CODEC
Study title
Chronotype of Patients with Diabetes and Effect on Glycaemic Control: The CODEC Study
Background
Research has shown that people who have later bedtimes (colloquially called ‘night owls’) are more likely to develop diabetes and other health problems, such as heart disease. This still holds true, even when the night owls get the same number of hours sleep as early risers. The underlying causes have not been clearly defined, but appear to be related to ‘circadian misalignment’. This is where societal pressures, such as work shifts, force us to wake earlier or stay awake longer than we naturally would.
The concept is called ‘social jetlag’ and has been developed to describe the damaging effects of chronic sleep deprivation related to this mismatching of sleep timing and chronotype. This is important because social jetlag has been associated with obesity, which increases the risk of developing type 1 and type 2 diabetes.
Study Aims
The CODEC study aims to identify the chronotypes in patients with type 1 and type 2 diabetes to find out what impact, if any, the chronotype (e.g. ‘night owl’ or ‘lark’) has on the patient’s ability to control their blood sugar levels, among other biological measures.
Study Summary
The CODEC Study is an observation study, recruiting adults between 18 and 75 years of age with established type 1 or type 2 diabetes and who do not have a known sleep disorder (with the exception of obstructive sleep apnoea).
It is a single-visit study that lasts approximately two hours and is based at the Leicester Diabetes Centre (LDC), Leicester General Hospital. This visit involves the completion of a lifestyle-related questionnaire as well as the collection of blood samples, clinical data such as height, weight, waist and blood pressure readings. Physical performance tests take place; these include a hand grip strength test and sitting/standing exercises. Clinical staff will also obtain demographic data and medical history information during this visit.
There is the option to take part in two additional sub-studies for CODEC. One will include a visit to the LDC, which will last approximately two hours and the second involves completing some measures at home (questionnaire booklet, wearing a physical activity monitor for eight days and completing a food diary).
Study Progress
The study is currently running across six sites: Leicester, Nottingham, Derby, Lincoln, Northampton and Kettering.
The study has successfully recruited 1196 participants out of a 3447 target. The study will be continuing recruitment until December 2027.
Funding and Sponsorship
The CODEC study has been funded by the Leicester Diabetes Centre & Biomedical Research Centre. University of Leicester are the Sponsor for this study.
Study Publications
Brady EM, Hall AP, Baldry E, Chatterjee S, Daniels LJ, Edwardson C, et al. 2019. Rationale and design of a cross-sectional study to investigate and describe the chronotype of patients with type 2 diabetes and the effect on glycaemic control: the CODEC study. BMJ Open, 9(11), http://dx.doi.org/10.1136/bmjopen-2018-027773
Baldry E, Brady E, Patel M, Hall A, Khunti K, and Davies MJ. Preliminary findings of a cross-sectional study to investigate and describe the impacts of circadian rhythm alignment in people with type 2 Diabetes (CODEC) poster presentation for the European Congress on Obesity (ECO), 2019.
Katsarova SS, Redman E, Arsenyadis F, Brady EM, Rowlands AV, Edwardson CL, Goff LM, Khunti K, Yates T, Hall AP, Davies MJ, Henson J. Differences in Dietary Intake, Eating Occasion Timings and Eating Windows between Chronotypes in Adults Living with Type 2 Diabetes Mellitus. Nutrients 2023;15(18).
Research Team
Principal Investigator – Professor Melanie Davies
Trial Research Manager – Sahar Khodabakhsh
For more information, please contact: sahar.khodabakhsh@uhl-tr.nhs.uk or CODEC@uhl-tr.nhs.uk