Diabetes is known to raise the risk of long-term health complications including cognitive decline, but researchers now suggest that the age of onset also plays a crucial role.
A recent study published in PLOS ONE revealed that being diagnosed with type 2 diabetes before age 50 may significantly increase the risk of developing dementia.
To understand the link, the researchers analyzed data from the Health and Retirement Study (2002–2016) which tracked 1,213 U.S. adults aged 50 and older with type 2 diabetes. Using blood tests they confirmed that the participants did not have dementia at the start of the study. Over 14 years, 216 participants (17.8%) developed dementia.
The analysis showed that earlier diabetes diagnoses increased dementia risk. Those diagnosed before age 50 were 1.9 times more likely to develop dementia compared to those diagnosed at 70 or older. Also, the diagnoses at ages 50–59 and 60–69 increased the risk by 1.72 and 1.7 times, respectively.
The most striking reveal was that with each year earlier a person is diagnosed with type 2 diabetes, their risk of developing dementia rises by 1.9%.
"Our study suggests that there may be cognitive consequences to earlier onset type 2 diabetes, and it points to the need for strategies to prevent dementia that consider both diabetes and obesity," said Xiang Qi, the study's first author, in a news release.
The study did not examine how diabetes onset increases dementia risk, but researchers suggest factors like high blood sugar, insulin resistance, and inflammation may contribute. They also noted that obesity heightened dementia risk in cases of diabetes diagnosed before 50, indicating it could be another contributing factor.
"While we do not know for sure why an earlier diabetes diagnosis would increase the risk for dementia, prior studies show that people diagnosed with type 2 diabetes in mid-life may experience more vascular complications, poor blood sugar control, and insulin resistance -- all of which are known risk factors for cognitive impairment," said Bei Wu, the study's senior author.
"Our study highlights the importance of one's age at diabetes diagnosis and suggests that specifically targeting obesity -- whether through diet and exercise or perhaps medication -- may play a role in staving off dementia in younger adults with diabetes," said Wu.
