Posts like this reflect one’s pre-occupations to an obvious – and almost embarrassing – extent. But in this case my post is partly motivated by watching for many years an elderly relative achieving a very substantial age but being beset gradually by a host of medical problems and increasing frailty. My thoughts on this topic are very provisional and based very much on my reading of a paper by James Fries.
We all know the story about ‘Fred’ the local greengrocer who didn’t have a sick day in his life, seemed unusually fit but had a heart attack at age 52 which abruptly killed him. This is an instance of the live-and- die model without a morbidity interlude.
The live-and-die model describes fairly exceptional lives in modern times – significant morbidity periods are the rule not the exception. My relative definitely does not fit into the live-and-die model – indeed she an instance of the more typical live-long-wear-out model. These are people who live to great ages but for 20 years or more experience gradually worsening health problems.
Our lifespans are increasing continuously with advances in health technology – over the past 20 years an actuarial colleague tells me that live span has been growing at 2 years per decade – so a female born today can expect to live to about age 95 years. Health costs accumulate mainly after age 65 – 80% of all US health costs are concentrated in this period. Moreover most illnesses after age 65 are specific problems related to aging rather than chronic diseases and certainly not infectious diseases. Forecast health costs for Australia’s aging population are discussed here.
Living longer but not reducing cumulative morbidity involves less lifetime gains than might be the case if the health risks which cause morbidity could be delayed. And the good news, according to the Fries paper, is that these health risks can be reduced to reduce the onset of disability by at least 10 years. Thus if you are aged 75 and will live to be aged 95 the period of morbidity can be approximatetely harved.
This isn’t an obvious conclusion since for the last 20 years the expectation of life at age 65 has barely increased (only by 0.5 years) while life expectancy at age 85 (namely 6.1 years) has not increased at all.
The compression of morbidity hypothesis suggests that morbidity can be delayed more than mortality can be extended so that there will be a ‘failure of sucess’ effect. Morbidity is then concentrated at the end of life which is a desirable outcome since quality of life is improved and medical costs are reduced.
Morbidity can be compressed by doing all the standard lifestyle things – not smoking, eating foods low in fat, exercising (Australia now has guidelines), not being obese. If great age is achieved then frailty rather than specific ’cause of death’ becomes important. At great ages pneumonia can be the ‘old mans’ friend’ – it terminates the infirmities of frailty. Indeed Fries points out that influenza epidemics increase death rates when they occur but reduce them for 6 months following the epidemic.
Frailty itself is associated with both reduced strength immune systems and organ failure. Strengthening immune systems might proximately reduce morbidity if it occurs well before multiple organ failures begin to occur but might slightly increase morbiodity if it occurs shortly before the time of natural death.