Associations of sedentary behavior and screen time with biomarkers of inflammation and insulin resistance.

Sedentary behavior (SB) has been linked to risk factors of cardiometabolic disease, with inconsistent findings reported in the literature. We aimed to assess the associations of SB with multiple biomarkers of inflammation and insulin resistance in adults. Domain-specific SB, sitting time and moderate-to-vigorous physical activity (MVPA) were measured in 78 adults (mean ± SD 52.0 ± 10.8 y). Body fat percentage (BF%) was assessed using multi-frequency bioelectrical impedance. A blood draw assessed glucose, insulin, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), leptin, and adiponectin. Adiponectin-leptin ratio (ALR), homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-ß) were calculated. Multivariable linear regression analyses, controlling for age, sex, MVPA, and BF%, were used to assess associations. After adjustment for age, sex and MVPA, total SB (7.5 ± 2.5 h/day) was positively associated with leptin, insulin, HOMA-IR, HOMA-ß (Standardized Beta (ß) range 0.21-0.32) and negatively associated with ALR (ß = -0.24, p < 0.05 for all). Similarly, total sitting time (7.2 ± 2.9 h/day) was associated with TNF-α (ß = 0.22) and ALR (ß = -0.26). These associations were attenuated to non-significance after adjustment for BF%. Leisure screen time was detrimentally associated with IL-6 (ß = 0.24), leptin (ß = 0.21), insulin (ß = 0.37), HOMA-IR (ß = 0.37), and HOMA-ß (ß = 0.34), independent of age, sex and MVPA (p < 0.05 for all). Only the associations with insulin (ß = 0.26), HOMA-IR (ß = 0.26), and HOMA-ß (ß = 0.23) remained significant after further controlling BF% (p < 0.05). Self-reported SB is associated with biomarkers of inflammation and insulin resistance, independent of MVPA, and in some cases BF%.

Associations of leisure screen time with cardiometabolic biomarkers in college-aged adults.

We examined whether screen time was associated with cardiometabolic disease (CMD) risk factors in young adults. Ninety-five adults (19.9 ± 11.4 years) self-reported medical and health behavior history, screen time (television viewing, video games and computer games), and dietary intake. Waist circumference, blood pressure, fasting glucose and lipid levels, cardiorespiratory fitness (VO2peak), and body composition were measured. Total sedentary behavior and moderate-to-vigorous physical activity (MVPA) were measured by accelerometer. On average, leisure screen time (2.0 ± 1.6 h day-1) accounted for 24% of total sedentary time (8.4 ± 1.5 h day-1). After adjustment for demographics, smoking, sleep duration, total energy intake, total sedentary time and MVPA, a 1-standard deviation increase in leisure screen time was associated with a 26% higher BMI, 29% higher waist circumference, 25% higher fat mass, 23% higher triglyceride, and 24% lower VO2peak (p < 0.05). Our findings suggest that screen time may contribute to the risk of obesity and CMD in young adults.

Regulation of metabolism during hibernation in brown bears (Ursus arctos): Involvement of cortisol, PGC-1α and AMPK in adipose tissue and skeletal muscle.

The purpose of this study was to investigate changes in expression of known cellular regulators of metabolism during hyperphagia (Sept) and hibernation (Jan) in skeletal muscle and adipose tissue of brown bears and determine whether signaling molecules and transcription factors known to respond to changes in cellular energy state are involved in the regulation of these metabolic adaptations. During hibernation, serum levels of cortisol, glycerol, and triglycerides were elevated, and protein expression and activation of AMPK in skeletal muscle and adipose tissue were reduced. mRNA expression of the co-activator PGC-1α was reduced in all tissues in hibernation whereas mRNA expression of the transcription factor PPAR-α was reduced in the vastus lateralis muscle and adipose tissue only. During hibernation, gene expression of ATGL and CD36 was not altered; however, HSL gene expression was reduced in adipose tissue. During hibernation gene expression of the lipogenic enzyme DGAT in all tissues and the expression of the FA oxidative enzyme LCAD in the vastus lateralis muscle were reduced. Gene and protein expression of the glucose transporter GLUT4 was decreased in adipose tissue in hibernation. Our data suggest that high cortisol levels are a key adaptation during hibernation and link cortisol to a reduced activation of the AMPK/PGC-1α/PPAR-α axis in the regulation of metabolism in skeletal muscle and adipose tissue. Moreover, our results indicate that during this phase of hibernation at a time when metabolic rate is significantly reduced metabolic adaptations in peripheral tissues seek to limit the detrimental effects of unduly large energy dissipation.

Associations between physical activity, resilience, and quality of life in people with inflammatory bowel disease.

AIM: Research has shown that moderate-to-vigorous physical activity (MVPA) is associated with higher health-related quality of life (HRQOL) in healthy individuals. Recent studies have suggested that low- to moderate-intensity physical activity can be beneficial to HRQOL in people with inflammatory bowel diseases (IBD); however, studies investigating associations between MVPA and HRQOL in this population are lacking. PURPOSE: To understand the relationships among walking, MVPA, resilience, and HRQOL in people with IBD. METHODS: People with IBD (n = 242) completed questions about physical activity, resilience and HRQOL. Pearson product-moment correlations and multiple regression analyses were used to identify associations between physical activity and HRQOL. Analysis of covariance was used to compare HRQOL over quartiles of walking and MVPA with demographic variables as covariates. RESULTS: Both walking and MVPA were independently associated with physical (ß = 0.21 and ß = 0.26, respectively; p ≤ 0.001) but not mental HRQOL (p > 0.05). Higher volumes of MVPA were significantly associated with physical HRQOL (quartile 1 40.3 ± 9.0 vs. quartile 4 47.4 ± 9.0; p < 0.001) while higher volumes of walking were associated with both physical and mental HRQOL (p ≤ 0.01). CONCLUSIONS: The findings suggest that engaging in higher volumes of MVPA above 150 min/week and walking, particularly above 60 min/week, are associated with improved HRQOL in people with IBD. Research would benefit from investigating participation in MVPA as a coping strategy, in a longitudinal manner, to determine which modes of activity may be most beneficial to people with IBD.

Associations of objectively measured sedentary behavior, light activity, and markers of cardiometabolic health in young women.

PURPOSE: To investigate the associations among objectively measured sedentary behavior, light physical activity, and markers of cardiometabolic health in young women. METHODS: Cardiovascular disease risk factors, homeostasis model assessment for insulin resistance (HOMA-IR), lipid accumulation product, and inflammatory markers were measured in 50 young, adult women. Accelerometers were worn over 7 days to assess sedentary time (<150 counts min(-1)), light physical activity (150-2,689 counts min(-1)), and moderate-to-vigorous physical activity (MVPA; ≥2,690 counts min(-1)). Multivariate regression examined independent associations of sedentary behavior and light physical activity with cardiometabolic health. Covariates included MVPA, cardiorespiratory fitness (VO2peak) and body mass, and body composition. RESULTS: Sedentary behavior was associated with triglycerides (p = 0.03) and lipid accumulation product (p = 0.02) independent of MVPA. These associations were attenuated by VO2peak and body mass or body composition (p ≥ 0.05). Light physical activity was independently associated with triglycerides and lipid accumulation product after adjustment for all covariates (p < 0.05). The association between light physical activity and HOMA-IR was independent of MVPA (p = 0.02) but was attenuated by VO2peak and body mass or body composition (p > 0.05). CONCLUSIONS: Sedentary behavior and light physical activity were independently associated with markers of cardiometabolic health in young, adult women. Our data suggest that VO2peak and body composition may be important mediators of these associations. Decreasing sedentary behavior and increasing light physical activity may be important for maintaining cardiometabolic health in young, adult women.

Development of a Fitness Surveillance System to Track and Evaluate Obesity in North Idaho.

BACKGROUND: Internationally 18% of youth are obese. Fitness testing can be used to establish fitness surveillance, which can inform policy and targeted interventions aimed at addressing obesity. The purpose of this study was to estimate the prevalence of overweight, obesity, and low fitness in Idaho school-aged youth through a pilot study. METHODS: A convenience sample of 13 teachers from 11 north Idaho rural schools collected FitnessGram fitness data: body composition (body mass index [BMI]), aerobic capacity (Progressive Aerobic Cardiovascular Endurance Run [PACER] test), muscular endurance (curl up), strength (pushup), and flexibility (sit and reach). RESULTS: A total of 761 students (aged 9-18 years) from grades 3&5, 7, and 9 to 12 participated in the study. Approximately 24% of 3&5 and 22% of 7th, and 12% of 9 to 12th-grade students were categorized as Needs Improvement/Health Risk by FitnessGram standards for BMI. Similarly, approximately 25% of 3&5, and 22% of 7 and 9 to 12th-grade students were considered Needs Improvement/Health Risk for PACER. IMPLICATIONS FOR SCHOOL HEALTH POLICY, PRACTICE, AND EQUITY: Results from fitness testing can provide school and public health representatives with a "needs assessment" of student health that can be used to help develop policies and practices to improve student health and wellbeing. CONCLUSIONS: This study provides a model for statewide annual fitness testing surveillance and reporting within K-12 public school physical education classrooms.

Associations of Sedentary Behavior and Screen Time with Human Gut Microbiome Composition and Diversity.

Human gut microbiome richness, diversity, and composition are associated with physical activity and impaired glycemic control; however, the associations with sedentary behavior and screen time are not as well-established. This study evaluated associations of sedentary behavior and screen time with the alpha diversity and composition of the human gut microbiome in adults with and without impaired glycemic control. Sedentary behavior and screen time data were collected via survey from 47 adults (38% with impaired glycemic control). Microbiome composition and alpha diversity were determined in fecal microbial DNA. Sedentary behavior was negatively associated with the number of observed operational taxonomic units (OTUs), Chao 1 Index, and Fisher's Alpha Index. These associations were slightly attenuated but remained significant when controlling for covariates. Screen time was negatively associated with the number of observed OTUs, Shannon Index, and Fisher's Alpha Index; however, only the association with observed OTUs was independent of all covariates. Our findings suggest sedentary behavior and screen time may be significant influencers of compositional changes in human gut microbiota. This may be a potential mechanism linking sedentary behavior and screen time to an increased risk of type 2 diabetes.

Levels of Sex Hormones and Abdominal Muscle Composition in Men from The Multi-Ethnic Study of Atherosclerosis.

Information on the associations of testosterone levels with abdominal muscle volume and density in men is limited, while the role of estradiol and SHBG on these muscle characteristics are unclear. Therefore, this study aimed to investigate the association between fasting serum sex hormones and CT-derived abdominal muscle area and radiodensity in adult men. Conducted as a cross sectional observational study using data from the Multi-Ethnic Study of Atherosclerosis, our analyses focused on a community-based sample of 907 men aged 45-84 years, with 878 men having complete data. CT scans of the abdomen were interrogated for muscle characteristics, and multivariable linear regressions were used to test the associations. After adjustment for relevant factors, higher levels of both total testosterone and estradiol were associated with higher abdominal muscle area (1.74, 0.1-3.4, and 1.84, 0.4-3.3, respectively). In the final analyses, levels of total testosterone showed a positive association, while an inverse relationship was observed for SHBG with abdominal muscle radiodensity (0.3, 0.0-0.6, and - 0.33, - 0.6 to - 0.1, respectively). Our results indicate a complex association between sex hormones and abdominal muscle characteristics in men. Specifically, total testosterone and estradiol were associated with abdominal muscle area, while only total testosterone was associated with muscle radiodensity and SHBG was inversely associated with muscle radiodensity.Clinical Trial: NCT00005487.

Sex Hormones and Abdominal Muscle Area and Radiodensity in Men: The Multi-Ethnic Study of Atherosclerosis.

Information on the associations of testosterone levels with abdominal muscle volume and quality in men is limited, while the role of estradiol and SHBG on these muscle characteristics are unclear. To investigate the association between fasting serum sex hormones and CT-derived abdominal muscle area and radiodensity in adult men. Cross sectional observational study using data from the Multi-Ethnic Study of Atherosclerosis. A community-based sample of 907 men aged 45-84 years; 878 men with complete data were included in the analysis. CT scans of the abdomen were interrogated for muscle characteristics. Multivariable linear regressions were used to test the associations. After adjustment, higher levels of both total testosterone and estradiol were associated with higher abdominal muscle area (1.79, 0.1-3.4, & 1.79, 0.4-3.2, respectively). In the final analyses, levels of total testosterone showed a positive association, while an inverse relationship was observed for SHBG with abdominal muscle radiodensity (0.3, 0.0-0.6, & -0.34, -0.6 - -0.1, respectively). Our results indicate a complex association between sex hormones and abdominal muscle characteristics in men. Specifically, total testosterone and estradiol were associated with abdominal muscle area, while only total testosterone was associated with muscle radiodensity and SHBG was inversely associated with muscle radiodensity.

Associations between muscle quality and N-terminal pro-B-type natriuretic peptide (NT-proBNP): The multi-ethnic study of atherosclerosis.

INTRODUCTION: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is widely used in clinical settings to identify cardiac stress, diagnose, and manage heart failure (HF). We explored the associations between NT-proBNP and both muscle area and density. METHODS: A cross-sectional analysis including 1,489 participants from the MESA. Plasma NT-proBNP concentrations and inflammatory biomarkers and health history questionnaires were analyzed. Computed tomography quantified abdominal body composition. Separate multivariable linear regression models were used to assess the associations between both muscle (MA) area and density (MD) and NT-proBNP. RESULTS: In models adjusted for sociodemographic characteristics, risk factors for cardiovascular disease, anthropometric variables, and subcutaneous and visceral adiposity, NT-proBNP was inversely associated with total abdominal and psoas MAs. Adjustment for inflammatory markers and MD attenuated these associations to the null. Stabilization MA and NT-proBNP were not significantly associated. Analyses per quartiles of MA confirmed lack of a consistent association between stabilization and total abdominal MAs and NT-proBNP. While the third and fourth quartiles of psoas MA were inversely associated with NT-proBNP, adding inflammation biomarkers and MD to the model attenuated the association to the null. Conversely, after full adjustment, NT-proBNP was inversely and significantly associated with total abdominal, stabilization and psoas MDs. For psoas MD, but not the other muscle density variables, the addition of MA to the model attenuated the association to the null. The quartiles of MD were consistently inversely associated with NT-proBNP, where higher MDs showed larger estimates of the association compared to the lowest quartiles, for all muscle groups investigated. CONCLUSION: Muscle density is inversely associated with NT-proBNP, while muscle area is not after adjustment for inflammation and muscle density.

Patterns and correlates of sedentary behavior among university students.

Objective: To characterize the context, patterns, and correlates of sedentary behavior (SB) in university students. Participants: A total of 95 adults (41% men) enrolled in 34 different undergraduate majors. Methods: SB was assessed by questionnaire and accelerometer. Results: Objective SB and moderate-to-vigorous physical activity (MVPA) accounted for 8.4 ± 1.5 and 1.2 ± 0.5 h·day-1, respectively. Most SB was spent in occupational, leisure, and screen time behaviors, and was accumulated in short bouts of 10 min or longer. Women were more sedentary than men (522.0 ± 80.3 vs. 486.1 ± 91.3 min·day-1, p = 0.03) and engaged in more prolonged bouts of SB. Correlates of SB included female sex, smoking, light activity, MVPA, and markers of obesity, with higher levels of light activity and current smoking the strongest and most consistent correlates of reduced SB. Conclusions: University students engage in high amounts of SB and accumulate most of their SB in short bouts, with differences in patterns of SB between men and women.

High-Resolution Taxonomic Characterization Reveals Novel Human Microbial Strains with Potential as Risk Factors and Probiotics for Prediabetes and Type 2 Diabetes.

Alterations in the composition of the gut microbiota is thought to play a key role in causing type 2 diabetes, yet is not fully understood, especially at the strain level. Here, we used long-read DNA sequencing technology of 16S-ITS-23S rRNA genes for high-resolution characterization of gut microbiota in the development of type 2 diabetes. Gut microbiota composition was characterized from fecal DNA from 47 participants divided into 4 cohorts based on glycemic control: normal glycemic control (healthy; n = 21), reversed prediabetes (prediabetes/healthy; n = 8), prediabetes (n = 8), or type 2 diabetes (n = 10). A total of 46 taxa were found to be possibly related to progression from healthy state to type 2 diabetes. Bacteroides coprophilus DSM 18228, Bifidobacterium pseudocatenulatum DSM 20438, and Bifidobacterium adolescentis ATCC 15703 could confer resistance to glucose intolerance. On the other hand, Odoribacter laneus YIT 12061 may be pathogenic as it was found to be more abundant in type 2 diabetes participants than other cohorts. This research increases our understanding of the structural modulation of gut microbiota in the pathogenesis of type 2 diabetes and highlights gut microbiota strains, with the potential for targeted opportunistic pathogen control or consideration for probiotic prophylaxis and treatment.

Physical Activity Type and Intensity Are Associated With Abdominal Muscle Area and Density: The Multiethnic Study of Atherosclerosis.

BACKGROUND: Using data from a multiethnic cohort, the authors tested associations of multiple types and intensities of physical activity (PA) with abdominal muscle area and density. METHODS: 1895 Multiethnic Study of Atherosclerosis participants (mean age 64.6 [9.6] y) completed health history and PA questionnaires and computed tomography to quantify body composition and measurements of cardiovascular and inflammatory biomarkers. Analyses included multivariable regression. RESULTS: Compared with those not meeting PA guidelines for Americans, those meeting the guidelines had higher total abdominal muscle area (odds ratio, 95% confidence interval 1.60, 1.20 to 2.15), stability muscle area (1.68, 1.28 to 2.20), and stability muscle density (1.35, 1.03 to 1.76). After adjustment for relevant covariates, each SD increase in total moderate to vigorous PA was associated with a higher total abdominal (ß, 95% confidence interval = 0.068, 0.036 to 0.173), stability (0.063, 0.027 to 0.099), and locomotor (0.069, 0.039 to 0.099) muscle area and higher locomotor muscle density (0.065, 0.022 to 0.108, P < .01). Only intentional and conditioning exercise were associated with total abdominal and stability muscle density (P < .05). Light PA and walking were not associated with muscle area or density. CONCLUSIONS: Most types of PA are positively associated with abdominal muscle area and density across functional categories, independent of relevant covariates. These results provide additional evidence for promoting PA for healthy muscle aging.

Associations between Weight-Adjusted Waist Index and Abdominal Fat and Muscle Mass: Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: The weight-adjusted waist index (WWI) reflected body compositional changes with aging. This study was to investigate the association of WWI with abdominal fat and muscle mass in a diverse race/ethnic population. METHODS: Computed tomography (CT) data from 1,946 participants for abdominal fat and muscle areas from the Multi-Ethnic Study of Atherosclerosis (785 Whites, 252 Asians, 406 African American, and 503 Hispanics) were used. Among them, 595 participants underwent repeated CT. The WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). The associations of WWI with abdominal fat and muscle measures were examined, and longitudinal changes in abdominal composition measures were compared. RESULTS: In all race/ethnic groups, WWI was positively correlated with total abdominal fat area (TFA), subcutaneous fat area, and visceral fat area, but negatively correlated with total abdominal muscle area (TMA) and abdominal muscle radiodensity (P<0.001 for all). WWI showed a linear increase with aging regardless of race and there were no significant differences in the WWI distribution between Whites, Asians, and African Americans. In longitudinal analyses, over 38.6 months of follow-up, all abdominal fat measures increased but muscle measures decreased, along with increase in WWI. The more the WWI increased, the more the TFA increased and the more the TMA decreased. CONCLUSION: WWI showed positive associations with abdominal fat mass and negative associations with abdominal muscle mass, which likely reflects the abdominal compositional changes with aging in a multi-ethnic population.

Cardiac function and arteriovenous oxygen difference during exercise in obese adults.

The purpose of this study was to assess cardiac function and arteriovenous oxygen difference (a-vO(2) difference) at rest and during exercise in young, normal-weight (n = 20), and obese (n = 12) men and women who were matched for age and fitness level. Participants were assessed for body composition, peak oxygen consumption (VO(2peak)), and cardiac variables (thoracic bioimpedance)-cardiac index (CI), cardiac output (Q), stroke volume (SV), heart rate (HR), and ejection fraction (EF)-at rest and during cycling exercise at 65% of VO(2peak). Differences between groups were assessed with multivariate ANOVA and mixed-model ANOVA with repeated measures controlling for sex. Absolute VO(2peak) and VO(2peak) relative to fat-free mass (FFM) were similar between normal-weight and obese groups (Mean ± SEE 2.7 ± 0.2 vs. 3.3 ± 0.3 l min(-1), p = 0.084 and 52.4 ± 1.5 vs. 50.9 ± 2.3 ml kg FFM(-1) min(-1), p = 0.583, respectively). In the obese group, resting Q and SV were higher (6.7 ± 0.4 vs. 4.9 ± 0.1 l min(-1), p < 0.001 and 86.8 ± 4.3 vs. 65.8 ± 1.9 ml min(-1), p < 0.001, respectively) and EF lower (56.4 ± 2.2 vs. 65.5 ± 2.2%, p = 0.003, respectively) when compared with the normal-weight group. During submaximal exercise, the obese group demonstrated higher mean CI (8.8 ± 0.3 vs. 7.7 ± 0.2 l min(-1) m(-2), p = 0.007, respectively), Q (19.2 ± 0.9 vs. 13.1 ± 0.3 l min(-1), p < 0.001, respectively), and SV (123.0 ± 5.6 vs. 88.9 ± 4.1 ml min(-1), p < 0.001, respectively) and a lower a-vO(2) difference (10.4 ± 1.0 vs. 14.0 ± 0.7 ml l00 ml(-1), p = 0.002, respectively) compared with controls. Our study suggests that the ability to extract oxygen during exercise may be impaired in obese individuals.

Physical activity recommendations and cardiovascular disease risk factors in young Hispanic women.

Despite the benefits associated with regular physical activity, there is little epidemiological evidence to support positive health outcomes when meeting physical activity guidelines in high-risk ethnic groups, such as Hispanic women. We compared cardiovascular disease risk factors between young Hispanic women who meet and those who do not meet current physical activity guidelines. Height, weight, waist circumference, and blood pressure were measured in 60 Hispanic women aged 20-39 years. Lipids, C-reactive protein, insulin, and glucose were assessed. Body composition and cardiovascular fitness were assessed by BodPod and maximal oxygen uptake (VO2(max)) respectively. Participants wore an accelerometer and average minutes (assessed in 10-min bouts) spent in light, moderate, and hard daily activity for weekdays and weekends was determined. Seventy percent of participants did not meet the recommended physical activity guidelines, whereas 30% did so. Following current physical activity guidelines was associated with significantly lower mean cholesterol (mean ± s: 4.2 ± 0.8 vs. 4.7 ± 0.9 mmol · l⁻¹) and triglycerides (0.7 ± 0.3 vs. 1.1 ± 0.6 mmol · l⁻¹), and higher fat-free mass (43.3 ± 3.8 vs. 40.2 ± 5.1 kg) and relative (40.4 ± 7.6 vs. 35.6 ± 7.0 ml · kg⁻¹ · min⁻¹) and absolute (2.5 ± 0.3 vs. 2.1 ± 0.4 litres · min⁻¹) VO2(max) (P < 0.05). These findings suggest an improved health status in women who meet versus those who did not meet current physical activity guidelines.

Computed Tomography-Derived Myosteatosis and Metabolic Disorders.

The role of ectopic adipose tissue infiltration into skeletal muscle (i.e., myosteatosis) for metabolic disorders has received considerable and increasing attention in the last 10 years. The purpose of this review was to evaluate and summarize existing studies focusing on computed tomography (CT)-derived measures of myosteatosis and metabolic disorders. There is consistent evidence that CT-derived myosteatosis contributes to dysglycemia, insulin resistance, type 2 diabetes mellitus, and inflammation, and, to some extent, dyslipidemia, independent of general obesity, visceral fat, and other relevant risk factors, suggesting that it may serve as a tool for metabolic risk prediction. Identification of which muscles should be examined, and the standardized CT protocols to be employed, are necessary to enhance the applicability of findings from epidemiologic studies of myosteatosis. Additional and longer longitudinal studies are necessary to confirm a role of myosteatosis in the development of type 2 diabetes mellitus, and examine these associations in a variety of muscles across multiple race/ethnic populations. Given the emerging role of myosteatosis in metabolic health, well-designed intervention studies are needed to investigate relevant lifestyle and pharmaceutical approaches.

Relationship of leptin, resting metabolic rate, and body composition in premenopausal hispanic and non-Hispanic White women.

OBJECTIVE: The purpose was to evaluate the relationships between fasting serum leptin, resting metabolic rate (RMR), and body composition in premenopausal Hispanic and non-Hispanic White (White) women. METHODS: Participants were 67 Hispanic and 43 White women who arrived at the laboratory in a fasted state for measurement of RMR by indirect calorimetry, bone mineral content measured by dual-energy X-ray absorptiometry, and body density measured by hydrodensitometry. Serum leptin levels were determined by EIA. RESULTS: Multiple regression analysis revealed that body mass and lean body mass were the best predictors of RMR. Leptin was not a significant predictor of RMR. CONCLUSION: Further research needs to be done to examine the role of leptin on metabolism, especially in ethnic groups predisposed to development of obesity and related disorders.

Perceived Risk and Intentions to Practice Health Protective Behaviors in a Mining-Impacted Region.

Effective risk communication strategies are critical to reducing lead exposure in mining-impacted communities. Understanding the strength of the associations between perceived risk and individuals' behavioral intentions to protect their health is important for developing these strategies. We conducted a survey within three communities of northern Idaho, USA (n = 306) in or near a Superfund Megasite with legacy mining contamination. Survey data were used to test a theoretical model based on the Health Belief Model. Respondents had higher intentions to practice health protective behaviors when they perceived the risk of lead contamination as severe and recognized the benefits of practicing health protective behaviors. Women reported higher behavioral intentions than men, but age and mining affiliation were not significantly associated with behavioral intentions. Although managing lead hazards in communities impacted by mining is challenging due to widely distributed contamination, effective health risk messages, paired with remediation, are powerful tools to protect the health and safety of residents.

Skeletal muscle area and density are associated with lipid and lipoprotein cholesterol levels: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Loss of muscle mass with age may be a key player in metabolic dysregulation. We examined the associations between abdominal muscle area and density with lipids and lipoproteins. METHODS: One thousand eight hundred and sixty eight adults completed health history and physical activity questionnaires, provided venous blood samples for lipids and inflammatory biomarkers, and underwent computed tomography to quantify body composition. Associations between muscle area and density with multiple lipid measures were assessed with multivariable linear and logistic regression. RESULTS: The mean age and body mass index of participants was 65 years and 28 kg/m2, respectively, and 50% were female. After adjustment for demographics, cardiovascular disease risk factors, lipid-lowering medications, physical activity, sedentary behavior, inflammatory biomarkers, and central obesity, a 1-standard deviation increase in total abdominal, stability, and locomotor muscle areas was associated with a 13%, 11%, and 8% lower high-density lipoprotein cholesterol level, respectively (P < .05). With similar adjustment, a 1-standard deviation increase in total abdominal and stability muscle area was associated with a 13% and 12% lower total cholesterol level, respectively (P < .01). Compared to the lowest quartiles of total, stability, and locomotor muscle area, those in the higher quartiles of muscle area had over a 40% reduction in the odds of triglyceride levels greater than 150 mg/dL (P < .05). Total abdominal muscle density was positively associated with total cholesterol (P < .05) but was not associated with the other lipid outcomes. CONCLUSION: Maintaining adequate skeletal muscle mass with age may decrease specific lipid levels related to hyperlipidemia and development of cardiometabolic disease.