Associations of Sedentary Time with Fat Distribution in a High-Risk Population

Association of daily sitting time and leisure-time physical activity with body fat among U.S. adults

BACKGROUND

Prolonged sitting and reduced physical activity lead to low energy expenditures. However, little is known about the joint impact of daily sitting time and physical activity on body fat distribution. We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.

METHODS

This was a cross-sectional analysis of U.S. nationally representative data from the National Health and Nutrition Examination Survey 2011-2018 among adults aged 20 years or older. Daily sitting time and leisure-time physical activity (LTPA) were self-reported using the Global Physical Activity Questionnaire. Body fat (total and trunk fat percentage) was determined via dual X-ray absorptiometry.

RESULTS

Among 10,808 adults, about 54.6% spent 6 h/day or more sitting; more than one-half reported no LTPA (inactive) or less than 150 min/week LTPA (insufficiently active) with only 43.3% reported 150 min/week or more LTPA (active) in the past week. After fully adjusting for sociodemographic data, lifestyle behaviors, and chronic conditions, prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes. When stratifying by LTPA, the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insufficiently active. In the joint analyses, inactive/insufficiently active adults who reported sitting more than 8 h/day had the highest total (female: 3.99% (95% confidence interval (95%CI): 3.09%-4.88%); male: 3.79% (95%CI: 2.75%-4.82%)) and trunk body fat percentages (female: 4.21% (95%CI: 3.09%-5.32%); male: 4.07% (95%CI: 2.95%-5.19%)) when compared with those who were active and sitting less than 4 h/day.

CONCLUSION

Prolonged daily sitting time was associated with increased body fat among U.S. adults. The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

Mouse models of accelerated aging in musculoskeletal research for assessing frailty, sarcopenia, and osteoporosis - A review

Musculoskeletal aging encompasses the decline in bone and muscle function, leading to conditions such as frailty, osteoporosis, and sarcopenia. Unraveling the underlying molecular mechanisms and developing effective treatments are crucial for improving the quality of life for those affected. In this context, accelerated aging models offer valuable insights into these conditions by displaying the hallmarks of human aging. Herein, this review focuses on relevant mouse models of musculoskeletal aging with particular emphasis on frailty, osteoporosis, and sarcopenia. Among the discussed models, PolgA mice in particular exhibit hallmarks of musculoskeletal aging, presenting early-onset frailty, as well as reduced bone and muscle mass that closely resemble human musculoskeletal aging. Ultimately, findings from these models hold promise for advancing interventions targeted at age-related musculoskeletal disorders, effectively addressing the challenges posed by musculoskeletal aging and associated conditions in humans.

Associations of objectively measured physical activity, sedentary time and cardiorespiratory fitness with adipose tissue insulin resistance and ectopic fat

BACKGROUND/OBJECTIVES

Inadequate movement, excess adiposity, and insulin resistance augment cardiometabolic risk. This study examined the associations of objectively measured moderate-to-vigorous intensity physical activity (MVPA), sedentary time and cardiorespiratory fitness (CRF), with adipose tissue insulin resistance and ectopic fat.

METHODS

Data were combined from two previous experimental studies with community volunteers (n = 141, male = 60%, median (interquartile range) age = 37 (19) years, body mass index (BMI) = 26.1 (6.3) kg·m-2). Adipose tissue insulin resistance was assessed using the adipose tissue insulin resistance index (Adipo-IR); whilst magnetic resonance imaging (MRI) was used to measure liver, visceral (VAT) and subcutaneous abdominal adipose tissue (ScAT). Sedentary time and MVPA were measured via an ActiGraph GT3X+ accelerometer. Generalized linear models examined the association of CRF, MVPA, and sedentary time with Adipo-IR and fat depots. Interaction terms explored the moderating influence of age, sex, BMI and CRF.

RESULTS

After controlling for BMI and cardiometabolic variables, sedentary time was positively associated with Adipo-IR (β = 0.68 AU [95%CI = 0.27 to 1.10], P < 0.001). The association between sedentary time and Adipo-IR was moderated by age, CRF and BMI; such that it was stronger in individuals who were older, had lower CRF and had a higher BMI. Sedentary time was also positively associated with VAT (β = 0.05 L [95%CI = 0.01 to 0.08], P = 0.005) with the relationship being stronger in females than males. CRF was inversely associated with VAT (β = -0.02 L [95%CI = -0.04 to -0.01], P = 0.003) and ScAT (β = -0.10 L [95%CI = -0.13 to -0.06], P < 0.001); with sex and BMI moderating the strength of associations with VAT and ScAT, respectively.

CONCLUSIONS

Sedentary time is positively associated with adipose tissue insulin resistance which regulates lipogenesis and lipolysis. CRF is independently related to central fat storage which is a key risk factor for cardiometabolic disease.

Relationship between liver fat content and lifestyle factors in adults with metabolic syndrome

The aim of this study was to investigate the associations between liver fat content (LFC), sedentary behaviour (SB), physical activity (PA), fitness, diet, body composition, and cardiometabolic risk factors in adults with metabolic syndrome. A total of 44 sedentary adults (mean age 58 [SD 7] years; 25 women) with overweight or obesity participated. LFC was assessed with magnetic resonance spectroscopy and imaging, SB and PA with hip-worn accelerometers (26 [SD 3] days), fitness by maximal bicycle ergometry, body composition by air displacement plethysmography and nutrient intake by 4-day food diaries. LFC was not independently associated with SB, PA or fitness. Adjusted for sex and age, LFC was associated with body fat%, body mass index, waist circumference, triglycerides, alanine aminotransferase, and with insulin resistance markers. There was and inverse association between LFC and daily protein intake, which persisted after further adjusment with body fat%. LFC is positively associated with body adiposity and cardiometabolic risk factors, and inversely with daily protein intake. SB, habitual PA or fitness are not independent modulators of LFC. However, as PA is an essential component of healthy lifestyle, it may contribute to liver health indirectly through its effects on body composition in adults with metabolic syndrome.

Dose-response association between sedentary time and incident of diabetes in Chinese middle-aged and older adults: The 4C study

AIMS

To investigate the dose-response relationship of total sedentary time with incident diabetes in Chinese middle-aged and older adults.

METHODS

The present study followed 100,525 participants aged ≥ 40 years old from the China Cardiometabolic Disease and Cancer Cohort (4C) Study, which was a prospective study conducted in 25 communities across mainland China. Associations between sedentary time and incident diabetes were assessed with Cox regression and restricted cubic splines.

RESULTS

During a median follow-up of 3.8 years, 7,529 participants developed diabetes. After adjustment for multiple variables, high levels of sedentary time (≥ 30 h/week) was associated with increased risk for developing diabetes (hazards ratio, 1.08; 95 % confidence intervals 1.02, 1.14) compared with low levels of sedentary time (<20 h/week). Restricted cubic spline analyses revealed an inverted U-shaped relation between sedentary time with diabetes. Subgroup analyses found that the observed association remained significant in subgroup of individuals with body mass index (BMI) ≥ 25 kg/cm² or diastolic blood pressure (DBP) ≥ 90 mm Hg. However, the significant association was diminished in participants with sufficient physical activity (PA) (P = 0.22).

CONCLUSIONS

The multicenter, population-based, prospective study suggested an inverted U-shaped relation between sedentary time with diabetes. PA alleviated the deleterious effects associated with sedentary time.

Association between alanine aminotransferase as surrogate of fatty liver disease and physical activity and sedentary time in adolescents with obesity

To compare patterns of sedentary (SED) time (more sedentary, SED + vs less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA + vs less active, MVPA-), and combinations of behaviors (SED-/MVPA + , SED-/MVPA-, SED + /MVPA + , SED + /MVPA-) regarding nonalcoholic fatty liver diseases (NAFLD) markers. This cross-sectional study included 134 subjects (13.4 ± 2.2 years, body mass index (BMI) 98.9 ± 0.7 percentile, 48.5% females) who underwent 24-h/7-day accelerometry, anthropometric, and biochemical markers (alanine aminotransferase (ALT) as first criterion, and aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), AST/ALT ratio as secondary criteria). A subgroup of 39 patients underwent magnetic resonance imaging-liver fat content (MRI-LFC). Hepatic health was better in SED- (lower ALT, GGT, and MRI-LFC (p < 0.05), higher AST/ALT (p < 0.01)) vs SED + and in MVPA + (lower ALT (p < 0.05), higher AST/ALT (p < 0.01)) vs MVPA- groups after adjustment for age, gender, and Tanner stages. SED-/MVPA + group had the best hepatic health. SED-/MVPA- group had lower ALT and GGT and higher AST/ALT (p < 0.05) in comparison with SED + /MVPA + group independently of BMI. SED time was positively associated with biochemical (high ALT, low AST/ALT ratio) and imaging (high MRI-LFC) markers independently of MVPA. MVPA time was associated with biochemical markers (low ALT, high AST/ALT) but these associations were no longer significant after adjustment for SED time.

CONCLUSION

Lower SED time is associated with better hepatic health independently of MVPA. Reducing SED time might be a first step in the management of pediatric obesity NAFLD when increasing MVPA is not possible.

WHAT IS KNOWN

• MVPA and SED times are associated with cardiometabolic risks in youths with obesity. • The relationships between NAFLD markers and concomitant MVPA and SED times have not been studied in this population.

WHAT IS NEW

• Low SED time is associated with healthier liver enzyme profiles and LFC independent of MVPA. • While low SED/high MVPA is the more desirable pattern, low SED/low MVPA pattern would have healthier liver enzyme profile compared with high MVPA/high SED, independent of BMI, suggesting that reducing SED time irrespective of MVPA is needed to optimize liver health.

Ten-Year Changes in Television Viewing and Physical Activity Are Associated With Concurrent 10-Year Change in Pericardial Adiposity: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

Longitudinal association of television (TV) viewing and moderate- to vigorous-intensity physical activity (MVPA) with pericardial adipose tissue (PAT) is unclear.

METHODS

We studied Coronary Artery Risk Development in Young Adults Study participants transitioning from early to middle age at Coronary Artery Risk Development in Young Adults (CARDIA) exam years 15 (2000-2001; N = 1975, mean age = 40.4, 55.4% women, 45.3% Black) and 25 (2010-2011). TV viewing (in hours per day) and MVPA (in exercise units) were measured using a self-report questionnaire. PAT volume (in milliliters) was measured using computed tomography. Multivariable linear regression was used to examine the associations of tertiles of 10-year change (years 25-15) in TV viewing and MVPA with a concurrent change in PAT with adjustments for covariates.

RESULTS

Participants in the highest tertile of 10-year increase in TV viewing had a greater increase in PAT (β = 2.96 mL, P < .01). Participants in both middle (β = -3.93 mL, P < .01) and highest (β = -6.22 mL, P < .01) tertiles of 10-year changes in MVPA had smaller mean increases in PAT over 10 years when compared with the lowest tertile in fully adjusted models.

CONCLUSIONS

Reducing or maintaining early-midlife levels of TV viewing and increasing MVPA may be associated with less PAT accumulation with age.

Cross-Sectional and Longitudinal Associations of Lifestyle Behaviors with Pericardial Adipose Tissue: The MESA Study

PURPOSE

We examined associations of sedentary behavior (SB), light-intensity physical activity (LPA), and moderate-to-vigorous intensity physical activity (MVPA) with pericardial adipose tissue (PAT).

METHODS

Adults from the Multi-Ethnic Study of Atherosclerosis were included from exam years 1 (2000-2002; N = 6057; mean age, 62.2 yr; 52.9% female, 38.0% White; 12.8% Chinese American, 26.7% African American, 22.5% Hispanic American), 2 (2002-2004), and 3 (2004-2005). Weekly volume of SB, LPA, and MVPA (in MET-hours per week) was reported using a questionnaire. PAT volume (in cubic centimeters) was quantified using computed tomography, analysis of covariance, and repeated-measures linear mixed models with adjustment for covariates (sociodemographics, cardiovascular disease risk factors, inflammation, waist circumference) tested cross-sectional and longitudinal associations, respectively.

RESULTS

In cross-sectional analysis, the highest tertile of SB (β = 2.71; 95% confidence interval (CI), 0.69 to 4.73; P < 0.01) and the middle tertile of MVPA (β = -1.97; 95% CI, -3.92 to -0.02; P < 0.05) were associated with PAT, whereas no association was observed for LPA in fully adjusted models. In longitudinal models, SB, LPA, and MVPA were not associated with PAT in the full study sample; however, LPA was inversely associated with PAT among Whites in stratified analysis (β = -0.54; 95% CI, -0.95 to -0.13; P < 0.05).

CONCLUSIONS

Lower SB and higher LPA (among Whites only) and MVPA may be associated with lower PAT, but additional longitudinal research is needed.

Association of sedentary behaviour and physical activity with cardiometabolic health in Japanese adults

Although the Asian population exhibits excessive sedentary behaviour and has a high susceptibility to metabolic syndrome (MetS), the nature of these associations remains unclear. This study aimed to investigate the association of sedentary time with cardiometabolic health and examine the association of reallocating sedentary time to light physical activity (LPA) or moderate-vigorous physical activity (MVPA) on cardiometabolic health in Japanese adults. A cross-sectional study was performed using data obtained from 758 Japanese adults. We assessed sedentary time, LPA, and MVPA using an accelerometer. Linear and logistic regression models were used to analyse the association between sedentary time and cardiometabolic risk factors. An isotemporal substitution model was used to estimate the theoretical influence of reallocating sedentary time to LPA or MVPA. A longer sedentary time was associated with worse cardiometabolic health, including MetS. Reallocating 30 min of sedentary time to LPA was significantly associated with lower body mass index, visceral fat, insulin resistance, triglyceride, and MetS levels and increased muscle mass and HDL-C (all P < 0.05). Reallocating 30 min of sedentary time to MVPA was strongly associated with the aforementioned factors. These results demonstrate the potential beneficial effects of reallocating sedentary time to LPA and MVPA on cardiometabolic health of Asians.

Waist circumference was associated with 2-year blood pressure change in community dwelling adults independently of BMI

OBJECTIVE

The present study aimed to analyze the association of 2-year changes in BMI and waist circumference with changes in blood pressure (BP) in a randomized sample of community-dwelling adults.

METHODS

A sample of 331 middle-aged and older adults (mean age of 59.6 ± 17.3 years) was randomly selected. Measurements of SBP and DBP, BMI, and waist circumference were collected at baseline and after 2-year follow-up. Chronological age, sex, socioeconomic status, ethnicity, and self-reported medical diagnosis and use of medication for hypertension, diabetes, and high low-density lipoprotein-cholesterol were covariates. Multiple linear regression models were adopted for statistical analysis.

RESULTS

SBP was positively associated with BMI (β = 0.48, P = 0.013) and waist circumference (β = 0.21, P = 0.005) at baseline and only with waist circumference at follow-up (β = 0.20, P = 0.007). DBP was positively associated with BMI (β = 0.31, P = 0.009) and waist circumference (β = 0.12, P = 0.006) values at baseline and at follow-up (BMI β = 0.42, P = 0.001; waist circumference β = 0.18, P = 0.001). Only the 2-year changes in waist circumference were associated to changes in SBP (β = 0.33, P = 0.013), regardless of confounding factors and BMI.

CONCLUSION

It is suggested that waist circumference is the main factor for control over the time in strategies focused on BP management in adult population.

Physiological Changes and Pathological Pain Associated with Sedentary Lifestyle-Induced Body Systems Fat Accumulation and Their Modulation by Physical Exercise

A sedentary lifestyle is associated with overweight/obesity, which involves excessive fat body accumulation, triggering structural and functional changes in tissues, organs, and body systems. Research shows that this fat accumulation is responsible for several comorbidities, including cardiovascular, gastrointestinal, and metabolic dysfunctions, as well as pathological pain behaviors. These health concerns are related to the crosstalk between adipose tissue and body systems, leading to pathophysiological changes to the latter. To deal with these health issues, it has been suggested that physical exercise may reverse part of these obesity-related pathologies by modulating the cross talk between the adipose tissue and body systems. In this context, this review was carried out to provide knowledge about (i) the structural and functional changes in tissues, organs, and body systems from accumulation of fat in obesity, emphasizing the crosstalk between fat and body tissues; (ii) the crosstalk between fat and body tissues triggering pain; and (iii) the effects of physical exercise on body tissues and organs in obese and non-obese subjects, and their impact on pathological pain. This information may help one to better understand this crosstalk and the factors involved, and it could be useful in designing more specific training interventions (according to the nature of the comorbidity).

Assessment of eating habits and lifestyle during the coronavirus 2019 pandemic in the Middle East and North Africa region: a cross-sectional study

Coronavirus disease 2019 (COVID-19) has rapidly spread globally, forcing countries to apply lockdowns and strict social distancing measures. The aim of this study was to assess eating habits and lifestyle behaviours among residents of the Middle East and North Africa (MENA) region during the lockdown. A cross-sectional study among adult residents of the MENA region was conducted using an online questionnaire designed on Google Forms during April 2020. A total of 2970 participants from eighteen countries participated in the present study. During the pandemic, over 30 % reported weight gain, 6·2 % consumed five or more meals per d compared with 2·2 % before the pandemic (P < 0·001) and 48·8 % did not consume fruits on a daily basis. Moreover, 39·1 % did not engage in physical activity, and over 35 % spent more than 5 h/d on screens. A significant association between the frequency of training during the pandemic and the reported change in weight was found (P < 0·001). A significantly higher percentage of participants reported physical and emotional exhaustion, irritability and tension either all the time or a large part of the time during the pandemic (P < 0·001). Although a high percentage of participants reported sleeping more hours per night during the pandemic, 63 % had sleep disturbances. The study highlights that the lockdown due to the COVID-19 pandemic caused a variety of lifestyle changes, physical inactivity and psychological problems among adults in the MENA region.

The longitudinal association between early-life screen viewing and abdominal adiposity-findings from a multiethnic birth cohort study

IMPORTANCE

Screen viewing in adults has been associated with greater abdominal adiposity, with the magnitude of associations varying by sex and ethnicity, but the evidence is lacking at younger ages. We aimed to investigate sex- and ethnic-specific associations of screen-viewing time at ages 2 and 3 years with abdominal adiposity measured by magnetic resonance imaging at age 4.5 years.

METHODS

The Growing Up in Singapore Towards healthy Outcomes is an ongoing prospective mother-offspring cohort study. Parents/caregivers reported the time their child spent viewing television, handheld devices, and computer screens at ages 2 and 3 years. Superficial and deep subcutaneous and visceral abdominal adipose tissue volumes were quantified from magnetic resonance images acquired at age 4.5 years. Associations between screen-viewing time and abdominal adipose tissue volumes were examined by multivariable linear regression adjusting for confounding factors.

RESULTS

In the overall sample (n = 307), greater total screen-viewing time and handheld device times were associated with higher superficial and deep subcutaneous adipose tissue volumes, but not with visceral adipose tissue volumes. Interactions with child sex were found, with significant associations with superficial and deep subcutaneous and visceral adipose tissue volumes in boys, but not in girls. Among boys, the increases in mean (95% CI) superficial and deep subcutaneous and visceral adipose tissue volumes were 24.3 (9.9, 38.7), 17.6 (7.4, 27.8), and 7.8 (2.1, 13.6) mL per hour increase in daily total screen-viewing time, respectively. Ethnicity-specific analyses showed associations of total screen-viewing time with abdominal adiposity only in Malay children. Television viewing time was not associated with abdominal adiposity.

CONCLUSION

Greater total screen-viewing time (and in particular, handheld device viewing time) was associated with higher abdominal adiposity in boys and Malay children. Additional studies are necessary to confirm these associations and to examine screen-viewing interventions for preventing excessive abdominal adiposity and its adverse cardiometabolic consequences.

Objectively measured sedentary time, physical activity and liver enzyme elevations in US Hispanics/Latinos

BACKGROUND & AIMS

Sedentariness and physical inactiveness are associated with deleterious health outcomes, but their associations with liver enzyme elevations remain uncertain.

METHODS

In 10 385 US Hispanics/Latinos from the Hispanic Community Health Study/Study of Latinos, we examined associations of sedentary time and moderate-to-vigorous physical activity (MVPA) measured by accelerometers with liver enzyme elevations. Elevated alanine aminotransferase (ALT), aspartate aminotransferase and γ-glutamyltransferase (GGT) were defined as the highest gender-specific deciles. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were calculated using weighted Poisson regressions.

RESULTS

After adjusting for demographical/socioeconomic factors and MVPA, increasing quartiles of sedentary time were associated with a higher prevalence of elevated ALT (PRs [95% CI] = 1.0, 1.17 [0.92-1.47], 1.21 [0.96, 1.53] and 1.51 [1.13-2.02]; P-trend = .007) and elevated GGT (PRs [95% CI] = 1.0, 1.06 [0.82-1.36], 1.35 [1.06-1.73] and 1.66 [1.27-2.16]; P-trend = .0001). These associations were attenuated but remained significant after further adjustment for cardiometabolic traits including body-mass index, waist-hip-ratio, lipids and homeostatic model assessment of insulin resistance. In contrast, increasing quartiles of MVPA were associated with a lower prevalence of elevated ALT (PRs [95% CI] =1.0, 0.97 [0.77-1.23], 0.84 [0.66-1.06] and 0.72 [0.54-0.96]; P-trend = .01) after adjusting for demographical/socioeconomic factors and sedentary time, but this association became non-significant after further adjustment for cardiometabolic traits. Notably, the association of sedentary time with GGT elevation was significant both in individuals meeting the US Physical Activity Guidelines for Americans (MVPA ≥150 minutes/week) and in those who did not (both P-trend ≤ .003).

CONCLUSIONS

Our findings suggest that objectively measured sedentary time is independently associated with elevated ALT and GGT in US Hispanics/Latinos.

The role of physical activity in metabolic homeostasis before and after the onset of type 2 diabetes: an IMI DIRECT study

AIMS/HYPOTHESIS

It is well established that physical activity, abdominal ectopic fat and glycaemic regulation are related but the underlying structure of these relationships is unclear. The previously proposed twin-cycle hypothesis (TC) provides a mechanistic basis for impairment in glycaemic control through the interactions of substrate availability, substrate metabolism and abdominal ectopic fat accumulation. Here, we hypothesise that the effect of physical activity in glucose regulation is mediated by the twin-cycle. We aimed to examine this notion in the Innovative Medicines Initiative Diabetes Research on Patient Stratification (IMI DIRECT) Consortium cohorts comprised of participants with normal or impaired glucose regulation (cohort 1: N ≤ 920) or with recently diagnosed type 2 diabetes (cohort 2: N ≤ 435).

METHODS

We defined a structural equation model that describes the TC and fitted this within the IMI DIRECT dataset. A second model, twin-cycle plus physical activity (TC-PA), to assess the extent to which the effects of physical activity in glycaemic regulation are mediated by components in the twin-cycle, was also fitted. Beta cell function, insulin sensitivity and glycaemic control were modelled from frequently sampled 75 g OGTTs (fsOGTTs) and mixed-meal tolerance tests (MMTTs) in participants without and with diabetes, respectively. Abdominal fat distribution was assessed using MRI, and physical activity through wrist-worn triaxial accelerometry. Results are presented as standardised beta coefficients, SE and p values, respectively.

RESULTS

The TC and TC-PA models showed better fit than null models (TC: χ² = 242, p = 0.004 and χ² = 63, p = 0.001 in cohort 1 and 2, respectively; TC-PA: χ² = 180, p = 0.041 and χ² = 60, p = 0.008 in cohort 1 and 2, respectively). The association of physical activity with glycaemic control was primarily mediated by variables in the liver fat cycle.

CONCLUSIONS/INTERPRETATION

These analyses partially support the mechanisms proposed in the twin-cycle model and highlight mechanistic pathways through which insulin sensitivity and liver fat mediate the association between physical activity and glycaemic control.

The Perceived Value of Reducing Sedentary Behavior in the Truck Driving Population

Purpose: To conduct rapid qualitative analysis early in the intervention design process to establish the perceived value of reducing sedentary behavior in the truck driver population.

Methods: A rapid assessment process for qualitative data collection was used to examine managerial and employee perceptions quickly and iteratively to inform intervention design. Managerial insights were collected during semi-structured interviews and employee insights were collected via an online survey and focus group. Thematic analyses were guided by the constructs of the Health Belief Model to establish; (a) perceived susceptibility to the health problem; (b) perceived severity of the health problem; (c) perceived benefits of the potential solutions; (d) perceived barriers to adopting the recommended solution; (e) cues to action; and (f) self-efficacy.

Results: Three managers (2 females; 1 male) participated in semi-structured interviews. Seven truck drivers (1 female; 6 males) took part in a focus group. Sixteen survey responses (all male, mean age 49.8 ± 12.4 years, 86% white Caucasian) were collected in total (11 paper based; 6 online). The most important managerial motivators for engagement in an intervention included; improved sleep, alertness and quality of life. The most important employee motivators included; stress reduction (3.3 ± 1.3), improved quality of life (3.3 ± 1.3) and alertness (3.2 ± 1.4). Managerial and employee perspectives indicated that sedentary behavior may be of lower priority than diet and exercise, and may not resonate with the truck driving population as a health risk.

Conclusion: Application of the Health Belief Model indicated a disconnect between the researcher, managerial and employee perspective and the perceived value of a sedentary behavior reduction intervention. Within the truck driving population, researchers should endeavor to include safety as well as health outcomes, use multi-level strategies, design for outcomes of high perceived value and leverage health communication strategies to communicate benefits that resonate with the end-user.

Different levels of physical activity and anthropometric profile in patients infected with hepatitis C virus

Study aim: To verify the relationship between different durations of regular practice of physical activity in aspects related to the anthropometric profile and hepatic function of patients infected by hepatitis C virus (HCV). Material and methods: 125 patients (aged 55.2 ± 10.4 years) participated in the study. Clinical data were obtained through medical records available at the Pernambuco Liver Institute. Physical activity levels were obtained through the International Physical Activity Questionnaire (IPAQ) short form to classify the patients according to the guidelines of the American College of Sports Medicine (ACSM). Results: Significant differences were found in GGT 141 (28-378 U/L) and HDL 39 (27-56 mg/dL) respectively in insuffi­ciently active and physically active groups, AST 71 (26-268 U/L), ALT 83 (36-452 U/L), GGT 78 (3-532 U/L), alkaline phos­phatase 74 (47-302 mg/dL) and total bilirubin 0.7 (0.1-2.8 mg/dL) in insufficiently active and very physically active groups. Anthropometric data showed significant differences in chest (p < 0.01), abdomen (p < 0.02) and waist measurement (p < 0.01) between insufficiently active and very physically active groups.

Conclusion: Physical activity, when practiced regularly for more than 300 minutes per week, can improve the clinical and an­thropometric profile in patients infected with HCV.

Reduced physical activity in young and older adults: metabolic and musculoskeletal implications

BACKGROUND

Although the health benefits of regular physical activity and exercise are well established and have been incorporated into national public health recommendations, there is a relative lack of understanding pertaining to the harmful effects of physical inactivity. Experimental paradigms including complete immobilization and bed rest are not physiologically representative of sedentary living. A useful 'real-world' approach to contextualize the physiology of societal downward shifts in physical activity patterns is that of short-term daily step reduction.

RESULTS

Step-reduction studies have largely focused on musculoskeletal and metabolic health parameters, providing relevant disease models for metabolic syndrome, type 2 diabetes (T2D), nonalcoholic fatty liver disease (NAFLD), sarcopenia and osteopenia/osteoporosis. In untrained individuals, even a short-term reduction in physical activity has a significant impact on skeletal muscle protein and carbohydrate metabolism, causing anabolic resistance and peripheral insulin resistance, respectively. From a metabolic perspective, short-term inactivity-induced peripheral insulin resistance in skeletal muscle and adipose tissue, with consequent liver triglyceride accumulation, leads to hepatic insulin resistance and a characteristic dyslipidaemia. Concomitantly, various inactivity-related factors contribute to a decline in function; a reduction in cardiorespiratory fitness, muscle mass and muscle strength.

CONCLUSIONS

Physical inactivity maybe particularly deleterious in certain patient populations, such as those at high risk of T2D or in the elderly, considering concomitant sarcopenia or osteoporosis. The effects of short-term physical inactivity (with step reduction) are reversible on resumption of habitual physical activity in younger people, but less so in older adults. Nutritional interventions and resistance training offer potential strategies to prevent these deleterious metabolic and musculoskeletal effects.

IMPACT

Individuals at high risk of/with cardiometabolic disease and older adults may be more prone to these acute periods of inactivity due to acute illness or hospitalization. Understanding the risks is paramount to implementing countermeasures.

Ectopic adiposity and cardiometabolic health in COPD

Rationale

Obesity/overweight is the most prevalent body composition abnormality in COPD. However, little is known about the impact of fat distribution on cardiometabolic health in COPD.

Objective

To study the associations between ectopic adiposity, cardiometabolic health, and COPD.

Methods

A total of 263 subjects (166 males; age=65±9 years) were randomly selected from the general population. Subjects were classified as non-COPD controls and COPD, according to the Global initiative for chronic Obstructive Lung Disease (GOLD) classification, and the presence of cardiometabolic comorbidities was recorded. Ectopic fat accumulation was documented from computed tomography measurements of visceral adipose tissue cross-sectional areas and muscle mean attenuation, assessed at L4–L5. Blood glucose, lipid, and adipokine profiles were also evaluated.

Results

After correcting for age, sex, and tobacco exposure, visceral adipose tissue cross-sectional area was higher in GOLD 2+ compared to GOLD 1 individuals. Consistent with this, mean muscle tissue attenuation was lower in GOLD 2+ vs GOLD 1 and non-COPD controls (P<0.001). In multiple regression models, visceral adipose tissue cross-sectional area was strongly associated with hypertension (P<0.001) and diabetes (P<0.001), while muscle attenuation was associated with coronary artery disease (P<0.001). Blood glucose, lipid, and adipokine profiles were similar across groups with the exception of leptin level which was higher in GOLD 2+ subjects compared to GOLD 1 and controls.

Conclusion

GOLD 2+ COPD was associated with ectopic fat accumulation which modulated cardiometabolic health.

Intermittent living; the use of ancient challenges as a vaccine against the deleterious effects of modern life - A hypothesis

Chronic non-communicable diseases (CNCD) are the leading cause of mortality in developed countries. They ensue from the sum of modern anthropogenic risk factors, including high calorie nutrition, malnutrition, sedentary lifestyle, social stress, environmental toxins, politics and economic factors. Many of these factors are beyond the span of control of individuals, suggesting that CNCD are inevitable. However, various studies, ours included, show that the use of intermittent challenges with hormetic effects improve subjective and objective wellbeing of individuals with CNCD, while having favourable effects on immunological, metabolic and behavioural indices. Intermittent cold, heat, fasting and hypoxia, together with phytochemicals in multiple food products, have widespread influence on many pathways related with overall health. Until recently, most of the employed challenges with hormetic effects belonged to the usual transient live experiences of our ancestors. Our hypothesis; we conclude that, whereas the total inflammatory load of multi-metabolic and psychological risk factors causes low grade inflammation and aging, the use of intermittent challenges, united in a 7-10 days lasting hormetic intervention, might serve as a vaccine against the deleterious effects of chronic low grade inflammation and it's metabolic and (premature) aging consequences.

Sedentary Time and MRI-Derived Measures of Adiposity in Active Versus Inactive Individuals

OBJECTIVE

The aim of this study was to examine cross-sectional associations between objectively measured sedentary time and magnetic resonance imaging (MRI)-assessed adiposity in a population at high risk for type 2 diabetes (T2DM) and to determine whether associations are modified by the recommended levels of moderate-to-vigorous physical activity (MVPA).

METHODS

Sedentary time and MVPA were measured objectively by using accelerometers. Linear regression models examined the association of sedentary time with liver, visceral, subcutaneous, and total abdominal fat (quantified by using MRI). Interaction terms determined whether results were consistent across activity categories (active [> 150 min/wk of MVPA] vs. inactive [< 150 min/wk of MVPA]).

RESULTS

One hundred and twenty-four participants (age = 64.0 ± 7.1 years; male = 65.3%; BMI = 31.8 ± 5.6 kg/m² ) were included. Following adjustment, each 60 minutes of sedentary time was associated with 1.74 L higher total abdominal fat, 0.62 L higher visceral fat, 1.14 L higher subcutaneous fat, and 1.86% higher liver fat. When results were stratified by MVPA (active vs. inactive), sedentary time was associated with greater liver, visceral, and total abdominal fat in the inactive group only.

CONCLUSIONS

These findings suggest that sedentary time is associated with higher levels of inter- and intraorgan fat, but associations with liver, visceral, and total abdominal fat were stronger in those who do not reach the current exercise recommendations for health.

Sedentary Behavior, Physical Activity, and Abdominal Adipose Tissue Deposition

PURPOSE

We examined whether sedentary lifestyle habits and physical activity level are associated with abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), intermuscular adipose tissue (IMAT), and liver attenuation, independently of one another and potential confounders.

METHODS

This study analyzed 3010 African American and Caucasian men and women, 42-59 yr old, from the Coronary Artery Risk Development in Young Adults (CARDIA) study, who completed multiple-slice abdominal computed tomography in 2010-2011. Participants reported average hours per day sitting (television, computing, paperwork, music, telephone, and car). Physical activity was assessed with the CARDIA physical activity history. VAT, SAT, IMAT, and liver attenuation were estimated from computed tomography. Multivariable general linear regression models regressed means of fat depots on total sedentary time, task-specific sedentary time, and total physical activity.

RESULTS

Television viewing was positively, and physical activity inversely, associated with fat depots. For each 1 SD increment in television viewing (1.5 h·d), VAT, SAT, and IMAT were greater by 3.5, 3.4, and 3.9 cm, respectively (P < 0.03 for all). For each 1 SD increment in physical activity (275 exercise units), VAT, SAT, and IMAT were lower by 7.6, 6.7, and 8.1 cm, respectively, and liver attenuation was greater (indicating more liver fat) by 0.5 Hounsfield units (P < 0.01 for all). Total sedentary time was associated with VAT, IMAT, and liver attenuation in White men only after controlling for physical activity, SAT, and other potential confounders (P ≤ 0.01 for all). No other task-specific sedentary behaviors were associated with fat depots.

CONCLUSIONS

Sedentary behaviors, particularly television viewing, and physical activity levels have distinct, independent associations with fat deposition.

Sedentary Time, Cardiorespiratory Fitness, and Cardiovascular Risk Factor Clustering in Older Adults--the Generation 100 Study

OBJECTIVE

To determine whether meeting physical activity (PA) recommendations and/or having high age-specific cardiorespiratory fitness (CRF) attenuate the adverse effect of prolonged sedentary time on cardiovascular risk factor (CV-RF) clustering in older adults.

PATIENTS AND METHODS

We conducted a cross-sectional study of Norwegian women (495) and men (379) aged 70 to 77 years from August 22, 2012, through June 30, 2013. Sedentary time and PA were assessed by accelerometers and CRF by directly measured peak oxygen uptake (VO_2peak). Logistic regression was used to estimate adjusted odds ratios (ORs) and CIs for the association between sedentary time and prevalence of CV-RF clustering (≥3 of the following: hypertension, high blood glucose level, high waist circumference, low high-density lipoprotein cholesterol level, or high triglyceride level) and for the modifying effect of PA and CRF.

RESULTS

Overall, 163 of the 495 women (32.9%) and 140 of the 379 men (36.9%) had CV-RF clustering. Each additional hour of sedentary time was associated with 22% (OR, 1.22; 95% CI, 1.02-1.45) and 27% (OR, 1.27; 95% CI, 1.04-1.55) higher likelihood of having CV-RF clustering in women and men, respectively, whereas a 1-metabolic equivalent decrement in VO_2peak corresponded to 57% (OR, 1.57; 95% CI, 1.34-1.84) and 67% (OR, 1.67; 95% CI, 1.44-1.95) higher likelihood of CV-RF clustering in women and men, respectively. High CRF (VO_2peak >27.5 mL/kg per minute in women and >34.4 mL/kg per minute in men) attenuated the adverse effects of high sedentary time on CV-RF clustering, even among individuals not meeting recommendations for PA.

CONCLUSION

High age-specific CRF fully attenuates the adverse effect of prolonged sedentary time on CV-RF clustering, independent of meeting the PA consensus recommendation in older adults.

Sitting Less and Moving More: Improved Glycaemic Control for Type 2 Diabetes Prevention and Management

Epidemiological evidence indicates that excessive time spent in sedentary behaviours (too much sitting) is associated with an increased risk of type 2 diabetes (T2D). Here, we highlight findings of experimental studies corroborating and extending the epidemiological evidence and showing the potential benefits for T2D of reducing and breaking up sitting time across the whole day. We also discuss future research opportunities and consider emerging implications for T2D prevention and management. This new evidence is stimulating an expansion of diabetes-related physical activity guidelines-suggesting that in addition to moderate-vigorous physical activity, reducing and regularly interrupting prolonged sitting time is likely to have important and varied benefits across the spectrum of diabetes risk.

Moderate to vigorous physical activity, not sedentary time, is associated with total and regional adiposity in a sample of UK adults at risk of type 2 diabetes

How sedentary time (ST) relates to total and regional adiposity and whether these associations are independent of moderate- to vigorous-intensity physical activity (MVPA) are of clinical and public health interest. We assessed the relationship between objectively measured MVPA, ST and ST breaks in adults at risk of type 2 diabetes. The sample consisted of 163 adults (37-75 years) recruited from primary care. Dual energy x-ray absorptiometry (iDXA, GE Corp) was used to estimate total and regional (appendages and trunk) fat mass as well as fat mass in the abdominal (android) and hip/thigh (gynoid) regions. The Actigraph GT3X was worn for 7 days (participants with  ⩾4 valid days included herein) and published cut-points were applied to 15 s epoch data to estimate mean MVPA, ST and breaks in ST. Multiple regression investigated associations between both ST and MVPA with total and regional adiposity without and with adjustment for known and potential confounders (including total lean mass) and for each other. MVPA was negatively and significantly associated with total (b  =  -62; p  =  0.002), and regional (p  <  0.05) adiposity before and after adjusting for confounders including ST. Although ST was positively and significantly associated with total (b  =  46.4; p  =  0.002) and regional adiposity (all p  ⩽  0.007), these relationships disappeared after adjustment for MVPA (p  >  0.05). Sedentary breaks were not significantly related to adiposity before or after adjustment. An age-by-MVPA interaction for total, android, gynoid and trunk fat revealed that MVPA did not remain significant when controlling for ST and other covariates in the adults over 65 years old. In this sample of adults at risk of type 2 diabetes, MVPA, and not ST, was associated with total and regional adiposity after adjustment for each other. However, in older adults at risk of T2D weight related benefits may be gained from reducing daily ST and increasing MVPA.

A Fit-Fat Index for Predicting Incident Diabetes in Apparently Healthy Men: A Prospective Cohort Study

Background

The purpose of this study was to examine the impact of combined cardiorespiratory fitness and waist-to-height ratio in the form of a fit-fat index on incident diabetes risk. Additionally, the independent predictive performance of cardiorespiratory fitness, waist-to-height ratio, and body mass index also were estimated and compared.

Methods

This was a prospective cohort study of 10,381 men who had a normal electrocardiogram and no history of major chronic disease at baseline from 1979 to 2005. Random survival forest models and traditional Cox proportional hazards models were used to predict diabetes at 5-, 10-, and 15-year incidence horizons.

Results

Overall, 4.8% of the participants developed diabetes. Receiver operating characteristic curve analyses for incidence risk demonstrated good discrimination using random survival forest models across fitness and fatness measures; Cox models were poor to fair. The differences between fitness and fatness measures across horizons were clinically negligible. Smoothed random survival forest estimates demonstrated the impact of each fitness and fatness measure on incident diabetes was intuitive and graded.

Conclusions

Although fitness and fatness measures showed a similar discriminative ability in predicting incident diabetes, unique to the study was the ability of the fit-fat index to demonstrate a better indication of incident risk when compared to fitness or fatness alone. A single index combining cardiorespiratory fitness and waist-to-height ratio may be more useful because it can indicate improvements in either or both of the measures.

Does duration of physical activity bouts matter for adiposity and metabolic syndrome? A cross-sectional study of older British men

Background

Older adults have low physical activity(PA) and high sedentary behaviour(SB) levels. We investigate how total volume and specific patterns of moderate to vigorous PA(MVPA), light PA(LPA) and SB are related to adiposity and metabolic syndrome (MS). Then, with reference to physical activity guidelines which encourage MVPA in bouts > =10 min and avoiding “long” sedentary bouts, we investigate whether accumulating PA and SB in bouts of different defined durations are differently associated with these outcomes.

Methods

Cross-sectional study of men (71–91 years) recruited in UK primary care centres. Nurses made physical measures (weight, height, bio-impedance, blood pressure) and took fasting blood samples. 1528/3137 (49 %) surviving men had ≥3 valid days (≥600 min) accelerometer data. 450 men with pre-existing chronic disease were excluded. 1009/1078 (93.6 %) had complete covariate data.

Results

Men (n = 1009, mean age 78.5(SD 4.7) years) spent 612(SD 83), 202(SD 64) and 42(SD 33) minutes in SB, LIPA and MVPA respectively. Each additional 30 min/day of SB and MVPA were associated with 0.32 (95 % CI 0.23, 0.40)Kg/m² higher Body Mass Index (BMI) and −0.72(−0.93, −0.51) lower BMI Kg/m² respectively. Patterns for waist circumference (WC), fat mass index (FMI), fasting insulin and MS were similar. MVPA in bouts lasting <10 min or ≥10 min duration were not associated differently with outcomes. In models adjusted for total MVPA, each minute accumulated in SB bouts lasting 1–15 min was associated with lower BMI −0.012 kg/m², WC −0.029 cm, and OR 0.989 for MS (all p < 0.05), and coefficients for LPA bouts 1–9 min were very similar in separate models adjusted for total MVPA. Minutes accumulated in SB bouts 1–15 min and LPA bouts 1–9 min were correlated, r = 0.62.

Conclusions

Objectively measured MVPA, LPA and SB were all associated with lower adiposity and metabolic risk. The beneficial associations of LPA are encouraging for older adults for whom initiating MVPA and maintaining bouts lasting ≥10 min may be particularly challenging. Findings that short bouts of LPA (1–9 min) and SB (1–15 min), but that all MVPA, not just MVPA accumulated in bouts ≥10 min were associated with lower adiposity and better metabolic health could help refine older adult PA guidelines.