Fasting as an intervention to alter the impact of simulated night-shift work on glucose metabolism in healthy adults: a cluster randomised controlled trial

• Published in: Diabetologia 2025-01, Vol.68 (1), p.203-216
• Main Authors: Centofanti, Stephanie, Heilbronn, Leonie K., Wittert, Gary, Dorrian, Jillian, Coates, Alison M., Kennaway, David, Gupta, Charlotte, Stepien, Jacqueline M., Catcheside, Peter, Yates, Crystal, Grosser, Linda, Matthews, Raymond W., Banks, Siobhan
• Format: Article
• Language: English
• Subjects: Adult; Blood Glucose - metabolism; Circadian Rhythm - physiology; Circadian rhythms; Clinical trials; Energy balance; Fasting; Fasting - physiology; Female; Food intake; Glucose; Glucose metabolism; Glucose tolerance; Glucose Tolerance Test; Human Physiology; Humans; Insulin; Insulin - blood; Insulin - metabolism; Insulin Resistance - physiology; Insulin secretion; Internal Medicine; Male; Medical research; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolism; Shift work; Shift Work Schedule; Sleep; Young Adult
• ISSN: 0012-186X; 1432-0428; 1432-0428
• DOI: 10.1007/s00125-024-06279-1

Aims/hypothesis Night-shift work causes circadian misalignment and impairs glucose metabolism. We hypothesise that food intake during night shifts may contribute to this phenomenon. Methods This open-label, multi-arm, single-site, parallel-group controlled trial involved a 6 day stay at the University of South Australia’s sleep laboratory (Adelaide, SA, Australia). Healthy, non-shift-working adults without obesity ( N =55; age 24.5 ± 4.8 years; BMI 24.8 ± 2.8 kg/m 2 ) were assigned to the next available run date and cluster randomised (1:1:1) to fasting-at-night ( N =20), snack-at-night ( N =17), or meal-at-night ( N =18) conditions. One participant withdrew from each group, prior to starting the study. Due to study design, neither participants nor people collecting their measurements could be blinded. Statistical and laboratory staff were concealed to study allocation. Participants were fed at calculated energy balance, with the macronutrient composition of meals being similar across conditions. The primary outcomes were a linear mixed-effects model of glucose, insulin and NEFA AUC in response to a 75 g OGTT that was conducted prior to and after 4 consecutive nights of shift work plus 1 night of recovery sleep. Insulin sensitivity, insulinogenic and disposition indexes were also calculated. Results Night-shift work impaired insulin sensitivity, as measured by insulin AUC ( p =0.035) and the insulin sensitivity index ( p =0.016) across all conditions. Insulin secretion, as measured by the insulinogenic index, was increased in the fasting-at-night condition only ( p =0.030), resulting in a day×condition interaction in glucose AUC ( p