Prevalence of insomnia and associated socio-demographic factors in a Brazilian community: the Bambuí study.

Background: Population-based studies of insomnia among adults residing in communities in developing countries are rare. The objectives of this population-based study were to determine the prevalence and factors associated with insomnia among adults (18 years and over) living in a Brazilian town with 15,000 inhabitants (Bambuí MG) and to determine how the use of different definitions of insomnia affect its prevalence.

Methods: A total of 87.3% of 1221 randomly selected individuals aged 18+ participated. Prevalences were estimated based on different definitions. To determine the associated characteristics, insomnia was defined as a complaint in the last month, occurring at least three times a week, causing distress.

Results: (1) Prevalence ranged from 12.0 to 76.3%; (2) prevalence of insomnia, as defined above, was 35.4%; (3) prevalence among women increased with age and was higher than that of men; (4) insomnia was independently associated with less education in both sexes, and among females it was associated with older age (60+ years).

Conclusions: The prevalence of insomnia in Bambuí was high, similar to that of urban centers of developed countries; this investigation substantiated the importance of operational criteria in studies of insomnia.