Are environmental pollutants risk factors for low birth weight? / Os poluentes ambientais são fatores de risco para o baixo peso ao nascer?

The aim of this study was to assess the association between prenatal exposure to air pollutants and low birth weight in a medium-sized city. An ecological study was performed, using live birth data from São José dos Campos, São Paulo State, Brazil. The environmental data were obtained from the São Paul State Environmental Agency. The study included full-term newborns whose mothers were 20 to 34 years of age and had at least a complete high school education, seven or more prenatal visits, singleton pregnancy, and vaginal delivery, in order to minimize potential confounding from these variables. Logistic regression was used to estimate the effect of each pollutant. Low birth weight was defined as less than 2,500g. The sample included a total of 2,529 data from 2001 that met the inclusion criteria (25.6 percent of the total). We identified 99 newborns (3.95 percent of the sample) with low birth weight, and the pollutants sulfur dioxide and ozone were associated with low birth weight. The final model was À(x) = -1.79 + 1.30 (SO2) + 1.26 (O3). Thus, sulfur dioxide and ozone were identified as risk factors for low birth weight in a medium-sized city in Southeast Brazil.

O objetivo foi estimar o papel de poluentes no baixo peso ao nascer numa cidade de porte médio. Foi um estudo ecológico com dados obtidos da Declaração de Nascido Vivo relativos a São José dos Campos, São Paulo, Brasil. Os dados ambientais foram fornecidos pela Companhia de Tecnologia de Saneamento Ambiental (CETESB). Foram incluídos no estudo recém-nascidos a termo, com mães entre 20 e 34 anos de idade, segundo grau completo, sete ou mais consultas realizadas no pré-natal, gravidez única e parto normal, para minimizar o efeito de confusão destas variáveis. Utilizou-se regressão logística para estimar o efeito de cada poluente. Baixo peso ao nascer foi considerado aquele inferior a 2.500g. Foram incluídos 2.529 dados de 2001 que atenderam aos critérios de inclusão (25,6 por cento do total). Identificamos 99 recém-nascidos (3,95 por cento dessa amostra) com baixo peso e os poluentes dióxido de enxofre e ozônio como associados ao baixo peso ao nascer. O modelo final foi À(x) = -1,79 + 1,30 (SO2) + 1,26 (O3). Assim, identificou-se o dióxido de enxofre e ozônio como responsáveis pelo baixo peso ao nascer numa cidade de porte médio do Sudeste brasileiro.

Urban air pollution in Latin America and the Caribbean: health perspectives

In the last few years, air pollution has become a major issue in some countries of Latin America and the Caribbean because of urben development and growing industrialization. In addition to industrial processes often concentrated in the cities, vehicle emission and stationary-source fuel combustion are the primary source of air pollution. Although air-quality standards have been established in some Latin American countries, these are frequently exceeded. Adverse health effects of air pollution have been mainly associated with the following pollutants: sulfur dioxide and pariculate matter, photochemical oxidants, nitrogen dioxide and carbon monoxide, and lead. Short-term as well as long-term effects can be expected at levels exceeding WHO guidelines. The Latin American urban areas most affected by anthropogenic pollutant emissions are: the area of Sao Paulo (Brazil), the city of Santiago (Chile) and the metropolitan area of Mexico city. However, situations similar to those prevailing in these cities could well occur in other cities of latin America and the Caribbean. The population exposed to air-pollutant levels exceeding WHO guidelines can be estimated to 81 million or 26.5 percent of the total urban population of Latin America and 19 percent of its total population. These estimates correspond to 30 million children (0-14), 47 million adults (15-59) and 4 million elderly people (60+). To date a very limited number of epicemiological studies have been carried out to determine the potential health effects of air pollutants in Latin America. To obtain a rough estimate, a scenario was hypothesized in which subjects living in cities would be exposed to a given level of air pollutant, using data from the international literature to extrapolate the expected number of events in different strata of the hypothetical population. The estimated health effects are considerable and warrant priorty control intervention. This is true although epidemiological studies are needed to evaluate the health impact of specific pollutant compounds as well as their interactions in Latin American populations exposed to high levels of pollution. (AU)