Researchers have found a possible link between infection with a strain of cold virus and the development of childhood obesity.
Among a group of 124 children, antibodies to adenovirus 36 were detected in 22 percent of those who were obese, compared with only 7 percent of those whose weight was in the normal range, according to Dr. Charles Gabbert of the University of California San Diego and colleagues.
Mean weight in those who carried antibodies to the virus was 92.9 kg, compared with 69.1 kg in those who were antibody-negative, the researchers reported in the October issue of Pediatrics.
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During the past three decades, the prevalence of obesity among young people has tripled, reaching 17 percent, according to data from the Centers for Disease Control and Prevention
Although consumption of excess calories and inadequate exercise are associated with obesity, other etiologic factors also may contribute.
While adenoviruses are most commonly associated with infections of the upper respiratory tract and the intestines, adenovirus 36 has been found in fat tissue in animal models.
In addition, an association between obesity and antibody positivity has been seen in adults.
To see if this virus also might influence body weight in children, Gabbert and colleagues studied 70 boys and 54 girls ages 8 to 18 years.
More than half of the patients were classified as obese, with a body mass index (BMI) at or above the 95th percentile for age.
Using a serum neutralization assay, the researchers detected neutralizing antibodies to adenovirus 36 in 15 percent of the entire cohort.
Antibody positivity was associated with older age (15.4 years versus 13.1 years), but not with sex, race or ethnicity.
Median BMI was higher in children who carried the antibodies (33.7 kg/m2 versus 25.4 kg/m2), and obese children who were antibody-positive weighed on average 16.1 kg more than the obese children who were antibody-negative.
Other possible explanations for the association of obesity with antibodies to adenovirus 36 could be obesity-related immune dysfunction, making the children more susceptible to infection and to persistence of the infection, the researchers suggested.
Obese children can be severely ostracized and stigmatized. "The possibility that excess weight gain in some children may be attributable to a viral infection could alter the public debate and perceptions regarding childhood obesity," the researchers wrote.
The possibility also exists that obese children who carry these antibodies may respond differently to weight-loss treatments and could require more intensive interventions.
Strengths of this study include the large and diverse sample size and the rigorous method of performing the antibody assay, the authors noted. Weaknesses include the cross-sectional design, which does not allow for conclusions about causality, and the lack of information about the timing of infection.
"Longitudinal data are needed to elucidate more thoroughly the role of [adenovirus] 36 exposure in human obesity," the researchers concluded.