Prescription of Step Counts for Targeted Changes in Body Composition and Cardiometabolic Risk in Overweight/Obese Adults
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 200
- 试验地点
- 2
- 主要终点
- weight
研究概览
简要总结
The prevalence of overweight and obesity remains epidemic in the United States, with some of the highest rates seen in older adults. While this phenomenon is certainly multifactorial, a good deal of evidence suggests that insufficient physical activity (PA) contributes significantly. Pilot data recently collected in a laboratory indicates a strong, inverse relationship between daily step counts and body fatness and cardiometabolic risk (CMR) factors when step counts are expressed relative to fat mass in young adults. This expression of PA may be especially predictive of body composition because it is influenced by factors that influence appetite and energy intake, energy expenditure, and the energy "reservoir" that is represented by body fat stores, all three elements of the "settling point" model of body weight. The strength of this relationship suggests that prescription of step counts that consider current body weight and composition, and weight loss goal, may yield predictable changes in weight and CMR in adults eating ad libitum. The long-term objective of this study is to quantify the relationship between daily step counts and body composition in young, middle aged, and older adults who are overweight/obese and develop a regression model that can be used to prescribe physical activity (daily step counts) for achieving a specific target body weight and predictably improving CMR risk for young, middle-aged, and older adult men and women over eight months while eating ad libitum. To achieve this objective, investigators will undertake two specific aims: 1) quantify the relationship between average steps·kg fat mass-1·day-1 and body composition/CMR profiles in healthy, overweight, and obese adults 20-39 years, 40-59 years, 60-79 years, and 80-plus years old, using inexpensive, widely available triaxial pedometers while eating ad libitum, and 2) quantify the efficacy of employing targeted step counts expressed as steps·kg fat mass-1·day-1 using the model developed in Aim 1 for producing predictable improvements in body composition and CMR factors in overweight and obese adults 20-39, 40-59, 60-79, and 80-plus years old, over 8 months while eating ad libitum. This study will result in a regression model that may significantly improve the way that PA is prescribed for weight management, with vast clinical and public health implications.
详细描述
Aim 1: Quantify the relationship between average steps·kg fat mass-1·day-1 and body composition/CMR profiles in healthy normal, overweight, and obese adults 20-39 years, 40-59 years, 60-79 years, and 80-plus years old, using inexpensive, widely available triaxial pedometers while eating ad libitum.
Introduction. Quantifying the relationship between PA and body composition/CMR factors will result in a model for prescribing PA for weight management in overweight and obese adults eating ad libitum. The objective for this aim is to quantify the relationship between average steps·kg fat mass-1·day-1 and body composition/CMR profiles in healthy overweight and obese adults in four age groups: 20-39 years, 40-59 years, 60-79 years, and 80-plus years old, using inexpensive, widely available triaxial pedometers. The working hypotheses are that i) steps·kg fat mass-1·day-1 will be strongly associated with body composition/CMR profiles in men and women in each age group, and ii) the relationship between steps·kg fat mass-1·day-1 and body composition/CMR profile will be affected by age and sex of participants, due in part to the influence of fat-free mass on energy intake, and age-related changes in body composition and the regulation of EBAL. The approach to test these hypotheses will be to measure body composition and key CMR markers, and quantify step counts over four weeks in young, middle-aged, and older adults who are overweight or obese. In pilot studies, accelerometers were worn for 3-4 weeks, a duration that was effective for characterizing average daily step counts. The rationale for Aim 1 is that, because this unit is influenced by all of the elements of the "settling point" model of body weight (energy inputs, energy outflow, and the energy reservoir), PA expressed as steps·kg fat mass-1·day-1 is strongly associated with body composition/CMR factors, and may be used to develop a model for prescribing PA that will produce predictable improvements in body composition/CMR profiles in overweight/obese adults eating ad libitum. The expected outcome for Aim 1 is the development of a regression model that may be used for prescribing PA in young, middle-age, and older overweight/obese adults that, if adhered to, will lead to predictable changes in body composition/CMR factors while eating ad libitum.
Research Design. A total of 200 adults, 50 in each age group and equally divided between men and women, will be recruited into the first phase of this study. Measures. The primary outcome measures will be body composition [determined using 4-compartment modeling] and step counts collected for four weeks using triaxial pedometers. CMR factors will be secondary outcome measures. CMR factors will include fasting plasma glucose and insulin, and glycosylated hemoglobin (A1c). In addition, blood lipids (cholesterol, HDL, LDL, VLDL, and triglycerides) will be measured, and a common indicator of whole-body inflammatory status (hsCRP) will be assessed.
Inclusion criteria.
- overweight or obese (BMI = 20.0 - 35.0 kg·m-2)
- ages of 20 years and older
- otherwise healthy adults on prescription medication to treat hypertension or osteoarthritic conditions are eligible to participate
- sedentary people, or people who report engaging in regular walking (no regular structured exercise for at least the past six months)
- relatively stable weight over the previous 6 months (less than 5% fluctuation in body weight) Exclusion criteria.
- any diagnosed cardiovascular, metabolic, renal, or pulmonary disease, or any diagnosed cognitive dysfunction
- women who are pregnant or plan on becoming pregnant
- people taking prescription medication to regulate plasma glucose, or that affect metabolism (e.g., thyroid medication)
- people who have undergone an increase or decrease in body weight of ≥ 5% over the previous six months
- current smokers
- people who have engaged in a program of structured exercise other than walking (e.g., weight training, jogging, swimming, cycling) within that last six months
- older adults (60-plus years old) who score > 4 on the Short Blessed Test for geriatric cognitive impairment during the first lab visit will be ineligible to participate Primary Recruitment Plan. Recruitment will be accomplished in a variety of ways, starting with the Kennesaw State University community of faculty, staff, and students. KSU currently serves nearly 43,000 students, and and full- and part-time positions employ over 14,000 people, and this community will be a rich source of participants. Additional collaborators will include various physicians' clinics in the area, including Bethesda Community Clinic, and the Wellstar Health System and its Center for Best Health. Participants will also be recruited from among the student and employee populations at Emory Hospital.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 20 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •ages of 20 years and older
- •otherwise healthy adults on prescription medication to treat hypertension or osteoarthritic conditions are eligible to participate
- •sedentary people, or people who report engaging in regular walking (no regular structured exercise for at least the past six months)
- •relatively stable weight over the previous 6 months (less than 5% fluctuation in body weight)
排除标准
- •any diagnosed cardiovascular, metabolic, renal, or pulmonary disease, or any diagnosed cognitive dysfunction
- •women who are pregnant or plan on becoming pregnant
- •people taking prescription medication to regulate plasma glucose, or that affect metabolism (e.g., thyroid medication)
- •people who have undergone an increase or decrease in body weight of ≥ 5% over the previous six months
- •current smokers
- •people who have engaged in a program of structured exercise other than walking (e.g., weight training, jogging, swimming, cycling) within that last six months
- •older adults (60-plus years old) who score > 4 on the Short Blessed Test for geriatric cognitive impairment during the first lab visit will be ineligible to participate
结局指标
主要结局
weight
时间窗: In phase one of the study, weight will be assessed at baseline (day 1), and 28-30 days later. In phase two of the study, weight will be measured 1) at baseline, 2) four months later, and 3) 8-months later
In phase one of the study, weight will be assessed for purposes of developing a regression model. In phase two of the study, weight will be assessed to establish a step count target, and to track changes during the 8-month intervention.
body composition
时间窗: In phase one of the study, body composition will be assessed at baseline (day 1), and 28-30 days later. In phase two of the study, body composition will assessed 1) at baseline, 2) 4 months later, and 3) 8 months later
In phase one of the study, body composition (percentage of body weight comprised of fat) will be determined for the purposes of developing a regression model to allow prediction of body composition. In phase two of the study, body composition (percentage of body weight comprised of fat) will be assessed to determine baseline levels, and to allow for tracking changes over the 8-month intervention.
Step counts
时间窗: In phase one of the study, step counts will be recorded every day for 4 weeks. In phase two of the study, step counts will be recorded each day for the duration of the 8-month walking intervention
Step counts (steps per day) will be recorded using pedometers that will be carried on the hips or torso. Step counts will be recorded for four weeks during phase one of the study, and for eight months during the intervention phase of the study (phase two).
次要结局
- cardiometabolic risk profiles(in phase one of the study, cardiometabolic risk factors will be 28-30 days after baseline body composition measurement. In phase two of the study, cardiometabolic risk factors will be assessed at baseline, and 8 months later.)
- insulin(in phase one of the study, insulin will be assessed after carrying a pedometer for 4 weeks; in phase two of the study, insulin will be assessed before and after the 8-month walking intervention.)