Sitting at work & waist circumference-A cross-sectional study of Australian workers.

Studies examining associations of sitting time at work with obesity measures have produced inconsistent findings. Different sample characteristics across studies, e.g., the composition of different occupational groups, may be one explanation for the mixed findings. We examined cross-sectional associations of workplace sitting time with waist circumference in workers engaged in desk-based work and those engaged in other work settings using a population-based sample of Australian workers. Participants (5878 full-time workers in the 2014-15 Australian National Health Survey) were categorized into desk-based (N = 3006) or non-desk-based (N = 2872) workers, based on self-reported predominant behavior at work (sitting, standing, walking, and physical labor) and occupational group. Linear regression analyses examined associations of measured waist circumference with self-reported sitting time at work for each group, which was further stratified by gender and leisure-time physical activity level. Longer sitting time at work was associated with greater waist circumference in desk-based workers (b = 0.45 [95%CI: 0.09, 0.80] cm for a 1 h/day increment of sitting) but not in non-desk-based workers (b = 0.25 [95%CI: -0.12, 0.63]). For desk-based workers, stratified analyses found significant associations in men and those who were insufficiently physically active during leisure time. Our findings support interventions to decrease occupational sitting time for desk-based workers to reduce their cardio-metabolic risk. Differential associations observed between desk-based and non-desk-based workers and between genders may be attributable to the ways in which sitting time is accumulated. Future research is needed to examine the impact of behavior patterns at work (sitting breaks, occupational physical activity) on adiposity in working adults.