EVIDENCE-BASED ANSWER
Yes. Overweight at any age in childhood increases the risk for overweight in adulthood. The relative risk (RR) ranges from 1.9 to 10.1 and increases as children get older. Not all overweight children become overweight adults, however (strength of recommendation: A, systematic review of consistent prospective and retrospective cohort studies).
Clinical commentary
Take a direct approach to excess weight
Mark B. Stephens, MD, MS
Uniformed Services Hospital, Bethesda, Md
For reasons of sensitivity and “correctness,” clinicians often avoid using the term obesity when talking about children. Does our zeal to be polite actually make things worse?
Studies show that parents often fail to recognize that their children are overweight.1 And physicians caring for overweight children often fail to record overweight as a diagnosis in their young patients’ medical records.2
Failure to document excess weight in children virtually guarantees that little if any constructive weight-oriented counseling occurs. By refusing to face the issue head-on, we enable denial of this essential point: Overweight children are far more likely to become obese adults. As we have done with tobacco, it’s now time to ask about weight problems in children, advise families about strategies for safe weight management, and assist where needed.
Evidence summary
The Centers for Disease Control and Prevention (CDC) doesn’t use the term obesity to describe weight in children. Instead, the CDC defines overweight as body mass index (BMI) or weight-for-length for age and sex greater than the 95th percentile. Children above the 85th percentile are called “at risk for overweight.” A national expert panel recently recommended changing “at risk for overweight” to “overweight” and “overweight” to “obese”—the terminology used in this Clinical Inquiry.3
Studies find a clear connection
A 2008 systematic review found 25 prospective or retrospective longitudinal studies that examined the risk of overweight in adulthood based on overweight in childhood or adolescence. Studies had to include at least 1 anthropomorphic measurement before age 18 and at least 1 after age 18. The informativeness and validity of the studies were assessed using a standard evaluation tool. Because the review sought to provide results that could be generalized to large populations, it didn’t include studies of specific populations, such as former premature infants.
All of the 13 studies judged to be high quality found an elevated RR or odds ratio (OR) for adult obesity among participants who had been overweight as children. The authors didn’t calculate a composite measure of effect, but RRs in the individual studies ranged from 1.9 to 10.1.4
Older overweight children are at heightened risk
The systematic review considered children (≤12 years) and adolescents (>12 years) separately. Four high-quality studies assessed how many overweight children became overweight adults; 2 high-quality studies examined how many overweight children became obese adults. Overweight children had RRs between 1.9 and 3.6 for being overweight in adulthood compared with average-weight children; 1 study reported an OR of 7.0.
One study showed older overweight children to be at greater risk than younger children for overweight in adulthood: children who were overweight at 2 years of age had an RR of 2.7, whereas children who were overweight at 11 years had an RR of 3.6.
Obese children had similar results. A study of 4 age cohorts showed that children who were obese at 1 or 2 years of age had an OR of 1.3 for obesity in adulthood compared with average-weight peers. Obese children in the 3- to 5-year-old cohort had an OR of 4.7; obese children in the 6- to 9-year-old cohort had an OR of 8.8; and obese 10- to 14-year-olds had an OR of 22.3.