The inverse relationship between number of steps per day and obesity in a population-based sample – the AusDiab study

Post-meal exercise under ecological conditions improves post-prandial glucose levels but not 24-hour glucose control

We investigated whether post-meal walking (PMW) improved post-prandial glucose and 24h glucose control under free-living conditions among physically inactive young women.

METHODS

Young women (Age: 20±1years; percent body fat: 28.2 ± 12%; BMI: 23.8 ± 4.2kg·m-1) completed a randomised crossover study to assess if PMW confers benefit. On the PMW day, women completed three bouts of brisk walks, and on the Control day they were instructed to follow normal habitual activities. Continuous glucose monitors captured post-prandial and 24h glucose, and physical activity monitors tracked physical activity throughout the study.

RESULTS

PMW walking increased total daily step count (Control = 9,159 ± 2,962 steps vs. PMW = 14,611±3,891 steps, p<0.001) and activity scores (Control=33.87±1.16 METs·h vs. PMW = 36.11±1.58 METs·h, p < 0.001). PMW led to lower 3h average post-prandial glucose (main effect of condition, p=0.011) and 3h post-prandial area under curve glucose responses (main effect of condition, p = 0.027) compared to the control condition. Post hoc analysis revealed the largest decline occurred after dinner (3h average glucose Control = 7.55±1.21 mmol/L vs. PMW = 6.71 ± 0.80mmol/L, p = 0.039), when insulin sensitivity is typically diminished. Despite improvements in post-prandial glucose control, this did not translate to improvements in 24h glucose control (p > 0.05).

CONCLUSION

Physically inactive and metabolically healthy young women, PMW improves post-prandial glucose but not 24h glucose control.

Physical Activity and Incident Obesity Across the Spectrum of Genetic Risk for Obesity

Importance

Despite consistent public health recommendations, obesity rates in the US continue to increase. Physical activity recommendations do not account for individual genetic variability, increasing risk of obesity.

Objective

To use activity, clinical, and genetic data from the All of Us Research Program (AoURP) to explore the association of genetic risk of higher body mass index (BMI) with the level of physical activity needed to reduce incident obesity.

Design, Setting, and Participants

In this US population-based retrospective cohort study, participants were enrolled in the AoURP between May 1, 2018, and July 1, 2022. Enrollees in the AoURP who were of European ancestry, owned a personal activity tracking device, and did not have obesity up to 6 months into activity tracking were included in the analysis.

Exposure

Physical activity expressed as daily step counts and a polygenic risk score (PRS) for BMI, calculated as weight in kilograms divided by height in meters squared.

Main Outcome and Measures

Incident obesity (BMI ≥30).

Results

A total of 3124 participants met inclusion criteria. Among 3051 participants with available data, 2216 (73%) were women, and the median age was 52.7 (IQR, 36.4-62.8) years. The total cohort of 3124 participants walked a median of 8326 (IQR, 6499-10 389) steps/d over a median of 5.4 (IQR, 3.4-7.0) years of personal activity tracking. The incidence of obesity over the study period increased from 13% (101 of 781) to 43% (335 of 781) in the lowest and highest PRS quartiles, respectively (P = 1.0 × 10-20). The BMI PRS demonstrated an 81% increase in obesity risk (P = 3.57 × 10-20) while mean step count demonstrated a 43% reduction (P = 5.30 × 10-12) when comparing the 75th and 25th percentiles, respectively. Individuals with a PRS in the 75th percentile would need to walk a mean of 2280 (95% CI, 1680-3310) more steps per day (11 020 total) than those at the 50th percentile to have a comparable risk of obesity. To have a comparable risk of obesity to individuals at the 25th percentile of PRS, those at the 75th percentile with a baseline BMI of 22 would need to walk an additional 3460 steps/d; with a baseline BMI of 24, an additional 4430 steps/d; with a baseline BMI of 26, an additional 5380 steps/d; and with a baseline BMI of 28, an additional 6350 steps/d.

Conclusions and Relevance

In this cohort study, the association between daily step count and obesity risk across genetic background and baseline BMI were quantified. Population-based recommendations may underestimate physical activity needed to prevent obesity among those at high genetic risk.

A Conceptual Model for Mobile Health-enabled Slow Eating Strategies

Ingestive behaviors (IBs) (eg, bites, chews, oral processing, swallows, pauses) have meaningful roles in enhancing satiety, promoting fullness, and decreasing food consumption, and thus may be an underused strategy for obesity prevention and treatment. Limited IB monitoring research has been conducted because of a lack of accurate automated measurement capabilities outside laboratory settings. Self-report methods are used, but they have questionable validity and reliability. This paper aimed to present a conceptual model in which IB, specifically slow eating, supported by technological advancements, contributes to controlling hedonic and homeostatic processes, providing an opportunity to reduce energy intake, and improve health outcomes.

Comparison of Wrist- and Hip-Worn Activity Monitors When Meeting Step Guidelines

Introduction

Physical activity (PA) guidelines aimed at accumulating 10,000 steps per day have become increasingly common with the advent of wristband PA monitors. However, accumulated steps measured with wristband PA monitors may not be equal to steps measured with validated, hip-worn pedometers. Consequently, evaluating and developing guidelines for step counts using wristband PA monitors for the general population is needed. We compared step counts accumulated with hip-worn pedometers with those accumulated with wrist-worn activity monitors during 1) treadmill exercise, 2) treadmill walking, and 3) activities of daily living (ADL) to determine their accuracy in meeting step count guidelines (ie, 10,000 steps/d).

Methods

Eighty-six adults (aged 18–65 y; body mass index, 19–45 kg/m²) completed 30 minutes of treadmill exercise while simultaneously using a hip-worn pedometer and wrist-worn PA monitor. Remaining steps needed to reach 10,000 steps (ie, 10,000 steps minus the number of pedometer steps recorded from treadmill exercise = remainder) were completed via treadmill walking or ADL. Steps were recorded for both devices after treadmill exercise, treadmill walking, and ADL for both devices.

Results

Fewer steps were accumulated via wrist-worn PA monitors than via hip-worn pedometers during treadmill exercise (3,552 [SD, 63] steps vs 3,790 [SD, 55] steps, P < .01) and treadmill walking (5,877 [SD, 83] steps vs 6,243 [SD, 49] steps, P < .01). More steps were accumulated via wrist-worn PA monitors than hip-worn pedometers during ADL (7,695 [SD, 207] steps vs 6,309 [SD, 57] steps, P < .01). Consequently, total steps were significantly higher for wristband PA monitors than hip-worn pedometers (11,247 [SD, 210] steps vs 10,099 [SD, 39] steps; P < .01).

Conclusion

The widely used 10,000-step recommendation may not be accurate for all users of all activity monitors, given the discrepancy in daily step count among wrist-worn and hip-worn devices. Having a more accurate indication of number of steps taken per day based on the device used could have positive effects on health.

Connectedness to Nature Does Not Explain the Variation in Physical Activity and Body Composition in Adults and Older People

Connectedness to nature (CN) is a significant predictor of pro-environmental behaviours, human health and well-being. However, research on how this connection to the natural world might promote a more active lifestyle and improve body mass composition according to gender is lacking. This study investigated the influence of CN on physical activity (PA) and body composition in adults and older people. We recruited a sample of 219 individuals (77 men and 142 women), and a self-administered questionnaire was used to measure CN and obtain demographic data. Body composition was assessed by bioimpedance, and PA was assessed by accelerometry. Correlations and stepwise multiple regressions were used in data analysis. CN's association with other variables was more pronounced in women than in men, and we only identified significant associations with steps/day and body composition. However, this variable would not be included in the regression models that we developed. Adiposity levels and muscle status were significant predictors of PA in women. In both genders, age, percentage of fat mass and fat-free mass were selected as regressors in the models developed for visceral fat area and muscle condition (R2 Adjusted ≥ 0.908).

Using Step Counts to Prescribe Physical Activity: What Is the Optimal Dose?

ABSTRACT

An activity goal of 10,000 steps per day is widely known but was not initially developed based on scientific evidence. The last several years have seen an increase in both the availability of consumer-based step counting devices and research examining the link between daily step counts and various health outcomes. Daily step counts are an intuitive metric of physical activity and are useful for goal-setting and motivating behavioral change. This article reviews the current evidence for daily step counts as related to common health conditions to determine activity goals to prescribe to patients, and also discusses factors to consider when counseling patients on physical activity.

Popliteal Vein Compression, Obesity, and Chronic Venous Disease

BACKGROUND

Obesity is a known risk factor for the development of chronic venous disease (CVD). However, some obese patients with lower limb skin changes suggestive of venous disease do not demonstrate venous reflux or obstruction. Popliteal vein compression (PVC) caused by knee hyper-extension during standing has been postulated by others to be more common in the obese due to the increased adipose content of the popliteal fossa. This compression may contribute to the development of venous disease.

OBJECTIVE

To examine the prevalence of PVC in obese and non-obese subjects, with and without venous disease.

METHODS

Participants were recruited across the range of clinical CEAP classifications and body mass. Those referred for venous studies had full venous ultrasound assessments. To assess for PVC, the popliteal vein was assessed via B-mode ultrasound whilst the subject stood and performed two manoeuvres: knee hyper-extension and a bilateral toe stand. Video clips of each manoeuvre were analysed offline.

RESULTS

There were 309 limbs (158 subjects), of which 131 were non-obese (BMI 26±3 kg/m²) and 178 obese (BMI 43±8 kg/m²). PVC with toe stand was more common in obese limbs (89% vs. 64%, P<0.001). It occurred mainly in the distal popliteal vein, associated with contraction of the gastrocnemius muscles. PVC with knee hyper-extension was also more frequent in obese limbs (39% vs. 10%, P<0.0001), and was distinct as it occurred more proximally in the popliteal vein. PVC with knee hyper-extension was significantly more frequent in all obese C classes of obese patients, most notably in the obese with C4-6 CVD (41% vs. 4%, P<0.0001) and was associated with more severe VCSS (median 8 (range: 0-19) vs. 5 (0-21), P = 0.034). There were 19 limbs with skin changes (C4-6) with no venous reflux or obstruction on ultrasound; exclusively obese limbs. These limbs, designated CEAP Pn limbs, were in older, shorter participants with a higher BMI than their counterparts demonstrating reflux, and they also had more frequent PVC with knee hyper-extension (63% vs. 37%, P=0.036).

CONCLUSIONS

PVC with toe stand and knee hyper-extension are both functional effects and more common in obese limbs. PVC(toe stand) is likely associated with normal functioning of the calf muscle pump. While PVC(lock) may contribute to CVD in some obese limbs, the demonstration of PVC(lock) alone is insufficient evidence for direct intervention.

Accelerometer-Measured Daily Step Counts and Adiposity Indicators among Latin American Adults: A Multi-Country Study

The aim of the present study was to examine the sex-related associations between accelerometer-measured daily step counts and adiposity indicators in adults from eight Latin American countries. We analyzed data from 2524 adults (aged 18–65 years) from the Latin American Study of Nutrition and Health. Device-measured daily step counts were measured by accelerometers (ActiGraph GT3X). The outcomes were body mass index (BMI; (kg/m2), waist and neck circumference (in cm). Overall, the mean of daily steps counts, BMI, waist and neck circumference were 10699.8, 27.3, 89.6, and 35.8. Weak and negative associations were observed between daily steps counts and BMI (r = −0.17; p < 0.05) and waist circumference (r = −0.16; p < 0.05); however, step counts was not associated with neck circumference. Daily steps counts were negatively associated with BMI (β: −0.054; 95%CI: −0.077; −0.012) and waist circumference (−0.098; −0.165; −0.030) independently of age and socioeconomic level. In men, there were significant negative associations between daily steps counts with BMI (−0.075; −0.119; −0.031) and waist circumference (−0.140; −0.233; −0.048), and in women, there was no significant association with either of the body composition indicators. The findings from this study need to be examined in prospective settings that use device-measured from Latin America.

Predictors of Disability Attributed to Symptoms of Increased Interrecti Distance in Women after Childbirth: An Observational Study

OBJECTIVE

The purpose of this study was to investigate how various physical and psychological factors are linked to disability attributed to symptoms from increased interrecti distance (IRD) in women after childbirth.

METHODS

In this cross-sectional observational study, 141 women with an IRD of at least 2 finger-widths and whose youngest child was between the ages of 1 and 8 years participated. A multiple linear regression model was performed, with disability as the outcome variable and fear-avoidance beliefs, emotional distress, body mass index, lumbopelvic pain, IRD, and physical activity level as predictor variables.

RESULTS

The regression model accounted for 60% (R2 = 0.604, adjusted R2 = 0.586) of the variance in disability (F6,132 = 33.5). The 2 strongest predictors were lumbopelvic pain, with a regression coefficient of 1.4 (95% CI = 1.017 to 1.877), and fear avoidance, with a regression coefficient of 0.421 (95% CI = 0.287 to 0.555). The actual IRD, with a regression coefficient of -0.133 (95% CI = -1.154 to 0.888), did not contribute significantly to the variation in disability.

CONCLUSION

Disability attributed to symptoms from an increased IRD is explained primarily by the level of lumbopelvic pain but also by the degree of fear-avoidance beliefs and emotional distress.

IMPACT

This study highlights pain intensity and psychological factors as crucial factors for understanding disability attributed to increased IRD.

Drivers of weight loss in a CDC-recognized digital diabetes prevention program

INTRODUCTION

To investigate the impact of the digital Livongo Diabetes Prevention Program (DPP) on weight at 12 months, understand participants' self-monitoring behaviors associated with greater weight loss, and evaluate the impact of coaching interactions on more frequent self-monitoring behaviors.

RESEARCH DESIGN AND METHODS

A retrospective analysis was performed using data from 2037 participants enrolled in the Livongo DPP who completed lesson 1 and recorded a starting weight during 2016-2017. Self-monitoring behaviors, including weigh-ins, food logging, activity, and coach-participant interactions, were analyzed at 6 and 12 months. Subgroup analysis was conducted based on those who were highly engaged versus those minimally engaged. Multiple regression analysis was performed using demographic, self-monitoring, and lesson attendance data to determine predictors of weight loss at 12 months and coaching impact on self-monitoring.

RESULTS

Participants had a mean age of 50 years (SD ±12), with a starting weight of 94 kg (SD ±21), were college-educated (78%), and were female (74%). Overall, participants lost on average 5.1% of their starting weight. Highly engaged participants lost 6.6% of starting body weight, with 25% losing ≥10% at 12 months. Logistic regression analysis showed each submitted food log was associated with 0.23 kg (p<0.05) weight loss, each lesson completed was associated with 0.14 kg (p<0.05) weight loss, and a week of 150 active minutes was associated with 0.1 kg (p<0.01) weight loss. One additional coach-participant message each week was associated with 1.4 more food logs per week, 1.6% increase in weeks with four or more weigh-ins, and a 2.7% increase in weeks with 150 min of activity.

CONCLUSIONS

Food logging had the largest impact on weight loss, followed by lesson engagement and physical activity. Future studies should examine further opportunities to deliver nutrition-based content to increase and sustain weight loss for DPP.

Step by step: Association of device-measured daily steps with all-cause mortality-A prospective cohort Study

Introduction

Walking is free, does not require special training, and can be done almost everywhere. Therefore, walking is a feasible behavior on which to tailor public health messages. This study assesses the prospective association and dose‐response relationship between daily steps and all‐cause mortality.

Materials and Methods

Daily steps were measured by waist‐mounted accelerometers in 2183 individuals (53% women) for seven consecutive days at baseline (2008‐09). Participants were followed for a median period of 9.1 years and associations between steps and all‐cause mortality determined by registry linkage were assessed using Cox proportional hazard regression with adjustment for relevant covariates.

Results

Mean age was 57.0 (SD 10.9) years at baseline. Median (IQR) daily steps across ascending quartiles were 4651 (3495‐5325), 6862 (6388‐7350), 8670 (8215‐9186), and 11 467 (10 556‐13 110), respectively. During follow‐up, 119 individuals died (68% men). Higher number of daily steps was associated with a lower risk of all‐cause mortality with hazard ratios of 1.00 (referent), 0.52 (0.29‐0.93), 0.50 (0.27‐0.94), and 0.43 (0.21‐0.88) across ascending quartiles of daily steps in the multivariable‐adjusted model with follow‐up commencing 2 years after baseline. Risk differences per 1000 individuals for ascending quartiles were 6.8 (2.9‐9.3), 7.1 (0.8‐11.1), and 8.0 (1.7‐12.1), respectively.

Conclusions

Daily steps were associated with lower mortality risk in a non‐linear dose‐response pattern. The risk is almost halved when comparing the least active referent against the second quartile equivalent to a difference of about 2200 daily steps. Encouraging those least active to increase their daily steps may have substantial public health implications.

Video-based smartphone app ('VIDEA bewegt') for physical activity support in German adults: a study protocol for a single-armed observational study

INTRODUCTION

Insufficient physical activity is one of the most important risk factors for non-communicable diseases. Physical activity should therefore be intensively promoted in all age groups. Several trials suggest that it can be effectively increased through smartphone interventions.However, few of the smartphone-interventions available on the market have been scientifically evaluated. Therefore, the described study aims to assess the short-term and long-term effects of the smartphone intervention 'VIDEA bewegt' to increase physical activity. The trial is designed as a single-armed observational trial to assess effects under real-life conditions.

METHODS AND ANALYSIS

The intervention consists of the smartphone-application 'VIDEA bewegt', which is a video-based preventative programme to improve physical activity in everyday life. The application contains several features and components including educational videos, documentation of activity and motivational exercises. A sample size of at least 106 participants is aimed for.The primary objective of this study is to determine the effect of the application on physical activity in German adults. Secondary objectives are to evaluate the self-efficacy, health-related quality of life and usability of 'VIDEA bewegt'.Data collection is based on online questionnaires, as well as system-internal recorded data.Changes of outcomes from baseline to programme completion and follow-up will be calculated.

ETHICS AND DISSEMINATION

The Ethics Committee of the Technical University Dresden approved the study on 25 May 2019 (EK 272062019). All data are processed anonymously and stored on servers only accessible by authorised personnel. The results of the study and the results of the usability test are aimed to be published in a scientific journal.

TRIAL REGISTRATION NUMBER

German Clinical Trials Registry (DRKS00017392).

Physical activity participation and the risk of chronic diseases among South Asian adults: a systematic review and meta-analysis

South Asia specific reviews on the role of physical activity (PA) domains on chronic disease prevention are lacking. This study aimed to systematically review published literature to identify the association between PA domains and chronic diseases and to provide summary estimates of the strength of association. Nine electronic databases were searched using the predefined inclusion criteria which included population (South Asian adults 40 years or older), exposure (PA or sedentary behaviour) and outcome (type 2 diabetes mellitus, breast cancer, colorectal cancer, coronary heart disease, stroke, vascular disease and musculoskeletal diseases and their markers). A random-effects meta-analysis was carried out for cardiometabolic outcomes whereas narrative synthesis was completed for other outcome variables. Inactive or less active South Asian adults were at 31% higher risk of being hypertensive. Likewise, the risk of cardiometabolic outcomes was 1.34 times higher among inactive adults. Household PA was found to have a protective effect  on breast cancer risk. Total and leisure time PA had a protective effect on osteoporosis among males and females respectively. Contemporary studies with a longitudinal design, representative samples, valid and reliable assessment of different domains are needed to establish the role of PA in chronic disease prevention in the region.

Evaluation of a Worksite-Based Small Group Team Challenge to Increase Physical Activity

PURPOSE

To investigate whether participants in a small group team challenge had greater completion rates in an institution-wide step-challenge than other participants.

DESIGN

A quasi-experimental, posttest-only design with a comparison group was used to evaluate group differences in completion rates.

SETTING

A large university system provided the opportunity to participate in a physical activity challenge.

PARTICIPANTS

The study was limited to employees who participated in the physical activity challenge.

INTERVENTION

Two institutions offered participants the chance to compete as smaller groups of teams within their institution. These team-challenge participants (N = 414) were compared to participants from the same institutions that did not sign up for a team and tracked their steps individually (N = 1454).

MEASURES

Participants who reported 50 000 steps per week for 5 of the 6 weeks were classified as challenge completers. We also evaluated total step count and controlled for several potential covariates including age, gender, and body mass index.

ANALYSIS

Logistic regression was used to model the dichotomous outcome of challenge completion.

RESULTS

Team-challenge participants were more likely to complete the physical activity challenge than other participants. Team-challenge participants had 1922 more steps per day than individual participants. However, at an institution level, overall completion rates were not higher at institutions that offered a team challenge.

Effective Weight Loss and Maintenance by Intensive Start with Diet and Exercise

INTRODUCTION

This 24-month study aimed to determine whether exercise intervention added to weight loss treatment at 6 months is effective for weight loss and maintenance.

METHODS

A total of 120 obese subjects (body mass index > 30) were randomly assigned to intensified behavioral modification (iBM) (n = 30), behavioral modification + exercise from 0 to 3 months (circuit weight training group 1 [CWT1]) (n = 30), behavioral modification + exercise from 6 to 9 months (CWT2) (n = 30), and a control group (CON) (n = 30). Health behavior, weight, waist circumference, and 2-h glucose tolerance test with insulin measurements were measured at 0, 3, 9, and 24 months.

RESULTS

Eighty-five subjects (mean age = 46 yr, body mass index = 36.3, 75.3% women) completed the trial. A significant weight loss occurred in CWT1 (-8.5 kg, P > 0.001), iBM (-5.5 kg, P > 0.001), and CWT2 (-4.4 kg, P = 0.007). CWT1 showed the highest reduction in waist circumference at 9 months (mean difference = -11.5 cm, P < 0.001) and 24 months (mean difference = -8.8 cm, P < 0.001). Both fasting and 2-h insulin values improved in the intervention groups compared with CON. A significant decrease in 2-h insulin values from baseline was found in CWT1 and CWT2. Matsuda index improved in the CWT1 group from the baseline to 24 months (2.03, P = 0.025).

CONCLUSION

The most effective weight loss regimen is a combination of iBM and weight training introduced from the very beginning of the weight loss period. Treatment of morbid obesity should include an intensive start with exercise and diet regardless of weight status.

Accuracy of a smartphone pedometer application according to different speeds and mobile phone locations in a laboratory context

BACKGROUND

The purpose of this study was to compare the accuracy of a smartphone application and a mechanical pedometer for step counting at different walking speeds and mobile phone locations in a laboratory context.

METHODS

Seventeen adults wore an iPphone6© with Runtastic Pedometer© application (RUN), at 3 different locations (belt, arm, jacket) and a pedometer (YAM) at the waist. They were asked to walk on an instrumented treadmill (reference) at various speeds (2, 4 and 6 km/h).

RESULTS

RUN was more accurate than YAM at 2 km/h (p < 0.05) and at 4 km/h (p = 0.03). At 6 km/h the two devices were equally accurate. The precision of YAM increased with speed (p < 0.05), while for RUN, the results were not significant but showed a trend (p = 0.051). Surprisingly, YAM underestimates the number of step by 60.5% at 2 km/h. The best accurate step counting (0.7% mean error) was observed when RUN is attached to the arm and at the highest speed.

CONCLUSIONS

RUN pedometer application could be recommended mainly for walking sessions even for low walking speed. Moreover, our results confirm that the smartphone should be strapped close to the body to discriminate steps from noise by the accelerometers (particularly at low speed).

Obesity in Women: Insights for the Clinician

As a leading cause of morbidity and mortality in the United States and worldwide, obesity is a disease that is frequently encountered in clinical practice today and requires a range of medical interventions. While obesity affects both men and women across all ages, multiple issues are particularly germane to women's health, particularly as obesity is more prevalent among women than men in the United States and obesity among women of reproductive health relates to the growing issue of childhood obesity. Discussed herein are the epidemiology and pathophysiology of obesity along with the impact of perinatal obesity on fetal programming. Guidance on screening and management of obesity through lifestyle intervention, pharmacologic therapy, and bariatric surgery, as well as avoidance of weight-promoting medications wherever possible, is elaborated. Particular attention is paid to the contribution of these modalities to weight loss as well as their impact on obesity-related comorbidities that affect a woman's overall health, such as type 2 diabetes and hypertension, and her reproductive and gynecologic health. With modest weight loss, women with obesity can achieve notable improvements in chronic medical conditions, fertility, pregnancy outcomes, and symptoms of pelvic floor disorders. Moreover, as children born to women after bariatric surgery-induced weight loss show improved metabolic outcomes, this demonstrates a role for maternal weight loss in reducing risk of development of metabolic disturbances in children. In light of the immense cost burden and mortality from obesity, it is important to emphasize the role of lifestyle intervention, pharmacologic management, and bariatric surgery for weight loss in clinical practice to mitigate the impact of obesity on women's health.

What Matters in Weight Loss? An In-Depth Analysis of Self-Monitoring

BACKGROUND

Using technology to self-monitor body weight, dietary intake, and physical activity is a common practice used by consumers and health companies to increase awareness of current and desired behaviors in weight loss. Understanding how to best use the information gathered by these relatively new methods needs to be further explored.

OBJECTIVE

The purpose of this study was to analyze the contribution of self-monitoring to weight loss in participants in a 6-month commercial weight-loss intervention administered by Retrofit and to specifically identify the significant contributors to weight loss that are associated with behavior and outcomes.

METHODS

A retrospective analysis was performed using 2113 participants enrolled from 2011 to 2015 in a Retrofit weight-loss program. Participants were males and females aged 18 years or older with a starting body mass index of ≥25 kg/m2, who also provided a weight measurement at the sixth month of the program. Multiple regression analysis was performed using all measures of self-monitoring behaviors involving weight measurements, dietary intake, and physical activity to predict weight loss at 6 months. Each significant predictor was analyzed in depth to reveal the impact on outcome.

RESULTS

Participants in the Retrofit Program lost a mean -5.58% (SE 0.12) of their baseline weight with 51.87% (1096/2113) of participants losing at least 5% of their baseline weight. Multiple regression model (R²=.197, P<0.001) identified the following measures as significant predictors of weight loss at 6 months: number of weigh-ins per week (P<.001), number of steps per day (P=.02), highly active minutes per week (P<.001), number of food log days per week (P<.001), and the percentage of weeks with five or more food logs (P<.001). Weighing in at least three times per week, having a minimum of 60 highly active minutes per week, food logging at least three days per week, and having 64% (16.6/26) or more weeks with at least five food logs were associated with clinically significant weight loss for both male and female participants.

CONCLUSIONS

The self-monitoring behaviors of self-weigh-in, daily steps, high-intensity activity, and persistent food logging were significant predictors of weight loss during a 6-month intervention.

Habitual physical activity is associated with improved anthropometric and androgenic profile in PCOS: a cross-sectional study

PURPOSE

To examine the effect of habitual physical activity (PA) on the metabolic and hormonal profiles of women with polycystic ovary syndrome.

MATERIALS AND METHODS

Anthropometric, metabolic and hormonal assessment and determination of habitual PA levels with a digital pedometer were evaluated in 84 women with PCOS and 67 age- and body mass index (BMI)-matched controls. PA status was defined according to number of steps (≥7500 steps, active, or <7500 steps, sedentary).

RESULTS

BMI was lower in active women from both groups. Active PCOS women presented lower waist circumference (WC) and lipid accumulation product (LAP) values versus sedentary PCOS women. In the control group, active women also had lower WC, lower values for fasting and 120-min insulin, and lower LAP than sedentary controls. In the PCOS group, androgen levels were lower in active versus sedentary women (p = 0.001). In the control group, free androgen index (FAI) was also lower in active versus sedentary women (p = 0.018). Homeostasis model assessment of insulin resistance and 2000 daily step increments were independent predictors of FAI. Each 2000 daily step increment was associated with a decrease of 1.07 in FAI.

CONCLUSIONS

Habitual PA was associated with a better anthropometric and androgenic profile in PCOS.

Do Short Spurts of Physical Activity Benefit Cardiovascular Health? The CARDIA Study

BACKGROUND

For optimal health benefits, moderate- to vigorous-intensity physical activity (MVPA) is recommended in sustained bouts lasting ≥10 min. However, short spurts of MVPA lasting <10 min are more common in everyday life. It is unclear whether short spurts of MVPA further protect against the development of hypertension and obesity in middle-age adults beyond bouted MVPA.

METHODS

Objectively measured physical activity was collected in the Coronary Artery Risk Development in Young Adults study at the 20-yr (2005-2006) examination, and blood pressure and BMI were collected at the 20- and 25-yr (2010-2011) examinations. Time spent in MVPA was classified as either bouted MVPA, i.e., ≥10 continuous minutes or short spurts of MVPA, i.e., <10 continuous minutes. To examine the association of short spurts of MVPA with incident hypertension and obesity over 5 yr, we calculated risk ratios adjusted for bouted MVPA and potential confounders.

RESULTS

Among 1531 and 1251 participants without hypertension and obesity, respectively, at year 20 (age, 45.2 ± 3.6 yr; 57.3% women; body mass index, 29.0 ± 7.0 kg·m(-2)), 14.8% and 12.1% developed hypertension and obesity by year 25. Study participants in the highest tertile of short spurts of MVPA were 31% less likely to develop hypertension 5 yr later (risk ratio = 0.69 (0.49-0.96)) compared with those in the lowest tertile. There was no statistically significant association of short spurts of MVPA with incident obesity.

CONCLUSIONS

These findings support the notion that accumulating short spurts of MVPA protects against the development of hypertension but not obesity in middle-age adults.

Reduction in pedometer-determined physical activity in the adult Danish population from 2007 to 2012

AIMS

To examine the development in pedometer-determined physical activity from 2007-2008 to 2011-2012 in the adult Danish population.

METHODS

The study population comprised two random samples of 18-75-year-old individuals who took part in cross-sectional studies in 2007-2008 (n=224) and 2011-2012 (n=1515). Pedometer data (sealed Yamax SW 200) were obtained for seven consecutive days. Data for 1624 participants (48.2% men) were included in the analysis. An overall step-defined activity level was examined based on a graduated step index (sedentary, low active, somewhat active, active, highly active). The pedometer-determined outcomes were analysed using regression models.

RESULTS

A borderline significant decline (p=0.077) from 8788 to 8341 steps/day (-446 (95% confidence intervals -50, 943)) was found between 2007-2008 and 2011-2012. Furthermore, a 23.7% (95% confidence intervals -41.7%, -0.1%) lower overall step-defined activity level was observed in 2011-2012 compared to 2007-2008. These changes were primarily due to a reduced level of activity among women. The proportion of individuals taking ⩾10,000 steps/day decreased non-significantly from 34.8% to 29.3%, whereas the proportion taking <5000 steps/day did not differ between survey periods.

CONCLUSIONS

This nationally representative survey suggests an overall reduction in the physical activity level among Danish adults. The reduction was due to a shift in the population distribution from higher to lower levels of activity. If this shift is true, it is worrying from a public health perspective. Our study result needs, however, to be confirmed by other population studies.

Does increasing steps per day predict improvement in physical function and pain interference in adults with fibromyalgia?

OBJECTIVE

To examine the concurrent and predictive associations between the number of steps taken per day and clinical outcomes in patients with fibromyalgia (FM).

METHODS

A total of 199 adults with FM (mean age 46.1 years, 95% women) who were enrolled in a randomized clinical trial wore a hip-mounted accelerometer for 1 week and completed self-report measures of physical function (Fibromyalgia Impact Questionnaire-Physical Impairment [FIQ-PI], Short Form 36 [SF-36] health survey physical component score [PCS], pain intensity and interference (Brief Pain Inventory [BPI]), and depressive symptoms (Patient Health Questionnaire-8 [PHQ-8]) as part of their baseline and followup assessments. Associations of steps per day with self-report clinical measures were evaluated from baseline to week 12 using multivariate regression models adjusted for demographic and baseline covariates.

RESULTS

Study participants were primarily sedentary, averaging 4,019 ± 1,530 steps per day. Our findings demonstrate a linear relationship between the change in steps per day and improvement in health outcomes for FM. Incremental increases on the order of 1,000 steps per day were significantly associated with (and predictive of) improvements in FIQ-PI, SF-36 PCS, BPI pain interference, and PHQ-8 (all P < 0.05). Although higher step counts were associated with lower FIQ and BPI pain intensity scores, these were not statistically significant.

CONCLUSION

Step count is an easily obtained and understood objective measure of daily physical activity. An exercise prescription that includes recommendations to gradually accumulate at least 5,000 additional steps per day may result in clinically significant improvements in outcomes relevant to patients with FM. Future studies are needed to elucidate the dose-response relationship between steps per day and patient outcomes in FM.

Physical activity and cardiorespiratory fitness as major markers of cardiovascular risk: their independent and interwoven importance to health status

The evolution from hunting and gathering to agriculture, followed by industrialization, has had a profound effect on human physical activity (PA) patterns. Current PA patterns are undoubtedly the lowest they have been in human history, with particularly marked declines in recent generations, and future projections indicate further declines around the globe. Non-communicable health problems that afflict current societies are fundamentally attributable to the fact that PA patterns are markedly different than those for which humans were genetically adapted. The advent of modern statistics and epidemiological methods has made it possible to quantify the independent effects of cardiorespiratory fitness (CRF) and PA on health outcomes. Based on more than five decades of epidemiological studies, it is now widely accepted that higher PA patterns and levels of CRF are associated with better health outcomes. This review will discuss the evidence supporting the premise that PA and CRF are independent risk factors for cardiovascular disease (CVD) as well as the interplay between both PA and CRF and other CVD risk factors. A particular focus will be given to the interplay between CRF, metabolic risk and obesity.

Validity of the Bite Counter device in a controlled laboratory setting

Body-borne sensors may be useful in assessing eating behaviors and have the potential to overcome some of the limitations of self-report instruments. The Bite Counter is a new commercial device, worn on the wrist that purports to track the number of bites taken per day. It contains a tri-axial accelerometer that detects an upward, arcing motion from the table to the mouth, known as a wrist roll.

PURPOSE

To examine the validity of the Bite Counter device for measuring bites in individuals while consuming various foods and beverages.

METHODS

15 adults (23-58 years old) wore the device on the wrist of their dominant hand. They were presented with a meal consisting of foods/beverages, each consumed with different utensils: meat (knife and fork), side items (fork), soup (spoon), pizza (hands), can of soda (hands), and a smoothie (straw). Each food or drink was consumed by itself, in consecutive order. A researcher observed them through a one-way mirror and counted the number of bites taken.

RESULTS

The percentage of actual bites taken varied as follows: Meat (127%), side items (82.6%), soup (60.2%), pizza (87.3%), soda (81.7%), and smoothie (57.7%). The overall mean was 81.2% of bites taken.

CONCLUSION

The results indicate that the Bite Counter holds promise for being able to count the number of hand-to-mouth movements. In general, it underestimated hand-to-mouth movements, but some types of hand movements caused overestimation of bites. Future studies should be undertaken to improve the sensitivity and specificity of the Bite Counter device.

The 'Healthy Dads, Healthy Kids' community randomized controlled trial: a community-based healthy lifestyle program for fathers and their children

OBJECTIVE

To evaluate the effectiveness of the 'Healthy Dads, Healthy Kids (HDHK)' program when delivered by trained facilitators in community settings.

METHOD

A two-arm randomized controlled trial of 93 overweight/obese fathers (mean [SD] age=40.3 [5.3] years; BMI=32.5 [3.8] kg/m(2)) and their primary school-aged children (n=132) from the Hunter Region, Australia. In 2010-2011, families were randomized to either: (i) HDHK intervention (n=48 fathers, n=72 children) or (ii) wait-list control group. The 7-week intervention included seven sessions and resources (booklets, pedometers). Assessments were held at baseline and 14-weeks with fathers' weight (kg) as the primary outcome. Secondary outcomes for fathers and children included waist, BMI, blood pressure, resting heart rate, physical activity (pedometry), and self-reported dietary intake and sedentary behaviors.

RESULTS

Linear mixed models (intention-to-treat) revealed significant between-group differences for fathers' weight (P<.001, d=0.24), with HDHK fathers losing more weight (-3.3 kg; 95%CI, -4.3, -2.4) than control fathers (0.1 kg; 95%CI, -0.9,1.0). Significant treatment effects (P<.05) were also found for fathers' waist (d=0.41), BMI (d=0.26), resting heart rate (d=0.59), energy intake (d=0.49) and physical activity (d=0.46) and for children's physical activity (d=0.50) and adiposity (d=0.07).

DISCUSSION

HDHK significantly improved health outcomes and behaviors in fathers and children, providing evidence for program effectiveness when delivered in a community setting.

Normal physical activity obliterates the deleterious effects of a high-caloric intake

A high-caloric intake combined with a sedentary lifestyle is an important player in the development of type 2 diabetes mellitus (T2DM). The present study was undertaken to examine if the level of physical activity has impact on the metabolic effects of a high-caloric (+2,000 kcal/day) intake. Therefore, healthy individuals on a high-caloric intake were randomized to either 10,000 or 1,500 steps/day for 14 days. Step number, total energy expenditure, dietary records, neuropsychological tests, maximal oxygen uptake (V̇o2max), whole body dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) scans, continuous glucose monitoring (CGM), and oral glucose tolerance tests (OGTT) with stable isotopes were performed before and after the intervention. Both study groups gained the same amount of body weight. However, the inactive group accumulated significantly more visceral fat compared with the active group. Following the 2-wk period, the inactive group also experienced a poorer glycemic control, increased endogenous glucose production, decreased hepatic insulin extraction, increased baseline plasma levels of total cholesterol and LDL, and a decreased cognitive function with regard to capacity of attention. In conclusion, we find evidence to support that habitual physical activity may prevent pathophysiological symptoms associated with diet-induced obesity.

Are baby boomers booming too much?

SUMMARY

OBJECTIVE

To provide a social, demographic, and health-related description of overweight and obese baby boomers (born between 1946 and 1964).

METHOD

Data were collected using a monthly chronic disease and risk factor surveillance system in which a representative random sample of South Australians are selected from the Electronic White Pages each month and interviewed using computer assisted telephone interviewing (CATI).

RESULTS

In 2006-2007, 65% of baby boomers in South Australia were overweight or obese, and 26% were obese. There were statistically significant increases in both categories between 2002 and 2007. In 2006-2007, the overweight or obese groups were significantly different on a wide range of social, demographic and health-related variables when compared to their non-overweight peers at the univariate level. In the multivariate analysis the obese group was more likely to have risk factors (high blood pressure, insufficient exercise) and chronic disease (diabetes, asthma, arthritis). They were also more likely to be in lower socio-economic areas, to be of Aboriginal or Torres Strait Islander origin and have lower levels of education.

CONCLUSIONS

Addressing the high rates of overweight and obesity within the baby boomers generation should be a policy priority. As this generation moves towards old age the significant associations between body mass index and chronic disease and disability promise to increase demand upon an already pressurized health system.

Physical activity, measures of obesity, and cardiometabolic risk: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

The influence of higher physical activity on the relationship between adiposity and cardiometabolic risk is not completely understood.

METHODS

Between 2000-2002, data were collected on 6795 Multi-Ethnic Study of Atherosclerosis (MESA) participants. Self-reported intentional physical activity in the lowest quartile (0-105 MET-minutes/week) was categorized as inactive and the upper three quartiles (123-37,260 MET-minutes/week) as active. Associations of body mass index (BMI) and waist circumference categories, stratified by physical activity status (inactive or active) with cardiometabolic risk factors (dyslipidemia, hypertension, upper quartile of homeostasis model assessment of insulin resistance [HOMA-IR] for population, and impaired fasting glucose or diabetes) were assessed using logistic regression analysis adjusting for age, gender, race/ethnicity, and current smoking.

RESULTS

Among obese participants, those who were physically active had reduced odds of insulin resistance (47% lower; P < .001) and impaired fasting glucose/diabetes (23% lower; P = .04). These associations were weaker for central obesity. However, among participants with a normal waist circumference, those who were inactive were 63% more likely to have insulin resistance (OR [95% CI] 1.63 [1.24-2.15]) compared with the active reference group.

CONCLUSIONS

Physical activity was inversely related to the cardiometabolic risk associated with obesity and central obesity.

Are behavioral interventions effective in increasing physical activity at 12 to 36 months in adults aged 55 to 70 years? A systematic review and meta-analysis

BACKGROUND

Retirement represents a major transitional life stage in middle to older age. Changes in physical activity typically accompany this transition, which has significant consequences for health and well-being. The aim of this systematic review was to evaluate the evidence for the effect of interventions to promote physical activity in adults aged 55 to 70 years, focusing on studies that reported long-term effectiveness. This systematic review adheres to a registered protocol (PROSPERO CRD42011001459).

METHODS

Randomized controlled trials of interventions to promote physical activity behavior with a mean/median sample age of 55 to 70 years, published between 2000 and 2010, were identified. Only trials reporting the long-term effect (≥ 12 months) on objective or self-reported physical activity behavior were included. Trials reporting physiological proxy measures of physical activity were excluded. Meta-analyses were conducted when trials provided sufficient data and sensitivity analyses were conducted to identify potential confounding effects of trials of poor methodological quality or with attrition rates ≥ 30%.

RESULTS

Of 17,859 publications identified, 32 were included which reported on 21 individual trials. The majority of interventions were multimodal and provided physical activity and lifestyle counselling. Interventions to promote physical activity were effective at 12 months (standardized mean difference (SMD) = 1.08, 95% confidence interval (CI) = 0.16 to 1.99, pedometer step-count, approximating to an increase of 2,197 steps per day; SMD = 0.19, 95% CI = 0.10 to 0.28, self-reported physical activity duration outcome), but not at 24 months based on a small subset of trials. There was no evidence for a relationship between intervention effectiveness and mode of delivery or number of intervention contacts; however, interventions which involved individually tailoring with personalized activity goals or provision of information about local opportunities in the environment may be more effective.

CONCLUSIONS

Interventions in adults aged 55 to 70 years led to long term improvements in physical activity at 12 months; however, maintenance beyond this is unclear. Identified physical activity improvements are likely to have substantial health benefits in reducing the risk of age-related illnesses. These findings have important implications for community-based public health interventions in and around the retirement transition.

A step-defined sedentary lifestyle index: <5000 steps/day

Step counting (using pedometers or accelerometers) is widely accepted by researchers, practitioners, and the general public. Given the mounting evidence of the link between low steps/day and time spent in sedentary behaviours, how few steps/day some populations actually perform, and the growing interest in the potentially deleterious effects of excessive sedentary behaviours on health, an emerging question is "How many steps/day are too few?" This review examines the utility, appropriateness, and limitations of using a reoccurring candidate for a step-defined sedentary lifestyle index: <5000 steps/day. Adults taking <5000 steps/day are more likely to have a lower household income and be female, older, of African-American vs. European-American heritage, a current vs. never smoker, and (or) living with chronic disease and (or) disability. Little is known about how contextual factors (e.g., built environment) foster such low levels of step-defined physical activity. Unfavorable indicators of body composition and cardiometabolic risk have been consistently associated with taking <5000 steps/day. The acute transition (3-14 days) of healthy active young people from higher (>10 000) to lower (<5000 or as low as 1500) daily step counts induces reduced insulin sensitivity and glycemic control, increased adiposity, and other negative changes in health parameters. Although few alternative values have been considered, the continued use of <5000 steps/day as a step-defined sedentary lifestyle index for adults is appropriate for researchers and practitioners and for communicating with the general public. There is little evidence to advocate any specific value indicative of a step-defined sedentary lifestyle index in children and adolescents.

The association of obesity with walking independent of knee pain: the multicenter osteoarthritis study

Practice guidelines recommend addressing obesity for people with knee OA, however, the association of obesity with walking independent of pain is not known. We investigated this association within the Multicenter Osteoarthritis Study, a cohort of older adults who have or are at high risk of knee OA. Subjects wore a StepWatch to record steps taken over 7 days. We measured knee pain from a visual analogue scale and obesity by BMI. We examined the association of obesity with walking using linear regression adjusting for pain and covariates. Of 1788 subjects, the mean steps/day taken was 8872.9 ± 3543.4. Subjects with a BMI ≥35 took 3355 fewer steps per day independent of knee pain compared with those with a BMI ≤25 (95% CI -3899, -2811). BMI accounted for 9.7% of the variability of walking while knee pain accounted for 2.9%. BMI was associated with walking independent of knee pain.

Joint associations of physical activity and screen time with overweight among japanese adults

BACKGROUND

Although both insufficient physical activity (PA) and high screen time (ST) are independent risk factors for obesity, how the combination of sufficient/insufficient PA and high/low ST could increase obesity risk among the adult population of Japan is not known. This study examined joint associations of PA and ST with overweight among Japanese adults.

METHODS

An Internet-based survey collected data on height, weight, self-reported time spent in PA and ST, and sociodemographic variables from 2832 adults. Respondents were categorized into sufficient PA/low ST, sufficient PA/high ST, insufficient PA/low ST, or insufficient PA/high ST categories as per public PA guidelines and the median of ST. Logistic regression analysis examined the odds ratios (OR) of being overweight (body mass index, ≥ 25 kg/m(2)) according to the categories of PA and ST.

RESULTS

In comparison with the sufficient PA/low ST category, participants in the insufficient PA/high ST category were significantly more likely overweight (OR, 1.48; 95% confidence interval [95%CI), 1.14, 1.93) after adjusting for sociodemographic variables. A significantly higher OR for overweight (including obesity) among insufficient PA/high ST category was also observed in men, but no significant association was found in women.

CONCLUSIONS

Both insufficient PA and prolonged ST contribute to overweight and obesity among Japanese adults. Public health initiatives addressing obesity in Japan need to consider both promoting PA and reducing ST, especially in men.

Relationship of obesity to physical activity, domestic activities, and sedentary behaviours: cross-sectional findings from a national cohort of over 70,000 Thai adults

BACKGROUND

Patterns of physical activity (PA), domestic activity and sedentary behaviours are changing rapidly in Asia. Little is known about their relationship with obesity in this context. This study investigates in detail the relationship between obesity, physical activity, domestic activity and sedentary behaviours in a Thai population.

METHODS

74,981 adult students aged 20-50 from all regions of Thailand attending the Sukhothai Thammathirat Open University in 2005-2006 completed a self-administered questionnaire, including providing appropriate self-reported data on height, weight and PA. We conducted cross-sectional analyses of the relationship between obesity, defined according to Asian criteria (Body Mass Index (BMI) ≥25), and measures of physical activity and sedentary behaviours (exercise-related PA; leisure-related computer use and television watching ("screen-time"); housework and gardening; and sitting-time) adjusted for age, sex, income and education and compared according to a range of personal characteristics.

RESULTS

Overall, 15.6% of participants were obese, with a substantially greater prevalence in men (22.4%) than women (9.9%). Inverse associations between being obese and total weekly sessions of exercise-related PA were observed in men, with a significantly weaker association seen in women (p(interaction) < 0.0001). Increasing obesity with increasing screen-time was seen in all population groups examined; there was an overall 18% (15-21%) increase in obesity with every two hours of additional daily screen-time. There were 33% (26-39%) and 33% (21-43%) reductions in the adjusted risk of being obese in men and women, respectively, reporting housework/gardening daily versus seldom or never. Exercise-related PA, screen-time and housework/gardening each had independent associations with obesity.

CONCLUSIONS

Domestic activities and sedentary behaviours are important in relation to obesity in Thailand, independent of exercise-related physical activity. In this setting, programs to prevent and treat obesity through increasing general physical activity need to consider overall energy expenditure and address a wide range of low-intensity high-volume activities in order to be effective.

How many steps/day are enough? For older adults and special populations

Older adults and special populations (living with disability and/or chronic illness that may limit mobility and/or physical endurance) can benefit from practicing a more physically active lifestyle, typically by increasing ambulatory activity. Step counting devices (accelerometers and pedometers) offer an opportunity to monitor daily ambulatory activity; however, an appropriate translation of public health guidelines in terms of steps/day is unknown. Therefore this review was conducted to translate public health recommendations in terms of steps/day. Normative data indicates that 1) healthy older adults average 2,000-9,000 steps/day, and 2) special populations average 1,200-8,800 steps/day. Pedometer-based interventions in older adults and special populations elicit a weighted increase of approximately 775 steps/day (or an effect size of 0.26) and 2,215 steps/day (or an effect size of 0.67), respectively. There is no evidence to inform a moderate intensity cadence (i.e., steps/minute) in older adults at this time. However, using the adult cadence of 100 steps/minute to demark the lower end of an absolutely-defined moderate intensity (i.e., 3 METs), and multiplying this by 30 minutes produces a reasonable heuristic (i.e., guiding) value of 3,000 steps. However, this cadence may be unattainable in some frail/diseased populations. Regardless, to truly translate public health guidelines, these steps should be taken over and above activities performed in the course of daily living, be of at least moderate intensity accumulated in minimally 10 minute bouts, and add up to at least 150 minutes over the week. Considering a daily background of 5,000 steps/day (which may actually be too high for some older adults and/or special populations), a computed translation approximates 8,000 steps on days that include a target of achieving 30 minutes of moderate-to-vigorous physical activity (MVPA), and approximately 7,100 steps/day if averaged over a week. Measured directly and including these background activities, the evidence suggests that 30 minutes of daily MVPA accumulated in addition to habitual daily activities in healthy older adults is equivalent to taking approximately 7,000-10,000 steps/day. Those living with disability and/or chronic illness (that limits mobility and or/physical endurance) display lower levels of background daily activity, and this will affect whole-day estimates of recommended physical activity.

How many steps/day are enough? For adults

Physical activity guidelines from around the world are typically expressed in terms of frequency, duration, and intensity parameters. Objective monitoring using pedometers and accelerometers offers a new opportunity to measure and communicate physical activity in terms of steps/day. Various step-based versions or translations of physical activity guidelines are emerging, reflecting public interest in such guidance. However, there appears to be a wide discrepancy in the exact values that are being communicated. It makes sense that step-based recommendations should be harmonious with existing evidence-based public health guidelines that recognize that "some physical activity is better than none" while maintaining a focus on time spent in moderate-to-vigorous physical activity (MVPA). Thus, the purpose of this review was to update our existing knowledge of "How many steps/day are enough?", and to inform step-based recommendations consistent with current physical activity guidelines. Normative data indicate that healthy adults typically take between 4,000 and 18,000 steps/day, and that 10,000 steps/day is reasonable for this population, although there are notable "low active populations." Interventions demonstrate incremental increases on the order of 2,000-2,500 steps/day. The results of seven different controlled studies demonstrate that there is a strong relationship between cadence and intensity. Further, despite some inter-individual variation, 100 steps/minute represents a reasonable floor value indicative of moderate intensity walking. Multiplying this cadence by 30 minutes (i.e., typical of a daily recommendation) produces a minimum of 3,000 steps that is best used as a heuristic (i.e., guiding) value, but these steps must be taken over and above habitual activity levels to be a true expression of free-living steps/day that also includes recommendations for minimal amounts of time in MVPA. Computed steps/day translations of time in MVPA that also include estimates of habitual activity levels equate to 7,100 to 11,000 steps/day. A direct estimate of minimal amounts of MVPA accumulated in the course of objectively monitored free-living behaviour is 7,000-8,000 steps/day. A scale that spans a wide range of incremental increases in steps/day and is congruent with public health recognition that "some physical activity is better than none," yet still incorporates step-based translations of recommended amounts of time in MVPA may be useful in research and practice. The full range of users (researchers to practitioners to the general public) of objective monitoring instruments that provide step-based outputs require good reference data and evidence-based recommendations to be able to design effective health messages congruent with public health physical activity guidelines, guide behaviour change, and ultimately measure, track, and interpret steps/day.

Objectively measured physical activity and the subsequent risk of incident dysglycemia: the Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

OBJECTIVE

To investigate pedometer-measured physical activity (PA) in 2000 and change in PA over 5 years with subsequent risk of dysglycemia by 2005.

RESEARCH DESIGN AND METHODS

This prospective cohort study in Tasmania, Australia, analyzed 458 adults with normal glucose tolerance and a mean (SD) age of 49.7 (12.1) years in 2000. Variables assessed in 2000 and 2005 included PA, by pedometer and questionnaire, nutrient intake, and other lifestyle factors. Incident dysglycemia was defined as the development of impaired fasting glucose or impaired glucose tolerance revealed by oral glucose tolerance testing in 2005, without type 2 diabetes.

RESULTS

Incident dysglycemia developed in 26 participants during the 5-year period. Higher daily steps in 2000 were independently associated with a lower 5-year risk of incident dysglycemia (adjusted odds ratio [AOR] 0.87 [95% CI 0.77-0.97] per 1,000-step increment). Higher daily steps in 2005, after controlling for baseline steps in 2000 (thus reflecting change in steps over 5 years), were not associated with incident dysglycemia (AOR 1.02 [0.92-1.14]). Higher daily steps in 2000 were also associated with lower fasting blood glucose, but not 2-h plasma glucose by 2005. Further adjustment for BMI or waist circumference did not remove these associations.

CONCLUSIONS

Among community-dwelling adults, a higher rate of daily steps is associated with a reduced risk of incident dysglycemia. This effect appears to be not fully mediated through reduced adiposity.

Metabolic disruptions induced by reduced ambulatory activity in free-living humans

Physical inactivity likely plays a role in the development of insulin resistance and obesity; however, direct evidence is minimal and mechanisms of action remain unknown. Studying metabolic outcomes that occur after transitioning from higher to lower levels of physical activity is the best tool to answer these questions. Previous studies have successfully used more extreme models of inactivity, including bed rest, or the cessation of exercise in highly trained endurance athletes, to provide novel findings. However, these models do not accurately reflect the type of inactivity experienced by a large majority of the population. Recent studies have used a more applicable model in which active (∼10,000 steps/day), healthy young controls are asked to transition to an inactive lifestyle (∼1,500 steps/day) for a 14-day period. The transition to inactivity resulted in reduced insulin sensitivity and increased central adiposity. This review will discuss the outcomes of these studies, their implications for the cause/effect relationship between central adiposity and insulin resistance, and provide rationale for why inactivity induces these factors. In addition, the experimental challenges of directly linking acute responses to inactivity to chronic disease will also be discussed.

Neighbourhood environment correlates of physical activity: a study of eight Czech regional towns

An adequate amount of physical activity (PA) is a key factor that is associated with good health. This study assessed socio-environmental factors associated with meeting the health recommendations for PA (achieving 10,000 steps per day). In total, 1,653 respondents randomly selected from across eight regional towns (each >90,000 inhabitants) in the Czech Republic participated in the study. The ANEWS questionnaire assessed the environment in neighbourhoods, and participants’ weekly PA was objectively monitored (Yamax Digiwalker SW-700 pedometer). About 24% of participants were sufficiently active, 27% were highly active; 28% participants were overweight and 5% were obese. Although BMI was significantly inversely associated with the daily step counts achieved only in females, for both genders, BMI was generally not significantly associated with the criterion of achieving 10,000 steps per day during the week. Increased BMI in both genders was accompanied with a decline in participation in organized PA and with increasing age. As regards to the demographic/lifestyle factors, for females, more participation in organized PA was significantly positively correlated with the achieved daily step counts. In contrast, older age and higher BMI (for females) and smoking (for males) were significantly negatively correlated with the achieved daily step counts. In terms of the environmental aspects, pleasant environments were significantly positively correlated to daily step counts for both genders. Additionally, for males, better residencies (more family homes rather than apartment blocks) in the neighbourhood were significantly positively correlated with their daily step counts. For females, less accessibility of shops and non-sport facilities (depending on walking distance in minutes) were significantly negatively correlated to the achieved daily step counts. Individuals who lived in pleasant neighbourhoods, with better access to shops and who participated in organized PA (≥2 times a week) tended to meet the recommendations for health-enhancing PA levels. The creation of physical activity-friendly environments could be associated with enhancing people’s achieved daily step counts and meeting the health criteria for PA.

Descriptive epidemiology of ambulatory activity in rural, black South Africans

PURPOSE

We investigated the distribution of objectively measured ambulation levels and the association of ambulation levels to adiposity levels in a convenience sample of adolescent and adult, rural black South Africans.

METHODS

We analyzed 7-d pedometry data, collected over a period of nine consecutive days, in 789 subjects (women, n = 516; men, n = 273). Adiposity measures included body mass index (BMI) and waist circumference (WC). Obesity was defined as BMI > or = 30 kg x m(-2) or WC > or = 102 cm for men and WC > or = 88 cm for women.

RESULTS

The average age- and BMI-adjusted 7-d ambulation level was 12,471 steps per day (95% confidence interval (CI) = 12,107-12,834). Ambulation levels differed between sexes (P = 0.0012), and weekday ambulation differed from weekend ambulation (P = 0.0277). Prevalences, age adjusted to the world population, for sedentarism (SED; <5000 steps per day), low active-somewhat active (5000-9999 steps per day), and active-very active (ACT; > or =10,000 steps per day) were 8.0%, 25.5%, and 66.6%, respectively. In contrast, published self-reported national prevalences for physical inactivity, insufficient physical activity, and physically active have been estimated to be 43%-49%, 20%-27%, and 25%-37%, respectively. After adjusting for sex and age, adiposity measures remained significantly associated with steps per day (BMI, r = -0.08; WC, r = -0.12; P < 0.03). Adjusting for sex, age, village, and season, SED increased the risk of obesity by more than twofold compared with ACT (P < 0.05). Achieving <10,000 steps per day compared with ACT was associated with an increased multivariate-adjusted obesity risk of 86%-89% (P < 0.001).

CONCLUSIONS

Ambulation levels were high for this rural African sample, and prevalences for SED and ACT differed from published self-reported estimates.

Pedestrian injuries in eight European countries: an analysis of hospital discharge data

Out of the 50,000 yearly road traffic deaths in the European Union (formed by 27 European countries and commonly designated as EU-27), some 8500 are pedestrians. While some studies focus on the increased risk for pedestrian mortality compared to other road users, there is a dearth of information on injury patterns that could be used to prioritize injury prevention measures. Hospital discharge data from eight European countries have been used in this study. Injury information from 10,341 pedestrians sustaining 19,424 injuries has been analyzed. Data have been augmented with Abbreviated Injury Scale, Functional Capacity Index and Injury Severity Score codes, and have been categorized into the Barell Matrix. Fractures (51.1%, 50.3-51.8) and internal injuries (21.3%, 20.7-21.9) are the most frequently found in the data; however, blood vessel injuries and internal injuries are the ones associated with the highest risk of death. Head and lower extremities account for 26% of the injuries each, being spinal and thoracic injuries those showing the highest threat to life risk. Hip and lower extremities injuries are the most frequent cause of functional limitation 1 year after discharge. Due to its intrinsic importance, different injury causation mechanisms for head injuries have been analyzed. Though current standards and regulations consider Head Injury Criterion (HIC) as the only tool to assess the risk of injuries to the head, real world injury data show that only 12.1% (11.0-13.2) of these injuries can be attributed to a pure translational mechanism and therefore susceptible to be predicted by HIC. Design of prevention strategies, particularly from the engineering point of view, should benefit from this information.

Screen-time, obesity, ageing and disability: findings from 91 266 participants in the 45 and Up Study

OBJECTIVE

To assess the relationship between obesity and sedentary behaviours, such as watching television or using a computer ('screen-time'), and describe how this relationship varies between population subgroups.

DESIGN

Cross-sectional analysis of the relationship between obesity (BMI ≥ 30 kg/m2) and screen-time, adjusted for age, sex, income and education and compared according to a range of personal characteristics.

SETTING

New South Wales, Australia.

SUBJECTS

A total of 91 266 men and women aged 45 years and above from the general population of New South Wales in 2006-2007 and providing self-reported information on height and weight and other factors.

RESULTS

Obesity prevalence was 21.4 %. Compared to individuals with <2 h of daily screen-time, the adjusted relative risks (RR) of obesity were 1.35 (95 % CI 1.26, 1.44), 1.70 (95 % CI 1.59, 1.82), 1.94 (95 % CI 1.81, 2.08) and 1.92 (95 % CI 1.80, 2.06) for 2-3, 4-5, 6-7 and ≥8 h, respectively. The increase in obesity with increasing screen-time was similar within categories of overall physical activity, but was attenuated in those in full-time paid work, compared to non-workers (P for interaction < 0.0001). Among non-workers, the overall obesity RR per 2 h increase in daily screen-time was 1.23 (95 % CI 1.21, 1.25) and was significantly elevated in all groups examined, ranging from 1.16 to 1.31 according to sex, level of age, education, income, smoking and fruit consumption. The RR did not differ significantly according to overall physical activity, region of residence and alcohol and vegetable consumption, but was substantially lower in disabled v. not-disabled individuals (P for interaction < 0.0001).

CONCLUSIONS

Obesity increases with increasing screen-time, independent of purposeful physical activity. This was observed in all population groups examined, although it is attenuated in full-time workers and disabled individuals.

Physical activity, fitness and fatness: relations to mortality, morbidity and disease risk factors. A systematic review

The purpose of this systematic review was to study the relative health risks of poor cardio-respiratory fitness (or physical inactivity) in normal-weight people vs. obesity in individuals with good cardio-respiratory fitness (or high physical activity). The core inclusion criteria were: publication year 1990 or later; adult participants; design prospective follow-up, case-control or cross-sectional; data on cardio-respiratory fitness and/or physical activity; data on BMI (body mass index), waist circumference or body composition; outcome data on all-cause mortality, cardiovascular disease mortality, cardiovascular disease incidence, type 2 diabetes or cardiovascular and type 2 diabetes risk factors. Thirty-six publications filled the criteria for inclusion. The data indicate that the risk for all-cause and cardiovascular mortality was lower in individuals with high BMI and good aerobic fitness, compared with individuals with normal BMI and poor fitness. In contrast, having high BMI even with high physical activity was a greater risk for the incidence of type 2 diabetes and the prevalence of cardiovascular and diabetes risk factors, compared with normal BMI with low physical activity. The conclusions of the present review may not be applicable to individuals with BMI > 35.

Physical activity of older Australians measured by pedometry

AIM

To established population norms for pedometer determined step counts in older Australians.

METHODS

A representative sample of 684 participants over the age of 55 years wore a pedometer for a week in Newcastle, Australia.

RESULTS

Response rate was 32%. Median daily step count was 8605 in those aged 55-59 years declining to 3778 in those over 80 years old. The proportion who reached 8000 steps per day was 62% in those 55-59 years and 12% in those over 80 years. Daily step counts were highest on Thursdays and Fridays and least on Sundays. Weekend days had on average 620 less steps than weekdays. After adjusting for age, there was a negative association of step count with body mass index >30, and with a history of arthritis but no significant association with other demographic variables.

CONCLUSION

Pedometry is feasible in an elderly sample, and research involving pedometers must take days of the week into account.