Train High Eat Low for Osteoarthritis study (THE LO study): protocol for a randomized controlled trial.

INTRODUCTION: Osteoarthritis (OA) is one of the most prevalent chronic conditions among older adults, with the medial tibio-femoral joint being most frequently affected. The knee adduction moment is recognized as a surrogate measure of the medial tibio-femoral compartment joint load and therefore represents a valid intervention target. This article provides the rationale and methodology for THE LO study (Train High, Eat Low for Osteoarthritis), which is a randomized controlled trial that is investigating the effects of a unique, targeted lifestyle intervention in overweight/obese adults with symptomatic medial knee OA. RESEARCH QUESTION: Compared to a control group given only lifestyle advice, do the effects of the following interventions result in significant reductions in the knee adduction moment: (1) gait retraining; and (2) combined intervention (which involves a combination of three interventions: (a) gait retraining, (b) high-intensity progressive resistance training, and (c) high-protein/low-glycaemic-index energy-restricted diet)? It is hypothesized that the combined intervention group will be superior to the isolated interventions of the high-protein/low-glycaemic-index diet group and the progressive resistance training group. Finally, it is hypothesized that the combined intervention will result in a greater range of improvements in secondary outcomes, including: muscle strength, functional status, body composition, metabolic profile, and psychological wellbeing, compared to any of the isolated interventions or control group. DESIGN: Single-blinded, randomized controlled trial adhering to the CONSORT guidelines on conduct and reporting of non-pharmacological clinical trials. PARTICIPANTS: One hundred and twenty-five community-dwelling people are being recruited. Inclusion criteria include: medial knee OA, low physical activity levels, no current resistance training, body mass index ≥ 25kg/m(2) and age ≥ 40 years. INTERVENTION AND CONTROL: The participants are stratified by sex and body mass index, and randomized into one of five groups: (1) gait retraining; (2) progressive resistance training; (3) high-protein/low-glycaemic-index energy-restricted diet (25 to 30% of energy from protein, 45% of energy from carbohydrates, < 30% of energy from fat, and glycaemic index diet value < 50); (4) a combination of these three active interventions; or (5) a lifestyle-advice control group. All participants receive weekly telephone checks for health status, adverse events and optimisation of compliance. MEASUREMENTS: Outcomes are measured at baseline, 6 and 12 months. The primary outcome is the peak knee adduction moment during the early stance phase of gait. The secondary outcome measures are both structural (radiological), with longitudinal reduction in medial minimal joint space width at 12 months, and clinical, including: change in body mass index; joint pain, stiffness and function; body composition; muscle strength; physical performance/mobility; nutritional intake; habitual physical activity and sedentary behaviour; sleep quality; psychological wellbeing and quality of life. DISCUSSION: THE LO study will provide the first direct comparison of the long-term benefits of gait retraining, progressive resistance training and a high-protein/low-glycaemic-index energy-restricted diet, separately and in combination, on joint load, radiographic progression, symptoms, and associated co-morbidities in overweight/obese adults with OA of the knee.

Zinc supplementation does not alter sensitive biomarkers of copper status in healthy boys.

The tolerable upper intake levels (UL) for zinc for children were based on limited data and there is concern that the UL may be set too low. The first effect of excessive zinc intake is a reduction in copper status. The primary objective of this study was to examine the effect of zinc supplementation on copper status in children. Healthy, 6- to 8-y-old boys from Ontario, Canada were assigned to take a placebo (n = 10) or 5 mg (n = 10), 10 mg (n = 9), or 15 mg (n = 8) of zinc supplement daily for 4 mo in a double-blinded, placebo-controlled, randomized trial. Biochemical measures were evaluated at baseline and after 2 and 4 mo of supplementation. Food records were completed near the baseline and 4-mo visits. Age and anthropometric measurements did not differ (P > 0.05) between treatment groups at baseline. Mean zinc intakes from food alone (10.9-14.8 mg zinc/d) approached or exceeded the UL of 12 mg/d. Compared with the placebo group, the zinc groups had a greater change in the urine zinc:creatinine ratio at 4 mo (P = 0.02). Traditional (plasma copper and ceruloplasmin activity) and more sensitive biomarkers of copper status, including erythrocyte SOD1 activity and the erythrocyte CCS:SOD1 protein ratio, were unchanged in zinc-supplemented boys, demonstrating that copper status was not depressed. Serum lipid measures and hemoglobin concentrations were also unaffected and gastrointestinal symptoms were not reported. These data provide evidence in support of the need for reexamining the current UL for zinc for children.

Effect of the transition from high school to university on anthropometric and lifestyle variables in males.

The obesity epidemic in North America has focused attention on the health risks of excess weight gain. The transition from high school to university is a critical period for weight gain, commonly referred to as the Freshman 15. The purpose of this study was to investigate the effect of the transition from high school to university on anthropometrics and physical and sedentary activities in males. A total of 108 males completed 3 study visits: the summer prior to first year university, and the ends of the first and second semesters. Outcome measures were body mass, height, body mass index (BMI), body fat, waist circumference, hip circumference, waist:hip ratio, dietary intake, and participation in physical and sedentary activities. Between the summer prior to and the end of first year university, male students experienced a significant weight gain, of 3.0 kg, with significant increases in BMI, body fat, waist circumference, hip circumference, and waist:hip ratio. Energy and nutrient intake did not change. Final body mass was significantly predicted by intention for body mass to stay the same, relative to weight loss intention. Fast aerobic physical activity significantly decreased between the summer prior to and the end of first year university, while slow aerobic physical activity, strength training, and flexibility training did not change. Computer and studying time significantly increased, while television time and hours of nightly sleep significantly decreased between the summer prior to and the end of first year university. Weekly alcoholic drinks and binge drinking frequency significantly increased over this time period. In conclusion, between the summer prior to and the end of first year university, male students gained an average of 3.0 kg, with increases in related anthropometrics. These changes may be due to body mass change intention and (or) the observed decreased physical and increased sedentary activities, but appear to be unrelated to dietary intake.