Frail 50-year-olds could expect about eight fewer years of healthy work, in data from 33 countries

Many countries are raising the retirement age so that people work longer. That only works if people are healthy enough to keep working. Researchers measure this with healthy working life expectancy: how many years, from the age of 50, a person can expect to spend both in good health and in a job.

A team working with ethics approval from Fudan University's School of Public Health asked how this number depends on frailty, a state of reduced reserves in which the body copes less well with stress such as an illness or a fall. Unlike many chronic diseases, frailty can sometimes improve again, which is why the question matters.

What they did

The team pooled five large surveys of people over 50 whose questions have been made comparable: the US Health and Retirement Study, the English Longitudinal Study of Ageing, the Survey of Health, Ageing and Retirement in Europe (SHARE), the Mexican Health and Aging Study and the China Health and Retirement Longitudinal Study. Together they covered 180,314 people in 33 countries, interviewed roughly every two years and followed for about eight years on average.

• Frailty was measured with a frailty index: the share of a standard list of health problems ("deficits") that a person has. People were called robust, pre-frail or frail, and they could move between these groups over time.
• Health was people's own rating: "excellent", "very good" or "good" counted as healthy.
• Work meant paid work or self-employment in the year of the interview.

A statistical model then tracked how people moved between five states (healthy and working, healthy and not working, unhealthy and working, unhealthy and not working, dead) and turned those moves into the expected number of healthy working years from age 50.

What they found

• Everyone together: about 9.6 healthy working years from age 50.
• A clear frailty gradient: 11.9 years for robust people, 7.3 years for pre-frail people and 3.8 years for frail people. That is 4.5 fewer years for the pre-frail group and 8.1 fewer for the frail group than for robust people.
• Same pattern in every cohort: the numbers varied a lot between studies (for robust people from 7.3 to 15.7 years), but in all five, robust people had the most healthy working years and frail people the fewest.
• Who else fared better: among robust and pre-frail people, men had about one more healthy working year than women. Non-smokers and people with more education had more healthy working years in all three frailty groups.
• Country matters too: living in a richer country (above the median income per person in the study) was linked to about 4.3 more healthy working years for robust people, 4.6 for pre-frail people and 2.7 for frail people. Higher health spending and better-rated government were linked to longer healthy working lives as well. Frail people gained the least from living in favourable countries.

The results held up when the team changed the frailty cut-offs, the model settings or the way gaps in the data were filled.

What to keep in mind

• Links, not causes. This is an observational study. Frailty, ill health and leaving work are tangled together, so the study can't say that preventing frailty would add these years.
• The authors' own limits. The surveys asked slightly different questions, so frailty may be measured a bit differently between them. Self-rated health depends on culture. Work did not include unpaid contributions such as caring. Effects of the generation people were born in were not modelled. Africa, South Asia, the Middle East and Oceania were not covered.
• Healthier volunteers. The surveys include people living at home, not in care homes, who are likely healthier; the authors say this may make the expected healthy working years look longer than they are.
• Country comparisons are broad. The authors stress that the country-level links are only "ecological" associations: rich, well-governed countries differ in many ways at once.

Why it matters

The study puts a number on something many people sense: frailty in later middle age goes with far fewer years of being healthy and able to work, in very different countries. The authors argue that frailty screening and programmes that aim to head it off or reverse it, together with age-friendly workplaces and broader social policy, should be part of any plan to keep people working longer. Whether such programmes actually add healthy working years would need to be tested directly.