Intensive caregiving may accelerate cognitive decline

Onerous caring responsibilities reduce brain function for people aged 50 and over, whereas light caring duties can actually be beneficial to middle-aged and older people's mental abilities, a new UCL study finds.

For the study, published in Age and Ageing, the researchers used 2004-05 to 2021-23 data from the English Longitudinal Study of Ageing (ELSA), a long-running, UCL-led nationally representative survey that gathers a wide range of information from around 20,000 people aged 50 and older in England who are re-interviewed every two years.

The survey, which is made up of 12 topics, includes information on the participants' caring responsibilities and their physical and mental health.

For this study, the researchers used information about caring responsibilities and responses under the Cognitive Function topic.

Cognitive Function relates to the mental processes in general including basic functions such as being able to pay attention and retain information.

To measure the rate at which brain function changed over time, the researchers focused on questions designed to assess an individual's "executive function" – that is, the more sophisticated ability to juggle competing tasks and make decisions – and memory.

Executive function was measured using survey participants' scores (from 0 to 63) when asked to name as many different animals as possible in a minute. Memory was assessed using participants' combined scores (from 0 to 20) when they were given ten common words to remember immediately and after a short delay.

Using a statistical technique known as Propensity Score Matching – which reduces selection bias by simulating randomisation – the researchers paired 2,765 carers with 2,765 non-carers, all aged 50 and above.

They found that those providing very intensive care (50 hours or more per week), caring within the household, or caring for a spouse/partner, showed a more rapid decline in brain function than non-carers.

Conversely, they found that taking on lower-intensity caring responsibilities (between five and nine hours per week), caring outside the household, and caring for parents/parents-in-law exhibited a slower decline in brain function than non-carers.

Building on previous UCL research, they found that heavy carers experienced an extra level of cognitive decline equivalent to about one‑third of the normal decline seen each year with ageing. By contrast, lighter carers showed a slower decline, effectively offsetting about one‑third of the usual annual decline in brain function.

Memory changes followed a similar but much weaker pattern than for executive function. These effects were not influenced by sex or the wealth of the carer.

Our study shows that the caring responsibilities many people take on later in life can be a double-edged sword.

On the one hand, lighter caring responsibilities can be good for you by providing mental stimulation from interacting with loved ones or others you're helping and a sense of purpose and usefulness, but being overloaded with caring tasks has exactly the opposite effect and can accelerate people's mental decline in terms of not being as mentally sharp or quick-thinking as they used to be.

We found that caring within the household or for a spouse or partner – as well as long hours – can have this negative effect because caring for a loved one at home is often associated with providing care for long periods of time."

Dr. Baowen Xue, Lead Author, UCL Institute of Epidemiology & Health Care

The researchers are calling for the Government to provide "intensive" carers – that is, people with high caring workloads – with better access to funded formal care and replacement care.

Dr Xue added: "By 2040, around 20% of adults in England will be living with major illnesses. With the NHS struggling to cope and social care in crisis, much of this growing demand for care will fall on family members and friends who step in as unpaid carers.

"Our findings show that this shift has profound implications: carers' wellbeing is often overlooked and there is a real danger that many people overburdened with caring responsibilities will suffer the consequences.

"Intensive carers are most at risk and need stronger support to prevent overload, such as better access to funded formal care and replacement care. Lower intensity carers, who may benefit cognitively, should be supported to keep their caring roles manageable.

"For policymakers, understanding carers' health outcomes – as highlighted by our findings – will be essential for designing policies and interventions that protect both those who provide care and those who receive it."

For the study, caring status was measured using responses to the question: 'Did you look after anyone in the last week?' and for those who answered yes, how many hours in the past week they had looked after someone.

The researchers also looked at the survey participants' responses to whether the person they cared for lived with them and their relationship to that person.

Study limitations

Data about caring responsibilities was not collected in the first wave of the survey in 2002, so the researchers aggregated data from its second (2004-5) to tenth (2021-23) iterations and excluded those partners younger than 50 years old.

Similarly, executive function was not measured in the six iteration of the study in 2009-11 (wave six). To address this, the researchers used the average of each participants' scores from Waves Five and Seven.