Lean Body Mass Associated with Upper Body Strength in Healthy Older Adults While Higher Body Fat Limits Lower Extremity Performance and Endurance

Impaired strength adversely influences an older person’s ability to perform activities of daily living. A cross-sectional study of 117 independently living men and women (age = 73.4 ± 9.4 year; body mass index (BMI) = 27.6 ± 4.8 kg/m²) aimed to assess the association between body composition and: (1) upper body strength (handgrip strength, HGS); (2) lower extremity performance (timed up and go (TUG) and sit to stand test (STS)); and (3) endurance (6-minute walk (SMWT). Body composition (% fat; lean body mass (LBM)) was assessed using bioelectrical impedance. Habitual physical activity was measured using the Minnesota Leisure Time Physical Activity Questionnaire (MLTPA) and dietary macronutrient intake, assessed using 24 h recalls and 3-day food records. Regression analyses included the covariates, protein intake (g/kg), MLTPA, age and sex. For natural logarithm (Ln) of right HGS, LBM (p < 0.001) and % body fat (p < 0.005) were significant (r² = 46.5%; p < 0.000). For left LnHGS, LBM (p < 0.000), age (p = 0.036), protein intake (p = 0.015) and LnMLTPA (p = 0.015) were significant (r² = 0.535; p < 0.000). For SMW, % body fat, age and LnMLTPA were significant (r² = 0.346; p < 0.000). For STS, % body fat and age were significant (r² = 0.251; p < 0.000). LBM is a strong predictor of upper body strength while higher % body fat and lower physical activity are associated with poorer outcomes on tests of lower extremity performance.     

Leptin and total cholesterol are predictors of weight gain in pre-pubertal children

OBJECTIVE: The aim of this study was to identify specifically which biochemical indices predict excessive weight gain over time in a cohort of pre-pubertal children. SUBJECTS: Fifty nine healthy pre-pubertal children (age: 6.3-9.8y). MEASUREMENTS: Children were defined anthropometrically and biochemically at baseline. Height and weight measurements were then repeated after six (n=52) and 12 months (n=37). RESULTS: Weight change after six months (defined by a change in body mass index (BMI) z-score from baseline) demonstrated no correlation with fasting plasma levels of leptin, insulin, insulin:glucose (IG) ratio, cholesterol, triglyceride or high density lipoprotein (HDL) cholesterol. However, after 12 months there was a significant negative correlation between BMI z-score change and initial plasma leptin (r=-0.35, P=0.048) and this relationship strengthened when adjusted for body fat (from bio-electrical impedance; r=-0.46, P=0.009). In addition, there was a significant positive relationship between plasma total cholesterol and BMI z score change (r=0.38, P=0.03) and this relationship remained unchanged when adjusted for body fat. No relationship was observed between weight change after 12 months and plasma levels of insulin, IG ratio, HDL cholesterol or triglyceride. CONCLUSION: Plasma leptin and total cholesterol were found to be predictive of weight gain over 12 months in a cohort of pre-pubertal children. These two potential predictors can be readily measured in clinical practice and these findings may represent a method of defining the 'at risk of obesity' state in childhood.     

Unconventional biological threats and the molecular biological response to biological threats

This article concludes this symposium on potential agents of warfare and terrorism with discussion of 3 topics. First, influenza A virus is discussed as a potential biological weapon. Although it does not receive much attention in this role, the potential for mass casualties and public panic certainly exist if an epidemic of a virulent influenza A virus were initiated. Second, agroterrorism, terrorism directed at livestock or poultry or crops, is briefly discussed. Finally, the potential role of techniques of modern molecular biology to create new agents for bioterrorism or enhance the terrorist potential of available agents, and the known roles of these techniques in defense against biological warfare or terrorism are discussed.