Diabetes, High Blood Pressure and Smoking Can Lead to Dementia

In a recently published article, researchers suggest that controlling cardiovascular risk factors in midlife may prevent dementia later on.

Lead author Alvaro Alonso, MD, from the University of Minnesota in Minneapolis, stated that,"Our study population included both whites and African Americans.… We were able, for the first time, to show that cardiovascular risk factors in midlife are associated with dementia later in life in both racial and ethnic groups." 

Overall, blacks had a 2.5 times higher rate of hospitalization for dementia than whites. Black women in particular had the highest rates of all. 

Current smokers were 70% more likely than those who had never smoked to develop dementia. People with high blood pressure were 60% more likely than those without high blood pressure to develop dementia, and people with diabetes were more than twice as likely as those without diabetes to experience cognitive impairment. 

The researchers also demonstrated that cardiovascular risk factors measured earlier in life are better predictors of dementia than risk factors measured in older age. "These results, again, support the need for paying special attention to cardiovascular risk factors in midlife," Dr. Alonso said. 

Investigators studied more than 11,000 people who were part of the Atherosclerosis Risk in Communities (ARIC) study. Participants were aged 46 to 70 years and underwent a physical examination and cognitive testing. Patients were followed up for more than a decade to see how many would later develop dementia. 

Researchers identified 203 patients hospitalized with dementia. Smoking, high blood pressure, and diabetes were all strongly associated with this diagnosis. 

In analyses including updated information on risk factors during follow-up, the hazard ratio of dementia in hypertensive versus nonhypertensive participants was 1.8 at age 55 years compared with 1.0 at age 70 years or older. Researchers observed similar results for diabetes, with a hazard ratio of 3.4 at age 55 years and 2.0 in those older than 70 years. For smoking, the hazard ratio was 4.8 at age 55 years and 0.5 in patients aged 70 years or older. 

"We were only able to identify individuals with dementia who were attended in a hospital," Dr. Alonso pointed out. "Therefore, it is very likely that we missed some people with dementia. Still, we did a number of additional analyzes to determine whether this could bias our results. Overall, we are confident that this limitation is not having a major impact in our overall conclusions." 

J Neurol Neurosurg Psychiatry. Published online August 19, 2009.