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| Bill Yates Brain Posts |
There has been significant public discussion on the topic of politicians running for office at an older age. I wanted to add a few comments to this discussion from a neuroscience perspective on the aging brain.I think there are three key elements in this topic. The first is pretty universal effect of age to produce a reduction in psychomotor speed.
The graph above shows norms for the completion of the Trails B Test by age. This test involves connecting an alternating number/letter series of dots in a timed test. The norms demonstrate that psychomotor speed as assessed in this test is relatively preserved until around 70 years of age and then decreases significantly and progressively.
How this task might effect day-to-day tasks for presidents and congressmen and women is unclear. However, it is a non-trivial issue that is an important aspect of the aging brain.
A second important topic of discussion is increased risk of incident cognitive decline and dementia. Risk of dementia increases progressively with age. Using data from a U.S. population based survey, the rates of incident dementia (all types) rises from 4.3 per 1000 individuals for those age 65-69, to 12.0 per 1000 for those age 70-74 and 21.1 for those age 75 to 79.
The rates of incident dementia are somewhat lower in women than in men by about 20%. Additionally, elected politicians typically have high educational levels, a factor that is know to reduce risk and potentially delay the timing of cognitive decline with age.
However, using the rates from the U.S., for an elderly politician elected president, the rate of incident cognitive impairment and dementia is also nontrivial. Based on my review of the data a president elected at age 70+ would have somewhere between a 5 and 15% chance of clinically significant cognitive impairment over the course of an 8 year presidential cycle.
Finally, there is the issue of mortality risk. Mortality risk climbs steadily with age and becomes a nontrivial issue for candidates approaching 70 and older.
The National Journal recently published an article stating that Hillary Clinton's age should not be considered a factor for mortality risk. They calculated that for her age at inauguration in 2016 she would have a life expectancy of 17 more years.
I don't contest the projection of life expectancy in their article, but it does neglect this issue of risk of death before one's projected life expectancy is met. Not all 69 year old women will live 17 more years. Some will live shorter, some longer.
The more appropriate estimate might be what is the risk of an elderly politician dying during an 8 year term in office. Using actuarial data from the Social Security Administration, I have put together a year by year table of estimated mortality risk for older men and women in the U.S.
These estimates are shown along with past, current and potential future presidents ages. The estimated 8 year mortality for a 69 year old woman in the U.S. is 17%. Note that this estimated risk in women is significantly lower than a similarly aged male who has about a 27 to 30% 8 year mortality risk.
These risks are significantly increased compared to younger presidents. For example, for a male age 48 (the age of Barack Obama at his first inauguration) the 8 year mortality risk is only 5% and the incident dementia risk is less than 1%
The 8 year mortality risk for men in the U.S. jumps to nearly 40% for men who 74 years of age (the age of Joe Biden if elected president in 2016). Exact estimates for specific individuals or candidates cannot be precisely made. Nevertheless, the Social Security Administration data is informative and provides a ball park guide to relative risks.
The dementia and mortality data show older women have a more favorable brain aging and mortality outcomes than men. I think this age-related gender advantage provides older women an opportunity to serve in elected office later in the human life-cycle.
In the case of Hillary Clinton, a lower gender-related risk for cognitive impairment and mortality may be an advantage. This is particularly true when contrasted against other male candidates in the same (or older) age range.
Obviously the potential impact of age and it's effect on the brain is only one issue of importance when selecting and voting for candidates for public office. The aging issue is nontrivial but may be less an issue if there are other factors supporting the value of older candidates, i.e. experience.
Figure at top of post is from data in the Tombaugh citation below and is an original figure made by the author.
Table is an original table from the author using SSA data.
Follow the author on Twitter @WRY999.
Disclaimer: The author is a registered Republican who has voted for the Democratic presidential candidate in two of eleven presidential elections. The review in this post has attempted to be science based. Any concern about bias may be mentioned in the comments section.
Social security administration actuarial data.
Tombaugh, T. (2004). Trail Making Test A and B: Normative data stratified by age and education Archives of Clinical Neuropsychology, 19 (2), 203-214 DOI: 10.1016/S0887-6177(03)00039-8.
Ganguli, M., Dodge, H., Chen, P., Belle, S., & DeKosky, S. (2000). Ten-year incidence of dementia in a rural elderly US community population: The MoVIES Project Neurology, 54 (5), 1109-1116 DOI: 10.1212/WNL.54.5.1109.
See the original article:
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