Younger Age at T2D Onset Tied to Increased Risk of Dementia

Pavankumar Kamat


May 19, 2021


  • Younger age at type 2 diabetes (T2D) onset was significantly associated with an increased risk of subsequent dementia.

Why this matters

  • While the association of early-onset T2D with cardiovascular outcomes is well known, its association with neurocognitive outcomes remains unclear.

Study design

  • The Whitehall II study, an ongoing prospective cohort study (n=10,095), established in 1985-1988 with clinical examinations in 1991-1993, 1997-1999, 2002-2004, 2007-2009, 2012-2013 and 2015-2016, and linkage to electronic health records until March 2019. 

  • Funding: National Institute on Aging and others.

Key results

  • The rate of dementia was 8.86 per 1000 person-years in participants without diabetes at age 70 years.

  • Similarly, rates of dementia per 1000 person-years were:

    • 10.0 for T2D onset ≤5 years earlier;

    • 12.99 for T2D onset 6 to 10 years earlier; and

    • 18.3 for T2D onset >10 years earlier.

  • Compared with participants without diabetes at age 70 years, the risk of dementia was higher in patients with T2D onset (adjusted HR [aHR]; 95% CI):

    • >10 years earlier (2.12; 1.50-3.00);

    • 6-10 years earlier (1.49; 0.95-2.32); and

    • ≤5 years earlier (1.11; 0.70-1.76).

  • Linear trend test (P<.001) showed a strong association between earlier age at T2D onset and dementia.


  • Dementia subtypes were not differentiated.


Barbiellini Amidei C, Fayosse A, Dumurgier J, Machado-Fragua MD, Tabak AG, van Sloten T, Kivimäki M, Dugravot A, Sabia S, Singh-Manoux A. Association Between Age at Diabetes Onset and Subsequent Risk of Dementia. JAMA. 2021;325(16):1640-1649. doi: 10.1001/jama.2021.4001. PMID: 33904867.  View abstract

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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