An Age Old Problem? Estimating the Impact of Dementia on Past Human Populations

Abstract

Abstract:Objectives: To model the impact of dementia on past societies. Methods: We consider multople lines of evidence indicating elderly individuals to have been more common throughout the past than is frequently accepted. We then apply known dementia incidence/ prevalence rates to plausible assumptions of past population structures to suggest prevalence in the past. Results: Dementia prevalence in pre-modern societies is likely to have been around 5% of the rate seen in modern, developed countries, but with a total past incidence running into billions. Discussion: Dementia is often seen as a 'modern' challenge which humans have not had to contend with before. We argue that this condition has had considerably greater effects than previously envisaged and is a challenge that humans have already withstood successfully, on one hand at a lower incidence but on the other without the considerable clinical, technological and social advances that have been made in recent times.http://mc.manuscriptcentral.com/jah Journal of Aging and Health F o r P e e r R e v i e w An age old problem? Estimating the impact of dementia on past human populations IntroductionThe cumulative effects of advances in medicine, sanitation and diets seen in the developed world over the last two centuries are a well-rehearsed story. First infectious diseases that previously resulted in frequent and sustained high mortality rates were effectively eradicated, followed more recently by lifestyle changes which reduced the risks of the cardiovascular and pulmonary diseases that came in their wake. As a result affluent regions are now characterised by populations with growing susceptibility to chronic conditions associated with ageing. As a category of disease that is incurable and which commonly increases in incidence with advancing age dementia is just such a condition.

Ageing and the Body in Archaeology

“…Smith et al note in reference to these two factors that: The mean age attained—which by definition will normally be superseded by a substantive portion of the population—is misread as a modal average, that is, the age at which most people might be expected to die. (Smith et al 2017, 71)…”

“…This idea has been widely critiqued by bioarchaeologists, palaeodemographers, anthropologists and historians (e.g. Agarwal & Grynpas 1996; Chamberlain 2006, 53–4; Smith et al 2017; Thane 2005), but remains a widely held belief even within archaeology. There are a number of reasons for the apparent deficit of the old in past populations.…”

“…There are a number of reasons for the apparent deficit of the old in past populations. The most widely discussed is the difficulty in ageing older adult individuals (Buckberry 2015; Smith et al 2017). Due to difficulties in accurately assigning age to people who died beyond middle age, older individuals tend to be grouped into a general category of 45+ or 50+.…”

“…Whilst we should therefore be wary of a ‘one size fits all’ interpretation of the numbers of older individuals in the past, we also need to acknowledge that older people were not rare. As Smith et al (2017, 92) note, if very few people survived to old age in the past, it ‘would raise the question “How the human life course as it now exists had ever evolved at all?”’.…”

“…The topic of old age has been relatively neglected in archaeology. The elderly were first the subject of a research paper in 2001 by Stig Welinder, and there have been a small, but significant, number of further papers in the decade and a half since then that concentrate on the old to a greater or lesser degree (Appleby 2010; 2011; Fahlander 2013; Gowland 2007; 2015; 2016; Ross & Oxenham 2015; Smith et al 2017); however, in comparison to other aspects of social identity (childhood, gender, ethnicity, status, kinship and so on), the old remain very under-studied. Archaeology is not alone in failing to consider the elderly (feminist scholarship, for example, has come late to the theorization of ageing (Twigg 2004)) and it may be that our failure to engage with the old is rooted in modern Western ambivalence about growing old and its inevitable end-point of death as much as it is in the theoretical and methodological difficulties that I will present below.…”