Associations of changes in physical activity and sedentary time with weight recurrence after bariatric surgery: a 5-year prospective study

Background Increasing physical activity and limiting sedentary time may minimize weight recurrence after bariatric surgery. However, few studies have evaluated potential associations of objectively-measured physical activity and sedentary time with post-surgical weight recurrence over time. Aims To evaluate associations of change in physical activity and sedentary time with weight recurrence after bariatric surgery. Methods Participants from the Oslo Bariatric Surgery Study, a prospective cohort study, wore an ActiGraph monitor for seven days at 1- and 5 years after surgery to assess daily physical activity and sedentary time. Participants’ weight was measured at in-person clinic visits. Chi-square Test and Paired-samples T-test evaluated group differences and change over time, while Pearson’s Correlation, multiple logistic and linear regression investigated associations between variables. Results Five years after surgery 79 participants (70.5% response rate, 81% female) (mean (sd) age: 54.0 (±9.3), BMI: 32.1 (±4.7)) had valid monitor data. Participants increased their sedentary time (71.4 minutes/day (95% CI: 54.2–88.6, p = <0.001)) and reduced daily steps (−1411.1 (95% CI: 737.8–208.4), p = <0.001), light physical activity (−54.1 min/day (95% CI: 40.9–67.2, p = <0.001)), and total physical activity (−48.2 (95% CI: 34.6–63.3), p = <0.001) from 1- to 5 years after surgery. No change was found for moderate-to-vigorous intensity physical activity. No associations were found between changes in steps, physical activity or sedentary time and weight recurrence. Conclusion Participants increased sedentary time and decreased light- and total physical activity between 1- and 5 years post-surgery. Overall, changes in physical activity and sedentary time were not associated with weight recurrence. Interventions to help patients increase physical activity and limit sedentary time after bariatric surgery are needed.publishedVersio

Estimating cut points: A simple method for new wearables

Wearable technology is readily available for continuous assessment due to a growing number of commercial devices with increased data capture capabilities. However, many commercial devices fail to support suitable parameters (cut points) derived from the literature to help quantify physical activity (PA) due to differences in manufacturing. A simple metric to estimate cut points for new wearables is needed to aid data analysis. Objective: The purpose of this pilot study was to investigate a simple methodology to determine cut points based on ratios between sedentary behaviour (SB) and PA intensities for a new wrist worn device (PRO-Diary™) by comparing its output to a validated and well characterised ‘gold standard’ (ActiGraph™). Study design: Twelve participants completed a semi-structured (four-phase) treadmill protocol encompassing SB and three PA intensity levels (light, moderate, vigorous). The outputs of the devices were compared accounting for relative intensity. Results: Count ratios (6.31, 7.68, 4.63, 3.96) were calculated to successfully determine cut-points for the new wrist worn wearable technology during SB (0–426) as well as light (427–803), moderate (804–2085) and vigorous (≥2086) activities, respectively. Conclusion: Our findings should be utilised as a primary reference for investigations seeking to use new (wrist worn) wearable technology similar to that used here (i.e., PRO-Diary™) for the purposes of quantifying SB and PA intensities. The utility of count ratios may be useful in comparing devices or SB/PA values estimated across different studies. However, a more robust examination is required for different devices, attachment locations and on larger/diverse cohorts

Weight regain after behavioural weight management programmes and its impact on quality of life and cost effectiveness: evidence synthesis and health economic analyses

Aims We used data from a recent systematic review to investigate weight regain after behavioural weight management programmes (BWMPs, sometimes referred to as lifestyle modification programmes) and its impact on quality-of-life and cost-effectiveness. Materials and Methods Trial registries, databases and forward-citation searching (latest search December 2019) were used to identify randomized trials of BWMPs in adults with overweight/obesity reporting outcomes at ≥12 months, and after programme end. Two independent reviewers screened records. One reviewer extracted data and a second checked them. The differences between intervention and control groups were synthesized using mixed-effect, meta-regression and time-to-event models. We examined associations between weight difference and difference in quality-of-life. Cost-effectiveness was estimated from a health sector perspective. Results In total, 155 trials (n > 150 000) contributed to analyses. The longest follow-up was 23 years post-programme. At programme end, intervention groups achieved –2.8 kg (95%CI –3.2 to –2.4) greater weight loss than controls. Weight regain after programme end was 0.12-0.32 kg/year greater in intervention relative to control groups, with a between-group difference evident for at least 5 years. Quality-of-life increased in intervention groups relative to control at programme end and thereafter returned to control as the difference in weight between groups diminished. BWMPs with this initial weight loss and subsequent regain would be cost-effective if delivered for under £560 (£8.80-£3900) per person. Conclusions Modest rates of weight regain, with persistent benefits for several years, should encourage health care practitioners and policymakers to offer obesity treatments that cost less than our suggested thresholds as a cost-effective intervention to improve long-term weight management