To What Degree is Alzheimer's Disease a Modern Phenomenon?

Here find an interesting commentary on what might be gleaned of the prevalence of Alzheimer's disease in antiquity from the body of ancient writings on the topic of aging, memory, and health. The consensus is that Alzheimer's disease is a creation of modernity, some combination of a longer life expectancy for a greater fraction of the population coupled with increased calorie intake and less active lives. Yet unlike type 2 diabetes, risk of Alzheimer's risk doesn't correlate well with the usual suspect lifestyle choices that raise the risk of age-related disease and lower life expectancy.

This line of thinking has led to many hypotheses on the contributing factors leading to Alzheimer's disease. Some are unsupported by anything other than coincidence, comparing the introduction of a new factor in modern lives with the rising incidence of Alzheimer's disease, such as the thought that paracetamol use is causing this form of neurodegeneration. Better supported by the evidence is the view that persistent viral infection is involved in the pathogenesis of Alzheimer's disease. Since viruses evolve rapidly over time, it is tempting to speculate on the role of this viral evolution in an increased burden of Alzheimer's in the aged population today - but this is indeed only speculation. It is also hard to reconcile this hypothesis with the relative lack of Alzheimer's disease in modern hunter-gatherer populations.

Did the ancient Greeks and Romans experience Alzheimer's?

You might think age-related dementia has been with us all along, stretching back to the ancient world. But a new analysis of classical Greek and Roman medical texts suggests that severe memory loss - occurring at epidemic levels today - was extremely rare 2,000 to 2,500 years ago, in the time of Aristotle, Galen, and Pliny the Elder. Ancient Greeks recognized that aging commonly brought memory issues we would recognize as mild cognitive impairment, or MCI, but nothing approaching a major loss of memory, speech and reasoning as caused by Alzheimer's and other types of dementia. Centuries later in ancient Rome, a few mentions crop up. Galen remarks that at the age of 80, some elderly begin to have difficulty learning new things. Pliny the Elder notes that the senator and famous orator Valerius Messalla Corvinus forgot his own name. Cicero prudently observed that "elderly silliness ... is characteristic of irresponsible old men, but not of all old men."

Dementia in the Ancient Greco-Roman World Was Minimally Mentioned

The possibility that Alzheimer's disease and related dementias (ADRD) is a modern disease arises from the minimal mention of advanced cognitive decline by ancient Greeks and Romans, who were mainly concerned with the physical frailties of older ages. Because standard medical histories of elderly health lacked mention of cognitive decline, we examined texts by Greek and Roman authors that mentioned memory loss and dementia. Primary texts of Greco-Roman authors, 8th century BCE into the 3rd century CE, that mentioned cognitive decline were identified and critically evaluated. Secondary sources were excluded.

No ancient account of cognitive loss is equivalent to modern clinical data. The term dementia was occasionally used in antiquity, but not invariably linked to old age. Ancient Greeks and Romans expected intellectual competence beyond age 60. While some memory loss was acknowledged, we found only four accounts of severe cognitive loss that might represent ADRD. The possibility of modest ADRD prevalence in ancient Greece and Rome is consistent with its low prevalence in the Tsimane of Bolivia. These contemporary Amerindians live under conditions of high mortality from frequent infections and minimal cardiovascular disease with physically demanding lives. Tsimane after age 60 had increased mild cognitive impairment; the few cases of dementia were not clinically consistent with AD.

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