LAUSR

Investigation on the effects of racial and socioeconomic parameters on sleep has markedly increased along the years. The vast majority of these studies take place on countries in North America or Europe, thus making it necessary that new initiatives are conducted in developing nations. The objective of this study was to evaluate how race and socioeconomic factors influence sleep in the city of São Paulo, Brazil. Health and sleep parameters of participants of the EPISONO (2007) study were assessed with validated questionnaires and a night of polysomnographic examination. Data regarding their self-identified race was collected during this protocol. Among the applied questionnaires, scores in the Critério de Classificação Econômica Brasil (CCEB) questionnaire were adopted in this analysis. General Linear Models were used to investigate the relationship between objective sleep parameters and the racial and socioeconomic classification according to the CCEB questionnaire. 1,008 participants of the EPISONO were included (mean age=42.3 years; 574 women). Class C Blacks had greater total sleep time (TST) than Class A Whites, while Class C Asians presented less TST. Indigenous participants had reduced wake after sleep onset (WASO) time when sided to Whites and, similarly, Class D Blacks presented lower WASO compared to Class A Whites. Arousal index was lower in Class B and C individuals when comparing to Class A individuals and higher in Class C Blacks when compared to Class A Whites. The variety of results when comparing socioeconomic and racial factors highlights the richness of the interplay between these parameters. While some findings are similar to those of North American and European studies, there are differences underlining the necessity of evaluating the socioeconomic and racial background of each population cautiously. Future research on sleep patterns of the Brazilian population concerning the effect of race and socioeconomic status is essential and a promising frontier of investigation to be explored. Our studies are supported by Associação Fundo de Incentivo à Pesquisa (AFIP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES Finance Code 001 to GLF) and Conselho Nacional de Desenvolvimento Científico Tecnológico (CNPq – Grant #141445/2021-1 to GLF); S.T. and M.L.A. received CNPq fellowships.