Spirometry reference values for Black adults in Brazil / Valores de referência para espirometria forçada em adultos negros no Brasil

ABSTRACT Objective: To derive reference equations for spirometry in healthy Black adult never smokers in Brazil, comparing them with those published in 2007 for White adults in the country. Methods: The examinations followed the standards recommended by the Brazilian Thoracic Association, and the spirometers employed met the technical requirements set forth in the guidelines of the American Thoracic Society/European Respiratory Society. The lower limits were defined as the 5th percentile of the residuals. Results: Reference equations and limits were derived from a sample of 120 men and 124 women, inhabitants of eight Brazilian cities, all of whom were evaluated with a flow spirometer. The predicted values for FVC, FEV1, FEV1/FVC ratio, and PEF were better described by linear equations, whereas the flows were better described by logarithmic equations. The FEV1 and FVC reference values derived for Black adults were significantly lower than were those previously derived for White adults, regardless of gender. Conclusions: The fact that the predicted spirometry values derived for the population of Black adults in Brazil were lower than those previously derived for White adults in the country justifies the use of an equation specific to the former population.

RESUMO Objetivo: Derivar equações de referência para a espirometria forçada em adultos brasileiros negros, saudáveis, que nunca fumaram, e comparar os resultados com os valores previstos para a raça branca publicados em 2007. Métodos: Os exames seguiram as normas recomendadas pela Sociedade Brasileira de Pneumologia e Tisiologia, e os espirômetros preencheram os requisitos técnicos exigidos pelas diretrizes da American Thoracic Society/European Respiratory Society. Os limites inferiores foram derivados pela análise do 5º percentil dos resíduos. Resultados: Equações e limites de referência foram derivados de uma amostra com 120 homens e 124 mulheres, habitantes de oito cidades brasileiras, utilizando-se um espirômetro de fluxo. Os valores previstos para CVF, VEF1, relação VEF1/CVF e PFE foram mais bem ajustados por regressões lineares, enquanto os fluxos, por equações logarítmicas. Os valores de referência de VEF1 e CVF para ambos os sexos foram significativamente menores quando comparados aos previstos para adultos da raça branca no Brasil. Conclusões: O fato de que os valores previstos da espirometria forçada derivados para a população negra no Brasil tenham sido inferiores aos previstos para a raça branca no país justifica a utilização de uma equação específica para adultos negros.

Spirometry reference values for Black adults in Brazil.

OBJECTIVE: To derive reference equations for spirometry in healthy Black adult never smokers in Brazil, comparing them with those published in 2007 for White adults in the country. METHODS: The examinations followed the standards recommended by the Brazilian Thoracic Association, and the spirometers employed met the technical requirements set forth in the guidelines of the American Thoracic Society/European Respiratory Society. The lower limits were defined as the 5th percentile of the residuals. RESULTS: Reference equations and limits were derived from a sample of 120 men and 124 women, inhabitants of eight Brazilian cities, all of whom were evaluated with a flow spirometer. The predicted values for FVC, FEV1, FEV1/FVC ratio, and PEF were better described by linear equations, whereas the flows were better described by logarithmic equations. The FEV1 and FVC reference values derived for Black adults were significantly lower than were those previously derived for White adults, regardless of gender. CONCLUSIONS: The fact that the predicted spirometry values derived for the population of Black adults in Brazil were lower than those previously derived for White adults in the country justifies the use of an equation specific to the former population.