Elsevier

The Lancet

Volume 366, Issue 9500, 26 November–2 December 2005, Pages 1875-1881
The Lancet

Articles
Chronic obstructive pulmonary disease in five Latin American cities (the PLATINO study): a prevalence study

https://doi.org/10.1016/S0140-6736(05)67632-5Get rights and content

Summary

Background

Both the prevalence and mortality attributable to chronic obstructive pulmonary disease (COPD) seem to be increasing in low-income and middle-income countries, but few data are available. The aim of the PLATINO study, launched in 2002, was to describe the epidemiology of COPD in five major Latin American cities: São Paulo (Brazil), Santiago (Chile), Mexico City (Mexico), Montevideo (Uruguay), and Caracas (Venezuela).

Methods

A two-stage sampling strategy was used in the five areas to obtain probability samples of adults aged 40 years or older. These individuals were invited to answer a questionnaire and undergo anthropometry, followed by prebronchodilator and postbronchodilator spirometry. We defined COPD as a ratio less than 0·7 of postbronchodilator forced expiratory volume in the first second over forced vital capacity.

Findings

Complete information, including spirometry, was obtained from 963 people in São Paulo, 1173 in Santiago, 1000 in Mexico City, 885 in Montevideo, and 1294 in Caracas. Crude rates of COPD ranged from 7·8% (78 of 1000; 95% CI 5·9–9·7) in Mexico City to 19·7% (174 of 885; 17·2–22·2) in Montevideo. After adjustment for key risk factors, the prevalence of COPD in Mexico City remained significantly lower than that in other cities.

Interpretation

These results suggest that COPD is a greater health problem in Latin America than previously realised. Altitude may explain part of the difference in prevalence. Given the high rates of tobacco use in the region, increasing public awareness of the burden of COPD is important.

Introduction

Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality worldwide. However, it is often underdiagnosed and undertreated, resulting in underestimation of the burden of this disease.1 The prevalence of COPD in many developed countries seems to be increasing.2, 3, 4 There is also some evidence from Latin American countries that COPD is a growing cause of death,5 but population-based prevalence data are virtually non-existent.6 To obtain a detailed picture of the global distribution of this severe condition, it is necessary to estimate its prevalence in less developed countries. Prevalence surveys could also help to identify new risk factors and measure the prevalence of known determinants.

The prevalence of the main risk factor for COPD—smoking—is high in Latin America. Mean annual cigarette consumption per person in most countries of Latin America ranges from 500 to 1499.7 As in most high-income countries, there is some evidence that smoking prevalence in men is slightly declining, whereas for women it is rising.7 Even if smoking prevalence rates fall slightly, the absolute number of smokers could increase because of population growth. The relative importance of other known risk factors for COPD has not been adequately assessed in Latin America.

The Latin American Project for the Investigation of Obstructive Lung Disease (PLATINO) was launched in 2002 with the objective of measuring COPD prevalence and associated risk factors in five major cities in Latin America: São Paulo (Brazil), Santiago (Chile), Mexico City (Mexico), Montevideo (Uruguay), and Caracas (Venezuela). These sites were chosen because of their geographical position, population size, and the availability of local collaborating research centres. They represent the different geographical areas of Latin America and the largest metropolitan area in each participating country. Their combined population is about 50 million, of whom around a third are 40 years or older. We report COPD prevalence in these five areas.

Section snippets

Study design

A similar multistage sampling strategy was used in all five areas. Metropolitan areas were first stratified into the main city and surrounding municipalities. These two subsets were further stratified by socioeconomic status. We selected 68 census tracts at each site, taking stratification into account and using a probability of selection proportionate to the number of households in each tract. Within each tract, we counted the number of people in each household and every count was updated from

Results

The contact failure rate at the household level was highest in Caracas, and questionnaire completion was lowest in Mexico City (table 1). Completion of spirometry was uniformly high. Information about age, sex, and smoking were obtained from approximately 50% of individuals who were identified but refused to respond to the questionnaire. On the basis of this information, we estimate that non-response was consistently higher for men, but only slightly higher among older people and current

Discussion

In people aged 40 years and older, we measured a crude prevalence of COPD ranging from 7·8% in Mexico City to almost 20% in Montevideo. The public health effect of this disease has yet to be fully explored in the region, but the PLATINO study is an important first step.

These results are higher than the expected range of 4–10% from an international review of COPD prevalence.18 Nevertheless, they are consistent with the only published population-based study of COPD in Latin America in which,

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