Association between sleep duration and all-cause mortality in old age: 9-year follow-up of the Bambuí Cohort Study, Brazil

Abstract

Summary This study investigates the association of sleep duration with risk of all‐cause mortality among elderly Brazilians using data from a 9‐year population‐based cohort study and applying a multivariable longitudinal categorical and continuous analysis using Cox’s proportional hazards models. This analysis used data from the Bambui Health and Ageing Study (BHAS), conducted in Bambuí city (approximately 15 000 inhabitants) in southeastern Brazil. The study population comprised 1512 (86.8%) of all eligible 1742 elderly residents. In multivariable analysis, using sleep duration as categorical variable and controlling for multiple measures of sociodemographic and health status, those who slept 9 h or more per night were found to be at higher risk of mortality than those who slept 7 h [hazard ratio (HR): 1.53; 95% confidence interval (CI): 1.12–2.09]. Excluding those whose deaths occurred within 2 years after entry, this association remained significant (HR: 1.56; 95% CI: 1.12–2.18). In analyses using sleep duration as a continuous variable, a linear correlation was found between sleep duration and mortality in all adjusted models in the whole sample (HR: 1.08; 95% CI: 1.02–1.15) and following exclusion of those whose deaths occurred within 2 years after entry (HR: 1.13; 95% CI: 1.06–1.21). Both linear and quadratic terms were significant, reflecting a predicted relationship, with mortality predominantly increasing in association with long sleep duration but with the addition of a slight decrease in association with shorter sleep duration. In conclusion, long rather than short sleep duration was associated principally with all‐cause mortality in this sample. It is therefore reasonable to suggest that clinicians should be aware of the potential adverse prognosis associated with prolonged sleep.

Sleep duration and health status self-assessment (SF-36) in the elderly: a population-based study (ISA-Camp 2008)

“…The categories used to analyze the association between sleep duration and health status are based on those used in studies demonstrating associations with mortality risk and the prevalence of illness 41,42,43 . A number of studies,especially those involving elderly individuals, also use the seven to eight-hour sleep duration category as a reference 28,42 , whereas some other studies use the seven-hour category as a reference 25,40 .The present study adopted the seven-hour reference category, leading to similar results.…”

“…In the present investigation, however, the analysis was controlled according to the number of chronic diseases, and individuals with physical or mental conditions were rendered incapable of answering the questionnaire and therefore excluded from the study. In a nine-year follow-up study carried out in Brazil, Castro-Costa et al 40 found a strong association between all-cause mortality in the case of long sleep duration patterns but not in the case of short sleep patterns.…”

Self‐Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose‐Response Meta‐Analysis

“…A total of 74 studies met the inclusion criteria; the process of study selection is shown in Figure 1 8, 9, 11, 12, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,...…”

“…** References 11, 21, 23, 25, 26, 27, 29, 32, 33, 34, 36, 39, 40, 41, 44, 46, 47, 48, 49, 51, 52, 53, 54, 56, 57, 61, 64, 66, 68, 70, 71, 72, 77, 79, 80, 84, 86, 87, 88.…”

Associação entre sintomas de insônia, cochilo diurno e quedas em idosos da comunidade

“…A frequência de cochilo diurno varia de 22% a 61% dependendo do local do estudo, das características da população estudada e da definição utilizada 28 . Tanto os sintomas de insônia quanto o cochilo diurno são associados à comorbidades e ao maior risco de mortalidade em idosos 24,29,30,31 .…”