Daytime Napping and the Risk of All-Cause and Cause-Specific Mortality: A 13-Year Follow-up of a British Population

Abstract

Epidemiologic studies have reported conflicting results on the relationship between daytime napping and mortality risk, and there are few data on the potential association in the British population. We investigated the associations between daytime napping and all-cause or cause-specific mortality in the European Prospective Investigation Into Cancer-Norfolk study, a British population-based cohort study. Among the 16,374 men and women who answered questions on napping habits between 1998 and 2000, a total of 3,251 died during the 13-year follow-up. Daytime napping was associated with an increased risk of all-cause mortality (for napping less than 1 hour per day on average, hazard ratio = 1.14, 95% confidence interval: 1.02, 1.27; for napping 1 hour or longer per day on average, hazard ratio = 1.32, 95% confidence interval: 1.04, 1.68), independent of age, sex, social class, educational level, marital status, employment status, body mass index, physical activity level, smoking status, alcohol intake, depression, self-reported general health, use of hypnotic drugs or other medications, time spent in bed at night, and presence of preexisting health conditions. This association was more pronounced for death from respiratory diseases (for napping less than 1 hour, hazard ratio = 1.40, 95% confidence interval: 0.95, 2.05; for napping 1 hour or more, hazard ratio = 2.56, 95% confidence interval: 1.34, 4.86) and in individuals 65 years of age or younger. Excessive daytime napping might be a useful marker of underlying health risk, particularly of respiratory problems, especially among those 65 years of age or younger. Further research is required to clarify the nature of the observed association.

Sleep Duration and Midday Napping with 5-Year Incidence and Reversion of Metabolic Syndrome in Middle-Aged and Older Chinese

“…Some studies have reported that napping is associated with a higher risk for diabetes and all-causes mortality among older adults. 27,28 In line with previous cross-sectional studies showing a positive relationship of longer napping with a higher risk for MetS, 10,29 we found that excessive napping ( ≥ 90 min) was also an independent predictor of incident MetS and might exert an adverse effect on the MetS reversion. Nonetheless, the findings should be interpreted cautiously because we did not see any significant difference between napping categories and incidence or reversion of MetS components.…”

Daytime napping and mortality from all causes, cardiovascular disease, and cancer: a meta-analysis of prospective cohort studies

“…We did not perform sensitivity and subgroup analyses for the association between daytime napping and cancer mortality because of few included studies. For studies that reported HRs separately for men and women [8,16,[23][24][25], or for different napping duration ranges [9,16,19], we employed a randomeffects model to yield overall estimates for our meta-analysis.…”

“…The frequency of napping usually increases with age [3][4][5][6], and it is higher in men than that in women [6,7]. Traditionally, daytime napping is usually considered a healthy habit, and it is often linked with the low incidence of coronary heart disease and high tendency of longevity [8] through a hypothetical "stress relief" mechanism [9] in Latin American and Mediterranean countries. The Chinese believe that daytime napping is complementary to nighttime sleep, and hence a beneficial behavior.…”

“…Recently, daytime napping has been linked with a series of adverse health outcomes, including nonalcoholic fatty liver disease [10], diabetes mellitus [2,11], breast cancer [12], and mortality [9,13]. The napping-mortality association has received significant attention, but it remains controversial.…”

“…The napping-mortality association has received significant attention, but it remains controversial. Several studies identified that daytime nappers were at an elevated risk of all-cause mortality [9,13,14], whereas others failed to observe a positive association between daytime napping and all-cause mortality [15,16]. A definite demonstration of the napping-mortality association is crucial to understand the effects of napping on health outcomes.…”