A pinboard by
Haya Al Khatib

PhD Student, King's College London


I am investigating how sleep impacts determinants of weight and metabolic disease.

Short sleep duration and poor sleep quality have been associated with a higher risk of weight gain and development of metabolic diseases. These links are based on large observational studies that rely on self-reported measures of sleep duration. My research aims to validate these links by objectively measuring sleep using wrist-worn activity measurement devices, and investigating associations with diet, energy expenditure, activity levels and markers of metabolic disease risk. To understand whether the links are causal, I also conduct human clinical trials that manipulate sleep duration, and study how this may energy balance, and cardio-metabolic risk. The outcomes of this research may inform future public health messages, and suggest sleep may be a novel platform in addition to diet and exercise to more effectively target weight management and metabolic disease prevention.


Role of sleep and circadian disruption on energy expenditure and in metabolic predisposition to human obesity and metabolic disease.

Abstract: Weight gain, obesity and diabetes have reached alarming levels in the developed world. Traditional risk factors such as over-eating, poor nutritional choices and lack of exercise cannot fully account for the high prevalence of metabolic disease. This review paper examines the scientific evidence on two novel risk factors that contribute to dys-regulated metabolic physiology: sleep disruption and circadian misalignment. Specifically, fundamental relationships between energy metabolism and sleep and circadian rhythms and the impact of sleep and circadian disruption on metabolic physiology are examined. Millions of individuals worldwide do not obtain sufficient sleep for healthy metabolic function, and many participate in shift work and social activities at times when the internal physiological clock is promoting sleep. These behaviours predispose an individual for poor metabolic health by promoting excess caloric intake in response to reduced sleep, food intake at internal biological times when metabolic physiology is not prepared, decreased energy expenditure when wakefulness and sleep are initiated at incorrect internal biological times, and disrupted glucose metabolism during short sleep and circadian misalignment. In addition to the traditional risk factors of poor diet and exercise, disturbed sleep and circadian rhythms represent modifiable risk factors for prevention and treatment of metabolic disease and for promotion of healthy metabolism.

Pub.: 07 Feb '17, Pinned: 30 Jun '17

Sleep Deprivation and Chronic Health Conditions among Sexual Minority Adults.

Abstract: Objectives - To examine associations between sleep duration and health outcomes among distinct groups of sexual minority adults. Methods - Using data from the 2014 Behavioral Risk Factor Surveillance System, we compared sleep duration (very short: ≤5 hours, short: 6 hours, normal: 7-8 hours, and long: ≥9 hours per day) between cisgender straight adults and distinct groups of sexual minorities. We further examined associations between sleep duration and 10 chronic health conditions among sexual minorities. Results - Of 146,893 respondents, 142,507 (96.2%) were cisgender straight and 4,386 (3.8%) were lesbian, gay, bisexual, transgender (LGBT). Overall, 17.3% of LGBT respondents reported very short sleep per day, compared with 12.2% for cisgender straight respondents (p < 0.0001). Among LGBT populations, the prevalence of very short sleep varied significantly among distinct groups, ranging from 13.2% among transgender female to male adults to 35.5% among transgender gender nonconforming adults. Very short sleep was further associated with increased odds of having stroke (aOR = 4.1, 95% CI [2.2-7.6]), heart attack (aOR = 3.0, CI [1.6-5.8]), coronary heart disease (aOR = 3.1, 95% CI [1.5-6.2]), asthma (aOR = 1.7, 95% CI [1.1-2.4]), chronic obstructive pulmonary disease (aOR = 2.5, CI [1.5-4.0]), arthritis (aOR = 2.1, CI [1.4-3.0]), and cancer (aOR = 1.8, 95% CI [1.0-3.2]) among sexual minorities. Disparities in the prevalence of stroke, heart attack, coronary health disease, COPD, diabetes, obesity, arthritis and cancer were found among LGBT populations. Conclusions - Sexual minorities have a higher prevalence of sleep deprivation as compared with their straight counterparts. Sleep deprivation varies by sexual identity and gender. Very short sleep duration is associated with some chronic health conditions among LGBT populations. Promotion of sleep health education and routine medical assessment of sleep disorders are critically needed for sexual minority adults.

Pub.: 29 Jun '17, Pinned: 30 Jun '17

A pilot study of a novel smartphone application for the estimation of sleep onset.

Abstract: The aim of the study was to investigate the accuracy of Sleep On Cue: a novel iPhone application that uses behavioural responses to auditory stimuli to estimate sleep onset. Twelve young adults underwent polysomnography recording while simultaneously using Sleep On Cue. Participants completed as many sleep-onset trials as possible within a 2-h period following their normal bedtime. On each trial, participants were awoken by the app following behavioural sleep onset. Then, after a short break of wakefulness, commenced the next trial. There was a high degree of correspondence between polysomnography-determined sleep onset and Sleep On Cue behavioural sleep onset, r = 0.79, P < 0.001. On average, Sleep On Cue overestimated sleep-onset latency by 3.17 min (SD = 3.04). When polysomnography sleep onset was defined as the beginning of N2 sleep, the discrepancy was reduced considerably (M = 0.81, SD = 1.96). The discrepancy between polysomnography and Sleep On Cue varied between individuals, which was potentially due to variations in auditory stimulus intensity. Further research is required to determine whether modifications to the stimulus intensity and behavioural response could improve the accuracy of the app. Nonetheless, Sleep On Cue is a viable option for estimating sleep onset and may be used to administer Intensive Sleep Retraining or facilitate power naps in the home environment.

Pub.: 29 Jun '17, Pinned: 30 Jun '17

The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis.

Abstract: It is unknown whether short sleep duration causatively contributes to weight gain. Studies investigating effects of partial sleep deprivation (PSD) on energy balance components report conflicting findings. Our objective was to conduct a systematic review and meta-analysis of human intervention studies assessing the effects of PSD on energy intake (EI) and energy expenditure (EE).EMBASE, Medline, Cochrane CENTRAL, Web of Science and Scopus were searched. Differences in EI and total EE following PSD compared with a control condition were generated using the inverse variance method with random-effects models. Secondary outcomes included macronutrient distribution and resting metabolic rate. Heterogeneity was quantified with the I(2)-statistic.Seventeen studies (n=496) were eligible for inclusion in the systematic review, and 11 studies (n=172) provided sufficient data to be included in meta-analyses. EI was significantly increased by 385 kcal (95% confidence interval: 252, 517; P<0.00001) following PSD compared with the control condition. We found no significant change in total EE or resting metabolic rate as a result of PSD. The observed increase in EI was accompanied by significantly higher fat and lower protein intakes, but no effect on carbohydrate intake.The pooled effects of the studies with extractable data indicated that PSD resulted in increased EI with no effect on EE, leading to a net positive energy balance, which in the long term may contribute to weight gain.European Journal of Clinical Nutrition advance online publication, 2 November 2016; doi:10.1038/ejcn.2016.201.

Pub.: 03 Nov '16, Pinned: 30 Jun '17