Previous studies have found a U-shaped relationship between mortality and (weekday) sleep duration. We here address the association of both weekday and weekend sleep duration with overall mortality. A cohort of 43,880 subjects was followed for 13 years through record-linkages. Cox proportional hazards regression models with attained age as time-scale were fitted to estimate multivariable-adjusted hazard ratios and 95% confidence intervals for mortality; stratified analyses on age (<65 years, ≥65 years) were conducted. Among individuals <65 years old, short sleep (≤5 hr) during weekends at baseline was associated with a 52% higher mortality rate (hazard ratios 1.52; 95% confidence intervals 1.15-2.02) compared with the reference group (7 hr), while no association was observed for long (≥9 hr) weekend sleep. When, instead, different combinations of weekday and weekend sleep durations were analysed, we observed a detrimental association with consistently sleeping ≤5 hr (hazard ratios 1.65; 95% confidence intervals 1.22-2.23) or ≥8 hr (hazard ratios 1.25; 95% confidence intervals 1.05-1.50), compared with consistently sleeping 6-7 hr per day (reference). The mortality rate among participants with short sleep during weekdays, but long sleep during weekends, did not differ from the rate of the reference group. Among individuals ≥65 years old, no association between weekend sleep or weekday/weekend sleep durations and mortality was observed. In conclusion, short, but not long, weekend sleep was associated with an increased mortality in subjects <65 years. In the same age group, short sleep (or long sleep) on both weekdays and weekend showed increased mortality. Possibly, long weekend sleep may compensate for short weekday sleep.

Prior work has shown that both short and long sleep predict mortality. However, sleep duration decreases with age and this may affect the relationship of sleep duration with mortality. The purpose of the present study was to assess whether the association between sleep duration and mortality varies with age. Prospective cohort study. 43,863 individuals (64% women), recruited in September 1997 during the Swedish National March and followed through record-linkages for 13 years. Sleep duration was self-reported and measured using the Karolinska Sleep Questionnaire, and grouped into 4 categories: ≤5, 6, 7 (reference) and ≥8 h. Up to 2010 3548 deaths occurred. Multivariable Cox proportional hazards regression models with attained age as time scale were fitted to estimate mortality rate ratios. Among individuals <65 years, short (≤5 h) and long (≥8 h) sleep duration showed a significant relationship with mortality (HR 1.37, 95% CI 1.09–1.71, and HR 1.27, 95% CI 1.08–1.48). Among individuals 65 years or older, no relationships between sleep duration and mortality were observed. The effect of short and long sleep duration on mortality was highest among young individuals and decreased with increasing age. The results suggest that age plays an important role in the relationship between sleep duration and mortality.Electronic supplementary materialThe online version of this article (doi:10.1007/s10654-017-0297-0) contains supplementary material, which is available to authorized users.

Objective Erectile dysfunction (ED) is associated with an increased risk of cardiovascular disease in healthy men. However, the association between treatment for ED and death or cardiovascular outcomes after a first myocardial infarction (MI) is unknown. Methods In a Swedish nationwide cohort study all men <80 years of age without prior MI, or cardiac revascularisation, hospitalised for MI during [2007][2008][2009][2010][2011][2012][2013] were included. Treatment for ED, defined as dispensed phosphodiesterase-5 inhibitors or alprostadil, was related to risk of death, MI, cardiac revascularisation or heart failure. Results Forty-three thousand one hundred and forty-five men with mean age 64 (±10) years were included, of whom 7.1% had ED medication dispensed during a mean 3.3 years (141 739 person-years) of follow -up. Men with, compared with those without treatment for ED, had a 33% lower mortality (adjusted HR 0.67 (95%CI 0.55 to 0.81)), and 40% lower risk of hospitalisation for heart failure (HR 0.60 (95% CI 0.44 to 0.82)). There was no association between treatment with alprostadil and mortality. The adjusted risk of death in men with 1, 2-5 and >5 dispensed prescriptions of phosphodiesterase-5 inhibitors was reduced by 34% (HR 0.66 (95% CI 0.38 to 1.15), 53% (HR 0.47 (95% CI 0.26 to 0.87) and 81% (HR 0.19 (95% CI 0.08 to 0.45), respectively, when compared with alprostadil treatment. Conclusions Treatment for ED after a first MI was associated with a reduced mortality and heart failure hospitalisation. Only men treated with phosphodiesterase-5 inhibitors had a reduced risk, which appeared to be dose-dependent. INTRODUCTIONErectile dysfunction (ED) is common. In men between 60 years and 70 years of age 20-40% will be affected depending on the definition of ED. Several previous studies in men without prevalent cardiovascular disease have shown an association between ED and increased risk of cardiovascular disease. [1][2][3] The onset of ED has commonly been thought to precede the onset of cardiovascular disease by 3-5 years in men without cardiovascular disease. 4 In a study of men with type 2 diabetes who underwent coronary angiography and were found to have coronary artery disease, ED was associated with a doubled risk of adverse outcome during follow-up. 5 In a similar high-risk population for cardiovascular disease, ED was associated with almost a doubling of the risk of death. 6To the best of our knowledge there is no study which has investigated the association between treatment for ED, and long-term outcomes in men after a first myocardial infarction (MI). In order to investigate the association between treatment for ED, mortality and cardiovascular outcomes we conducted a nationwide cohort study which included all men with a first MI during 7 years in Sweden. METHODS Study populationFrom 1 January 2007 through 31 December 2013 we included all men 18-80 years of age with a first MI in Sweden. The patients were identified from the Swedish Patient Register, where all hospital stays are registered wi...