Occupational Sitting Time and Overweight and Obesity in Australian Workers W. Kerry Mummery, PhD, Grant M. Schofield, PhD, Rebekah Steele, BHSc, Elizabeth G. Eakin, PhD, Wendy J. Brown, PhD Background: One of the major immediate and long-term health issues in modern society is the problem of overweight and obesity. This paper examines the role of the workplace in the problem by studying the association between occupational sitting time and overweight and obesity (body mass index [BMI] 25) in a sample of adult Australians in full-time employment. Methods: Data on age, gender, occupation, physical activity, occupational sitting time, and BMI were collected in September 2003 from a sample of 1579 adult men and women in full-time employment at the time of the survey. Logistic regression was used to examine the association between occupational sitting time and overweight and obesity. Results: Mean occupational sitting time was 3 hours/day, and significantly higher in men (209 minutes) than in women (189 minutes, p =0.026). Univariate analyses showed significant associations between occupational sitting time and BMI of 25 in men but not in women. After adjusting for age, occupation, and physical activity, the odds ratio for BMI 25 was 1.92 (confidence interval: 1.17–3.17) in men who reported sitting for 6 hours/day, compared with those who sat for 45 minutes/day. Conclusions: Occupational sitting time was independently associated with overweight and obesity in men who were in full-time paid work. These results suggest that the workplace may play an important role in the growing problem of overweight and obesity. Further research is needed to clearly understand the association between sitting time at work and overweight and obesity in women. (Am J Prev Med 2005;29(2):91–97) © 2005 American Journal of Preventive Medicine Introduction O ne of the major immediate and long-term health issues in modern society is the problem of overweight and obesity. The burden of overweight and obesity includes increased risk of pre- mature death and chronic disease, 1 as well as a reduc- tion in the overall quality of life. 2 Obesity has been identified as a risk factor for numerous chronic dis- eases, including type 2 diabetes, coronary heart disease, high blood pressure, stroke, and certain forms of cancer. 1 In 2000, the World Health Organization esti- mated the number of obese adults in the world to be more than 300 million. 3 In Australia, recent data show a 28% increase in the prevalence of overweight and obesity through the decade of the 1990s, with 58% of men and 42% of women now classified as overweight or obese. 4,5 The causes of overweight and obesity are often varied and complex but, at a population level, have generally been attributed to energy imbalance—as a society we are expending less energy than we are taking in. 6–8 Although logical to attribute the in- creased prevalence of overweight and obesity to reduced physical activity levels, most population data indicate that activity levels— especially leisure-time physical activity levels—are not changing sufficiently to explain the current increases in overweight and obesity. 9,10 In any event, the emphasis on leisure-time physical activity levels may not accurately reflect the estimation of total energy expenditure at a popula- tion level. Studies that have attempted to imitate the energy expenditures of previous generations, either through the study of historical replications 11 or by study of groups who use traditional methods for farming and tilling the land 12 conclude that there has been a large decline in total physical activity in most developed countries over the past century. It would appear therefore that this decrease reflects From the School of Health and Human Performance, Central Queensland University (Mummery, Steele), Rockhampton, Queens- land, Australia; Division of Sport and Recreation, Auckland Univer- sity of Technology (Schofield), Auckland, New Zealand; Queensland Cancer Fund, Viertel Centre for Research in Cancer Control (Eakin), Brisbane, Queensland, Australia; and School of Human Movement Studies, University of Queensland (Brown), Brisbane, Queensland, Australia Address correspondence and reprint requests to: Kerry Mummery, PhD, School of Health and Human Performance, Central Queens- land University, Rockhampton, Queensland 4702, Australia. E-mail: k.mummery@cqu.edu.au. 91 Am J Prev Med 2005;29(2) 0749-3797/05/$–see front matter © 2005 American Journal of Preventive Medicine • Published by Elsevier Inc. doi:10.1016/j.amepre.2005.04.003