Lead author Juan A. Rivera, Ph.D., Director of the Center for Nutrition and Health, National Institute of Public Health, Cuernavaca, Mexico, presented the findings of the study today at a JAMA media briefing at the National Press Club in Washington, D.C.
According to background information in the article, more than half of the yearly 10.8 million deaths of children younger than 5 years worldwide are attributed to malnutrition. Malnourished children who survive have a high risk of impaired health and function throughout life, which contributes to the intergenerational continuation of poverty. In developing countries more than one-quarter of all children younger than 5 years, about 150 million total, are estimated to be malnourished. Existing malnutrition interventions are effective under controlled conditions; however, little information is available on their effectiveness in large-scale programs.
Rivera and colleagues conducted a study to determine the short-term nutritional impact of the large-scale, incentive-based development welfare program in Mexico, Progresa (Program for Education, Health, and Nutrition, currently called Oportunidades). Progresa has been applied by the Mexican federal government since 1997. As part of the program, children and pregnant and lactating women in participating households received fortified nutrition supplements called papilla, and the families received nutrition education, health care, and cash transfers.
The families received the cash transfers if they complied with requirements concerning school attendance and maintaining certain health care appointments for services such as immunizations, well baby care and growth monitoring of children, prenatal and postnatal care, check-up visits for other family members, and a mandatory session on nutrition and health education.
The study included 347 communities randomly assigned to immediate incorporation to the program in 1998 (intervention group; n = 205) or to incorporation in 1999 (crossover intervention group; n=142). A random sample of infants in those communities was surveyed at baseline and at 1 and 2 years afterward. Participants were from low-income households in poor rural communities in 6 central Mexican states. Infants (N = 650) 12 months of age or younger (n = 373 intervention group; n = 277 crossover intervention group) were included in the analyses.
The researchers found that participating in the Progresa program was associated with better growth in height among the poorest and younger infants. Adjusted height was greater by 1.1 cm (.4 inch) (26.4 cm [10.4 inches] in the intervention group vs. 25.3 cm [9.9 inches] in the crossover intervention group) among infants younger than 6 months at baseline. The rate of anemia in 1999 was 10.6 percentage points lower in the intervention group (44.3 percent) after 1 year in the Progresa program relative to that in the crossover intervention group (54.9 percent), who had not yet received Progresa benefits that year. In 2000, rates of anemia in the two groups were no longer significantly different after both groups had been in the program during the previous year.
"This experimental study showed improvements in height increments and anemia rates associated with exposure to Progresa, a program with a nutrition component, which covered about 2.6 million families by the end of the evaluation period and that today reaches 4.5 million families [about 20 percent of all families in Mexico]. The randomized design of the study allowed us to attribute the biologically important differences between intervention groups to the effect of the program. This evaluation is important because it is one of the few well-controlled effectiveness evaluations of large-scale programs that showed positive effects on nutrition and that also promises to support informed program improvements," the authors conclude.
(JAMA. 2004;291:2563-2570. Available post-embargo at JAMA.com).
Editor's Note: The study was funded by the Mexican Ministry of Health (Dr. Rivera).
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