Aims: To examine the risk association of insomnia with incident chronic cognitive impairment in older adults with type 2 diabetes mellitus (T2D)., Methods: Between July 2010 and June 2015, patients with T2D aged ≥60 years enrolled in the Hong Kong Diabetes Register completed the Insomnia Severity Index (ISI) questionnaire. Patients were considered having insomnia if they had ISI score > 14. We prospectively followed up the cohort and censored outcome through reviewing diagnoses and clinical notes entered by attending physicians in electronic medical record to identify incident cases of mild cognitive impairment and dementia., Results: After excluding shift workers and those with established chronic cognitive impairment at baseline, we included 986 patients with T2D in this study (58.3 % men, mean age ± standard deviation: 62.5 ± 2.6 years, disease duration of diabetes: 10.7 ± 8.2 years, HbA1c: 7.4 ± 1.3 %, insulin users: 28.7 %, insomnia: 9.1 %). After a median follow-up of 7.6 (interquartile range = 2.0) years, 41 (4.2 %) developed chronic cognitive impairment. Using Cox regression analysis, insomnia (hazard ratio, HR 2.909, p = 0.012) and HbA1c ≥ 7 % (HR 2.300, p = 0.038) were positively associated with incident chronic cognitive impairment while insulin use (HR 0.309, p = 0.028) showed negative association., Conclusions: Insomnia, suboptimal glycemic control and non-insulin use are independent risk factors for incident chronic cognitive impairment in older adults with T2D., Competing Interests: Declaration of competing interest Conflicts of interest were disclosed according to the disclosure form of International Committee of Medical Journal Editors. A.O. Luk declared (2) Grants or contracts from any entity (if not indicated in item #1 above): Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Eli Lilly, Lee Pharmaceutical, MSD, Novo Nordisk, Roche, Sanofi, Sugardown, Takeda; (5) Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: AstraZeneca, Bayer, Boehringer Ingelheim, Eli Lilly, MSD; (7) Support for attending meetings and/or travel: AstraZeneca, Boehringer Ingelheim, Eli Lilly; (10) Leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid: Deputy Chair of the Joint-Chinese University of Hong Kong – New Territories East Cluster Clinical Research Ethics Committee Phase 1 Panel, Deputy Director of Clinical Research Management Office of the Chinese University of Hong Kong, Vice President of the Hong Kong Association on the Study of Obesity. R.C. Ma declared (2) Grants or contracts from any entity (if not indicated in item #1 above): Research Grants Council of the Hong Kong Special Administrative Region (CU R4012-18), Research Grants Council General Research Fund (Ref. 14118718), Innovation and Technology Fund (MPR/054/20X), Health and Medical Research Fund (CFS-CUHK2), Croucher Foundation, AstraZeneca, Bayer, Novo Nordisk, Pfizer, Tricida Inc., Roche Diagnostics (all the above payment to institution); (4) Consulting fees: Merck, Kyowa Kirin; (5) Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: AstraZeneca, Bayer, Boehringer Ingelheim, Medtronic (all the above were donated to institution to support diabetes research); (8) Patents planned, issued or pending: Hold issued patents relating to genetic markers of diabetes or diabetes complications; (10) Leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid: Council Member, Hong Kong College of Physicians (unpaid), Board Member, Asian Association for the Study of Diabetes (unpaid), Past Board Member of Worldwide Initiative for Diabetes Education (WorldWIDE Diabetes) (up to 3/2021), Member, FIGO Committee on the Impact of Pregnancy on Long-term Health (unpaid); (13) Other financial or non-financial interests: Cofounder of GemVCare, a technology start-up which provides genetic testing for diabetes and diabetes complications, established with support from the Hong Kong Government Technology Start-up Support Scheme for Universities (TSSSU) (No income or renumeration received from the company). J.C. Chan declared (2), (4), (5), (8), (10), (11): J.C. Chan reported receiving grants and/or honoraria for consultancy or giving lectures from Applied Therapeutics, AstraZeneca, Bayer, Boehringer Ingelheim, Celltrion, Eli Lilly, Hua Medicine, Lee Pharm, Merck Serono, Merck Sharp & Dohme, Pfizer, Sanofi, Servier and Viatris Pharmaceutical. She is the chief executive officer (pro bono) of the Asia Diabetes Foundation that designed and implemented the web-based JADE platform for data-driven diabetes management. She holds patents for using biomarkers to predict diabetes and its complications for precision care. She is the co-founder of GemVCare, a biotech start-up company, with partial support from the Hong Kong Government, which uses biogenetic markers and information technology in pursuit of prevention and precision care in diabetes through partnerships. Y.K. Wing declared (2) Grants or contracts from any entity (if not indicated in item #1 above): Grants from Research Grant Council General Research Fund (GRF) & Collaborative Research Fund (CRF) (received grants support for research projects which is outside the submitted work.); (4) Consulting fees: Consultation fee from Eisai Co., Ltd. (received personal fees from Eisai Co., Ltd., which is outside the submitted work); (5) Honorarium from Eisai Hong Kong (received personal fees from Eisai Co., Ltd. for lecture, which is outside the submitted work). A.P. Kong declared (4) Consulting fees: Abbott, Astra Zeneca, Bayer, Boehringer Ingelheim, Eli-Lilly, Kyowa Kirin, Merck Serono, Nestle, Novo-Nordisk, Pfizer and Sanofi (all the above payment to her); (5) Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Abbott, Astra Zeneca, Bayer, Boehringer Ingelheim, Eli-Lilly, Kyowa Kirin, Merck Serono, Nestle, Novo-Nordisk, Pfizer and Sanofi (all the above payment to her); (7) Support for attending meetings and/or travel: Abbott, Astra Zeneca, Bayer, Boehringer Ingelheim, Eli-Lilly, and Sanofi; (9) Participation on a Data Safety Monitoring Board or Advisory Board: Advisory Board member of Abbott, Astra Zeneca, Eli-Lilly, and Kyowa Kirin (all the above payment to her), (11) Stock or stock options: Aptorum. C. O, B.W. Siu, V.W. Leung, Y. Lin, C. Ding, E.S. Lau, J. Cheung, E.Y. Chow declared no conflicts of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)