Younger Age at Diabetes Onset Associated With Higher Risk of Subsequent Dementia
April 28, 2021

By Denise Baez

Younger age at onset of diabetes was significantly associated with a higher risk for incident dementia, according to a study published in JAMA.

Data spanning 35 to 75 years for age of diabetes onset showed that every 5-year earlier onset of diabetes was significantly associated with a higher hazard of dementia. Late-onset diabetes was not significantly associated with subsequent dementia.

“As diabetes is associated with higher risk for a wide range of vascular diseases, it is important to consider whether vascular comorbidity is associated with onset of dementia in those with diabetes,” wrote Claudio Barbiellini Amidei, MD, Université de Paris, Paris, France, and colleagues.

The UK population-based study (the Whitehall II study) was established in the 80s. Participants were examined in 1991-1993, 1997-1999, 2002-2004, 2007-2009, 2012-2013, and 2015-2016, and linkage to electronic health records (EHRs) were done until March 2019. The date of final follow-up was March 31, 2019. Incident dementia ascertained through linkage to electronic health records.

Among 10,095 participants (67.3% men), a total of 1,710 cases of diabetes and 639 cases of dementia were recorded over a median follow-up of 31.7 years. Dementia rates per 1,000 person-years were 8.9 in participants without diabetes at age 70 years, and rates were 10.0 per 1,000 person-years for participants with diabetes onset up to 5 years earlier, 13.0 for 6 to 10 years earlier, and 18.3 for more than 10 years earlier.

In multivariable-adjusted analyses, compared with participants without diabetes at age 70, the HR of dementia in participants with diabetes onset more than 10 years earlier was 2.12 (95% confidence interval [CI], 1.50-3.00), 1.49 (95% CI, 0.95-2.32) for diabetes onset 6 to 10 years earlier, and 1.11 (95% CI, 0.70-1.76) for diabetes onset 5 years earlier or less.

In analyses adjusted for sociodemographic factors, health behaviours, and health-related measures, at age 70, every 5-year younger age at onset of type 2 diabetes was significantly associated with an HR of dementia of 1.24 (95% CI, 1.06-1.46).

“Continuing follow-up in the study will allow further examination of the importance of age at onset of type 2 diabetes for dementia,” the authors concluded.

Reference: https://jamanetwork.com/journals/jama/fullarticle/2779197