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Complex interventions for a complex problem

Posted by plosmedicine on 31 Mar 2009 at 00:15 GMT

Author: Alejandro Lazo-Langner
Position: Assistant Professor
Institution: Dept. of Medicine, University of Western Ontario
Submitted Date: October 31, 2007
Published Date: November 1, 2007
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

Although simple single interventions are likely to have an impact on health improvement(1), this might be overly simplistic and the complex nature of the problem requires a multi-faceted approach and an active involvement of the community. An example is the Progresa (currently Oportunidades) program of the Mexican federal government. This is a nation-wide incentive-based program comprising nutritional, health, and educational interventions including cash transfers and provision of micronutrient fortified foods and health services. Eligible households within communities are selected based on demographic and socioeconomic factors but approval by community assemblies is required. Beneficiaries are requested to comply with key components (such as attending regular health appointments, immunization and educational activities) in order to receive some of the benefits, and especially cash transfers, thus fostering an active involvement of the participants in the program.

Formal evaluations have shown that the program has had a positive impact on health indicators in children, with better growth rates and lower rates of anemia after 2 years of inclusion, especially among the poorest and youngest(2). In addition, children that benefit from the program have a lower prevalence of respiratory tract infections and diarrheal diseases(3). Most importantly, in participating municipalities there has been a decrease in maternal and infant mortality rates by 11 and 2%, respectively, and the program has also resulted in higher utilization of preventive health services, such as diabetes and hypertension detection programs and breast and cervical cancer screening(3,4).

The program has also had important effects in other relevant social aspects. It has resulted in improved household sanitation, higher enrolment in secondary education, higher rates of entrepreneurial activities, increased goods consumption and has promoted the creation of cooperative social networks(4). During the years that the program has been running Mexico has had a 2-fold increase in the per capita gross national income and although certainly the program is not the only factor, it has undoubtedly contributed to this change(5). Currently the program enrolls approximately 5 million families and its global yearly budget is around 23 billion Mexican pesos (about 2.5 billion US dollars), resulting in a cost of around 500 US dollars per family per year. The Progresa (Oportunidades) program is a working example showing that a carefully designed single –albeit complex– intervention is able to have a positive impact on the health of people living in poverty in a relatively short time period and at a reasonable cost, and it highlights the importance of community involvement and other non-biomedical aspects in line with the perspectives depicted in a recent Editorial of the journal(6).


1. Yamey G. Which Single Intervention Would Do the Most to Improve the Health of Those Living on Less Than $1 Per Day? PLoS Med 2007; 4: e303;
2. Rivera JA, Sotres-Alvarez D, Habicht JP, Shamah T, Villalpando S. Impact of the Mexican program for education, health, and nutrition (Progresa) on rates of growth and anemia in infants and young children: a randomized effectiveness study. JAMA 2004; 291: 2563-2570;
3. Olaiz-Fernandez G, Rojas-Martinez R, Palma O, and Franco A. Componente de Oportunidades de la Encuesta Nacional de Salud y Nutricion (ENSANUT) 2006. Indicadores de salud. Instituto Nacional de Salud Publica, Cuernavaca, Mexico, 2007;
4. Cruz C, De la Torre R, and Velazquez C. Informe compilatorio. Evaluación externa de impacto del Programa Oportunidades 2001-2006. Instituto Nacional de Salud Pública, Cuernavaca, Mexico, 2006;
5. World Bank. Mexico, Country Brief. Available at: Accessed on 10-31-2007;
6. The PLoS Medicine Editors. Thirty Ways to Improve the Health of the World's Poorest People. PLoS Med 2007; 4: e310]

Competing interests declared: I declare that I have no competing interests.