The authors aimed to test the relationship between childhood cognitive function and long-term sick leave in adult life and whether any relationship was mediated by educational attainment, adult social class or adult mental ill-health.
The authors used data from the 1946, 1958 and 1970 British birth cohorts. Initial study populations included all live births in 1 week in that year. Follow-up arrangements have differed between the cohorts.
The authors included only those alive, living in the UK and not permanent refusals at the time of the outcome. The authors further restricted analyses to those in employment, full-time education or caring for a family in the sweep immediately prior to the outcome. 2894 (1946), 15 053 (1958) and 14 713 (1970) cohort members were included. Primary and secondary outcome measures: receipt of health-related benefits (eg, incapacity benefit) in 2000 and 2004 for the 1958 and 1970 cohorts, respectively, and individuals identified as ‘permanently sick or disabled’ in 1999 for 1946 cohort.
After adjusting for sex and parental social class, better cognitive function at age 10/11 was associated with reduced odds of being long-term sick (1946: 0.70 (0.56 to 0.86), p=0.001; 1958: 0.69 (0.61 to 0.77), p<0.001; 1970: 0.80 (0.66 to 0.97), p=0.003). Educational attainment appeared to partly mediate the associations in all cohorts; adult social class appeared to have a mediating role in the 1946 cohort.
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. Education should form part of the policy response to long-term sick leave such that young people are better equipped with skills needed in a flexible labour market.
To what extent does cognitive function in childhood predict long-term sick leave.
To what extent might any association be mediated through educational attainment, adult social class or adult mental ill-health.
There is a clear dose–response relationship between lower cognitive function in childhood and increased odds of being on long-term sick leave in adulthood.
This association applies to younger as well as older workers and holds true irrespective of the decade of birth.
This association is mediated in part by education attainment suggesting improved education, especially for those with lower cognitive abilities, may help inoculate them from the risk of long-term sickness absence.
Strengths and limitations of this study
Three large birth cohorts with data from across 50 years.
Cohorts broadly representative of the UK population born in that year.
Cognitive function assessed using well-recognised tools.
Different measures of cognitive function, long-term sickness absence and depression used across the cohorts.