Weight Gain: Natural History and prognosis

Long-term effects of weight control treatments have been somewhat disappointing. After an initial rapid weight loss, most subjects gradually regain their original excess fat. The best results suggest that average weight losses of 5 to 10% in relative weight may be maintained at up to 10 years after treatment, which leaves the majority of patients obese. These results are further limited by the recognition that subjects and families who volunteer for treatment studies may not represent the average obese patient or family. Population-based natural history studies have found that less than 50% of obese preadolescents but about 75% of obese adolescents go on to be obese adults. In addition, not all obese children and adolescents suffer from obesity-associated physical morbidities.

A number of factors associated with increased risk of adiposity or morbidity in adulthood have been identified. Because of a combination of genetic, environmental, and behavioral influences, obesity clusters strongly in families, and the presence of obese parents or siblings is a strong risk factor.

Similarly, a family history of potential comorbidities such as hypertension, diabetes, or coronary heart disease may be helpful in predicting greater risk for an individual child. Tracking studies demonstrate that both the absolute severity of obesity and the age of the child are predictors of future obesity; the more overweight and the older the overweight child, the more likely that the child will be an obese adult. Several researchers have also noted an association between adult adiposity and timing of the normal second rise in body fat, usually occurring around 6 years of age. An early "adiposity rebound," assessed by plotting serial BMI or triceps skinfold thickness measures, and usually defined as younger than 5.5 years of age, is a better predictor of adult obesity than childhood weight status alone. Finally, a relative predominance of truncal or abdominal fat, as indicated by an increased ratio of waist circumference to hip circumference, has been associated with increased obesity-associated morbidity among adolescents. However, the clinical utility of this measure among prepubertal children is questionable. The presence or absence of these factors may help the clinician to decide on the appropriate intensity of intervention to recommend.

References

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DIETZ WH: Health consequences of obesity in youth: childhood predictors of adult disease. Pediatrics 101:518-525, 1998

DIETZ WH: Critical periods in childhood for the development of obesity. Am J Clin Nutr 59:955-959, 1994

EPSTEIN LH: New developments in childhood obesity. In: STUNKARD AJ , WADDEN TA , eds: Obesity: Theory and Therapy, 2nd ed. New York, Raven, 1993:301-312