The study shows 10 percent of all people in that age group who are not in employment cite ill health or disability as their reason for not working.
The figures shed new light on the spiralling numbers of people out of work due to long-term sickness in Britain, which hit a record 2.55 million earlier this year.
The Platinum Pound report, by think-tank Demos and not-for-profit housing group Anchor, shows almost half those out of work due to ill health or disability are over 50.
It says the economy could unlock about £6.6billion a year by returning to pre-pandemic later-life workforce levels.
The figures come amid the cost-of-living crisis, rising inflation and skills shortages across many industries, and have led to calls to improve public health and remove “barriers” to later working to “future proof” the economy.
The report says the number of workers aged 50-64 has fallen by 182,000 since 2019 – equivalent to one-sixth of current job vacancies.
An additional 330,000 retirees may also have stopped working because they couldn’t access flexible working, the report found.
Andrew O’Brien, director of policy and impact at Demos, said: “We need to do more to encourage flexible working, increase provision of occupational health and encourage employers to monitor the wellbeing of their workers.”