Obesity and sickness absence: results from the CHAP study

Occup Med (Lond). 2010 Aug;60(5):362-8. doi: 10.1093/occmed/kqq031. Epub 2010 Mar 22.


Background: Obesity is an increasing public health problem. A small number of studies have examined the relationship between obesity and sickness absence, with mixed results, particularly regarding short-term sickness absence.

Aims: To determine if obesity is associated with short- and long-term sickness absence and to investigate the mechanisms that may underlie any association.

Methods: Cross-sectional (n = 1489) and prospective (n = 625) analyses were conducted on staff from London Underground Ltd. All participants underwent regular clinical examinations that involved their height and weight being measured, obesity-related medical problems being diagnosed and psychiatric disorders being identified. The number of days taken for short- (<10 days in an episode) and long-term sickness absence were recorded by managers on an electronic database.

Results: There was a positive linear association between employees' body mass index (BMI) and the number of days' work missed due to sickness absence on both cross-sectional and prospective analyses (P < 0.001). Obesity was a risk factor for both short- and long-term sickness absence. Obese individuals typically took an extra 4 days sick leave every year. The majority of the increased risk for long-term sickness absence appeared to be mediated via co-morbid chronic medical conditions. The excess short-term sickness absence was not explained by obesity-related medical problems, psychiatric disorders or workplace factors.

Conclusions: Obese employees take significantly more short- and long-term sickness absence than workers of a healthy weight. There is growing evidence to support employers becoming more involved in tackling obesity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absenteeism
  • Adolescent
  • Adult
  • Aged
  • Cross-Sectional Studies
  • Female
  • Humans
  • London / epidemiology
  • Male
  • Middle Aged
  • Obesity / epidemiology*
  • Occupational Diseases
  • Prospective Studies
  • Railroads / statistics & numerical data
  • Sick Leave / statistics & numerical data*
  • Time Factors
  • Young Adult