Janice O'Connor

Muscle fibre type composition in infant and adult populations and relationships with obesity.

OBJECTIVES: To investigate the fibre type composition of skeletal muscle in infants and young children and to compare the findings to an adult population. To relate the fibre type profile of skeletal muscle in adults to measures of adiposity. DESIGN: Cross-sectional studies of skeletal muscle fibre composition in infants and adults with measures of adiposity in the adults. SUBJECTS: 21 healthy infants and young children (age: 3–21 months) and 40 healthy adult Australian Caucasians (age: 26–62 y; BMI: 18–48 kg/m2). MEASUREMENTS: Skeletal muscle fibre type composition (by myosin ATPase method) and relative body fatness (BMI, waist circumference and waist/hip ratio (WHR)). RESULTS: Infants and young children had significantly lesser proportions of glycolytic Type 2b fibres (6.2±1.1%; range 0.3–18.9%) compared with adults (20.5±1.6%; range 4.9–36.0%) (p<0.0001). The percentage of Type 2b fibres was directly related to BMI (r=0.44, p=0.02), waist circumference (r=0.49, p=0.009) and WHR (r=0.44, p=0.02) in adults. A significant, direct relationship was also found between the proportion of glycolytic Type 2b fibres and age in the adults (r=0.45, p=0.01). CONCLUSION: Skeletal muscle fibre type composition is different in infants and adults and there is an age-dependent increase in Type 2b fibres over the lifespan. An increased proportion of glycolytic Type 2b fibres is associated with obesity in adults. Results support a gene-environment interaction on fibre type composition in human skeletal muscle.

Two-year outcomes of an adjunctive telephone coaching and electronic contact intervention for adolescent weight-loss maintenance: the Loozit randomized controlled trial

This paper reports the final 24-month outcomes of a randomized controlled trial evaluating the effect of additional therapeutic contact (ATC) as an adjunct to a community-based weight-management program for overweight and obese 13–16-year-olds. ATC involved telephone coaching or short-message-service and/or email communication once per fortnight. Adolescents were randomized to receive the Loozit group program—a two-phase behavioral lifestyle intervention with (n=73), or without (n=78), ATC in Phase 2. Adolescents/parents separately attended seven weekly group sessions (Phase 1), followed by quarterly adolescent sessions (Phase 2). Assessor-blinded, 24-month changes in anthropometry and metabolic health included primary outcomes body mass index (BMI) z-score and waist:height ratio (WHtR). Secondary outcomes were self-reported psychosocial and lifestyle changes. By 24 months, 17 adolescents had formally withdrawn. Relative to the Loozit program alone, ATC largely had no impact on outcomes. Secondary pre-post assessment of the Loozit group program showed mean (95% CI) reductions in BMI z-score (−0.13 (−0.20, −0.06)) and WHtR (−0.02 (−0.03, −0.01)) in both arms, with several metabolic and psychosocial improvements. Adjunctive ATC did not provide further benefits to the Loozit group program. We recommend that further work is needed to optimize technological support for adolescents in weight-loss maintenance. Australian New Zealand Clinical Trials Registry Number ACTRNO12606000175572.

Recruitment challenges and recommendations for adolescent obesity trials

Aim:  To report our experiences with recruiting overweight and obese 13‐ to 16‐year‐olds for the Loozit® weight management randomised control trial (RCT) and to identify effective strategies for recruiting adolescents from the community to a treatment trial.

Obesity and under-nutrition in a tertiary paediatric hospital

Objective:  (i) To determine the prevalence of over‐ and under‐nutrition in both inpatients and outpatients in a tertiary paediatric hospital; (ii) to compare the prevalence of over‐nutrition with that in the Australian community and (iii) to determine whether nutritional status has an impact on length of stay in hospital.

Outcomes of a nutrition audit in a tertiary paediatric hospital: Implications for service improvement

Objective:  To examine the process of anthropometric assessment of nutritional status in a tertiary paediatric hospital, to identify the barriers and to make recommendations for service improvement.