Experts Say Men Are More At Risk Of Worse Memory Loss Than Women

Researchers recently found out that males with normal cognition are more likely to have worse memory and exhibit low hippocampal symptoms during the middle and old age. In addition, the study suggests that normal memory loss and brain shrinkage in these age groups are not influenced by APOE ε4 gene, nor is there a direct association between normal brain changes and early clinical presentation of Alzheimer’s disease.

The study was headed by Clifford Jack Jr, MD, Mayo Clinic and Foundation, Rochester, Minnesota, and was published in JAMA Neurology on March 16. The authors of the study have this to say, "Our results paint a different picture than is presented in much of the recent imaging literature, which has focused great attention on the effect of APOE ε4 but little on the effect of sex on brain structure and function." Jack confirms this by saying, "While the APOE 4 gene has large effect on predicting preclinical Alzheimer's disease, it does not seem to affect normal memory and brain volume loss in cognitively normal people."

Jack also said to Medscape Medical News that amyloid levels are uncommon to develop earlier than the age of 70, and that both memory function and hippocampal volume decline in a stable manner starting from the age of 30. Therefore, it is highly suggested that memory loss and decreased brain volume during the middle and older adult stage can simply be attributed to the normal ageing process, with possible exacerbations brought by cerebrovascular disease.

The breakthrough discovery from this recent research clearly refutes former theories linking memory loss in middle age to early Alzheimer’s disease. Jack further notes that Alzheimer’s biomarkers develop decades after memory loss and decreased brain volume are initially noted. He confirms, "Just because you may experience memory loss in middle age doesn't mean you are going to develop Alzheimer's in the vast majority of people. This is normal. It happens to everyone. The brain is like any other organ system in the body — it doesn't function as well aged 90 as it does aged 30. The memory decline we experience from middle age is just the inescapable nature of aging."

An interesting factor of the study is the investigation of the authors regarding the relationship between gender and memory/brain function decline. It is suggested that gender has a significant impact on hippocampal volume and memory. "In men, brain volume and memory decline quicker from age 40 onwards than it does in women. This has been seen before but it has largely been ignored; gender has been treated as a nuisance variable. I think that is a big mistake. We need to focus on this difference," Jack said.

Men are more likely to develop worse memory loss and brain shrinkage than women due to their increased risk of vascular diseases, such as hypertension, diabetes and high cholesterol levels. Such diseases are said to affect brain volume according to Jack. Although these conditions are more associated with men, he said these factors are modifiable and that the occurrence of such health disorders are typically based on lifestyle choices. "And men lack the protective effect of estrogen on vascular risk. Women have 4 decades of estrogen protection," he adds.

Charles DeCarli from the Davis Alzheimer's Disease Center, said in an editorial that the study "challenges the notion that amyloid accumulation explains memory performance across the entire age range." He iterates that vascular conditions and hypertension are linked to minor cognitive decline among individuals aged 47-57, and major cerebral atrophy among individuals aged 40 respectively. He concludes by saying, "Establishing what is normal creates avenues for new research, increasing the likelihood of discovering novel therapeutics for late-life disease states, which is a laudable goal indeed.”

The study involved 1,246 individuals with normal cognitive function aged 30-95. The participants underwent hippocampal volume measurement on MRI, amyloid positron emission tomography (PET), and memory testing including the Auditory Verbal Learning Test. The results of the study are as follows: brain volume declines gradually from 30-60 years of age, amyloid PET levels increase only after the age of 70, and memory starts to worsen at the age of 30 through 90.

Looking at the gender and age of the participants, the study found that memory (P < .001) was worse in men than in women, particularly among those aged beyond 40. The brain volume (P < .001) was also reduced in men than in women, particularly among those aged beyond 60. However, amyloid PET scans did not reveal significant results associated with gender, as there were no difference between hippocampal volume and APOE ε4 among men and women across all age groups. Amyloid PET levels are more increased in APOE ε4 carriers than noncarriers after the age of 70. Furthermore, 10 percent of individuals with positive amyloid PET levels were aged 57 years (APOE ε4 carriers) and 64 years (noncarriers of APOE ε4).

After the presentation of the study, the authors have these words to say: "Our findings are consistent with a model of late-onset Alzheimer disease in which β-amyloidosis arises in later life on a background of preexisting structural and cognitive decline that is associated with aging and not with β-amyloid deposits."

To contact the writer, email rinadoctor00@gmail.com