Background Little is known about the role that work-related factors play in the decline of cognitive function. This study examined the association between perceived organisational justice and cognitive function among middle-aged men and women.

Methods Perceived organisational justice was measured at phases 1 (1985–8) and 2 (1989–90) of the Whitehall II study when the participants were 35–55 years old. Assessment of cognitive function at the screening clinic at phases 5 (1997–9) and 7 (2003–4) included the following tests in the screening clinic: memory, inductive reasoning (Alice Heim 4), vocabulary (Mill Hill), and verbal fluency (phonemic and semantic). Mean exposure to lower organisational justice at phases 1 and 2 in relation to cognitive function at phases 5 and 7 were analysed using linear regression analyses. The final sample included 4531 men and women.

Results Lower mean levels of justice at phases 1 and 2 were associated with worse cognitive function in terms of memory, inductive reasoning, vocabulary and verbal fluency at both phases 5 and 7. These associations were independent of covariates, such as age, occupational grade, behavioural risks, depression, hypertension and job strain.

Conclusions This study suggests an association between perceived organisational justice and cognitive function. Further studies are needed to examine whether interventions designed to improve organisational justice would affect employees' cognition function favourably.