Sleep duration and risk of fatal and nonfatal stroke: a prospective study and meta-analysis.

OBJECTIVE: To study the association between sleep duration and stroke incidence in a British population and to synthesize our findings with published results through a meta-analysis. METHODS: The prospective study included 9,692 stroke-free participants aged 42-81 years from the European Prospective Investigation into Cancer-Norfolk cohort. Participants reported sleep duration in 1998-2000 and 2002-2004, and all stroke cases were recorded until March 31, 2009. For the meta-analysis, we searched Ovid Medline, EMBASE, and the Cochrane Library for prospective studies published until May 2014, and pooled effect estimates using a weighted random-effect model. RESULTS: After 9.5 years of follow-up, 346 cases of stroke occurred. Long sleep was significantly associated with an increased risk of stroke (hazard ratio [HR] = 1.46 [95% confidence interval (CI) 1.08, 1.98]) after adjustment for all covariates. The association remained robust among those without preexisting diseases and those who reported sleeping well. The association for short sleep was smaller (and not statistically significant) (HR = 1.18 [95% CI 0.91, 1.53]). There was a higher stroke risk among those who reported persistently long sleep or a substantial increase in sleep duration over time, compared to those reporting persistently average sleep. These were compatible with the pooled HRs from an updated meta-analysis, which were 1.15 (1.07, 1.24) and 1.45 (1.30, 1.62) for short and long sleep duration, respectively. CONCLUSIONS: This prospective study and meta-analysis identified prolonged sleep as a potentially useful marker of increased future stroke risk in an apparently healthy aging population.The design and conduct of the EPIC-Norfolk study was supported by program grants from the Medical Research Council of the United Kingdom (grants G9502233 and G1000143) and Cancer Research UK (grants SP2024/0204 and C864/A14136). Ms. Leng is supported by Cambridge Commonwealth, European & International Trusts. Prof. Cappuccio leads the Sleep Health & Society Programme at the University of Warwick supported, in part, by the University of Warwick RDF and IAS. It has received funding by the NHS National Workforce Projects and the Economic & Social Research Council (ES/K002910/1).This is the final published version. It first appeared at http://www.neurology.org/content/early/2015/02/25/WNL.0000000000001371.short

Daytime napping and increased risk of incident respiratory diseases: symptom, marker, or risk factor?

BACKGROUND: We have identified a strong association between daytime napping and increased mortality risk from respiratory diseases, but little is known about the relationship between daytime napping and respiratory morbidity. METHODS: Data were drawn from the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort. Participants reported napping habits during 1998-2000 and were followed up for respiratory disease hospital admissions until March 2009. Cox proportional hazards regression was used to examine the association between daytime napping and respiratory disease incidence risk. RESULTS: The study sample included 10,978 men and women with a mean age of 61.9 years, and a total of 946 incident respiratory disease cases were recorded. After adjustment for age, sex, social class, education, marital status, employment status, nightshift work, body mass index, physical activity, smoking, alcohol intake, self-reported general health, hypnotic drug use, habitual sleep duration, and preexisting health conditions, daytime napping was associated with an increase in the overall respiratory disease incidence risk (hazard ratio (HR) = 1.32, 95% confidence interval (CI) 1.15, 1.52 for napping <1 h; HR = 1.54, 95% CI 1.14, 2.09 for napping ≥1 h). This association was more pronounced for lower respiratory diseases, especially for the risk of chronic lower respiratory diseases (HR = 1.52, 95% CI: 1.18, 1.96 for napping <1 h; HR = 1.72, 95% CI: 1.01, 2.92 for napping ≥1 h, overall p = 0.003). CONCLUSIONS: Excessive daytime napping might be a useful marker of future respiratory disease incidence risk. Further studies are required to confirm these findings and help understand potential mechanisms.Medical Research Council (Grant IDs: G9502233, G1000143); Cancer Research UK (Grant IDs: SP2024/0204, C864/A14136)This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.sleep.2016.06.01

Daytime napping and the risk of all-cause and cause-specific mortality: a 13-year follow-up of a British population.

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.The funding sources did not have a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript

Daytime napping, sleep duration and serum C reactive protein: a population-based cohort study.

OBJECTIVES: To explore whether daytime napping and sleep duration are linked to serum C reactive protein (CRP), a pro-inflammatory marker, in an older aged British population. DESIGN: Cross-sectional study. SETTING: European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study. PARTICIPANTS: A total of 5018 men and women aged 48-92 years reported their sleep habits and had serum CRP levels measured. OUTCOME AND MEASURES: CRP was measured (mg/L) during 2006-2011 in fresh blood samples using high-sensitivity methods. Participants reported napping habits during 2002-2004, and reported sleep quantity during 2006-2007. Multivariable linear regression models were used to examine the association between napping and log-transformed CRP, and geometric mean CRP levels were calculated. RESULTS: After adjustment for age and sex, those who reported napping had 10% higher CRP levels compared with those not napping. The association was attenuated but remained borderline significant (β=0.05 (95% CI 0.00 to 0.10)) after further adjustment for social class, education, marital status, body mass index, physical activity, smoking, alcohol intake, self-reported health, pre-existing diseases, systolic blood pressure, hypnotic drug use, depression and in women-only hormone replacement therapy use. The geometric means (95% CI) of CRP levels were 2.38 (2.29 to 2.47) mg/L and 2.26 (2.21 to 2.32) mg/L for those who reported napping and no napping, respectively. A U-shaped association was observed between time spent in bed at night and CRP levels, and nighttime sleep duration was not associated with serum CRP levels. The association between napping and CRP was stronger for older participants, and among extremes of time spent in bed at night. CONCLUSIONS: Daytime napping was associated with increased CRP levels in an older aged British population. Further studies are needed to determine whether daytime napping is a cause for systemic inflammation, or if it is a symptom or consequence of underlying health problems.The design and conduct of the EPIC-Norfolk study and collection and management of the data was supported by programme grants from the Medical Research Council UK (G9502233, G0300128) and Cancer Research UK (C865/A2883). YL is supported by the Cambridge Overseas Trust. FPC leads the Sleep Health & Society Programme at the University of Warwick supported, in part, by the University of Warwick RDF and IAS. It has received funding by the NHS National Workforce Projects and the Economic & Social Research Council (ES/K002910/1).This is the final version. It was first published by BMJ Group at http://bmjopen.bmj.com/content/4/11/e006071.full

Daytime napping and the risk of all-cause and cause-specific mortality: a 13-year follow-up of a British population.

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.The funding sources did not have a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript

Self-reported sleep patterns in a British population cohort.

OBJECTIVES: Sleep patterns have been linked to various health outcomes, but sleep patterns in the British population have not been extensively reported. We aimed to describe the sleep characteristics reported by the European Prospective Investigation of Cancer (EPIC)-Norfolk participants, with a particular emphasis on the comparison of measures of sleep quantity. METHODS: From 2006 to 2007, a total of 8480 participants aged 45-90 years reported sleep timing, nighttime sleep duration, and sleep difficulties. Time in bed (TIB) was calculated from the difference between rise time and bedtime, and sleep proportion was defined as the ratio of sleep duration and TIB. RESULTS: On average, the reported TIB was more than 1.5h longer than sleep durations. Compared to men, women spent 15 min longer in bed, but they slept for 11 min less and reported more sleep difficulties. In multivariate analysis sleep duration and TIB varied with socioeconomic factors, but sleep proportion was consistently lower among women, nonworkers, and older individuals, as well as those who were widowed, separated, or divorced; those who reported sleep difficulties and more frequently used sleep medication; and those who had lower education, poorer general health, or a major depressive disorder (MDD). CONCLUSIONS: Self-reported sleep duration and TIB have different meanings and implications for health. Sleep proportion may be a useful indicator of sleep patterns in the general population.This work was supported by programme grants from the Medical Research Council UK (G9502233, G0300128) and Cancer Research UK (C865/A2883). FPC leads the Sleep Health & Society Programme at the University of Warwick supported, in part, by the University of Warwick RDF and IAS. It has received funding by the NHS National Workforce Projects and the Economic & Social Research Council (ES/K002910/1)

Changes in HDL cholesterol and cardiovascular outcomes after lipid modification therapy

BACKGROUND: Lipid modification therapy (LMT) produces cardiovascular benefits principally through reductions in low density lipoprotein cholesterol (LDL-C). While recent evidence, using data from 454 participants in the Framingham Offspring Study (FOS), has suggested that increases in high density lipoprotein cholesterol (HDL-C) are also associated with a reduction in cardiovascular outcomes, independently of changes in LDL-C, replication of this finding is important. We therefore present further results using data from the EPIC Norfolk (UK) and Rotterdam (Netherlands) prospective cohort studies. METHODS: A total of 1,148 participants, 446 from the EPIC-Norfolk and 702 from the Rotterdam study were assessed for lipids before and after starting LMT. Subsequent risk of cardiovascular events, ascertained through linkage with mortality records and hospital databases, was investigated using Cox Proportional hazards regression. Random effects meta-analysis was used to combine results across studies. RESULTS: Based on combined data from the EPIC-Norfolk and Rotterdam studies there was some evidence that change in HDL-C resulting from LMT was associated with reduced cardiovascular risk (hazard ratio per pooled SD (= 0. 34 mmol/l) increase = 0.74, 95% CI 0.56-0.99, adjusted for age, sex, and baseline HDL-C). However, this association was attenuated and was not (statistically) significant with further adjustments for non-HDL-C and for cigarette smoking history, prevalent diabetes, SBP, BMI, use of antihypertensive medication, previous MI, prevalent angina, previous stroke (0.92, 0.70-1.20). CONCLUSIONS: Following adjustment for conventional non-lipid CVD risk factors, this study provides no evidence to support a significant benefit from increasing HDL-C independent of the effect of lowering non-HDL-C