title: Association Between Sedentary Work and BMI in a U.S. National Longitudinal Survey.
abstract: BACKGROUND
  Technological advancements have made life and work more sedentary, and long hours of sitting are known to be associated with many health concerns. Several studies have reported an association between prolonged sitting time at work and weight gain, but the results are inconsistent. This study examined the relationship between sitting time at work and BMI using data from a large prospective cohort of U.S. men and women from 2002 to 2010. Initial analyses were performed in 2013, with additional analyses in 2014 and 2015.
  
  
  METHODS
  The sample size at the base year (2002) was 5,285 and the age range 38-45 years. The outcome, BMI, was based on self-reported measures of height and weight. Estimates of workplace sitting time were linked from an external database (Occupational Information Network), and the occupation-wide rating for sitting time was linked to survey participants by occupation. Fixed-effects models controlling for time-invariant effects of all time-invariant characteristics were employed to examine the association, controlling for age, education, work hours, and hours of vigorous and light/moderate physical activities.
  
  
  RESULTS
  Longer sitting time was significantly associated with higher BMI for the overall sample (β = 0.054; p<0.05) and men (β = 0.086; p<0.01). For women, the association was not statistically significant.
  
  
  CONCLUSIONS
  The findings provide further support for initiatives to reduce workplace sitting time as a means of reducing the risk of weight gain and related health conditions.
authors.affiliation: Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, Massachusetts; Environmental and Occupational Medicine and Epidemiology Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts. Electronic address: tin-chi.lin@libertymutual.com.
authors.forename: Tin-chi
authors.initials: TC
authors.lastname: Lin
authors.affiliation: Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, Massachusetts; Environmental and Occupational Medicine and Epidemiology Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
authors.forename: Theodore K
authors.initials: TK
authors.lastname: Courtney
authors.affiliation: Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, Massachusetts; Environmental and Occupational Medicine and Epidemiology Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
authors.forename: David A
authors.initials: DA
authors.lastname: Lombardi
authors.affiliation: Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, Massachusetts; Department of Family Medicine and Community Health, University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Santosh K
authors.initials: SK
authors.lastname: Verma
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D057185:Sedentary Behavior; D057566:Self Report; D014481:United States; D017132:Workplace