Nick Wainwright

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.

BACKGROUND: Studies have suggested that mood status is associated with an increased risk of stroke, though mostly based on measures of depression defined by symptoms alone rather than diagnostic criteria representative of clinically important distress and impairment. We investigated this association based upon a large population-based prospective cohort study. METHODS: Baseline assessment of major depressive disorder (MDD) and of mental health well-being (defined by the Mental Health Inventory, MHI-5) was completed by 20,627 stroke-free participants, aged 41 to 80 years, in the United Kingdom European Prospective Investigation into Cancer-Norfolk study. RESULTS: During 8.5 years of follow-up, 595 incident (fatal and nonfatal) stroke endpoints were recorded. Neither past year nor lifetime MDD was associated with stroke. A one SD decrease in MHI-5 scale score (representing greater emotional distress) was associated with an 11% increased risk of stroke after adjustment for age, sex, cigarette smoking, systolic blood pressure, cholesterol, obesity, preexisting myocardial infarction, diabetes, social class, education, hypertension treatment, family history of stroke, and antidepressant medication use (hazard ratio 1.11, 95% CI 1.00 to 1.22). This association was consistent for men and for women, for fatal and nonfatal stroke, and conformed to a dose-response relationship. CONCLUSIONS: Findings from this large prospective cohort study suggest that increased psychological distress is associated with elevated stroke risk. Episodic major depressive disorder was not associated with incident stroke in this study.

We investigated the association between psychological stress, emotional health, and relative mean telomere length in an ethnically homogeneous population of 4,441 women, aged 41-80 years. Mean telomere length was measured using high-throughput quantitative real-time polymerase chain reaction. Social adversity exposure and emotional health were assessed through questionnaire and covariates through direct measurement and questionnaire. This study found evidence that adverse experiences during childhood may be associated with shorter telomere length. This finding remained after covariate adjustment and showed evidence of a dose-response relationship with increasing number of reported childhood difficulties associated with decreasing relative mean telomere length. No associations were observed for any of the other summary measures of social adversity and emotional health considered. These results extend and provide support for some previous findings concerning the association of adverse experience and emotional health histories with shorter telomere length in adulthood. Replication of these findings in longitudinal studies is now essential.

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.