Type 2 Diabetes Mellitus (T2DM) is a significant risk factor for developing dementia which has become incredibly prevalent among younger individuals. Obesity, on the other hand, is not a primary risk factor for impaired cognitive functioning, but it can exacerbate the effects of cardiovascular risk factors on cognition. However, the association between the age a person receives a T2DM diagnosis with their risk of developing dementia and whether obesity moderates that association is still unknown. In a new study published in the journal PLOS ONE, a team of researchers led by Dr Bei Wu from New York University (US) investigated the link between age at T2DM diagnosis and dementia risk, and whether obesity moderates this relationship among adults aged 50 or over with previously diagnosed T2DM.
This research involved 1,213 Black and Hispanic adults recruited from the Health and Retirement Study. All of them were aged 50 and over without dementia upon joining the study and with T2DM confirmed by blood tests. The participants were followed for up to 14 years, after which the development of dementia was checked based on cognitive tests. A total of 17.8% of the participants (216) developed dementia during a medium 10-year follow-up period. The researchers also found that adults diagnosed with T2DM at a younger age were at increased risk for developing dementia compared to those diagnosed at 70 or older. Specifically, individuals diagnosed with diabetes before the age of 50 were 1.9 times more likely to develop dementia, while those diagnosed between 50 and 59 were 1.72 times as likely, and those receiving the diagnosis between 60 and 69 years were 1.7 times as likely.
In addition to these findings, the research team found that obesity influences the link between T2DM and dementia. Individuals with obesity who were diagnosed with T2DM before the age of 50 had the highest risk of dementia among all the participants. Although this study has some limitations (e.g. measurement of dementia was based on cognitive tests only, T2DM was self-reported at baseline, etc.), it shows the link between the age of T2DM diagnosis and the risk for dementia, as well as the influence that obesity has on this association. More studies are needed to explore the mechanisms of the diabetes-dementia relationship, and interventions targeting obesity in dementia prevention for adults with T2DM, particularly for those receiving the diagnosis before the age of 50.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0310964