Seven signs that may indicate a higher risk of dementia (Image: Getty)
A fading sense of smell or frequently falling asleep during the day, even without feeling tired, may appear insignificant. However, scientists say these behaviours could point to a deeper health issue. A recent study published in the Journals of Gerontology found that unplanned daytime naps were associated with a greater risk of developing dementia.
Dementia is an umbrella term for a group of conditions that affect memory, thinking, reasoning and a person’s ability to handle everyday tasks.
Alzheimer’s disease is the most widespread form, but several other types can also lead to progressive cognitive decline.
Common symptoms include memory loss, confusion, problems with concentration or decision-making, difficulties with language and communication, and changes in mood or behaviour.
The risk of dementia rises with age, but the condition is not an inevitable part of getting older. Recognising possible symptoms early can help people receive treatment, practical support and care sooner.
For a decade, researchers at the Johns Hopkins Bloomberg School of Public Health in the US followed 995 adults aged 65 and over who did not have dementia when the study began.
The analysis showed that participants who napped every day or on most days were 48 per cent more likely to develop dementia than those who rarely or never slept during the day.
This elevated risk remained after researchers accounted for factors including existing medical conditions and the amount of sleep participants got at night.
Here are seven important warning signs to know:
1. Falling asleep during the day unintentionally:
Earlier studies have also identified a link between daytime sleeping and dementia risk. However, researchers have not yet confirmed whether changes in the brain linked to dementia interfere with normal sleep, leaving people more fatigued during the day, said Catherine Loveday, professor of neuropsychology at the University of Westminster and host of Mempathy, a podcast focused on living well with dementia. She added that even small declines in cognitive function can make routine tasks far more demanding, which may increase tiredness.
2. A slower walking pace: While gradually walking more slowly is often viewed as a normal consequence of ageing, Ms Loveday noted that substantial research has connected reduced walking speed with dementia risk. A nine-year study published in the Journal of Gerontology found that walking 0.204 metres per second below the average pace was associated with a 59 per cent higher likelihood of developing dementia. The relationship was still present when walking speed had been measured as many as seven years before diagnosis.
3. Changes in appetite or unexplained weight loss: Reduced appetite is recognised as a symptom of dementia, but changes in eating patterns may begin well before diagnosis. A 16-year longitudinal study in the Journal of Aging and Health examined body mass index and dementia using data from the American Health and Retirement Study. It found that weight loss could begin more than 10 years before dementia was diagnosed, with reduced appetite suggested as one possible reason.
Eating less can also be a normal feature of ageing, so weight loss on its own should not automatically be viewed as a sign of dementia. Dr Simon Wheeler, senior knowledge officer at the Alzheimer’s Society, said appetite changes may nonetheless be an indication that something is wrong.
4. Hearing loss or persistent ringing in the ears:
Multiple studies have identified hearing impairment as a possible dementia risk factor. A 2024 report led by Gill Livingston, Professor of Psychiatry of Older People at University College London, associated hearing loss with a 37 per cent higher risk of developing dementia. The report also found that each 10-decibel reduction in hearing ability corresponded with an additional 16 per cent increase in risk.
5. A diminished sense of smell:
Ms Loveday pointed to a strong connection between a declining sense of smell and memory problems. The olfactory bulbs, which handle smell-related information, are positioned near the front of the brain and close to the hippocampus, the area involved in memory.
She said both regions could be affected by the same underlying disease process. A systematic review published last year in the International Forum of Allergy & Rhinology supports the association: after examining 48 studies involving 37,783 people, researchers found that those with a reduced sense of smell were 2.14 times more likely to develop dementia than people with normal olfactory function.
6. Difficulty judging space and distance:
Posterior cortical atrophy (PCA) is an uncommon form of Alzheimer’s disease that affects the brain’s visual-processing areas. The condition, which contributed to the death of author Terry Pratchett in 2015, can cause visual problems that originate in the brain rather than the eyes, Dr Simon Wheeler said.
Anyone experiencing sudden changes in vision should contact their GP and ask about a referral to a neurologist. For people noticing more gradual changes, keeping a written record of symptoms may help show how they progress over time.
7. Persistent low mood: Ongoing depression or low mood can sometimes appear during the early stages of Alzheimer’s disease. Ms Loveday explained that the hippocampus, where the condition often begins, is also linked to depression.
Changes caused by the disease may contribute directly to feelings of sadness. At the same time, becoming aware of growing difficulties with everyday activities can leave people feeling anxious, frustrated or depressed.
