Published Online: July 8, 2015
Both obesity and asthma are increasing in incidence and prevalence in the United States. While studies have demonstrated higher rates of asthma in obese individuals compared to normal weight controls for both children and adults, and that obesity is associated with worse control and a lower quality of life, few studies have examined how developing obesity in early adulthood affects the course of asthma.
Strunk et al. report in The Journal of Allergy and Clinical Immunology: In Practice an analysis of 771 subjects with mild-moderate asthma who were not obese when enrolled in the Childhood Asthma Management Program at ages 5-12 years and were then followed to age > 20 years. For visits at ages > 20 years, spirometry values and asthma symptom scores and prednisone exposure were compared between 579 subjects who were non-obese at all visits and 151 who were obese (adult definition of BMI > 30 kg/m2) on at least one visit. Compared to participants who were non-obese, those who became obese had significant decreases in FEV1/FVC and FEV1, without differences in FVC during visits at ages > 20 years. For each unit increase of BMI, FEV1 percent predicted decreased by 0.29. The relationship between BMI and lung function did not differ when adjusted for sex or BMI at baseline. Asthma impairment (symptom scores) and risk (prednisone use) did not differ between the two groups.
Becoming obese in early adulthood was associated with increased airway obstruction. The pulmonary function changes in the obese group during young adulthood were not associated with increased symptoms or exacerbation risk. However, the association between obesity and overall worsening of asthma control in adults suggests that obesity in young adults observed in CAMP may progress to having worsening asthma due to their obesity later in life. As those in the CAMP cohort who were obese in early adulthood differentiated themselves at school age with a higher BMI percentile, school age children with mild-moderate asthma who have a BMI indicative of an overweight status may represent an at risk group requiring careful monitoring of weight gain and early education about diet and exercise.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.