What do pneumonia, cardiovascular disease and diabetes have in common? Each is a focal point of recent dementia-related research.
In one study, researchers from the University of Pittsburgh found that elderly patients who were hospitalized with pneumonia and other infections were more than twice as likely to develop dementia than those who did not have an infection.
“These findings explain in part why seemingly healthy older adults progress to a state of disability following infection and how a single episode of infection may lead to cognitive decline in older adults,” says senior author Sachin Yende, MD. “Most people think infection is a short-term illness, but patients who look and feel recovered may have downstream consequences.”
The study involved 5,888 participants each aged more than 65 years. Of these participants, 639 were hospitalized with pneumonia at least once. The investigators also found that patients with dementia may be more susceptible to infection: patients who showed signs of impaired cognitive function before their hospitalizations had an 11 percent higher risk for pneumonia and other infections than those with healthy cognitive function.
“Even a small change in cognition predisposed patients to pneumonia,” says lead author Faraaz Shah, MD. “Once they had an infection, they were at a higher risk for worsening of cognitive function and dementia. This cycle could perpetuate and ultimately lead to disability and loss of independence.”
In a study out of Taiwan, researchers found that high doses of statins, used to reduce the risk of cardiovascular disease by lowering cholesterol levels, prevent dementia in older adults.
Tin-Tse Lin, MD, and a colleague studied 57,669 people aged more than 65 years; 5,516 had new diagnoses of dementia in the follow-up period, and the remaining participants belonged to the control group.
“The adjusted risks for dementia were significantly inversely associated with increased total or daily equivalent statin dosage,” Lin says. “Patients who received the highest total equivalent doses of statins had a three-fold decrease in the risk of developing dementia. Similar results were found with the daily equivalent statin dosage.”
The potency of the drug, rather than its solubility, determined whether dementia risk was reduced, Lin says, adding, “Higher doses of high-potency statins gave the strongest protective effects against dementia.”
When taken at higher daily doses, almost all of the statins studied, except lovastatin, decreased the risk for new-onset dementia.
URINE TEST HELPFUL
In another study, researchers found that the presence of protein in the urine may be a marker of risk for future cognitive decline in patients with type 2 diabetes and normal kidney function.
Investigators at Kaiser Permanente of Georgia/Emory University and the National Institute on Aging studied 2,977 people with diabetes to evaluate whether albuminuria — a kidney complication characterized by protein excretion in the urine — predicts cognitive decline in older adults with diabetes.
Participants, aged an average of 62 years, underwent tests of their information processing speed, verbal memory and executive function at the start of the study and again 20 and 40 months later. Those with persistent albuminuria (present at baseline and at follow up) over four to five years had greater declines in information processing speed than those without albuminuria. Persistent albuminuria and progressive albuminuria (present at follow up but not at baseline) were linked with a decline of greater than five percent in information processing speed scores but not with such a decline in verbal memory or executive function performance.
“Our finding was a subtle change in cognition; however, were this decline to continue over 10 to 15 years, it could translate into noticeable cognitive decline by the age of 75 to 80 years, when cognitive impairment generally becomes clinically evident,” say first author Joshua Barzilay, MD. “Given how common albuminuria and diabetes are in the older population, these findings have a great deal of importance from a population point of view. Moreover, albuminuria is also common among older people with hypertension without diabetes.”
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