Chhanda Dutta

Significance of Sarcopenia in the Elderly

At the present time, there is only limited understanding of the public health significance of sarcopenia. The well-recognized functional consequences of sarcopenia include gait and balance problems and increased risk for fall. Ultimately, these impairments can lead to the loss of physical functional independence. However, sarcopenia may also contribute to an increased risk for chronic diseases such as diabetes and osteoporosis. Future studies of the pathophysiologic significance of sarcopenia need to consider the contribution(s) of muscle properties (e.g., muscle fiber composition, muscle blood flow, fatigue characteristics, innervation) to alterations in physical performance, metabolism and physiology, and skeletal health. More comprehensive studies on the sequelae of sarcopenia are critical to an accurate assessment of the public health burden that sarcopenia poses to the elderly population.

Low or Moderate Dietary Energy Restriction for Long-term Weight Loss: What Works Best?

Theoretical calculations suggest that small daily reductions in energy intake can cumulatively lead to substantial weight loss, but experimental data to support these calculations are lacking. We conducted a 1‐year randomized controlled pilot study of low (10%) or moderate (30%) energy restriction (ER) with diets differing in glycemic load in 38 overweight adults (mean ± s.d., age 35 ± 6 years; BMI 27.6 ± 1.4 kg/m2). Food was provided for 6 months and self‐selected for 6 additional months. Measurements included body weight, resting metabolic rate (RMR), adherence to the ER prescription assessed using 2H218O, satiety, and eating behavior variables. The 10%ER group consumed significantly less energy (by 2H218O) than prescribed over 12 months (18.1 ± 9.8%ER, P = 0.04), while the 30%ER group consumed significantly more (23.1 ± 8.7%ER, P < 0.001). Changes in body weight, satiety, and other variables were not significantly different between groups. However, during self‐selected eating (6–12 months) variability in % weight change was significantly greater in the 10%ER group (P < 0.001) and poorer weight outcome on 10%ER was predicted by higher baseline BMI and greater disinhibition (P < 0.0001; adj R2 = 0.71). Weight loss at 12 months was not significantly different between groups prescribed 10 or 30%ER, supporting the efficacy of low ER recommendations. However, long‐term weight change was more variable on 10%ER and weight change in this group was predicted by body size and eating behavior. These preliminary results indicate beneficial effects of low‐level ER for some but not all individuals in a weight control program, and suggest testable approaches for optimizing dieting success based on individualizing prescribed level of ER.

Activity-Related Energy Expenditure in Older Adults: A Call for More Research.

The purposes of this article were to 1) provide an overview of the science of physical activity-related energy expenditure in older adults (≥65 yr), 2) offer suggestions for future research and guidelines for how scientists should be reporting their results in this area, and 3) present strategies for making these data more accessible to the layperson. This article was meant to serve as a preliminary blueprint for future empirical work in the area of energy expenditure in older adults and translational efforts to make these data useful and accurate for older adults. This document was based upon deliberations of experts involved in the Strategic Health Initiative on Aging Committee of the American College of Sports Medicine. The article was designed to reach a broad audience who might not be familiar with the complexities of assessing energy expenditure, especially in older adults.

Report: NIA Workshop on Measures of Physiologic Resiliencies in Human Aging

Background/Objectives Resilience, the ability to resist or recover from adverse effects of a stressor, is of widespread interest in social, psychologic, biologic, and medical research and particularly salient as the capacity to respond to stressors becomes diminished with aging. To date, research on human resilience responses to and factors influencing these responses has been limited. Methods The National Institute on Aging convened a workshop in August 2015 on needs for research to improve measures to predict and assess resilience in human aging. Effects of aging-related factors in impairing homeostatic responses were developed from examples illustrating multiple determinants of clinical resilience outcomes. Research directions were identified by workshop participants. Results Research needs identified included expanded uses of clinical data and specimens in predicting or assessing resilience, and contributions from epidemiological studies in identifying long-term predictors. Better measures, including simulation tests, are needed to assess resilience and its determinants. Mechanistic studies should include exploration of influences of biologic aging processes on human resiliencies. Important resource and infrastructure needs include consensus phenotype definitions of specific resiliencies, capacity to link epidemiological and clinical resilience data, sensor technology to capture responses to stressors, better laboratory animal models of human resiliencies, and new analytic methods to understand the effects of multiple determinants of stress responses. Conclusions Extending the focus of care and research to improving the capacity to respond to stressors could benefit older adults in promoting a healthier life span.