High blood pressure, diabetes and smoking could hamper thinking skills in middle age, study reveals
Certain risk factors such as high blood pressure, smoking, and diabetes may lead to the steepest decline in thinking skills in middle age, according to researchers. After adjusting for age, race, education and other factors that could affect the risk of cognitive decline, a research team found that people who smoked were 65% more likely to have accelerated cognitive decline, those with high blood pressure were 87% more likely, and those with diabetes were nearly three times as likely to have faster cognitive decline.
“Cardiovascular risk factors, especially high blood pressure and diabetes, become more common in midlife. We found those two risk factors, as well as smoking, are associated with higher odds of having accelerated cognitive decline, even over just a short span of five years,” explains study author Kristine Yaffe, MD, University of California, San Francisco, in the analysis published in Neurology, the medical journal of the American Academy of Neurology.
“In other words, people with these risk factors had a greater chance of having faster cognitive decline than a group of their peers who did not smoke, or have high blood pressure or diabetes. It's encouraging to know that there are behaviors people can modify in midlife to help prevent the steepest declines in thinking and memory as they age,” says Yaffe, who is a member of the American Academy of Neurology.
The study was supported by the National Heart, Lung, and Blood Institute, the National Institute on Aging, the University of Alabama at Birmingham, Northwestern University, University of Minnesota, and Kaiser Foundation Research Institute. It involved 2,675 people with an average age of 50 who did not have dementia. Researchers measured their cardiovascular risk factors at the start of the study: 43% were considered obese, 31% had high blood pressure, 15% were smokers, 11% had diabetes, and 9% had high cholesterol.
Participants were given thinking and memory tests at the beginning of the study and five years later. Then researchers estimated the association of the five cardiovascular risk factors with a decline in their performance on the thinking and memory tests that were not defined as dementia but were faster than what was seen in a group of adults of similar ages.
According to the analysis, 5% of the participants had accelerated cognitive decline over five years. A total of 7.5% of those with high blood pressure had a faster decline, compared to 4.3% of those who did not have high blood pressure. Further, 10.3% of those with diabetes had a faster decline, compared to 4.7% of those who did not have diabetes. A total of 7.7% of current smokers had a faster decline, compared to 4.3% of those who never smoked, says the research team.
People who had one or two of the risk factors were nearly twice as likely to have accelerated decline than people with no risk factors. People with three or more of the risk factors were nearly three times as likely to have a faster decline than those with no risk factors. Of the 1,381 people with one or two risk factors, 71 had a faster decline, or 5.1%, compared to 19 of the 700 people with no risk factors, which is 2.7%, and 53 of the 594 people with three or more risk factors, which is 8.9%.
The authors found it surprising that people who were considered obese and those with high cholesterol did not have a greater risk of cognitive decline. “Other studies have shown a link between obesity and dementia, but mostly in older adults. Meanwhile, the studies that examine high cholesterol and dementia have had mixed results, so our research adds to those studies,” writes Yaffe.