Now that many of the childhood infectious diseases cause fewer infant deaths the bulk of illness is borne by the elderly. This is reflected in prescription rates: the over 60s make up around 18% of the UK population but this group consume 33% of medicines. Almost 80% of over 65’s are on one or more medicinal drugs.
In some ways this is a good thing; many of these drugs help older people to lead longer and more comfortable lives. However the burden on healthcare systems is considerable and growing, leading to increasing interest in the response of the elderly to disease and in keeping them as fit as possible.
Fitness in the Elderly
In younger people there is not much variation in fitness levels between individuals but this is not so in the elderly. Because people age at different rates and in different ways depending on genes and life-style, by the time we reach late middle age big differences in fitness levels exist between individuals. This of course has considerable bearing on response to illness or injury both of which are more likely in old age.
Regular exercise, good diet and keeping the mind active are important for everyone regardless of age but much more so in the elderly since these will help aging body systems stay in good condition. “Use it or lose it” applies here.
Response to Illness in the Elderly
Older people often respond to illness in different ways to younger people. This is usually due to having less reserve. Frequently they will produce different symptoms or no symptoms at all. For example, urinary tract infections, which are common in the elderly, may show no symptoms at all or seemingly unrelated features. Often there will be no pain in the bladder or back or on passing urine and no fever, however there may well be mental confusion and sometimes hallucinations.
The mental effects are probably due to having insufficient reserve in the blood circulation. If blood is being diverted to the area of the infection and to support the immune system then blood flow through the brain will be less.
The lack of pain and fever is thought due to the nervous system becoming less sensitive. This has the potential to compound the problem since pain is a warning that something is wrong and fever helps combat infection and alerts us to its presence. Since senior citizens are likely to be given less warning of illness it highlights the need for regular check-ups and vigilance on the part of relatives or carers.
Response of the Elderly to Drugs
Most drugs are broken down by the liver and got rid of by the kidneys. The level of a drug in circulation at any one time depends on the efficiency of these organs. As we age these organs along with all the others become less efficient. A dose of a drug suitable for a young adult will rise to greater levels and stay in the blood for longer in an older person and therefore the drug dose needs to be adjusted accordingly. However, as has been said there is much individual variation in fitness levels in older people and this naturally applies to their livers and kidneys as well as everything else. This makes predicting the effects of a drug and the likelihood of adverse reactions more difficult.
In addition drug companies, for obvious reasons, test their drugs mainly on young fit adults so much of their research on adverse drug reactions doesn’t apply that closely to the elderly.
All this may sound a bit worrying but it should be remembered that older people are living longer and healthier lives. If you are worried about your health you should consult your doctor.