title: Age and BMI interact to determine work ability in seafarers.
abstract: BACKGROUND
  Seafaring is known to be a demanding occupation but the implications of ageing in seafarers are poorly understood.
  
  
  OBJECTIVE
  To investigate task demands and work ability in merchant seamen at sea and to identify factors predicting work ability.
  
  
  METHODS
  This was a cross-sectional study carried out on a single vessel during a summer deployment. Instantaneous heart rate (HR) was recorded at 5-s intervals during representative 8-h shifts in 41 merchant seamen. Participants completed the work ability index and also rated their daily task demands using the National Aeronautics and Space Administration Task Load Index (NASA-TLX). Body mass index (BMI), waist circumference and demographic details were recorded.
  
  
  RESULTS
  Work demands were found to be moderate according to both HR data and TLX scores. The mean BMI was 27.5 kg/m(2) (standard deviation 3.3) and the mean age was 47 years. The majority of participants rated their work ability as 'good' to 'excellent'. The best predictor of work ability was the interaction between BMI and age, whereas there was a statistically significant negative correlation between HR and age.
  
  
  CONCLUSIONS
  Work ability in this group of seafarers was found to be high and the work was shown to be moderately demanding, on average. Although work ability declined with age and with BMI independently, the best predictor of work ability was the interaction between BMI and age, with increased BMI having a deleterious effect on work ability in older employees doing moderately demanding work.
authors.affiliation: Human Factors Department, Institute of Naval Medicine, Crescent Road, Alverstoke PO12 2DL, UK. Bob.Bridger300@mod.uk
authors.forename: R S
authors.initials: RS
authors.lastname: Bridger
authors.forename: A I
authors.initials: AI
authors.lastname: Bennett
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009326:Naval Medicine; D012767:Ships; D014938:Work Capacity Evaluation; D016526:Workload; D055815:Young Adult