An association between sleep and health? A systematic review

1. An association between sleep and health? A systematic review Barras Z1, Smith E1(The University of Warwick) INTRODUCTION Sleep has a huge impact on physiology and homeostasis. It has already been proven to impact on cardiovascular1, metabolic and psychological2 processes and has been implicated in a range of common diseases, such as diabetes, depression, and coronary artery disease. Despite this, it is unclear how long-term changes in sleep affects health and disease progression. Our project has contributed to the initial stages of a systematic review investigating the effects of longitudinal changes in sleep quality and duration on a range of health outcomes. AIMS • Project-specific: • Refine the research question • Develop and finalise keywords for the literature search. • Gain an understanding of the range of health outcomes which have been investigated in relation to sleep. • Understand if changes in sleep quality and duration impact on health and disease • Understand if there is a prospective relationship between sleep and health. • Research-specific: • Familiarise how to use major medical databases: Medline, EMBASE, PsychINFO. • Learn how to conduct a systematic review according to the Cochrane standard. • Identify goals and steps throughout the project to ensure targets are met. METHODS • Refining the review question • - Change in sleep over time e.g quality/duration • Range of health outcomes, not just pain Sleep search terms • Sleep* • Circadian rhythm • Apnoea/ apnea • Insomnia • Parasomnia • Exploding head syndrome • Confusional arousal (s) • Hypersomnia • Narcolepsy • Cataplexy • Kleine-levin syndrome • Inadequate sleep hygiene • Bruxism • Restless leg syndrome • Periodic limb movement disorder • Hypoxaemia • Breathing difficult* • Congenital central alveolar hypoventilation syndrome • Conducted pilot searches • Medline • EMBASE • PyschINFO Study design search terms • Longitudinal • Prospective • Cohort (s) • Follow-up (s) • Association (s) • Survey (s) • Long-term • Cross-section* • Refined search terms • Skimmed similar articles/ reviews for relevant search terms • Consulted Cochrane handbook and International classification of Sleep disorders Performed primary search Citations returned: MEDLINE: 2080 EMBASE: 2063 psychINFO: 778 Excluded from title screen EXCLUSION CRITERIA: A= wrong study type B= wrong population C= no sleep measure D= No health outcome measure Title and abstract screen Retained n=? Medline:565 EMBASE:451 PsychINFO:105 Search strategy #1 or #2 or#3 or#4 or #5 or #6 or #7 or #8- any of the study design search terms AND #9 or #10 or #11 or #12 or #13 or #14 or #15 or #16 or #17 or #18 or #19 or #20 or #21 or #22 or #23 or #24 or #25- any of the sleep search terms • CONCLUSIONS • Project-specific: • We screened ~4000 articles in our primary search, which contained data on the association between sleep and health; thus justifying the review question. • Trends in health outcomes noted in searches show areas for sub-discussion within the overall review. • We are yet to draw final conclusions upon the impact of changes of sleep in health however the project so far has revealed an exciting glimpse. • Research-specific: • Gained knowledge and confidence in using medical databases • Familiarised the steps in conducting a systematic review • Independently driven forward a research project with clear goals for the future. Secondary screen:: full read through Retained n=? Medline Embase PsychINFO Stratify results into health outcome groups Excluded from final screen EXCLUSION CRITERIA E= Duration of follow-up ≥ 1yr • Secondary screen: • A full read through of selected studies for final inclusion. • Risk of bias analysis: • To assess the reliability of the search strategies between researchers ZB and ES. • Stratification of studies based upon health outcomes: • Psychiatric illnesses, cognition, metabolism, diabetes, hypertension, cardiovascular disease, cancer • Data extraction and review write up: • The final retained studies will be pooled for meta-analysis and discussion. FURTHER WORK • After screening: • Risk of bias assessment • Finalise and submit Prospero form (International prospective register of systematic reviews) • Extract and analyse data • Write-up review REFERENCES 1. Cappuccio, F. P., Cooper, D., D' Elia, L., Strazzullo, P. and Miller, M. A. (2011) 'Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies ' European Heart Journal 2. Spiegel, K., Leproult, R., Van Cauter, E. (1999) Impact of sleep debt on metabolic and endocrine function. Lancet. 3. Cochrane Handbook of Systematic Reviews of Interventions (March 2011), The Cochrane Collaboration ACKNOWLEDGEMENTS Dr Nicole Tang (Department of Psychology, The University of Warwick), Dr Michelle Miller (Warwick Medical School, The University of Warwick), Professor Franco Cappuccio (Warwick Medical School, The University of Warwick), The Undergraduate Research Scholarship Scheme