Blood Sugar—Food for Thought?

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Science Translational Medicine  04 Sep 2013:
Vol. 5, Issue 201, pp. 201ec147
DOI: 10.1126/scitranslmed.3007372

With the continuous rise in life expectancy and the aging of the population, increasing rates of dementia have become a major public health concern. However, detection of early risk factors for dementia remains a challenge. Strikingly, there is a parallel increase in the rates of obesity and diabetes. However, studies assessing the association between obesity or diabetes and the risk of dementia have yielded inconsistent results. A large longitudinal study now suggests that higher concentrations of glucose, even among subjects without diabetes, may be a risk factor for dementia.

During a median follow-up of almost 7 years, the authors collected over 35,000 measurements of glucose concentrations from 2067 participants in the Adult Changes in Thought Cohort (mean age at baseline was 76 years). Among participants with diabetes, higher average glucose concentrations were significantly linked to a higher risk of dementia. Notably, a higher risk for dementia was also observed among study participants without diabetes. Strikingly, a relatively moderate increase in average blood glucose from 100 mg/dL to 115 mg/dL was associated with an 18% increase in the incidence of dementia (95% confidence interval 1.04 to 1.33). The increase in the risk attributed to elevated blood glucose was confirmed in a multivariate model to be independent of other confounders such as age, sex, exercise, blood pressure, coronary artery disease or cerebrovascular disease, atrial fibrillation, and smoking. The increased risk for dementia was documented across the entire spectrum of observed glucose concentrations. Although the exact mechanisms linking increased glucose concentrations and dementia cannot be elucidated from this observational study, the authors discuss potential mechanisms such as acute and chronic hyperglycemia and insulin resistance and increased microvascular disease in the central nervous system.

This large longitudinal study provides the first evidence for a strong correlation between elevated blood glucose (in the presence or absence of diabetes) and an increased risk of dementia. This important observation provides the rationale for interventional studies aimed at primary prevention of dementia using glucose lowering medications.

P. K. Crane et al., Glucose levels and risk of dementia. N. Engl. J. Med. 369, 540–548 (2013). [Abstract]

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