The share of frail older people in England barely changed in 20 years, but their number grew by more than a million

Frailty is the state in which the body has little reserve left: a fall, an infection or an operation that a fit person would shrug off can lead to disability, a move into a care home or death. As people live longer, health services want to know whether frailty is becoming more common, and how many frail people they will need to care for in the coming decades.

Earlier estimates for the UK range widely, from about 4% to nearly 39% of older people, mostly because studies measured frailty in different ways and looked at a single moment. This study follows the same national survey, measured the same way, over 20 years.

What they did

A team at King's College London used the English Longitudinal Study of Ageing (ELSA), a survey that has interviewed a representative sample of people aged 50 and over living in their own homes in England every two years since 2002. New, younger participants are added regularly so the sample keeps representing the population. Ten waves, from 2002 to 2022, were analysed, with between 6,226 and 11,218 people per wave.

Frailty was measured with a frailty index: a count of 31 possible health problems, such as chronic illnesses, difficulties with daily tasks, mood and memory problems. Someone with a quarter or more of these deficits was classed as frail.

The researchers then did three things:

• Trends: how the share of frail people changed from 2002 to 2022, overall and by age, sex, education and whether people lived with a partner.
• Drivers: a statistical breakdown of which factors pushed frailty up or down, including an ageing population, education, physical activity, smoking, housing problems and a national index of income, schooling and fertility.
• Projections: what the share and number of frail people might be in 2040 if recent trends continue. The authors stress that these are scenarios, not predictions.

What they found

• Roughly stable share. 15.5% of people aged 50 and over were frail in 2002 and 17.8% in 2022. The small rise was not statistically significant.
• A growing number. Because the population got older and larger, the estimated number of frail people living at home rose from about 2.56 million to 3.79 million.
• Big gaps between groups. In 2022, 42.6% of people aged 85 and over were frail, against 12.9% of those aged 50 to 64. Frailty was more common in women (21.8%) than men (13.5%), in people with less education (32.1% against 8.2% with a degree or similar), and in people living without a partner.
• Rising in some groups. Frailty became more common over time among people with lower and middle levels of education.
• What held it back. An ageing population, more people living alone and more housing problems pushed frailty up. Social and economic development, better education, more physical activity and less smoking were linked to pulling it down, roughly cancelling the rise. A large part of the change could not be tied to any measured factor.
• By 2040: under the authors' scenario, about 20.5% of people aged 50 and over living at home would be frail, around 5.2 million people.

What to keep in mind

• Self-reported health. The frailty index is built from what people report in interviews, which can be affected by memory and how people answer.
• Care homes not included. Frailty is more common and more severe in care homes, so the authors say their numbers probably underestimate the total burden.
• Unknown drivers. The biggest single contributor to the rise was the passage of time itself, a stand-in for things the model did not measure, such as economic changes, the COVID-19 pandemic or other exposures. Nutrition, alcohol and social isolation were not included.
• Associations, not causes. The breakdown shows which factors moved together with frailty, not that changing them would change frailty.
• Projections depend on assumptions. The 2040 figures assume recent trends continue, and their uncertainty range (19.2% to 21.9%) covers only part of the true uncertainty.

Why it matters

A stable share of frail people can hide a large rise in their number, and it is the number that determines how much care is needed. The study suggests that England's older population did not become frailer on average over two decades, perhaps partly thanks to better schooling, more exercise and less smoking, but that the ageing of the population will still bring well over a million more frail people by 2040. The authors suggest that education, healthy habits, income support and housing are places where policy could help.