Sleep and Cardiometabolic Disease

University of Minnesota Ph.D. dissertation. July 2017. Major: Epidemiology. Advisors: Pamela Lutsey, Aaron Folsom. 1 computer file (PDF); xi, 160 pages.Sleep is a universal part of human physiology yet sleep disturbances such as short sleep duration and sleep apnea are common. Cardiovascular disease and its risk factors are also common, and it has been hypothesized that sleep disturbances may be linked to greater cardiovascular risk. This dissertation reports on epidemiological associations of sleep duration with eating behaviors and obesity, as well as associations between obstructive sleep apnea and cardiovascular events. Using data from Project EAT, the first manuscript examines the association between several self-reported sleep indices and problematic eating behaviors in young adults. Late sleep timing was most consistently associated with poor eating behaviors, while fewer associations were found for other sleep indices. In the second manuscript, data from the Multi-Ethnic Study of Atherosclerosis were used to evaluate the association between actigraphy-measured sleep indices and adiposity in older adults. Those sleeping less than 5 hours per night had higher BMIs, larger waists, and more kilograms of body fat than those who slept 7-8 hours a night. Those with low sleep efficiency and high sleep variability also had greater adiposity. Using data from the Sleep Heart Health Study, the third manuscript examines the relationship between daytime sleepiness and obstructive sleep apnea in relation to incident coronary heart disease and stroke. We found no significant interaction or synergy, indicating that measuring both sleep characteristics provides little additional information about cardiovascular disease incidence. In the fourth manuscript, we examine the association between diagnosed sleep apnea and atherosclerotic cardiovascular disease among patients with atrial fibrillation in the MarketScan administrative databases. Counterintuitively, we found that sleep apnea was associated with reduced risk of stroke and myocardial infarction, potentially due to error in the measurement of the exposure. This dissertation explores the epidemiology of sleep and cardiometabolic disease, including its clinical and public health implications

Improved privacy-preserving training using fixed-Hessian minimisation

The fixed-Hessian minimisation method can be used to implement privacy-preserving machine learning training from homomorphic encryption. This is a relatively under-explored part of the literature, with the main prior work being that of Bonte and Vercauteren (BMC Medical Genomics, 2018), who proposed a simplified Hessian method for logistic regression training over the BFV homomorphic encryption scheme. Our main contribution is to revisit the fixed- Hessian approach for logistic regression training over the CKKS homomorphic encryption scheme. We improve on the prior work in several aspects, most notably showing how the native encoding in CKKS can be used to take advantage of SIMD operations. We implement our new fixed-Hessian approach in SEAL and compare it to more commonly-used minimisation methods, based on Gradient Descent and Nesterov’s Accelerated Gradient Descent. We find that the fixed-Hessian approach exhibits fast run time and comparable accuracy to these alternative approaches. Moreover, it can be argued to be more practical in the privacy-preserving training context, as no step size parameter needs to be chosen. As an additional contribution, we describe and implement three distinct training algorithms, based on Gradient Descent, Nesterov’s Accelerated Gradient Descent, and a fixed-Hessian method respec- tively, to achieve privacy-preserving ridge regression training from homomorphic encryption. To the best of our knowledge, this is the first time homomorphic encryption has been used to implement ridge regression training on encrypted data

Dietary intake and peripheral arterial disease incidence in middle-aged adults: the Atherosclerosis Risk in Communities (ARIC) Study

Background: Peripheral arterial disease (PAD) is a costly source of morbidity and mortality among older persons in the United States. Dietary intake plays a role in the development of atherosclerotic cardiovascular disease; however, few studies have examined the relation of food intake or dietary patterns with PAD

On the precision loss in approximate homomorphic encryption

Since its introduction at Asiacrypt 2017, the CKKS approximate homomorphic encryption scheme has become one of the most widely used and implemented homomorphic encryption schemes. Due to the approximate nature of the scheme, application developers using CKKS must ensure that the evaluation output is within a tolerable error of the corresponding plaintext computation. Choosing appropriate parameters requires a good understanding of how the noise will grow through the computation. A strong understanding of the noise growth is also necessary to limit the performance impact of mitigations to the attacks on CKKS presented by Li and Micciancio (Eurocrypt 2021). In this work we present a comprehensive noise analysis of CKKS, that considers noise coming both from the encoding and homomorphic operations. Our main contribution is the first average-case analysis for CKKS noise, and we also introduce refinements to prior worst-case noise analyses. We develop noise heuristics both for the original CKKS scheme and the RNS variant presented at SAC 2018. We then evaluate these heuristics by comparing the predicted noise growth with experiments in the HEAAN and FullRNS-HEAAN libraries, and by comparing with a worst-case noise analysis as done in prior work. Our findings show mixed results: while our new analyses lead to heuristic estimates that more closely model the observed noise growth than prior approaches, the new heuristics sometimes slightly underestimate the observed noise growth. This evidences the need for implementation-specific noise analyses for CKKS, which recent work has shown to be effective for implementations of similar schemes

Driving under the influence behaviours among high school students who mix alcohol with energy drinks

Published by Elsevier via http://dx.doi.org/10.1016/j.ypmed.2017.11.035 © 2017. Made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Alcohol and energy drinks are commonly used substances by youth in Canada, and are often mixed (AmED). While several studies have shown that AmED can have dangerous effects, less well understood is how AmED is associated with driving under the influence of either alcohol or drugs. This study sought to determine whether youth who use AmED were more likely to engage in driving, or being a passenger of a driver, under the influence of alcohol or cannabis compared to youth who use either alcohol or energy drinks alone. This study used data from grade 10–12 students who took part in the 2014/2015 Canadian Student Tobacco, Alcohol and Drugs Survey (N=17,450). The association of past-year AmED use with past-30day: driving under the influence of alcohol or cannabis, and riding with an alcohol- or cannabis-influenced driver, was assessed using logistic regression. One in four youth had consumed AmED in the previous 12months. AmED users were more likely to engage in all risk behaviours except riding with a drinking driver, relative to youth who only consumed alcohol. No association was observed for youth who consumed alcohol and energy drinks on separate occasions. Youth who use AmED demonstrate a higher risk profile for driving under the influence of alcohol or cannabis, than youth who use alcohol alone. Future research should explore the biopsychosocial pathways that may explain why using energy drinks enhances the already heightened risk posed by alcohol on other health-related behaviours such as driving under the influence.Canadian Cancer Society (grant #2011-701019

Who knows best? A Q methodology study to explore perspectives of professional stakeholders and community participants on health in low-income communities

Abstract Background Health inequalities in the UK have proved to be stubborn, and health gaps between best and worst-off are widening. While there is growing understanding of how the main causes of poor health are perceived among different stakeholders, similar insight is lacking regarding what solutions should be prioritised. Furthermore, we do not know the relationship between perceived causes and solutions to health inequalities, whether there is agreement between professional stakeholders and people living in low-income communities or agreement within these groups. Methods Q methodology was used to identify and describe the shared perspectives (‘subjectivities’) that exist on i) why health is worse in low-income communities (‘Causes’) and ii) the ways that health could be improved in these same communities (‘Solutions’). Purposively selected individuals (n = 53) from low-income communities (n = 25) and professional stakeholder groups (n = 28) ranked ordered sets of statements – 34 ‘Causes’ and 39 ‘Solutions’ – onto quasi-normal shaped grids according to their point of view. Factor analysis was used to identify shared points of view. ‘Causes’ and ‘Solutions’ were analysed independently, before examining correlations between perspectives on causes and perspectives on solutions. Results Analysis produced three factor solutions for both the ‘Causes’ and ‘Solutions’. Broadly summarised these accounts for ‘Causes’ are: i) ‘Unfair Society’, ii) ‘Dependent, workless and lazy’, iii) ‘Intergenerational hardships’ and for ‘Solutions’: i) ‘Empower communities’, ii) ‘Paternalism’, iii) ‘Redistribution’. No professionals defined (i.e. had a significant association with one factor only) the ‘Causes’ factor ‘Dependent, workless and lazy’ and the ‘Solutions’ factor ‘Paternalism’. No community participants defined the ‘Solutions’ factor ‘Redistribution’. The direction of correlations between the two sets of factor solutions – ‘Causes’ and ‘Solutions’ – appear to be intuitive, given the accounts identified. Conclusions Despite the plurality of views there was broad agreement across accounts about issues relating to money. This is important as it points a way forward for tackling health inequalities, highlighting areas for policy and future research to focus on

Improving Rehabilitation Research to Optimize Care and Outcomes for People with Chronic Primary Low Back Pain: Methodological and Reporting Recommendations from a WHO Systematic Review Series

Chronic primary low back pain (CPLBP) is a prevalent and disabling condition that often requires rehabilitation interventions to improve function and alleviate pain. This paper aims to advance future research, including systematic reviews and randomized controlled trials (RCTs), on CPLBP management. We provide methodological and reporting recommendations derived from our conducted systematic reviews, offering practical guidance for conducting robust research on the effectiveness of rehabilitation interventions for CPLBP. Our systematic reviews contributed to the development of a WHO clinical guideline for CPLBP. Based on our experience, we have identified methodological issues and recommendations, which are compiled in a comprehensive table and discussed systematically within established frameworks for reporting and critically appraising RCTs. In conclusion, embracing the complexity of CPLBP involves recognizing its multifactorial nature and diverse contexts and planning for varying treatment responses. By embracing this complexity and emphasizing methodological rigor, research in the field can be improved, potentially leading to better care and outcomes for individuals with CPLBP

Setting up a Paediatric Rapid Access Outpatient Unit: Views of general practice teams

<p>Abstract</p> <p>Background</p> <p>Rapid Access Outpatient Units (RAOUs) have been suggested as an alternative to hospital inpatient units for the management of some acutely unwell children. These units can provide ambulatory care, delivered close to home, and may prevent unnecessary hospital admission. There are no qualitative data on the views of primary care practitioners regarding these types of facilities. The aim of the study was to explore the opinions of primary care practitioners regarding a newly established RAOU.</p> <p>Methods</p> <p>The RAOU was established locally at a district general hospital when inpatient beds were closed and moved to an inpatient centre, based six miles away at the tertiary teaching hospital.</p> <p>Qualitative, practice based group interviews with primary care practitioners (general practitioners (GPs), nurse practitioners and practice nurses) on their experiences of the RAOU. The data collection consisted of three practice based interviews with 14 participants. The interviews were recorded and transcribed verbatim. Thematic content analysis was used to evaluate the data.</p> <p>Results</p> <p>There was positive feedback regarding ease of telephone access for referral, location, and the value of a service staffed by senior doctors where children could be observed, investigated and discharged quickly. There was confusion regarding the referral criteria for the assessment unit and where to send certain children. A majority of the practitioners felt the utility of the RAOU was restricted by its opening hours. Most participants felt they lacked sufficient information regarding the remit and facilities of the unit and this led to some uneasiness regarding safety and long term sustainability.</p> <p>Conclusion</p> <p>Practitioners considered that the RAOU offered a rapid senior opinion, flexible short term observation, quick access to investigations and was more convenient for patients. There were concerns regarding opening hours, safety of patients and lack of information about the unit's facilities. There was confusion about which children should be sent to the unit. This study raises questions regarding policy in regard to the organisation of paediatric services. It highlights that when establishing alternative services to local inpatient units, continual communication and engagement of primary care is essential if the units are to function effectively.</p