Workplace interventions for reducing sitting at work.

Abstract

The number of people working whilst seated at a desk keeps increasing worldwide. As sitting increases, occupational physical strain declines at the same time. This has contributed to increases in cardiovascular disease, obesity and diabetes. Therefore, reducing and breaking up the time that people spend sitting while at work is important for health. To evaluate the effects of workplace interventions to reduce sitting at work compared to no intervention or alternative interventions. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, OSH UPDATE, PsycINFO, Clinical trials.gov and the World Health Organization (WHO) search trial portal up to 14 February, 2014. We also searched reference lists of articles and contacted authors. We included randomised controlled trials (RCT), cluster-randomised controlled trials (cRCTs), and quasi-randomised controlled trials of interventions to reduce sitting at work. For changes of workplace arrangements, we also included controlled before-and-after studies (CBAs) with a concurrent control group. The primary outcome was time spent sitting at work per day, either self-reported or objectively measured by means of an accelerometer coupled with an inclinometer. We considered energy expenditure, duration and number of sitting episodes lasting 30 minutes or more, work productivity and adverse events as secondary outcomes. Two review authors independently screened titles, abstracts and full-text articles for study eligibility. Two review authors independently extracted data and assessed risk of bias. We contacted authors for additional data where required. We included eight studies, four RCTs, three CBAs and one cRCT, with a total of 1125 participants. The studies evaluated physical workplace changes (three studies), policy changes (one study) and information and counselling (four studies). No studies investigated the effect of treadmill desks, stepping devices, periodic breaks or standing or walking meetings. All the studies were at high risk of bias. The quality of the evidence was very low to low. Half of the studies were from Australia and the other half from Europe, with none from low- or middle-income countries. Physical workplace changesWe found very low quality evidence that sit-stand desks with or without additional counselling reduced sitting time at work per workday at one week follow-up (MD -143 minutes (95% CI -184 to -102, one study, 31 participants) and at three months' follow-up (MD - 113 minutes, 95% CI -143 to -84, two studies, 61 participants) compared to no intervention. Total sitting time during the whole day decreased also with sit-stand desks compared to no intervention (MD -78 minutes, 95% CI -125 to -30, one study, 31 participants) as did the duration of sitting episodes lasting 30 minutes or more (MD -52 minutes, 95% CI -79 to -26, two studies, 74 participants). Sit-stand desks did not have a considerable effect on work performance and had an inconsistent effect on musculoskeletal symptoms and sick leave. Policy changesWalking strategies had no considerable effect on sitting at work (MD -16 minutes, 95% CI -54 to 23, one study, 179 participants, low quality evidence). Information and counsellingGuideline-based counselling by occupational physicians reduced sitting time at work (MD -28 minutes, 95% CI -54 to -2, one study, 396 participants, low quality evidence). There was no considerable effect on reduction in total sitting time during the whole day.Mindfulness training induced a non-significant reduction in workplace sitting time (MD -2 minutes, 95% CI -22 to 18) at six months' follow-up and at 12 months' follow-up (MD -16 minutes, 95% CI -45 to 12, one study, 257 participants, low quality evidence).There was an inconsistent effect of computer prompting on sitting time at work. One study found no considerable effect on sitting at work (MD -18 minutes, 95% CI -53 to 17, 28 participants, low quality evidence) at 10 days' follow-up, while another study reported a significant reduction in sitting at work (MD -55 minutes, 95% CI -96 to -14, 34 participants, low quality evidence) at 13 weeks' follow-up. Computer prompting software also led to a non-significant increase in energy expenditure at work (MD 278 calories/workday, 95% CI 0 to 556, one study, 34 participants, low quality evidence) at 13 weeks' follow-up. At present there is very low quality evidence that sit-stand desks can reduce sitting time at work, but the effects of policy changes and information and counselling are inconsistent. There is a need for high quality cluster-randomised trials to assess the effects of different types of interventions on objectively measured sitting time. There are many ongoing trials that might change these conclusions in the near future.