A study finds that people without diabetes with high blood glucose levels have a greater risk of developing dementia.
A recent study found a positive correlation between one's level of blood glucose and his or her risk of developing dementia in the next 6-7 years. (Glucose levels and risk of dementia, 2013. Paul Crane, et al.). This association was found in patients without diabetes, but not those with diabetes. The study was published in the New England Journal of Medicine.
The study utilized 2,067 study participants with an average age of 76. 232 of the patients were diagnosed with dementia. Glycemia measurements were averaged over the course of five years. Dementia was assessed during a follow-up period that lasted a median of 6.8 years. 524 of the patients developed dementia during the follow-up period. Dementia was assessed by all causes including Alzheimer's disease, vascular disease and Lewybody disease.
Different relationships were found in diabetics and non-diabetics. A positive relationship was found across the entire range of blood glucose levels in non-diabetics. This means that an increase in blood glucose would be associated with a higher risk of dementia. Likewise, diabetics demonstrated a positive association between blood glucose levels and risk of developing dementia at above average blood glucose levels. However, at low blood glucose levels, diabetics showed a negative relationship between risk of developing dementia and blood glucose levels. The authors acknowledge that this negative relationship may be driven by three diabetic patients with atypical courses of Type II diabetes. The figures below illustrate these relationships between blood glucose levels and risk of dementia in diabetics and non-diabetics.
Although this study shows a clear, positive relationship between dementia risk and blood glucose levels in non-diabetics, the mechanism has not been determined. Possible mechanisms include acute and chronic hyperglycemia and insulin resistance, and microvascular disease of the central nervous system. Whether actively lowering blood glucose would decrease the risk of dementia has not been determined, but it may be advisable for elderly patients with high levels of blood glucose to partake in dementia prevention strategies such as exercise and maintaining a healthy diet.