Childhood intelligence linked to long-term sick leave

The findings come from a study of over 30,000 people in Britain, and suggest that long-term sick leave may be linked to individuals’ ability to deal with problems and return to work as well as their physical health or employment issues. 

The researchers used data from people born in 1946, 1958 and 1970. Cognitive ability was measured at ages 10 or 11 in terms of a number of factors including verbal and non-verbal intelligence, arithmetic, word pronunciation and vocabulary, and data was collected of the extent of individuals’ long-term sick leave (typically defined as over 6 months) later in life. 

Individuals with better childhood cognitive function had a lower risk of being on long-term sick leave in adult life, even after a range of health and work factors had been taken into account. Additionally, the effect was similar across all three age groups. 

Dr Max Henderson from the IoP at King’s and lead author of the study published in BMJ Open this month explains: ‘In many instances long-term sick leave is less about an individual becoming unwell, and more about that individual struggling to recover, or to return to work as they begin to get better. It may be that stronger cognitive abilities enable an individual to steer a course through their illness and back to work, whereas an individual who was equally unwell but with less strong cognitive abilities might find such a course more difficult to steer.’

The study supports earlier findings that long term sick leave is not just about health or work, but that it also reflects the choices an individual makes and the strategies they develop to deal with the problems they face. 

Dr Henderson says: ‘Long term sickness absence is bad for individuals, bad for their families, bad for their employers and bad for the wider economy. The proportion of working age adults claiming long term sickness benefits has risen sharply in the last three decades. 

‘Much of the work being done to better understand and tackle the problem of long-term sick leave has focused on “health” or “work”, which are of course important, but until now, little work has looked at the individuals themselves. This study examines individual risk factors, measured before an individual starts work that might be associated with long term sickness absence.’

The authors warn that focusing solely on health or employment issues may not solve the problem of long-term sick leave, and suggest that education should form part of the policy response to long-term sick leave, so that young people are better equipped with the skills needed in a flexible labour market, such as communication skills and problem-solving. 

The research was funded by the Medical Research Council and the National Institute for Health Research (NIHR) Biomedical Research Centre for Mental Health at the South London and Maudsley NHS Foundation Trust and the Institute of Psychiatry at King’s College London.

More information: Henderson, M. et al. ‘The association between childhood cognitive ability and adult long-term sickness absence in three British birth cohorts: a cohort study’ BMJ Open (2012) doi: 10.1136/bmjopen-2011-000777

Provided by King's College London