In industrialized countries, noncommunicable diseases have caused more deaths than have infectious diseases for a number of decades. That same pattern is becoming increasingly true for developing nations as well. Knowing more about the prevalence and distribution of such risk factors as high blood pressure, smoking, high cholesterol, and obesity could help to design, implement, and evaluate disease prevention and control programs.
Recent risk-factor prevalence studies have applied a wide range of approaches, and they have varied in the types of information they present when published. By standardizing more of their research and reporting techniques, such studies could produce more useful information and make it easier to compare results conducted in different locations and during different time periods--as well as improve preventive programs intended to reduce the disease burdens that countries will face in the future.
To remedy methodological shortcomings of prevalence studies, the co-authors of the "Pan American Journal" article propose a standardized "assessment tool," a series of 19 questions to evaluate the studies' usefulness. The questions cover six technical aspects: declared objectives, the population under study, sampling design, methods for gathering information, processing of information, and communicating the results. The evaluation instrument could be used both to assess existing studies and to better plan future studies.
Four standards are proposed for a study to be useful for surveillance purposes, that is, for collecting, analyzing, and interpreting health data and for disseminating the resulting information to policymakers and others. These minimum standards are that: 1) the study must be population-based, 2) the sampling design must be described in the work, 3) the sampling design must be probabilistic, and 4) estimates must be broken down by sex and well-defined age groups. If a study meets those four requirements, it is then rated through a series of 15 additional questions and given a score ranging from 0 to 100.
While this article in the "Pan American Journal" focuses on hypertension, a similar methodology could be used with other risk factors for noncommunicable diseases, according to the article's co-authors. Hypertension is one of the most important risk factors for major cardiovascular diseases, such as cerebrovascular disease and ischemic heart disease, which are leading causes of premature death among adults in most countries.
The lead author of the piece, Luis Carlos Silva Ayçaguer, is head of Postgraduate Research at the Higher Institute of Medical Sciences of Cuba, in Havana, and an epidemiologic research expert who has written several authoritative books on the subject. The three other authors--Pedro Ordúñez, María Paz Rodríguez, and Sylvia Robles--are all members of the staff of the Pan American Health Organization, in Washington, D.C. Those four authors have also written a case study for the "Pan American Journal" that applies their assessment tool to studies of hypertension in Latin America and the Caribbean.
The "Pan American Journal of Public Health," known in Spanish as the "Revista Panamericana de Salud Pública," is the leading scientific and technical publication of the Pan American Health Organization (PAHO). A monthly publication, it carries articles dealing with public health concerns throughout the Americas, in English, Spanish, and Portuguese. The article describing the new assessment tool appeared in the September 2001 issue of the "Journal"; the October 2001 issue of the "Journal" has the case study and an accompanying editorial commenting on the significance of the ideas presented in the September article. All three of those pieces can be viewed and printed for free at the Internet Web site of the Pan American Health Organization, at http://www.paho.org, by doing a search for the phrase "prevalence methodology."
PAHO, which was founded in 1902, works to improve health and raise living standards in all the countries of the Americas. It also serves as the Regional Office for the Americas of the World Health Organization.