinal studies, which follow a given population over a period of time (e.g., years), have consistently found that obese individuals are at a higher risk of developing asthma over the long term than are their normal-weight counterparts.

Research suggests that the association goes both ways: for every year after a diagnosis of asthma, children may experience an incremental increase in body mass index (BMI).

This does not appear to be the case in adults, however.

Higher Rates in Minority and Inner-City Populations

It has been noted that both obesity and asthma affect certain minority and inner-city groups more than other populations. In addition, it appears that even a little excess weight can directly affect lung function, particularly in minority children.

When researchers looked at this phenomenon in Hispanic and African-American children, who have higher rates of asthma than do Caucasian children, it was found that lung function was detrimentally affected in both overweight and obese Hispanic and African-American children, while only obese Caucasian children showed the same reduced lung function.

Possible Mechanisms

How might obesity be causing this effect on childhood asthma? Research has identified one characteristic that they have in common: inflammation. The presence of obesity-related hormones--also known as “adipokines”--such as leptin, can penetrate the lungs and cause inflammation in the airways. Obesity can also, through sheer physical weight, make it more difficult for the lungs to expand normally in the chest. This results in lower lung volumes.

Interestingly, a genetic role may also be at play. Scientists have discovered a number of genes that appear to be associated with both obesity and asthma. These genetic variants appear to increase the tendency for the development of both asthma and obesity.

Obesity and Asthma Management

Clinicians have been aware for some time that the presence of obesity can complicate the management of childhood asthma. Some experts have noted that children with asthma who are obese seem to experience more asthma symptoms, and have a higher likelihood of requiring emergency department or hospital care.

In addition to the usual methods employed in the management of childhood asthma, several experts recommend that, for overweight and obese children, interventions to encourage weight loss should also be incorporated as part of asthma treatment. These include increasing daily physical activity, decreasing the intake of nutrient-poor “empty” calories and sugared beverages, and increasing the intake of nutrient-rich, balanced whole foods.


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