Does your wife claim to remember much more than you do? She could be right — up to a point, of course.
Most people overestimate their capacity for recall, for instance, by thinking that more vivid memories are especially accurate. That said, women may have the edge over men. Although nearly two-thirds of Americans with Alzheimer’s disease, the most common form of dementia, are women, men may suffer more from other kinds of memory loss.
One large 2015 study by a Mayo Clinic team set out to document decline over time in people with no known memory problems, aged 30 to 95. The researchers found that memory began declining gradually after the age of 30, with a steeper drop after the mid-60s. But men did worse than women after the age of 40. As expected, the team saw steady shrinkage in the hippocampus region of the brain, which forms, stores, and organizes memory. Male shrinkage was worse than female after age 60.
One theory has it that accumulation of proteins, called amyloid deposits, between brain cells is an early sign on the path to dementia. The Mayo Clinic team noted that people who carry a gene called APOE ɛ4, which research suggests is a risk factor for Alzheimer’s, showed signs of amyloid accumulation beginning at age 57, compared to 64 in people without the gene. But the team did not find more amyloid accumulation in men, which, they argued, suggests that mental decline associated with aging is not caused by amyloid deposits.
In another Mayo Clinic study, when researchers looked for signs of mild cognitive impairment in 1,450 men and women aged 70 to 89 over three years, they found that men were more likely to suffer these pre-dementia signs.
So what can men do to preserve their capacity for memory? Both mild cognitive impairment and dementia may be tied to diabetes, high blood pressure, and obesity. Studies have found that diabetes may be associated with mild cognitive impairment as early as age 47 and have linked high blood pressure to brain shrinkage even younger. Obesity has been associated with poorer cognitive functioning at all ages, and obesity in middle age has been linked to dementia in later years.
The good news is that at least nine population-based studies have shown drops in the risk of dementia in richer countries such as the United States, England, The Netherlands, Sweden, and Denmark. More aggressive treatment of high blood pressure and high cholesterol may be improving brain health. Join the crowd: keep your weight in a reasonable range and do all you can to treat chronic conditions.
April 28, 2015
Christopher Nystuen, MD, MBA