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Graduate Student Supervision
Doctoral Student Supervision
Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.
South Asian immigrants are at high risk of chronic disease partly due to low levels of physical activity (PA). Accurate assessment of PA and sedentary time is imperative for monitoring PA trends and designing interventions. Few studies have used device-worn measures to assess PA and sedentary time in South Asians or investigated the potential association of socio-demographic factors. Objectives of this dissertation are to: 1) synthesize data on accelerometer-based studies in South Asians, 2) assess PA and sedentary time in a sample of South Asian adults using accelerometers, 3) examine potential socio-demographic correlates of PA and sedentary time, 4) and explore socio-cultural factors that influence PA.Methods: For objective 1, I systematically searched major databases for studies assessing device-worn measures of PA and sedentary time in South Asians. For objective 2 and 3, a subset of 100 South Asian participants self-reported socio-demographic information and wore Actical accelerometer for 7 days. For objective 4, I conducted four Focus Group Discussions (FGDs) with a sub-sample of 22 participants to understand socio-cultural influences of PA. Results: Only 14 studies used an accelerometer to measure PA and sedentary time with considerable variability in reported outcomes. In the accelerometer trial, participants accumulated 673.5 (95% CI: 656.6, 691.0) mean min/day of sedentary time, 130.5 (95% CI: 117.3, 145.3) min/day of light PA (LPA) and 6.8 (95% CI: 4.7, 10.1) min/day of moderate-to-vigorous PA (MVPA). Sex and Body Mass Index explained 51% of the variability in sedentary time and LPA. Sex and an interaction between education and presence of children under 12 explained 23% of the variability in MVPA. FGDs revealed participants’ understanding of PA was culturally embedded thus highlighting the need to understand influence of socio-cultural factors including immigration status on PA behavior.Conclusion: High sedentary time and low MVPA indicates a need to focus health promotion efforts on shifting sedentary time into LPA. FGDs reveal inadequate understanding of PA guidelines among women and difficulties in assessing intensity of activities. Self-report alone may not be an ideal method of PA assessment in South Asians. Future studies need to be based on representative samples of South Asians.
Master's Student Supervision
Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.
Introduction: Hip fracture is a serious event with longstanding implications for older adults. These fractures frequently lead to reduced mobility, prolonged periods of sitting time, and consequently, a lack of physical activity. Objectives: I aimed to test how a comprehensive geriatric management clinic affects sedentary behaviour and physical activity patterns over a 12-month period, and to characterise the recovery patterns of sedentary behaviour and physical activity for older adults after hip fracture. Methods: This study collected prospective objective measurements (accelerometry) of sedentary behaviour and physical activity patterns from older adults with hip fracture. I described and tested sedentary behaviour and physical activity using accelerometry at baseline, 6 and 12 months from a parallel-group, 1:1 single-blinded randomised controlled trial for older adults 3-12 months after hip fracture. The usual care group received standard post-operative management; the intervention group received usual care plus a clinical management by health professionals. Results: The study enrolled 53 participants [mean age (SD) 79(8) years], 3-12 months post-fracture. Forty-five participants had valid data (intervention (n=22) or usual care (n=23) group). Participants had a mean (SD) age of 79.2 (7.4) years, ranged 65-98 years, with a median (p10, p90) of 203 (143, 335) days since fracture. Participants from both groups spent approximately 10 hours/day in sedentary behaviour. There were no statistically significant differences between groups for sedentary behaviour or physical activity variables at midpoint and final assessment. Men engaged in significantly more sedentary time (47 minutes; p=0.049), and spent less time in light physical activity (44 minutes; p=0.044) compared with women, across the study. Although men had more sedentary time at each time point, the difference was attenuated at final assessment and was no longer statistically significant. Conclusion: Older adults after hip fracture spend prolonged periods of waking hours sedentary and without much activity. Decreasing and breaking up sedentary time and increasing physical activity is an important target for rehabilitation. Differences between sexes should be acknowledged and addressed by health professionals. Further, strategies should be developed and tested to reduce time spent in sedentary behaviour and increase physical activity for older adults after hip fracture.
Objective: To describe the change in objectively measured sitting, standing and stepping time for officebased workers as they transitioned from a conventional to an activity-permissive workplace physical environment. Methods: This pre-post study observed 17 office-based working adults [mean age 33 (SD 7) years] from an academic research centre as they transitioned from a conventional to a purpose-built, innovative activity-permissive workplace physical environment with flexible layouts, workspaces, and working conditions. Participants wore an activity monitor (activPAL3, PAL Technologies Limited, Glasgow, UK) forseven consecutive days at both the conventional and innovative workplaces to determine time spent sitting, standing, stepping, the number of sit to stand transitions and the length and number of sitting bouts ≥ 30 minutes. They also completed a self-reported log of workplace time and monitor wear time. Participants’ height, weight, descriptive characteristics, body composition (measured by DXA) and moderate-to-vigorousphysical activity (measured by ActiGraph GT3X+; LLC, Fort Walton Beach, FL) were recorded. Istandardized results to an 8-hour workday and compared outcomes between the conventional andinnovative workplaces using Hodges-Lehmann median point estimate (90% CI). Results: The transition to the innovative workplace resulted in a non-significant decrease in workplace sitting time (-24 minutes/ 8-hour workday; 90% CI = -55 to 9 minutes/ 8-hour workday) and a correspondingincrease in workplace standing (12 minutes/ 8- hour workday; 90% CI = -42 to 61 minutes/ 8-hourworkday). There were no differences in the number of sit to stand transitions or sitting bouts ≥ 30 minutes in the workplace. Participants spent more time sitting in bouts ≥ 30 minutes at the innovative workplace (increase of 16 minutes/ 8-hour workday; 90% CI = -7 to 44 minutes/ 8-hour workday). None of these changes were statistically significant. Conclusions: This group of office workers did not significantly change their total workplace sitting time or how it was accumulated with the transition to the innovative workplace physical environment. The results of this preliminary investigation suggest that interventions include a multifaceted approach to complement physical environment changes in order to reduce prolonged sitting time.
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