Normalization of Muscle Strength Measurements in the Assessment of Cardiometabolic Risk Factors in Adolescents.

Muscle strength (MS) has been associated with cardiometabolic risk factors (CMR) in adolescents, however, the impact attributed to body size in determining muscle strength or whether body size acts as a confounder in this relationship remains controversial. We investigated the association between absolute MS and MS normalized for body size with CMR in adolescents. This was a cross-sectional study comprising 351 adolescents (44.4% male; 16.6 ± 1.0 years) from Brazil. MS was assessed by handgrip and normalized for body weight, body mass index (BMI), height, and fat mass. CMR included obesity, high blood pressure, dyslipidemia, glucose imbalance, and high inflammation marker. When normalized for body weight, BMI, and fat mass, MS was inversely associated with the presence of two or more CMR among females. Absolute MS and MS normalized for height was directly associated with the presence of two or more CMR among males. This study suggests that MS normalized for body weight, BMI, and fat mass can be superior to absolute MS and MS normalized for height in representing lower CMR among females. Absolute MS and MS normalized for height were related to higher CMR among males.

Area-level Socioeconomic Environment and Cardiorespiratory Fitness in Youth.

INTRODUCTION: Cardiorespiratory fitness is one of the most important markers of cardiometabolic health and is a strong predictor of cardiovascular disease and all-cause mortality across the lifespan. However, little is known regarding the relationship of area-level socioeconomic environment on cardiorespiratory fitness during childhood and adolescence. PURPOSE: To examine the relationship between area-level socioeconomic environment and cardiorespiratory fitness in a diverse sample of school-age youth; and to determine the extent to which grade level, sex, race/ethnicity, and student poverty status moderate this relationship. METHODS: South Carolina FitnessGram data for school year 2015 to 2016 were obtained for 44,078 youth. Cardiorespiratory fitness was determined using Progressive Aerobic Cardiovascular Endurance Run or 1-mile run/walk test. Area-level socioeconomic environment was expressed as a composite index score at the census tract level using data from the American Community Survey. Multilevel logistic regression analyses were conducted, controlling for individual-level characteristics and nesting within schools and districts. Interaction terms were then introduced to the model to examine their effect of multiple sociodemographic moderators. RESULTS: Approximately half of the sample had inadequate cardiorespiratory fitness for health. The odds of achieving the Healthy Fitness Zone for cardiorespiratory fitness decreased by approximately 25% to 34% with increasing deprivation of the area-level socioeconomic environment, after controlling for covariates. The association between area-level socioeconomic environment and cardiorespiratory fitness also varied significantly by sex, grade level, and race/ethnicity subgroups. CONCLUSIONS: Cardiorespiratory fitness was positively associated with area-level socioeconomic environment; however, the relationship varied by demographic characteristics. These results highlight the importance of examining the influence of area-level socioeconomic environment on health across the life span. Additional research is needed to explore how area-level socioeconomic environment may impact evidence-based efforts to improve youth cardiorespiratory fitness levels.

Addition of estimated cardiorespiratory fitness to the clinical assessment of 10-year coronary heart disease risk in asymptomatic men.

The Framingham Risk Score (FRS) was developed to quantify a patient's coronary heart disease (CHD) risk. Non-exercise estimated CRF (e-CRF) may provide a clinically practical method for describing cardiorespiratory fitness. We computed e-CRF and tested its association with the FRS and CHD. Male participants (n = 29,854) in the Aerobics Center Longitudinal Study (ACLS) who completed a baseline examination between 1979-2002 were followed for 12 years to determine incident CHD defined by self-report of myocardial infarction, revascularization, or CHD mortality. e-CRF was defined from a 7-item scale and categorized using age-specific tertiles. Multivariable survival analysis determined associations between FRS, e-CRF, and CHD. Interaction between e-CRF and FRS was tested by stratified analysis by 'low' and 'moderate or high' 10-year CHD risk. Men with high e-CRF were significantly (p-value < 0.0001) younger, and less likely to be smokers, compared to men with low e-CRF. Multivariable survival analysis reported men with high e-CRF were 29% (HR = 0.71; 95% 0.56, 0.88) less likely to experience a CHD event compared to men with low e-CRF. Stratified analyses showed men with 'low' 10-year FRS predicted CHD risk and high e-CRF had a 28% (HR = 0.72; 95% CI 0.57, 0.91) lower CHD-mortality risk compared to men with low e-CRF, no association was found in this group and men with moderate e-CRF. Men who were more fit had a decreased risk for CHD compared to men in the lowest third of fitness. Estimated CRF may add clinical value to the FRS and help clinicians better predict long-term CHD risk.

Effects of insufficient physical activity on mortality and life expectancy in Jiangxi province of China, 2007-2010.

BACKGROUND: Physical inactivity remains an under-researched field in terms of studying burden of disease at provincial level, and no studies have examined the effects of inactivity on life expectancy (LE) in China. The purpose of this study was to estimate mortality risk and LE effects associated with insufficient levels of physical activity in Jiangxi province. METHODS/FINDINGS: Prevalence of risk factors and mortality counts were extracted from Chronic Diseases and Risk Factors Surveillance Survey (CDRFSS) and Disease Surveillance Points system (DSP), respectively. Insufficient physical activity (IPA) was defined as less than 150 minutes of moderate-intensity physical activity or 60 minutes of vigorous-intensity physical activity per week, accumulated across work, home, transport and discretionary domains. Population-attributable fractions (PAF) were used to calculate the mortality attributable to risk factors, and life table methods were used to estimate the LE gains and LE shifts. Monte Carlo simulation techniques were used for uncertainty analysis. Overall, 5 885 (95% uncertainly interval (UI), 5 047-6 506) and 8 578 (95% UI, 8 227-9 789) deaths in Jiangxi province were attributable to IPA in 2007 and 2010, respectively. The LE gains for elimination of attributable deaths were 0.68 (95% UI, 0.61-076) in 2007, and increased to 0.91 (95% UI, 0.81-1.10) in 2010. If the prevalence of IPA in 2010 had been decreased by 50% or 30%, 3 678 (95% UI, 3 220-4 229) or 2 090 (95% UI, 1 771-2 533) deaths would be avoided, and 0.40 (95% UI, 0.34-0.53) or 0.23 (95% UI, 0.16-0.31) years of LE gained, respectively. CONCLUSIONS: Adults in Jiangxi province of China have a high and increasing prevalence of IPA. Due to the deaths and potential LE gains associated with IPA, there is an urgent need to promote physical activity, one of the most modifiable risk factors, within China's health care reform agenda.

Age-specific exercise capacity threshold for mortality risk assessment in male veterans.

BACKGROUND: Mortality risk decreases beyond a certain fitness level. However, precise definition of this threshold is elusive and varies with age. Thus, fitness-related mortality risk assessment is difficult. METHODS AND RESULTS: We studied 18 102 male veterans (8305 blacks and 8746 whites). All completed an exercise test between 1986 and 2011 with no evidence of ischemia. We defined the peak metabolic equivalents (METs) level associated with no increase in all-cause mortality risk (hazard ratio, 1.0) for the age categories of <50, 50 to 59, 60 to 69, and ≥70 years. We used this as the threshold group to form additional age-specific fitness categories based on METs achieved below and above it: least-fit (>2 METs below threshold; n=1692), low-fit (2 METs below threshold; n=4884), moderate-fit (2 METs above threshold; n=4646), fit (2.1-4 METs above threshold; n=1874), and high-fit (>4 METs above threshold; n=1301) categories. Multivariable Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality across fitness categories. During follow-up (median=10.8 years), 5102 individuals died. Mortality risk for the cohort and each age category increased for the least-fit and low-fit categories (HR, 1.51; 95% CI, 1.37-1.66; and HR, 1.21; 95% CI, 1.12-1.30, respectively) and decreased for the moderate-fit; fit and high-fit categories (HR, 0.71; 95% CI, 0.65-0.78; HR, 0.63; 95% CI, 0.56-0.78; and HR, 0.49; 95% CI, 0.41-0.58, respectively). The trends were similar for 5- and 10-year mortality risk. CONCLUSION: We defined age-specific exercise capacity thresholds to guide assessment of mortality risk in individuals undergoing a clinical exercise test.

Longitudinal cardiorespiratory fitness algorithms for clinical settings.

BACKGROUND: Non-exercise algorithms are cost-effective methods to estimate cardiorespiratory fitness (CRF) in healthcare settings. The limitation of current non-exercise models is that they were developed with cross-sectional data. PURPOSE: To extend the non-exercise research by developing algorithms for men and women using longitudinal data on indicators available in healthcare settings. METHODS: The sample included 1325 women (aged 20-78 years) and 10,040 men (aged 20-86 years) who completed two to 21 maximal treadmill tests between 1977 and 2005. The data were analyzed in 2011 and 2012. The dependent variable was CRF measured by treadmill test. The independent variables were age; body composition (percentage fat or BMI); waist circumference; self-reported physical activity; resting heart rate; and smoking behavior. RESULTS: Linear mixed-models regression showed that all variables were independently related to CRF. There was a positive association between CRF and physical activity. Higher levels of body composition were linked to lower CRF. High resting heart rate and smoking resulted in lower estimates of CRF. The error estimates of the percentage fat algorithms were as follows: women, 1.41 METs (95% CI=1.35, 1.47); and men, METs 1.54 (95% CI=1.51, 1.55). The BMI models were somewhat less accurate: women, METs 1.51 (95% CI=1.45, 1.58); and men, 1.66 METs (95% CI=1.63, 1.68). CONCLUSIONS: These results showed that the CRF of women and men can be estimated from easily obtained health indicators. The longitudinal non-exercise algorithms provide models to accurately estimate CRF changes associated with aging and provide cost-effective algorithms to track CRF over time with health indicators available in healthcare settings.

Ideal cardiovascular health and mortality: Aerobics Center Longitudinal Study.

OBJECTIVE: To analyze the relationship of ideal cardiovascular health to disease-specific death. PATIENTS AND METHODS: We used data from the Aerobics Center Longitudinal Study from October 9, 1987, to March 3, 1999, to estimate the prevalence of ideal cardiovascular health in 11,993 individuals (24.3% women) and to examine its relationship with deaths from all causes, cardiovascular disease (CVD), and cancer. RESULTS: During a mean follow-up of 11.6 years, 305 deaths occurred: 70 (23.0%) from CVD and 127 (41.6%) from cancer. In the entire cohort, only 29 individuals (0.2%) had 7 ideal metrics. After adjusting for age, sex, examination year, alcohol intake, and parental history of CVD, risk of death due to CVD was 55% lower in those participants who met 3 or 4 ideal metrics (hazard ratio, 0.45; 95% confidence interval, 0.27-0.77) and 63% lower in those with 5 to 7 ideal metrics (hazard ratio, 0.37; 95% confidence interval, 0.15-0.95), compared with those who met 0 to 2 ideal metrics. Although not significant, there was also a trend toward lower risk of death due to all causes across incremental numbers of ideal metrics. No association was observed for deaths due to cancer. CONCLUSION: The prevalence of ideal cardiovascular health was extremely low in a middle-aged cohort of men and women recruited between 1987 and 1999. The American Heart Association construct reflects well the subsequent risk of CVD, as reflected by graded CVD mortality in relation to the number of ideal metrics.

An economic analysis of traditional and technology-based approaches to weight loss.

BACKGROUND: The financial burden and human losses associated with noncommunicable diseases necessitate cost-effective and efficacious interventions. PURPOSE: An economic analysis of the Lifestyle Education for Activity and Nutrition (LEAN) Study; an RCT that examined the efficacy of traditional and technology-based approaches to weight loss. METHODS: Economic analyses from an organizational perspective were conducted for four approaches: standard care control (SC); group weight-loss education (GWL); a multisensor armband (SWA); and the armband in combination with group weight-loss education (GWL+SWA). Data were collected in 2008-2009. Weight loss was the primary outcome. Total costs, costs per participant, costs per kilogram lost, and incremental cost-effectiveness ratios (ICERs) were calculated in 2010-2011. All costs are the actual expenses (i.e., staff time and materials) incurred by the LEAN study (except where noted) and reported in 2010 U.S. dollars. RESULTS: In the sample population of 197 sedentary, overweight, and obese adults (mean [±SD] age=46.9 ± 0.8 years, BMI=33.3 ± 5.2, weight=92.8 ± 18.4 kg), the GWL+SWA was the most expensive intervention in costs/participant ($365/partic) while yielding the greatest weight loss/partic (6.59 kg). The GWL was next in cost/partic ($240), but the SWA was less expensive in cost/partic ($183) and more efficacious (3.55 vs 1.86 kg/partic). The SC did not achieve significant weight loss. The SWA was the most cost effective ($51/partic/kg lost), followed by the GWL+SWA ($55) and GWL alone ($129). The ICER suggests that for each additional kilogram lost, the GWL+SWA cost $60 more than the SWA alone. CONCLUSIONS: The SWA was the most cost-effective intervention ($51/partic/kg lost). The addition of the GWL increased the efficacy of the SWA intervention but increased costs by $60/partic for each additional kilogram lost. The technology-based approaches were more cost effective and efficacious than traditional approaches in promoting weight loss via lifestyle changes in sedentary, overweight, and obese adults.

In fitness and health? A prospective study of changes in marital status and fitness in men and women.

The authors examined the prospective associations between marital status transitions and changes in fitness in men and women. Between 1987 and 2005, a total of 8,871 adults (6,900 men) aged 45.6 (standard deviation, 9.1) years were examined at the Cooper Clinic, Dallas, Texas; the median follow-up was ∼3 years. Marital transition categories (from single to married, married to divorced, divorced to remarried) were derived from self-reported marital status at baseline and follow-up. Fitness (maximal oxygen consumption) was assessed by a maximal treadmill test. Analyses were adjusted for baseline levels and changes in body mass index, physical activity, smoking, alcohol consumption, and major chronic diseases. Compared with the corresponding "control" groups (remaining single, married, or divorced), transitioning from being single to married was associated with a reduction in fitness in women (P = 0.03); divorce was associated with an increase in fitness in men (P = 0.04); and remarriage was associated with a reduction in fitness in men (P = 0.05). The authors conclude that the transitions to being married (from single to married or from divorced to remarried) are associated with a modest reduction, while divorce is associated with a modest increase in fitness levels in men. Study results suggest that these patterns may be different in women, but further research is required to confirm this.