Your Older Cat Looks Healthy. But Is It?

A new UK study screened 549 cats aged eight and older at two veterinary clinics. Many had conditions their owners may not have known were there.

Cats are unusually good at making ageing look uneventful. They sleep more, jump a little less, perhaps lose some weight, drink a little more, become fussier about food. Individually, these changes are easy to dismiss as simply getting older. But a newly published UK study provides a useful reminder that an older cat can appear reasonably well while carrying a disease that hasn't yet produced an obvious reason for its owner to seek veterinary care.

Researchers screened 549 cats aged eight years and older at two UK veterinary clinics. Among the cats for whom the relevant tests were available, they identified hyperthyroidism in 19.2%, azotaemic chronic kidney disease in 11.4%, hypertension in 7.1% and severe dental disease in 6.1%. That doesn't mean one in five apparently healthy older cats everywhere has hyperthyroidism — this wasn't a random sample of Britain's entire cat population. But it does make a strong case for something cat owners often underestimate: waiting for an older cat to look ill may mean waiting until disease has already progressed.

What the researchers did

The study, published in the Journal of Veterinary Internal Medicine, examined disease detected during health screening of older cats at two UK veterinary clinics, with 549 cats and a median age of 13.5 years. Rather than starting with cats brought in because their owners had noticed a specific illness, the researchers were interested in what systematic health screening could find in an older population.

Not every cat received every test, which is important when interpreting the percentages. Hyperthyroidism was identified in 89 of 464 cats tested — 19.2%. Azotaemic chronic kidney disease was identified in 62 of 542 cats — 11.4%. Hypertension was found in 37 of 524 cats — 7.1%. Severe dental disease was recorded in 32 of 522 cats — 6.1%. Bacteriuria — bacteria detected in urine — was identified in 22 of the 227 cats tested for it, or 9.7%. Researchers also detected smaller numbers of cats with suspected neoplasia, diabetes and gastrointestinal disease.

The precise percentages are interesting. But the broader finding matters more: screening found clinically relevant disease in cats that might otherwise have remained undetected for longer.

Why cats make this difficult

Cats don't consciously hide illness, but feline behaviour can make gradual disease remarkably difficult for an owner to recognise. A dog that stops wanting its usual walk produces an obvious change. An older cat that spends another hour asleep each day may not. A cat with chronic kidney disease may gradually drink more. A hyperthyroid cat may lose weight despite continuing to eat well. A cat with arthritis may simply stop jumping onto one particular surface. A cat with dental pain may continue eating, but chew differently or prefer softer food. It's the same pattern we describe in how to tell if your cat is unwell — the signals are there, they're just quiet.

Because these changes often occur slowly, an owner's mental picture of what is normal can shift alongside the cat. That is why trends become particularly valuable in older animals. A weight recorded every few months can reveal something that looking at the cat every day simply doesn't.

Hyperthyroidism: the standout finding

The largest proportion in the study was hyperthyroidism — 89 of 464 cats tested, or 19.2%. Feline hyperthyroidism is caused by excessive thyroid hormone production and is primarily a disease of older cats. Classic signs include weight loss, increased appetite, increased thirst and urination, restlessness, vomiting or diarrhoea, and coat changes. But early disease doesn't necessarily present as the textbook hyperactive, ravenously hungry, very thin cat. Weight loss can be gradual, and in an older animal owners may interpret it simply as ageing.

That is one reason why weighing an older cat regularly is so useful. "She seems fine" and "she has lost 600 grams since last year" are very different pieces of information.

Kidney disease: another condition that can creep up

Chronic kidney disease is one of the major diseases of older cats, and 11.4% of the cats assessed in this study met the criteria for azotaemic CKD. Azotaemic refers to increased concentrations of nitrogenous waste products in the blood because the kidneys are no longer clearing them normally. By the time obvious illness develops, kidney function may have been declining for some time.

Possible signs include drinking more, urinating more, weight loss, reduced appetite, vomiting, lethargy and a poorer coat. Again, several of these can be rationalised as old age. A blood test can identify changes in kidney markers, while urine testing provides additional information about the kidneys' ability to concentrate urine. Blood pressure matters here too — kidney disease and hypertension can occur together, making a broader screening approach more informative than a single blood test.

High blood pressure is particularly easy to miss

Hypertension was identified in 7.1% of the cats assessed for it, and it is a good example of why physical appearance alone isn't sufficient. A cat can have clinically important hypertension without an owner seeing anything obviously wrong. When hypertension becomes severe, however, it can damage organs including the eyes, kidneys, brain and heart — and sometimes the first dramatic sign an owner notices is a problem with vision.

Blood pressure measurement is therefore particularly valuable, because hypertension isn't something you can diagnose by watching a cat at home. It has to be measured. The veterinary environment can temporarily increase a cat's blood pressure, so vets interpret measurements carefully and may take repeated readings in a calm setting, but without measuring at all there is little chance of detecting silent hypertension.

And then there are the teeth

Severe dental disease was recorded in 6.1% of cats assessed — which may seem less consequential beside kidney disease or hypertension, but isn't. Cats can continue eating despite significant oral disease, and owners may not routinely examine the back of their cat's mouth. Dental pain may show up as eating more slowly, dropping food, chewing on one side, preferring softer food, reduced grooming, bad breath, or reluctance to have the face touched. Or there may be surprisingly little that an owner notices. A veterinary examination gives someone the opportunity to look deliberately for something the cat has quietly adapted around. Our dental care guide covers what routine care can realistically achieve at home.

What this study does — and doesn't — tell us

There is a temptation with a study like this to reach for a headline: one in five older cats has hidden hyperthyroidism. That is too strong. These 549 cats came from two UK veterinary clinics and are not necessarily representative of every cat aged eight and above in Britain. Nor does the research prove that putting every cat through every available test at a particular age improves longevity.

What it does show is simpler and more useful: systematic screening of older cats can uncover clinically important disease that might otherwise not yet have prompted veterinary investigation. That is a different claim — and a better reason to pay attention to the research.

So when does a cat become senior?

There isn't one age at which a healthy adult cat suddenly becomes old. Different veterinary organisations use slightly different life-stage terminology, and biological ageing varies between individuals. The cats in this study were eight years and older, while the median participant was 13.5 years. The practical question therefore isn't whether your cat has crossed an arbitrary threshold — it's whether the way you monitor its health should change as it ages. For a young adult cat, seeing a vet when something appears wrong may catch many problems. For an older cat, waiting for obvious illness becomes a less reliable strategy.

What an older-cat check can involve

A health check doesn't mean running every available test. The appropriate approach depends on age, history, previous results, medications, examination findings and the individual animal. But useful components can include weight and body condition trends across multiple visits, a thorough physical examination including the mouth, heart, abdomen, coat, muscles and joints, blood pressure measurement, blood testing for kidney function, thyroid hormone, blood glucose, liver parameters and blood cells, and urine testing to complement blood results and assess urinary health. The aim isn't to find abnormalities for the sake of it — it's to identify problems where earlier recognition changes what can be done next.

What you can monitor at home

Screening doesn't begin at the veterinary practice. Owners have something vets don't: hundreds of observations of the same animal in the same environment. Pay attention to trends in body weight, appetite, water consumption, urination, jumping, grooming, activity, sleep, interactions with people, litter tray habits, vomiting and stool. Changes in mood and engagement matter too — cats can experience low mood and withdrawal, sometimes as a consequence of underlying physical illness.

You don't need to turn your cat into a daily spreadsheet. But weighing an older cat periodically is particularly useful, as is noticing whether you're filling the water bowl more often, buying litter more frequently, or seeing changes in which furniture your cat still chooses to jump onto. Small changes become more informative when you know what normal used to look like.

Try this today

Find your cat's weight from its last veterinary appointment and compare it with earlier records if you have them. A slow downward trend can be very difficult to see when you live with an animal every day. And at the next appointment, don't just ask whether your cat looks healthy. Ask: given my cat's age, is there anything we should be screening for before symptoms appear? That is a much more useful conversation.

The bottom line

Looking well and being disease-free aren't necessarily the same thing in an older cat. In this new UK study of 549 cats aged eight and above, screening identified hyperthyroidism, chronic kidney disease, hypertension, severe dental disease and several other conditions in cats whose owners may not have suspected a problem. The study doesn't tell us that every older cat has hidden disease. It tells us that waiting for obvious symptoms isn't the only way to find it.

As cats age, the routine things become increasingly useful: recording weight, noticing small behavioural changes, measuring blood pressure, and deciding with a vet when blood or urine testing makes sense. Your cat doesn't need to look ill for a health check to be worthwhile. Sometimes that's precisely the point.

This is general information and not a substitute for veterinary advice. Screening recommendations should be discussed with your veterinary practice based on your cat's age, history and individual circumstances.