Wrist-worn accelerometers: recommending ~1.0 mg as the minimum clinically important difference (MCID) in daily average acceleration for inactive adults

Physical activity is increasingly assessed using wrist-worn accelerometry.1 The primary unit of measurement is acceleration which lacks an obvious concrete meaning in the clinical and public health settings. If the scientific community agreed on a minimum clinically important difference (MCID) that would greatly help users interpret accelerometry data in a more meaningful way. Here we present converging evidence to inform estimation of the MCID in physical activity for inactive adults, expressed as average acceleration measured from wrist-worn accelerometers

Physical Activity for Bone Health: How Much and/or How Hard?

Purpose:High-impact physical activity is associated with bone health, but higher volumes of lower intensity activity may also be important. The aims of this study were to: 1) investigate the relative importance of volume and intensity of physical activity accumulated during late adolescence for bone health at age 23; and 2) illustrate interpretation of the results.Methods:This is a secondary analysis of data from the Iowa Bone Development Study, a longitudinal study of bone health from childhood through to young adulthood. The volume (average acceleration) and intensity distribution (intensity gradient) of activity at ages 17, 19, 21 and 23 were calculated from raw acceleration ActiGraph data and averaged across ages. Hip areal bone mineral density (aBMD), total body bone mineral content (BMC), spine aBMD and hip structural geometry (DXA, Hologic QDR4500A) were assessed at age 23.Valid data, available for 220 participants (124 females),were analysed with multiple regression. To elucidate significant effects, we predicted bone outcomes when activity volume and intensity were high (+1SD), medium (mean),and low (-1SD).Results:There were additive associations of volume and intensity with hip aBMD and total body BMC(low-intensity/low-volume cf. high-intensity/high-volume = ∆0.082g·cm-2and ∆169.8g, respectively). or males’ only spine aBMD intensity was associated independently of volume(low-intensity cf. high-intensity = ∆0.049g.cm-2). For hip structural geometry, volume was associated independently of intensity(low-volume cf. high-volume = ∆4.8-6.6%).Conclusion: The activity profile associated with optimal bone outcomes was high in intensity and volume. The variation in bone health across the activity volume and intensity distribution suggests intensity is key for aBMD and BMC, while high volumes of lower intensity activity may be beneficial for hip structural geometry.</p

Differences in levels of physical activity between White and South Asian populations within a healthcare setting: impact of measurement type in a cross-sectional study

Objective: We investigate differences between White and South Asian (SA) populations in levels of objectively measured and self-reported physical activity. Design: Cross-sectional study. Setting: Leicestershire, United Kingdom, 2010-2011. Participants: Baseline data was pooled from two diabetes prevention trials which recruited a total of 4282 participants from primary care with a high risk score for type 2 diabetes. For this study, 2843 White (age = 64 ± 8, female = 37%) and 243 SA (age = 58 ± 9, female = 34%) participants had complete physical activity data and were included in the analysis. Outcome measures: Moderate- to vigorous-intensity physical activity (MVPA) and walking activity were measured using the International Physical Activity Questionnaire (IPAQ) and a combination of piezoelectric pedometer (NL-800) and accelerometer (Actigraph GT3X) were used to objectively measure physical activity. Results: Compared to White participants, SA participants self-reported less MVPA (30 vs. 51 minutes per day; P < 0.001) and walking activity (11 vs 17 minutes per day; P = 0.001). However, there was no difference in objectively measured ambulatory activity (5992 steps/day vs. 6157 steps/day; p = 0.75) or in time spent in MVPA (21.5 vs. 18.0 minutes/day; p = 0.23). Results were largely unaffected when adjusted for age, sex and social deprivation. 3 Compared to accelerometer data, White participants overestimated their time in MVPA by 51 minutes/day and SA participants by 21 minutes/day. Conclusions: SA and White groups undertook similar levels of physical activity when measured objectively despite self-reported estimates being around 40% lower in the SA group. This emphasises the limitations of comparing self-reported lifestyle measures across different populations and ethnic groups. Reports baseline data from: Walking Away from Type 2 Diabetes (ISRCTN31392913) and Let’s Prevent Diabetes (NCT00677937

Walking away from type 2 diabetes: trial protocol of a cluster randomised controlled trial evaluating a structured education programme in those at high risk of developing type 2 diabetes.

Background:The prevention of type 2 diabetes is a recognised health care priority globally. Within the United Kingdom, there is a lack of research investigating optimal methods of translating diabetes prevention programmes, based on the promotion of a healthy lifestyle, into routine primary care. This study aims to establish the behavioural and clinical effectiveness of a structured educational programme designed to target perceptions and knowledge of diabetes risk and promote a healthily lifestyle, particularly increased walking activity, in a multi-ethnic population at a high risk of developing type 2 diabetes. Design:Cluster randomised controlled trial undertaken at the level of primary care practices. Follow-up will be conducted at 12, 24 and 36 months. The primary outcome is change in objectively measured ambulatory activity. Secondary outcomes include progression to type 2 diabetes, biochemical variables (including fasting glucose, 2-h glucose, HbA1c and lipids), anthropometric variables, quality of life and depression. Methods:10 primary care practices will be recruited to the study (5 intervention, 5 control). Within each practice, individuals at high risk of impaired glucose regulation will be identified using an automated version of the Leicester Risk Assessment tool. Individuals scoring within the 90th percentile in each practice will be invited to take part in the study. Practices will be assigned to either the control group (advice leaflet) or the intervention group, in which participants will be invited to attend a 3 hour structured educational programme designed to promote physical activity and a healthy lifestyle. Participants in the intervention practices will also be invited to attend annual group-based maintenance workshops and will receive telephone contact halfway between annual sessions. The study will run from 2010–2014. Discussion:This study will provide new evidence surrounding the long-term effectiveness of a diabetes prevention programme run within routine primary care in the United Kingdom. Trial Registration:ClinicalTrials.Gov identifier: NCT0094195

Physical behaviours and chronotype in people with Type 2 diabetes

Introduction Previous investigations have suggested that evening chronotypes may be more susceptible to obesity-related metabolic alterations. However, whether device-measured physical behaviours differ by chronotype in those with T2DM remains unknown. Research design and methods This analysis reports data from the ongoing Chronotype of Patients with Type 2 Diabetes and Effect on Glycaemic Control (CODEC) observational study. Eligible participants were recruited from both primary and secondary care settings in the Midlands area, UK. Participants were asked to wear an accelerometer (GENEActiv, ActivInsights Ltd, Kimbolton, UK) on their non-dominant wrist for 7 days to quantify different physical behaviours (sleep, sedentary, light, moderate-to-vigorous physical activity (MVPA), intensity gradient, average acceleration and the acceleration above which the most active continuous 2, 10, 30 and 60 minutes are accumulated). Chronotype preference (morning, intermediate or evening) was assessed using the Morningness-Eveningness Questionnaire. Multiple linear regression analyses assessed whether chronotype preference was associated with physical behaviours and their timing. Evening chronotypes were considered as the reference group. Results 635 participants were included (age=63.8±8.4 years, 34.6% female, BMI=30.9±5.1kg/m2). 25% (n=159) of the cohort were morning chronotypes, 52% (n=330) intermediate and 23% (n=146) evening chronotypes. Evening chronotypes had higher sedentary time (28.7 minutes/day, 95% CI 8.6, 48.3), and lower MVPA levels (-9.7mins/day, -14.9, -4.6) compared to morning chronotypes. The intensity of the most active continuous 2-60 minutes of the day, average acceleration and intensity gradient were lower in evening chronotypes. The timing of physical behaviours also differed across chronotypes, with evening chronotypes displaying a later sleep onset and consistently later physical activity time. Conclusions People with T2DM lead a lifestyle characterised by sedentary behaviours and insufficient MVPA. This may be exacerbated in those with a preference for ‘eveningness’ (i.e., go to bed late and get up late).</p

Stand Out in Class: investigating the potential impact of a sit–stand desk intervention on children’s sitting and physical activity during class time and after school

Sedentary behaviour (sitting) is a risk factor for adverse health outcomes. The classroom environment has traditionally been associated with prolonged periods of sitting in children. The aim of this study was to examine the potential impact of an environmental intervention, the addition of sit–stand desks in the classroom, on school children’s sitting and physical activity during class time and after school. The ‘Stand Out in Class’ pilot trial was a two-arm cluster randomised controlled trial conducted in eight primary schools with children from a mixed socioeconomic background. The 4.5 month environmental intervention modified the physical (six sit–stand desks replaced standard desks) and social (e.g., teachers’ support) environment. All children wore activPAL and ActiGraph accelerometers for 7 days at baseline and follow-up. In total 176 children (mean age= 9.3 years) took part in the trial. At baseline, control and intervention groups spent more than 65% of class time sitting, this changed to 71.7% and 59.1% at follow-up, respectively (group effect p < 0.001). The proportion of class time spent standing and stepping, along with the proportion of time in light activity increased in the intervention group and decreased in the control group. There was no evidence of any compensatory effects from the intervention after school. Incorporating sit–stand desks to change the classroom environment at primary school appears to be an acceptable strategy for reducing children’s sedentary behaviour and increasing light activity especially during class time. Trial registration: ISRCTN12915848 (registered: 09/11/16)

Ethnic differences in the relationship between step cadence and physical function in older adults.

This study investigated associations between step cadence and physical function in healthy South Asian (SA) and White European (WE) older adults, aged ≥60. Participants completed the 60-s Sit-to-Stand (STS-60) test of physical function. Free-living stepping was measured using the activPAL3™. Seventy-one WEs (age = 72 ± 5, 53% male) and 33 SAs (age = 71 ± 5, 55% male) were included. WEs scored higher than SAs in the STS-60 (23 vs 20 repetitions, p = 0.045). Compared to WEs, SAs had significantly lower total and brisk (≥100 steps/min) steps (total: 8971 vs 7780 steps/day, p = 0.041; brisk: 5515 vs 3723 steps/day, p = 0.001). In WEs, 1000 brisk steps and each decile higher proportion of steps spent brisk stepping were associated with STS-60 (β = 0.72 95% CI 0.05, 1.38 and β = 1.01 95% CI 0.19, 1.82, respectively), with associations persisting across mean peak 1 min (β = 1.42 95% CI 0.12, 2.71), 30 min (β = 1.71 95% CI 0.22, 3.20), and 60 min (β = 2.16 95% CI 0.62, 3.71) stepping periods. Associations were not observed in SAs. Ethnic differences in associations between ambulation and physical function may exist in older adults which warrant further investigation.</p

Four-Year Increase in Step Cadence Is Associated with Improved Cardiometabolic Health in People with a History of Prediabetes

Purpose  To investigate associations between 4-year change in step cadence and markers of cardiometabolic health in people with a history of prediabetes and to explore whether these associations are modified by demographic factors. Methods  In this prospective cohort study, adults, with a history of prediabetes, were assessed for markers of cardiometabolic health (body mass index (BMI), waist circumference, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, and glycated haemoglobin (HbA1c) and free-living stepping activity (activPAL3™) at baseline, 1-year, and 4-years. Brisk steps/day were defined as the number of steps accumulated at ≥100 steps/minute and slow steps/day as those accumulated at Results  794 participants were included (age = 59.8 ± 8.9 years, 48.7% women, 27.1% ethnic minority, total steps/day = 8445 ± 3364, brisk steps/day = 4794 ± 2865, peak 10-minute step cadence = 128 ± 10 steps/minute. Beneficial associations were observed between change in brisk steps/day and change in BMI, waist circumference, HDL-C, and HbA1c. Similar associations were found between peak 10-minute step cadence and HDL-C and waist circumference. Interactions by ethnicity revealed change in brisk steps/day and change in peak 10-minute step cadence had a stronger association with HbA1c in White Europeans, whereas associations between change in 10-minute peak step cadence with measures of adiposity were stronger in South Asians. Conclusions  Change in the number of daily steps accumulated at a brisk pace was associated with beneficial change in adiposity, HDL-C, and HbA1c; however, potential benefits may be dependent on ethnicity for outcomes related to HbA1c and adiposity.</p

Improvements in glycaemic control after acute moderate-intensity continuous or high-intensity interval exercise are greater in South Asians than white Europeans with nondiabetic hyperglycaemia: a randomised crossover study

Objective: To examine whether circulating metabolic responses to low-volume high-intensity interval (LV-HIIE) or continuous moderate-intensity aerobic (CME) exercise differ between white Europeans and South Asians with nondiabetic hyperglycaemia (NDH). Research Design and Methods: 13 white Europeans and 10 South Asians (combined median (IQR) age 67 (60–68) years, HbA1c 5.9 (5.8–6.1)% [41.0 (39.9–43.2) mmol·mol-1]) completed three 6-hour conditions (sedentary control [CON], LV-HIIE, CME) in a randomised order. Exercise conditions contained a single bout of LV-HIIE and CME respectively (each ending at 2h), with meals provided at 0 and 3h. Circulating glucose (primary outcome), insulin, insulin resistance index (IRI), triglyceride and non-esterified fatty acids were measured at 0, 0.5, 1, 2, 3, 3.5, 4, 5 and 6h. Data were analysed as post-exercise time-averaged area under the curve (AUC), adjusted for age, sex and pre-exercise AUC. Results: Glucose was similar in each condition and ethnicity, with no condition-by-ethnicity interaction (P≥0.28). However, insulin was lower in LV-HIIE (mean [95% CI]: -44.4 [-23.7, -65.1] mU·L-1) and CME (-33.8 [-13.7, -53.9] mU·L-1) compared to CON. Insulin responses were greater in South Asians (interaction P=0.03) such that values were similar in each ethnicity during exercise conditions, despite being 33% higher in South Asians during CON. IRI followed a similar pattern to insulin. Lipids were unaffected by exercise. Conclusions: Reductions in insulin and insulin resistance after acute LV-HIIE and CME are greater in South Asians than white Europeans with NDH. Further trials are required to examine longer-term impact of LV-HIIE and CME on cardiometabolic health

Effects of empagliflozin, diet, or both on physical activity and sedentary behaviour in people with type 2 diabetes: analyses from the SEESAW trial [Abstract]

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