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Physical Activity Intensity and Adiposity in Obese Youth: The POWER Trial
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Errata / Can J Diabetes 37 (2013) 433e434
adipocyte FAK disruption in obese diabetic mice. aP2Cre+FAKfl/fl mice had increased adiposity under basal conditions but, surprisingly, with HFD or in a genetically obese model, did not gain as much weight as wild type littermate controls and had decreased adipose tissue fat pad weights. Despite these differences, aP2Cre+FAKfl/fl mice were more insulin resistant compared to littermate controls in both conditions, with increased adipose tissue inflammation shown by macrophage infiltration and adipocyte apoptosis seen by TUNEL, suggesting that FAK plays an essential role in adipocyte turnover and insulin resistance. Together, these results demonstrate a new and important role for FAK in adipose tissue remodelling and whole body glucose homeostasis. 12 Is Lean Body Mass Index Associated with Liver Fat in Youth at Risk of Type 2 Diabetes? MARTIN SÉNÉCHAL, BRANDY WICKLOW, KRISTY WITTMEIER, JACQUELINE HAY, ANDREA C. MACINTOSH, JONATHAN M. MCGAVOCK Winnipeg, MB Background: Insulin resistance and liver fat are both predictors of type 2 diabetes (T2D) in youth. Although lean body mass (LBM) is known to influence insulin resistance, the association of LBM with liver fat has received little attention in youth at risk of T2D. Objective: To investigate the association between insulin resistance and liver fat with LBM in youth at risk of T2D. Methods: One hundred thirteen overweight and obese (97.13.1 BMI percentile) youth (15.31.7 years) participated in this crosssectional study. The primary outcome measures were insulin resistance (measured by HOMA-IR), liver transaminases (ALT/AST) and liver fat (MRS measured). The primary exposure variable was LBM index (LBMI; lean body mass [kg]/height] m2]). Results: LBMI was positively associated with fat mass (r¼0.56, p¼0.0001) and visceral fat mass (r¼0.39, p¼0.0001). LBMI was negatively associated with HDL-cholesterol (r¼-0.28, p¼0.006) and positively associated with AST (r¼0.27, p¼0.002), ALT (r¼0.46, p¼0.0001) and liver fat (r¼0.28, p¼0.002). Multiple linear regressions revealed that LBMI was associated with HOMA-IR (ß¼0.216 SE 0.061, p¼0.0006) and ALT (ß¼1.557 SE 0.482, p¼0.001) independently of age, sex, ethnicity, visceral fat mass and fitness level, but not with liver fat (p¼0.186). Conclusions: These results suggest that LBMI contributes to insulin resistance and liver fat in youth at risk of T2D. Considering that liver fat is the strongest predictor of T2D in youth, LBMI should be considered in risk assessment in youth at high risk of T2D. 16 Physical Activity Intensity and Adiposity in Obese Youth: The POWER Trial JONATHAN M. MCGAVOCK*, JACQUELINE HAY, TODD DUHAMEL, BRANDY WICKLOW, HEATHER DEAN, ELIZABETH SELLERS, ELIZABETH READY, LORI BERARD Winnipeg, MB Study Hypothesis: We conducted a randomized controlled trial to test the hypothesis that compared to controls, vigorous-intensity physical activity (PA) would lead to a greater reduction in visceral
adiposity than moderate-intensity PA despite similar caloric expenditure. Methods: Following a 2-week run-in phase, overweight youth 13 to 19 years with 1 risk factor for type 2 diabetes were randomized to either vigorous PA at >70% of peak fitness (VPA), moderate PA at 40% to 55% of peak fitness (MPA) or control arms (CTRL). PA was delivered 3 times weekly for 30 to 45 minutes for 6 months. Outcome measures included MRI-derived visceral adipose tissue (VAT), DXA-derived total body fat and waist circumference. Results: One hundred twenty obese youth (BMI Z ¼ 2.10.4) were randomized to VPA (n¼48); MPA (n¼36) and CTRL (n¼36). Using intention to treat analysis, no statistical differences were observed in any outcome measure between the groups; however, VAT was reduced over time (pre/post) in VPA (-3.2; 95% CI: -12.4 to +6.1 cm2) and MPA (-7.2; -18.0 to +3.6 cm2) as compared to CTRL (+1.1;-9.6 to +11.8 cm2). VPA also reduced waist circumference (-1.8; -1.3 to ¼0.6 cm) that was not observed in MPA (+2.4;-0.3 to +5.1 cm) or CRTL (+1.6;-1.3 to +4.5 cm). In efficacy analyses, reduction in VAT in both PA groups was significantly different from CTRL (p¼0.02). Conclusions: Increased PA, regardless of intensity leads to clinically meaningful reductions in VAT in obese youth. VPA was not associated with greater reductions in measures of adiposity relative to MPA.
17 Weight Loss Intervention for Individuals with Diabetes and Serious Mental Illness: A Pragmatic Experiment in Community Settings ROHAN GANGULI*, TODD JENKINS, KINNON MACKINNON, MEHREEN BHAMANI Toronto, ON Background: The rate of diabetes in individuals with serious mental illness is 2 to 3 times the general population rate. Diabetic co-morbidities are also higher in this population. The most severely affected often reside in board and care homes managed by nonprofessional staff. We studied the effects of training these staff in behavioural techniques for weight loss. Methods: Staff of 5 board and care homes was recruited to participate in a year-long program to improve nutrition and physical activities for residents. The subjects were 18 residents who had type 2 diabetes mellitus and a psychotic illness. The primary outcome was change in weight from baseline to the end of the study. Research staff recorded the participants’ weights. All other aspects of the intervention were taught to and carried out by the staff of the homes. Results: In initial focus groups, staff expressed pessimism about persuading residents to change their behaviour, but still agreed to participate. Baseline and endpoint data from 18 subjects showed weight was lost by all except 3 subjects (mean weight loss 6.73 kg; 95% (CI -9.93 to -3.53 kg); p less than 0.001 [t¼4.44; df¼17]). Conclusions: Despite the initial pessimism of the staff, almost all the subjects lost weight. Since the intervention was delivered by the existing staff of the residential facilities, there was minimal increase of cost to the system. The quasi-experimental design of the study is a limitation, but these encouraging results should justify a rigorous randomized controlled trial of the intervention in similar settings.
Errata / Can J Diabetes 37 (2013) 433e434
adipocyte FAK disruption in obese diabetic mice. aP2Cre+FAKfl/fl mice had increased adiposity under basal conditions but, surprisingly, with HFD or in a genetically obese model, did not gain as much weight as wild type littermate controls and had decreased adipose tissue fat pad weights. Despite these differences, aP2Cre+FAKfl/fl mice were more insulin resistant compared to littermate controls in both conditions, with increased adipose tissue inflammation shown by macrophage infiltration and adipocyte apoptosis seen by TUNEL, suggesting that FAK plays an essential role in adipocyte turnover and insulin resistance. Together, these results demonstrate a new and important role for FAK in adipose tissue remodelling and whole body glucose homeostasis. 12 Is Lean Body Mass Index Associated with Liver Fat in Youth at Risk of Type 2 Diabetes? MARTIN SÉNÉCHAL, BRANDY WICKLOW, KRISTY WITTMEIER, JACQUELINE HAY, ANDREA C. MACINTOSH, JONATHAN M. MCGAVOCK Winnipeg, MB Background: Insulin resistance and liver fat are both predictors of type 2 diabetes (T2D) in youth. Although lean body mass (LBM) is known to influence insulin resistance, the association of LBM with liver fat has received little attention in youth at risk of T2D. Objective: To investigate the association between insulin resistance and liver fat with LBM in youth at risk of T2D. Methods: One hundred thirteen overweight and obese (97.13.1 BMI percentile) youth (15.31.7 years) participated in this crosssectional study. The primary outcome measures were insulin resistance (measured by HOMA-IR), liver transaminases (ALT/AST) and liver fat (MRS measured). The primary exposure variable was LBM index (LBMI; lean body mass [kg]/height] m2]). Results: LBMI was positively associated with fat mass (r¼0.56, p¼0.0001) and visceral fat mass (r¼0.39, p¼0.0001). LBMI was negatively associated with HDL-cholesterol (r¼-0.28, p¼0.006) and positively associated with AST (r¼0.27, p¼0.002), ALT (r¼0.46, p¼0.0001) and liver fat (r¼0.28, p¼0.002). Multiple linear regressions revealed that LBMI was associated with HOMA-IR (ß¼0.216 SE 0.061, p¼0.0006) and ALT (ß¼1.557 SE 0.482, p¼0.001) independently of age, sex, ethnicity, visceral fat mass and fitness level, but not with liver fat (p¼0.186). Conclusions: These results suggest that LBMI contributes to insulin resistance and liver fat in youth at risk of T2D. Considering that liver fat is the strongest predictor of T2D in youth, LBMI should be considered in risk assessment in youth at high risk of T2D. 16 Physical Activity Intensity and Adiposity in Obese Youth: The POWER Trial JONATHAN M. MCGAVOCK*, JACQUELINE HAY, TODD DUHAMEL, BRANDY WICKLOW, HEATHER DEAN, ELIZABETH SELLERS, ELIZABETH READY, LORI BERARD Winnipeg, MB Study Hypothesis: We conducted a randomized controlled trial to test the hypothesis that compared to controls, vigorous-intensity physical activity (PA) would lead to a greater reduction in visceral
adiposity than moderate-intensity PA despite similar caloric expenditure. Methods: Following a 2-week run-in phase, overweight youth 13 to 19 years with 1 risk factor for type 2 diabetes were randomized to either vigorous PA at >70% of peak fitness (VPA), moderate PA at 40% to 55% of peak fitness (MPA) or control arms (CTRL). PA was delivered 3 times weekly for 30 to 45 minutes for 6 months. Outcome measures included MRI-derived visceral adipose tissue (VAT), DXA-derived total body fat and waist circumference. Results: One hundred twenty obese youth (BMI Z ¼ 2.10.4) were randomized to VPA (n¼48); MPA (n¼36) and CTRL (n¼36). Using intention to treat analysis, no statistical differences were observed in any outcome measure between the groups; however, VAT was reduced over time (pre/post) in VPA (-3.2; 95% CI: -12.4 to +6.1 cm2) and MPA (-7.2; -18.0 to +3.6 cm2) as compared to CTRL (+1.1;-9.6 to +11.8 cm2). VPA also reduced waist circumference (-1.8; -1.3 to ¼0.6 cm) that was not observed in MPA (+2.4;-0.3 to +5.1 cm) or CRTL (+1.6;-1.3 to +4.5 cm). In efficacy analyses, reduction in VAT in both PA groups was significantly different from CTRL (p¼0.02). Conclusions: Increased PA, regardless of intensity leads to clinically meaningful reductions in VAT in obese youth. VPA was not associated with greater reductions in measures of adiposity relative to MPA.
17 Weight Loss Intervention for Individuals with Diabetes and Serious Mental Illness: A Pragmatic Experiment in Community Settings ROHAN GANGULI*, TODD JENKINS, KINNON MACKINNON, MEHREEN BHAMANI Toronto, ON Background: The rate of diabetes in individuals with serious mental illness is 2 to 3 times the general population rate. Diabetic co-morbidities are also higher in this population. The most severely affected often reside in board and care homes managed by nonprofessional staff. We studied the effects of training these staff in behavioural techniques for weight loss. Methods: Staff of 5 board and care homes was recruited to participate in a year-long program to improve nutrition and physical activities for residents. The subjects were 18 residents who had type 2 diabetes mellitus and a psychotic illness. The primary outcome was change in weight from baseline to the end of the study. Research staff recorded the participants’ weights. All other aspects of the intervention were taught to and carried out by the staff of the homes. Results: In initial focus groups, staff expressed pessimism about persuading residents to change their behaviour, but still agreed to participate. Baseline and endpoint data from 18 subjects showed weight was lost by all except 3 subjects (mean weight loss 6.73 kg; 95% (CI -9.93 to -3.53 kg); p less than 0.001 [t¼4.44; df¼17]). Conclusions: Despite the initial pessimism of the staff, almost all the subjects lost weight. Since the intervention was delivered by the existing staff of the residential facilities, there was minimal increase of cost to the system. The quasi-experimental design of the study is a limitation, but these encouraging results should justify a rigorous randomized controlled trial of the intervention in similar settings.