Screening for nutrition interventions: the risk or the differential-benefit approach?

The risk approach has been promoted to improve screening for nutrition interventions on the premise that indicators of risk also predict greater response to interventions. This study tested whether the determinants of the risk of poor growth (eg, low length-for-age) at 36 mo of age were the same as the determinants of differential benefit from food supplementation. The sample included 460 Guatemalan children who were exposed to either a high-energy, high-protein drink (atole) or a low-energy, no-protein drink (fresco) during their first 36 mo of life [INCAP (Institute of Nutrition of Central America and Panama) supplementation trial]. Low maternal stature, poor socioeconomic status, inadequate home diet, high diarrhea rates, and low anthropometry scores at 3 or 6 mo were all determinants of the risk of poor growth. Only indicators of child's thinness at 3 or 6 mo of age (low weight-for-age, weight-for-length, or midupper arm circumference) were determinants of differential benefit from supplementation. Thus, the development of screening indicators should be based on analyses of the predictors of differential benefit, not on conventional risk-factor analysis.