There is a "clear" relationship between lower standards of intellectual ability in childhood and a greater likelihood of taking long-term sick leave as adults, researchers have claimed.

Cognitive ability at a young age has a "strong impact" on whether sickness stops people from working several decades later, they said.

The study involved more than 23,000 people whose cognitive behaviour was measured in either 1946, 1958 or 1970.

In the 1946 group, 47% of those who were on long-term sick leave had been in the bottom quarter of childhood ability, compared to 13% who were in the highest category.

Some 41% of those off sick from the 1958 cohort were in the lowest quartile of ability, while 32% of the 1970 interviewees were also in this category.

The authors, writing in the journal BMJ Open, stated that over 2.5 million people receive health-related benefits in the UK, including Incapacity Benefit and Employment and Support Allowance.

They claimed that strategies to reduce long-term sick leave should involve education.

"Our findings suggest that health is only one factor in understanding long-term sickness absence. We suggest that education should form part of the policy response to long-term sickness absence: for future generations, equipping children with skills necessary for labour market flexibility may inoculate them from the risk of long-term sickness absence," they wrote.

According to the study low cognitive ability and/or educational attainment is "likely" to limit the ability to transfer skills. It gives the example of a person with few skills who goes off sick from a labouring job having few options to find alternative employment.

The report, written by experts including Max Henderson of King's College London, concluded: "Long-term sick leave is a complex outcome with many risk factors beyond health.

"Cognitive abilities might impact on the way individuals are able to develop strategies to maintain their employment or rapidly find new employment when faced with a range of difficulties."