Overweight babies may have decreased risk for asthma
MedWire News: Being overweight during infancy appears to reduce the risk for asthma in genetically susceptible individuals, research suggests.
However, the research team also found that being overweight after infancy, at the ages 6 to 8 years, did not protect against asthma, and may even increase the risk.
Zhumin Zhang (University of Wisconsin College of Agriculture and Life SciencesUniversity of Wisconsin College of Agriculture and Life SciencesUniversity of Wisconsin College of Agriculture and Life Sciences, Madison, USA) and colleagues noted that asthma and obesity both often begin in childhood, share some common risk factors, and have increased in prevalence over the past 20 years.
They write: "A natural speculation arose that the development of asthma and obesity might be related."
To find out, they investigated the relationship between weight status from birth to age 5 years, with the occurrence of asthma at ages 6 and 8 years.
This focused on 285 full-term newborns enrolled in the Childhood Origin of Asthma project who were deemed at high risk for asthma because they had at least one asthmatic or atopic parent.
Overweight was defined as a body mass index greater than the 85th percentile for age.
When assessed separately at each year of age, no significant concurrent association was found between overweight status and risk for wheezing/asthma.
However, when assessed longitudinally, data showed a complex relationship between overweight and asthma.
Being overweight at age 1 year was associated with a significantly decreased risk for asthma at age 6 (odds ratio [OR]=0.32; p=0.02) and 8 years, at odds ratios of 0.32 and 0.35, respectively, compared with not being overweight. It was also associated with better lung function.
In contrast, being overweight beyond infancy was not associated with the occurrence of asthma. And an increased risk for asthma at age 6 years was found in children who were overweight at 5 years and not overweight at 1 year of age, at an odds ratio of 5.78.
Zhang et al conclude: "In children genetically at high risk of asthma, being overweight at age 1 year was associated with a decreased risk of asthma and better lung function at ages 6 and 8 years.
"However, being overweight beyond infancy did not have any protective effect and even could confer a higher risk for asthma."
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