Demography & Life Course PDF

**[Objectives ]** - - - - Kirkwood, 2005: *"Aging is commonly characterized as a progressive, generalized impairment of function, resulting in an increasing vulnerability to environmental challenge and a growing risk of disease and death."* It's important to look at demographic changes...

**[Objectives ]** - - - - Kirkwood, 2005: *"Aging is commonly characterized as a progressive, generalized impairment of function, resulting in an increasing vulnerability to environmental challenge and a growing risk of disease and death."* It's important to look at demographic changes in order to understand the societal impact of aging and to adjust health care accordingly. Scientific and medical advances have influenced demographic change to a large extent because they have impacted lifespan. Two concepts increasingly used by policy makers: - - **Evolutionary perspective** Common ideas of why organisms age: - - BUT: - - - This led to a few evolutionary theories of aging: - - - - Out of these theories, the disposable soma theory gained the most support: - - - Disposable soma theory = **aging is a byproduct of an evolutionary strategy that maximizes reproductive success at the expense of longevity.** The ultimate examples of disposable soma can be seen in some salmon, mice and octopi: they have 1 chance to reproduce so all resources are switched to reproductive success which leads to death afterward.  But there are always exceptions to the rule (see right). So how do we explain these differences in species' longevity? An organism\'s fitness and longevity pattern depends on how efficiently it balances the costs and benefits of competing biological demands such as reproduction and repair. Trade-offs between the energy investment into each of these demands define the species' life history and therefore much of its longevity pattern. I.e. How much survival must be sacrificed to gain how much reproduction and vice versa? For some species, not much survival has to be sacrificed to gain sufficient reproduction = extremely slow aging. Take home messages 1. 2. 3. 4. Implications from evolutionary research into aging: - - - - - - **Demography** In the Netherlands: - In Ghana (prof.Bodegom did field work here): - **But** over time, this structure changed because of the demographic transition taking place: - - What set this demographic transition in motion? 1. a. b. Broader implications: - - - The Ghana case study shows how simple interventions---like access to safe drinking water--- can lead to profound demographic and health changes. It also highlights the importance of anticipating the rise of chronic diseases as countries undergo demographic transitions. Reminder for both developing and developed nations to focus not just on extending lifespan but on improving health span. *Related article: Christensen K, Doblhammer G, Rau R, et al. Ageing populations: the challenges ahead. Lancet 2009;374(9696):1196-208.* Chronic diseases significantly affect the elderly population, with diabetes, heart disease, arthritis and cancer being the most prevalent. There is a global trend in the rise of these diseases that poses challenges to health expectancies among older adults. As the prevalence of chronic diseases increases, we need to understand their implications: - - Data from Japan (highest proportion of centenarians) shows that more recently centenarians exhibit worse health than their predecessors. Cross-country comparisons reveal that increased survival to advanced ages is often associated with poorer health outcomes. This trend raises concerns about the functional abilities of the oldest-old population. There are also significant gender differences among the elderly. Females tend to have worse physical function than males. As life expectancy continues to rise, health promotion strategies need to address chronic diseases and their impact on functional limitations.