title: School education, physical performance in late midlife and allostatic load: a retrospective cohort study.
abstract: The mechanisms underlying the social gradient in physical functioning are not fully understood. Cumulative physiological stress may be a pathway. The present study aimed to investigate the association between highest attained school education and physical performance in late midlife, and to determine to what extent cumulative physiological stress mediated these associations.
  
  
  
  The study is based on data from the Copenhagen Aging and Midlife Biobank (CAMB; n=5467 participants, aged 48-62 years, 31.5% women). School education was measured as highest examination passed in primary or secondary school (3 categories). Cumulative stress was operationalised as allostatic load (AL), and measured as the number of biological parameters (out of 14) in which participants scored in the poorest quartile. Physical performance included dynamic muscle performance (chair rise ability, postural balance, sagittal flexibility) and muscle strength (jump height, trunk extension and flexion, and handgrip strength).
  
  
  
  Among women, higher school education was associated with better performance in all physical performance tests. Among men, higher school education was associated with better performance only in chair rise and jump height. AL partially mediated the association between school education and physical performance, and accounted only for 2-30% of the total effect among women. Similar results were observed among men for chair rise and jump height.
  
  
  
  These results might indicate that AL plays a minor role in the association between school education and late midlife dynamic muscle performance in both men and women, and in muscle strength among women.
authors.affiliation: Department of Public Health, University of Copenhagen, Copenhagen, Denmark National Research Centre for the Working Environment, Copenhagen, Denmark Copenhagen Stress Research Center, Copenhagen, Denmark.
authors.forename: Åse M
authors.initials: ÅM
authors.lastname: Hansen
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark.
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen
authors.affiliation: Department of Epidemiology, Center for Social Epidemiology and Population Health, University of Michigan School of Public Health, Chicago, Michigan, USA.
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Mendes de Leon
authors.affiliation: Department of Clinical Immunology, Center for Inflammation and Metabolism, and National University Hospital, Copenhagen, Denmark.
authors.forename: Helle
authors.initials: H
authors.lastname: Bruunsgaard
authors.affiliation: Department of Public Health, University of Copenhagen, Copenhagen, Denmark Center for Healthy Ageing, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Rikke
authors.initials: R
authors.lastname: Lund
mesh_terms: D052636:Allostasis; D004522:Educational Status; D005260:Female; D018737:Hand Strength; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
keywords: AGEING; PHYSICAL FUNCTION; PHYSIOLOGY; SOCIAL CLASS