Individuals may experience worse cognitive function during midlife if they had moderate-to-high risk of kidney failure as a young adult, according to a study published in Neurology.
“We know that people with complete kidney failure are about 3 times more likely to have thinking, learning, and remembering problems than their peers,” said study author Sanaz Sedaghat, PhD, of Northwestern University Feinberg School of Medicine, in Chicago, and a member of the American Academy of Neurology. “Our study shows that if your kidney function starts declining as early as your 30s, you may perform like someone 9 years older on certain cognitive tests 20 years later. Yet many people can have a decline in kidney function without being aware of it.”
There were 2,604 participants, mean age 35 years, at the beginning of the study. Participants had 4 blood and urine tests to measure kidney function, a test every 5 years, for 20 years. The participants were categorized as having: 0 episodes of kidney failure risk, 1 episode of kidney failure risk, and more than 1 episode of kidney failure risk. At the end of the study, participants had cognitive assessments that measure executive function, memory, impulse control, and verbal fluency.
Over the 20-year study, 427 participants had 1 or more episodes of kidney failure risk, putting them in the higher risk group, which had mean scores that were 4 times lower than those in the low-to-mid risk groups. Other potential risk factors for cognitive deficits, including high cholesterol, high blood pressure, and diabetes were controlled for with statistical analysis.
“Comparing the estimated effect of age on thinking skills to the effect of kidney failure risk, we observed that the people who had high risk of kidney failure were performing in their thinking tests as if they were about 9 years older than those in the group with no risk,” Sedaghat said. “Recent studies indicate that even losing just a small amount of kidney function can be toxic for the brain and increase the risk of cognitive decline. Our study adds to the evidence and suggests preserving kidney function in young age needs to be investigated as a potential strategy to keep thinking skills sharp in midlife.”