Miu Lam

Effects of Exercise Modality on Insulin Resistance and Functional Limitation in Older Adults: A Randomized Controlled Trial

BACKGROUND Authorities advocate that resistance and aerobic exercise are essential for reducing risk factors for chronic disease and disability in older adults. However, the incremental effects of combined resistance and aerobic exercise compared with either modality alone on risk factors for disease and disability is generally unknown. METHODS Participants were 136 sedentary, abdominally obese older men and women recruited from September 30, 2002, through November 15, 2006, at Queens University. Participants were randomized to 1 of the following 4 groups for 6 months: resistance exercise, aerobic exercise, resistance and aerobic exercise (combined exercise), or nonexercise control. Primary outcomes were analyzed by an intent-to-treat model and included changes in insulin resistance by hyperinsulinemic-euglycemic clamp and functional limitation using the average change in 4 tests combined (average z score). RESULTS After controlling for age, sex, and baseline value, insulin resistance improved compared with controls in the aerobic exercise and the combined exercise groups but not in the resistance exercise group. Improvement (mean [SE]) in the combined exercise group was greater than in the resistance exercise group (9.2 [1.3] vs 1.8 [1.3] mg/mL/microIU per kilogram of skeletal muscle per minute x100 [P < .001]) but not in the aerobic exercise group (9.2 [1.3] vs 6.5 [1.3] mg/mL/microIU per kilogram of skeletal muscle per minute x100 [P = .46]). Functional limitation improved significantly in all groups compared with the control group. Improvement in the combined exercise group was greater than in the aerobic exercise group (0.5 [0.1] vs -0.0 [0.1]; standard units, z score [P = .003]) but not in the resistance exercise group. Improvement in the resistance exercise group was not different from the aerobic exercise group. CONCLUSION The combination of resistance and aerobic exercise was the optimal exercise strategy for simultaneous reduction in insulin resistance and functional limitation in previously sedentary, abdominally obese older adults. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00520858.

Impact of perioperative pain intensity, pain qualities, and opioid use on chronic pain after surgery: a prospective cohort study.

Background and Objectives A better understanding of the pathogenesis of chronic postsurgical pain is needed in order to develop effective prevention and treatment interventions. The objective of this study was to evaluate the incidence and risk factors for chronic postsurgical pain in women undergoing gynecologic surgery. Methods Pain characteristics, opioid consumption, and psychologic factors were captured before and 6 months after surgery. Analyses included univariate statistics, relative risks (RRs) and 95% confidence intervals (95% CIs), and modified Poisson regression for binary data. Results Pain and pain interference 6 months after surgery was reported by 14% (n = 60/433) and 12% (n = 54/433), respectively. Chronic postsurgical pain was reported by 23% (n = 39/172) with preoperative pelvic pain, 17% (n = 9/54) with preoperative remote pain, and 5.1% (n = 10/197) with no preoperative pain. Preoperative state anxiety (RR = 1.8; 95% CI, 1.1–2.8), preoperative pain (pelvic RR = 3.7; 95% CI, 1.9–7.2; remote RR = 3.0; 95% CI, 1.3–6.9), and moderate/severe in-hospital pain (RR = 3.0; 95% CI, 1.0–9.4) independently predicted chronic postsurgical pain. The same 3 factors predicted pain-interference at 6 months. Participants describing preoperative pelvic pain as “miserable” and “shooting” were 2.8 (range, 1.3–6.4) and 2.1 (range, 1.1–4.0) times more likely to report chronic postsurgical pain, respectively. Women taking preoperative opioids were 2.0 (range, 1.2–3.3) times more likely to report chronic postsurgical pain than those not taking opioids. Women with preoperative pelvic pain who took preoperative opioids were 30% (RR = 1.3; 95% CI, 0.8–1.9) more likely to report chronic postsurgical pain than those with preoperative pelvic pain not taking opioids. Conclusions Preoperative pain, state anxiety, pain quality descriptors, opioid consumption, and early postoperative pain may be important predictors of chronic postsurgical pain, which require further investigation.

Trial of Prevention and Reduction of Obesity Through Active Living in Clinical Settings: A Randomized Controlled Trial

BACKGROUND The efficacy of physical activity with a healthful diet to reduce obesity is established; however, little is known about the translation of effective lifestyle strategies for obesity reduction in primary care settings. METHODS We assessed the effectiveness of a 2-year behaviorally based physical activity and diet program implemented entirely within clinical practices to reduce obesity. A total of 490 sedentary, obese adults were randomized to usual care (n = 241) or to the behavioral intervention (n = 249). The usual care group received advice from their physicians about lifestyle as a strategy for obesity reduction. The behavioral intervention included individual counseling from health educators to promote physical activity with a healthful diet. The primary outcome was change in waist circumference (WC). RESULTS A total of 396 participants completed the trial (80.8%). A significant main effect was observed for WC change within the intervention compared with usual care (P < .001) that was sustained at 24 months (mean [SE], -0.9 [0.4] vs 0.2 [0.4] cm; P = .05). Secondary analyses revealed significant main effects for change in WC in men (P = .009) and women (P = .02). In men, the mean (SE) reduction in WC at 24 months was greater with behavioral intervention compared with usual care (-1.6 [0.6] vs 0.1 [0.6] cm; P = .049). In women, the behavioral intervention was associated with differences in WC compared with usual care at 6 and 12 months (P ≤ .01) but not at 24 months (P = .10). CONCLUSIONS Behavioral intervention in clinical settings is associated with modest reductions in WC during a 2-year study in obese patients. However, the effectiveness of the intervention is restricted to men. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00665158.

Dietary patterns and the risk of mortality: impact of cardiorespiratory fitness

BACKGROUND While dietary patterns that are both predictive of chronic disease and mortality have been identified, the confounding effects of cardiorespiratory fitness have not been properly addressed. The primary objective was to assess the relation between dietary patterns with all-cause mortality, while controlling for the potentially confounding effects of fitness. METHODS This was a prospective cohort study. Participants consisted of 13 621 men and women from the Aerobics Center Longitudinal Study (ACLS). Participants completed a clinical exam and 3-day diet record between 1987 and 1999. Participants were followed for mortality until 2003. Reduced rank regression (RRR) was used to identify dietary patterns that predicted unfavourable total and high-density lipoprotein-cholesterol, triglyceride, glucose, blood pressure, uric acid, white blood cell and body mass index values. RESULTS One primary dietary pattern emerged and was labelled the Unhealthy Eating Index. This pattern was characterized by elevated consumption of processed and red meat, white potato products, non-whole grains, added fat and reduced consumption of non-citrus fruits. The hazard ratio for all-cause mortality in the fifth vs the first quintile of the Unhealthy Eating Index was 1.40 (1.02-1.91). This risk estimate was reduced by 13.5 and 55.0% after controlling for self-reported physical activity and fitness, respectively. CONCLUSION In this study the association between diet and overall mortality was, in large part, confounded by fitness.

Influence of overweight and obesity on physician costs in adolescents and adults in Ontario, Canada.

The study purpose was to perform an obesity cost‐of‐illness analysis for individuals living in the province of Ontario, Canada. The participants consisted of a representative sample of 25 038 adults and 2440 adolescents (aged 12–17 years) who participated in the 2000/2001 Canadian Community Health Survey (CCHS). The CCHS data set includes measures of body mass index (BMI) (classified as normal weight, overweight or obese) and relevant covariates (age, income, smoking, alcohol, physical activity). The CCHS data set was linked to the Ontario Health Insurance Plan providers’ database to obtain physician costs for 2002–2003. A two‐part modelling approach was used to calculate and compare the average annual physician cost according to BMI. After adjusting for the covariates, physician costs were not significantly higher in overweight men and women compared with those with a normal weight. Physician costs were 14.7% higher in obese men and 18.2% higher in obese women than in men and women with a normal weight. Average physician costs were comparable in normal‐weight and overweight/obese adolescents (

A primary care pragmatic cluster randomized trial of the use of home blood pressure monitoring on blood pressure levels in hypertensive patients with above target blood pressure

233 per year in both groups). Because Ontario operates a publicly funded healthcare system, the findings of this study have relevance for other provinces/states and countries that operate similar healthcare systems.

Exercise-Induced Improvement in Insulin Sensitivity Is Not Mediated by Change in Cardiorespiratory Fitness

BACKGROUND The measurement of blood pressure (BP) at home by patients with hypertension is increasingly used to assess and monitor BP. Evidence for its effectiveness in improving BP control is mixed. METHODS To determine if home BP monitoring improves BP a pragmatic cluster randomized contolled trial was carried out in family practices in southeastern Ontario, Canada. Family practice patients with uncontrolled hypertension were recruited to the trail. Patients were divided into two groups: one with at least weekly measurements of BP at home, recording those measurements and showing those to the family physician during office visits for hypertension and the control group were given usual care. The primary outcome was mean awake BP on ambulatory monitoring at 6- and 12-month follow-up and the secondary outcomes were mean BP on full 24-hour ambulatory blood pressure monitoring (ABPM), mean sleep BP on ABPM and BP on the BpTRU device, all at 6- and 12-month follow-up. RESULTS Home BP monitoring did not improve BP compared to usual care at 12-month follow-up: mean awake systolic BP on ABPM [141.1 versus 142.8 mmHg, mean difference 1.7 mmHg; 95% confidence interval (CI) -0.6 to 4.0, P = 0.314] and mean awake diastolic BP on ABPM (78.7 versus 79.4 mmHg, mean difference 0.7 mmHg; 95% CI -7.7 to 9.1, P = 0.398). Similar negative results were obtained for men and women separately. However, outcomes using the full 24-hour ABPM and the BpTRU device showed a significantly lower diastolic BP at 12 months. When analysis was done by sex, this effect was shown to be only in men. CONCLUSION Home BP monitoring may improve BP control in men with hypertension.

Abdominal Adiposity, Not Cardiorespiratory Fitness, Mediates the Exercise-Induced Change in Insulin Sensitivity in Older Adults.

Although exercise-induced improvement in cardiorespiratory fitness (CRF) and reduction in abdominal obesity are putative mechanisms by which chronic exercise attenuates insulin resistance (1), the independent contribution of each is unknown. We therefore investigated whether improvement in abdominal obesity and/or CRF mediates the effect of exercise on insulin sensitivity in abdominally obese adults. Participants included sedentary, abdominally obese men and women who participated in two previously published exercise interventions (2,3). Participants were randomized to control ( n = 18) or supervised aerobic exercise ( n = 59) for 3 (women) or 4 (men) months. CRF (VO2peak) was measured using a maximal treadmill test, abdominal obesity by magnetic resonance imaging and waist circumference (WC), and insulin sensitivity by the hyperinsulinemic-euglycemic clamp. Simple mediation analysis (Table 1) revealed that with the exception of …

The Ontario Asthma Regional Variation Study* Emergency Department Visit Rates and the Relation to Hospitalization Rates

Abdominal obesity and low cardiorespiratory fitness (CRF) are associated with insulin resistance in older adults. Exercise is associated with improvement in insulin sensitivity. Whether this association is mediated by change in CRF and/or abdominal obesity is unclear. The current study is a secondary analysis of data from a randomized controlled trial in Kingston, Ontario. Sedentary older adults (60–80 years) (N = 80) who completed the exercise (N = 59) or control (N = 21) conditions for 6 months were included. CRF was measured using a treadmill test, adipose tissue (AT) by magnetic resonance imaging, and insulin sensitivity by hyperinsulinemic-euglycemic clamp. Waist circumference (WC) was measured at the iliac crest. Mediation analyses were used to assess whether abdominal AT and/or CRF mediated the exercise-induced change in insulin sensitivity. By comparison to controls, reduction (mean ± SD) was observed for visceral (-0.4 ± 0.4 kg) and abdominal subcutaneous (-0.4 ± 0.4) AT depots, WC (-4.1 ± 3.2 cm) and BMI (-0.9 ± 0.8 kg/m2) (p < 0.05). Insulin sensitivity (4.2 ± 5.2 M/I) and CRF (0.2 ± 0.3 L/min) improved in the exercise group (p < 0.05). All AT variables, BMI and WC were mediators of the change in insulin sensitivity (p < 0.05). After adjustment for change in total AT, abdominal AT remained a mediator with an effect ratio of 0.79 (p < 0.05), whereas total AT was not significant when adjusted for abdominal AT (p > 0.05). The effect ratio for change in WC and BMI combined (0.63, p<0.05) was greater than either alone. In conclusion, CRF did not mediate the exercise-induced change in insulin sensitivity in older adults. Abdominal adiposity was a strong mediator independent of change in total adiposity.