Intervening during infancy to prevent pediatric obesity.

Benjamin Franklin famously wrote, “An ounce of prevention is worth a pound of cure.” This statement is considered axiomatic when pediatric obesity is the subject. Those who develop obesity during childhood acquire increased risks for later morbidity and mortality (1), independent of their adult body mass (2). In addition to the manifold obesity-related cardiovascular and metabolic disorders that may arise at any age and are increasingly common among children, there are unique consequences of early-onset obesity that are not reversible by subsequent weight reduction (3). We are all united in believing that obesity prevention should be our goal; what has held back progress has been the dearth of strategies with clearly demonstrated efficacy for the prevention of pediatric obesity (4,5). In the February 2011 issue of Obesity, Paul et al. (6) present pilot data for a bold and innovative approach to the prevention of undue weight gain in infancy. The authors tested the effects of two complementary interventions initiated 2-3 weeks after birth. First, based on the epidemiologic data suggesting that children who sleep fewer hours at night tend to have greater weight gain than those with an average sleep duration, they reasoned that a program that successfully promoted longer overnight infant sleep might diminish subsequent weight gain. Their sleep-lengthening program involved teaching parents nonfeeding approaches to addressing infants’ fussiness, so that offering energy intake would not be the first strategy used. Second, based on the notions that solid foods are often introduced earlier than recommended and that older infants consuming a diet that contains more vegetables and other healthful foods should gain less weight, they studied the effects of teaching mothers about hunger and satiety cues, the appropriate age at which to introduce foods, and ways to overcome neophobia when introducing vegetables (which are often initially rejected by infants). A total of 160 mother–infant dyads, with mothers who planned to breast-feed, were enrolled and randomized using a 2 × 2 design such that approximately 40 dyads received either no intervention, each of the interventions alone, or both interventions together. The results were quite striking. Among the 110 infants with data collected at age 1 year, coadministration of the two interventions had a significant effect on weight-for-length gain, whereas administration of either intervention alone was associated with no difference vs. the control condition. The double-intervention group had a mean weight for length at the 33rd percentile, while the other three groups had mean weight for length at the 50th to 56th percentiles. These results were confirmed with a last-observation-carried-forward approach for those with at least some follow-up data. Subanalyses suggested that the interventions were particularly effective among infants who continued to be predominantly breast-fed but might be less so for infants who were no longer being mostly breast-fed at 16 weeks of age. Notwithstanding these groundbreaking results, there are some limitations of this study that must be carefully considered. First, the components of the primary outcome—weight for length—were measured by study nurses who were aware of group assignments. It is thus conceivable that the results obtained were, to some extent, affected by unconscious biases, given the known difficulties in measuring supine length in infants (7) and the known effects of being unblinded on heightmeasurement error (8). Second, there are some statistical concerns, among which is the use of data obtained after the interventions were initiated as covariates in models—for example, the number of feedings reported at 16 weeks, which might plausibly be expected to be altered in some of the intervention groups, was a covariate for the main study outcome, weight for length at 1 year