Greater male variability in daily energy expenditure develops through puberty.

There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decreasing GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages.

Energy expenditure and intensity of ritual jumping-dancing in male Maasai.

OBJECTIVES: Traditional jumping-dance rituals performed by Maasai men involve prolonged physical exertion that may contribute significantly to overall physical activity level. We aimed to objectively quantify the metabolic intensity of jumping-dance activity and assess associations with habitual physical activity and cardiorespiratory fitness (CRF). METHODS: Twenty Maasai men (18-37 years) from rural Tanzania volunteered to participate in the study. Habitual physical activity was monitored using combined heart rate (HR) and movement sensing over 3 days, and jumping-dance engagement was self-reported. A 1-h jumping-dance session resembling a traditional ritual was organized, during which participants' vertical acceleration and HR were monitored. An incremental, submaximal 8-min step test was performed to calibrate HR to physical activity energy expenditure (PAEE) and assess CRF. RESULTS: Mean (range) habitual PAEE was 60 (37-116) kJ day-1 kg-1 , and CRF was 43 (32-54) mL O2 min-1 kg-1 . The jumping-dance activity was performed at an absolute HR of 122 (83-169) beats·min-1 , and PAEE of 283 (84-484) J min-1 kg-1 or 42 (18-75)% when expressed relative to CRF. The total PAEE for the session was 17 (range 5-29) kJ kg-1 , ~28% of the daily total. Self-reported engagement in habitual jumping-dance frequency was 3.8 (1-7) sessions/week, with a total duration of 2.1 (0.5-6.0) h/session. CONCLUSIONS: Intensity during traditional jumping-dance activity was moderate, but on average sevenfold higher than habitual physical activity. These rituals are common, and can make a substantial contribution to overall physical activity in Maasai men, and thus be promoted as a culture-specific activity to increase energy expenditure and maintain good health in this population.

Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure.

Obesity is caused by a prolonged positive energy balance1,2. Whether reduced energy expenditure stemming from reduced activity levels contributes is debated3,4. Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor.

Quantifying the Relationship Between Physical Activity Energy Expenditure and Incident Type 2 Diabetes: A Prospective Cohort Study of Device-Measured Activity in 90,096 Adults.

OBJECTIVE: To investigate the association between accelerometer-derived physical activity energy expenditure (PAEE) and incident type 2 diabetes (T2D) in a cohort of middle-aged adults and within subgroups. RESEARCH DESIGN AND METHODS: Data were from 90,096 UK Biobank participants without prevalent diabetes (mean 62 years of age; 57% women) who wore a wrist accelerometer for 7 days. PAEE was derived from wrist acceleration using a population-specific method validated against doubly labeled water. Logistic regressions were used to assess associations between PAEE, its underlying intensity, and incident T2D, ascertained using hospital episode and mortality data up to November 2020. Models were progressively adjusted for demographic, lifestyle factors, and BMI. RESULTS: The association between PAEE and T2D was approximately linear (n = 2,018 events). We observed 19% (95% CI 17-21) lower odds of T2D per 5 kJ · kg-1 · day-1 in PAEE without adjustment for BMI and 11% (9-13) with BMI adjustment. The association was stronger in men than women and weaker in those with obesity and higher genetic susceptibility to obesity. There was no evidence of effect modification by genetic susceptibility to T2D or insulin resistance. For a given level of PAEE, odds of T2D were lower among those engaging in more moderate-to-vigorous activity. CONCLUSIONS: There was a strong linear relationship between PAEE and incident T2D. A difference in PAEE equivalent to an additional daily 20-min brisk walk was associated with 19% lower odds of T2D. The association was broadly similar across population subgroups, supporting physical activity for diabetes prevention in the whole population.

Cardiorespiratory fitness assessment using risk-stratified exercise testing and dose-response relationships with disease outcomes.

Cardiorespiratory fitness (CRF) is associated with mortality and cardiovascular disease, but assessing CRF in the population is challenging. Here we develop and validate a novel framework to estimate CRF (as maximal oxygen consumption, VO2max) from heart rate response to low-risk personalised exercise tests. We apply the method to examine associations between CRF and health outcomes in the UK Biobank study, one of the world's largest and most inclusive studies of CRF, showing that risk of all-cause mortality is 8% lower (95%CI 5-11%, 2670 deaths among 79,981 participants) and cardiovascular mortality is 9% lower (95%CI 4-14%, 854 deaths) per 1-metabolic equivalent difference in CRF. Associations obtained with the novel validated CRF estimation method are stronger than those obtained using previous methodology, suggesting previous methods may have underestimated the importance of fitness for human health.

Evaluation of a very brief pedometer-based physical activity intervention delivered in NHS Health Checks in England: The VBI randomised controlled trial.

BACKGROUND: The majority of people do not achieve recommended levels of physical activity. There is a need for effective, scalable interventions to promote activity. Self-monitoring by pedometer is a potentially suitable strategy. We assessed the effectiveness and cost-effectiveness of a very brief (5-minute) pedometer-based intervention ('Step It Up') delivered as part of National Health Service (NHS) Health Checks in primary care. METHODS AND FINDINGS: The Very Brief Intervention (VBI) Trial was a two parallel-group, randomised controlled trial (RCT) with 3-month follow-up, conducted in 23 primary care practices in the East of England. Participants were 1,007 healthy adults aged 40 to 74 years eligible for an NHS Health Check. They were randomly allocated (1:1) using a web-based tool between October 1, 2014, and December 31, 2015, to either intervention (505) or control group (502), stratified by primary care practice. Participants were aware of study group allocation. Control participants received the NHS Health Check only. Intervention participants additionally received Step It Up: a 5-minute face-to-face discussion, written materials, pedometer, and step chart. The primary outcome was accelerometer-based physical activity volume at 3-month follow-up adjusted for sex, 5-year age group, and general practice. Secondary outcomes included time spent in different intensities of physical activity, self-reported physical activity, and economic measures. We conducted an in-depth fidelity assessment on a subsample of Health Check consultations. Participants' mean age was 56 years, two-thirds were female, they were predominantly white, and two-thirds were in paid employment. The primary outcome was available in 859 (85.3%) participants. There was no significant between-group difference in activity volume at 3 months (adjusted intervention effect 8.8 counts per minute [cpm]; 95% CI -18.7 to 36.3; p = 0.53). We found no significant between-group differences in the secondary outcomes of step counts per day, time spent in moderate or vigorous activity, time spent in vigorous activity, and time spent in moderate-intensity activity (accelerometer-derived variables); as well as in total physical activity, home-based activity, work-based activity, leisure-based activity, commuting physical activity, and screen or TV time (self-reported physical activity variables). Of the 505 intervention participants, 491 (97%) received the Step it Up intervention. Analysis of 37 intervention consultations showed that 60% of Step it Up components were delivered faithfully. The intervention cost £18.04 per participant. Incremental cost to the NHS per 1,000-step increase per day was £96 and to society was £239. Adverse events were reported by 5 intervention participants (of which 2 were serious) and 5 control participants (of which 2 were serious). The study's limitations include a participation rate of 16% and low return of audiotapes by practices for fidelity assessment. CONCLUSIONS: In this large well-conducted trial, we found no evidence of effect of a plausible very brief pedometer intervention embedded in NHS Health Checks on objectively measured activity at 3-month follow-up. TRIAL REGISTRATION: Current Controlled Trials (ISRCTN72691150).

Descriptive epidemiology of energy expenditure in the UK: findings from the National Diet and Nutrition Survey 2008-15.

BACKGROUND: Little is known about population levels of energy expenditure, as national surveillance systems typically employ only crude measures. The National Diet and Nutrition Survey (NDNS) in the UK measured energy expenditure in a 10% subsample by gold-standard doubly labelled water (DLW). METHODS: DLW-subsample participants from the NDNS (383 males, 387 females) aged 4-91 years were recruited between 2008 and 2015 (rolling programme). Height and weight were measured and body-fat percentage estimated by deuterium dilution. RESULTS: Absolute total energy expenditure (TEE) increased steadily throughout childhood, ranging from 6.2 and 7.2 MJ/day in 4- to 7-year-olds to 9.7 and 11.7 MJ/day for 14- to 16-year-old girls and boys, respectively. TEE peaked in 17- to 27-year-old women (10.7 MJ/day) and 28- to 43-year-old men (14.4 MJ/day), before decreasing gradually in old age. Physical-activity energy expenditure (PAEE) declined steadily with age from childhood (87 kJ/day/kg in 4- to 7-year-olds) through to old age (38 kJ/day/kg in 71- to 91-year-olds). No differences were observed by time, region and macronutrient composition. Body-fat percentage was strongly inversely associated with PAEE throughout life, irrespective of expressing PAEE relative to body mass or fat-free mass. Compared with females with <30% body fat, females with >40% recorded 29 kJ/day/kg body mass and 18 kJ/day/kg fat-free mass less PAEE in analyses adjusted for age, geographical region and time of assessment. Similarly, compared with males with <25% body fat, males with >35% recorded 26 kJ/day/kg body mass and 10 kJ/day/kg fat-free mass less PAEE. CONCLUSIONS: This first nationally representative study reports levels of human-energy expenditure as measured by gold-standard methodology; values may serve as a reference for other population studies. Age, sex and body composition are the main determinants of energy expenditure. Key Messages This is the first nationally representative study of human energy expenditure, covering the UK in the period 2008-2015. Total energy expenditure (MJ/day) increases steadily with age throughout childhood and adolescence, peaks in the 3rd decade of life in women and 4th decade of life in men, before decreasing gradually in old age. Physical activity energy expenditure (kJ/day/kg or kJ/day/kg fat-free mass) declines steadily with age from childhood to old age, more steeply so in males. Body-fat percentage is strongly inversely associated with physical activity energy expenditure. We found little evidence that energy expenditure varied by geographical region, over time, or by dietary macronutrient composition.

Prenatal and birth predictors of objectively measured physical activity and sedentary time in three population-based birth cohorts in Brazil.

Physical inactivity is a global pandemic with no signs of improvement. Prolonged sitting time is an emerging risk factor that exacerbates the health consequences of physical inactivity. Both behaviours are influenced by various individual and environmental factors but it remains unknown whether early-life exposures "program" these behaviours in later life. The current evidence is limited by a small number of studies which were primarily conducted in high-income countries, and a narrow range of early-life variables examined. Using data from three population-based Brazilian birth cohorts (analytical samples: n = 2740 for 1982 cohort, aged 30 years; n = 3592 for 1993 cohort, aged 18; n = 2603 for 2004 cohort, aged 6), we show that being female and higher family socioeconomic status at birth are strong and consistent predictors of lower physical activity and higher sedentary time from childhood to adulthood. Meanwhile, higher birth weight and lower birth order may also predict lower physical activity and higher sedentary time. Our findings are distinct from evidence from high-income countries, suggesting the importance of broader socioeconomic context in determining individual's activity patterns through the life- course. Such evidence is essential for understanding the biological etiology and socioeconomic context of physical activity and sedentary behaviour at an early stage in life.

Descriptive epidemiology of physical activity energy expenditure in UK adults (The Fenland study).

BACKGROUND: Physical activity (PA) plays a role in the prevention of a range of diseases including obesity and cardiometabolic disorders. Large population-based descriptive studies of PA, incorporating precise measurement, are needed to understand the relative burden of insufficient PA levels and to inform the tailoring of interventions. Combined heart and movement sensing enables the study of physical activity energy expenditure (PAEE) and intensity distribution. We aimed to describe the sociodemographic correlates of PAEE and moderate-to-vigorous physical activity (MVPA) in UK adults. METHODS: The Fenland study is a population-based cohort study of 12,435 adults aged 29-64 years-old in Cambridgeshire, UK. Following individual calibration (treadmill), participants wore a combined heart rate and movement sensor continuously for 6 days in free-living, from which we derived PAEE (kJ•day- 1•kg- 1) and time in MVPA (> 3 & > 4 METs) in bouts greater than 1 min and 10 min. Socio-demographic information was self-reported. Stratum-specific summary statistics and multivariable analyses were performed. RESULTS: Women accumulated a mean (sd) 50(20) kJ•day- 1•kg- 1 of PAEE, and 83(67) and 33(39) minutes•day- 1 of 1-min bouted and 10-min bouted MVPA respectively. By contrast, men recorded 59(23) kJ•day- 1•kg- 1, 124(84) and 60(58) minutes•day- 1. Age and BMI were also important correlates of PA. Association with age was inverse in both sexes, more strongly so for PAEE than MVPA. Obese individuals accumulated less PA than their normal-weight counterparts, whether considering PAEE or allometrically-scaled PAEE (- 10 kJ•day- 1•kg- 1 or - 15 kJ•day- 1•kg-2/3 in men). Higher income and manual work were associated with higher PA; manual workers recorded 13-16 kJ•kg- 1•day- 1 more PAEE than sedentary counterparts. Overall, 86% of women and 96% of men accumulated a daily average of MVPA (> 3 METs) corresponding to 150 min per week. These values were 49 and 74% if only considering bouts > 10 min (15 and 31% for > 4 METs). CONCLUSIONS: PA varied by age, sex and BMI, and was higher in manual workers and those with higher incomes. Light physical activity was the main driver of PAEE; a component of PA that is currently not quantified as a target in UK guidelines.

Impact of sit-stand desks at work on energy expenditure, sitting time and cardio-metabolic risk factors: Multiphase feasibility study with randomised controlled component.

Uncertainties remain about the overall effect of sit-stand desks for reducing prolonged sitting among office-based workers. This study assessed the feasibility of a randomised controlled trial of the impact of workplace sit-stand desks on overall energy expenditure, sitting time and cardio-metabolic outcomes. It involved four phases: Phase I: online survey; Phase II: workspace auditing; Phase III: randomised intervention (provision of sit-stand desks at work for 3 months); Phase IV: qualitative component. Participants were office-based employees of two companies in Cambridge, England. Among Phase I participants interested in the trial, 100 were randomised to Phase II. Of those with workspaces suitable for sit-stand desks, 20 were randomised to Phase III. Those allocated to the intervention completed Phase IV. Outcomes included: trial participation interest, desk-type (full desks/desk mounts) and assessment location (work/laboratory/home) preferences (Phase I); proportion of workspaces permitting sit-stand desk installation (Phase II); energy expenditure, sitting time and cardio-metabolic outcomes (Phase III); study participation experiences (Phase IV). Data were collected between May 2015 and December 2016. Recruitment and trial implementation were feasible: 92% of survey respondents expressed participation interest; 80% of workspaces could accommodate sit-stand desks; assessments were done in workplaces, preferred by 71%. Sit-stand desk provision reduced workplace sitting time by 94 min/day (95% CI 17.7-170.7). Their impact on energy expenditure and cardio-metabolic outcomes is unclear. The results confirm the feasibility of a trial assessing sit-stand desks' impact on energy expenditure, sitting time and cardio-metabolic outcomes, which should reduce uncertainty concerning the intervention's potential to reduce the health risks of prolonged sitting. Trial registration ISRCTN44827407.

Estimating energy expenditure from wrist and thigh accelerometry in free-living adults: a doubly labelled water study.

BACKGROUND: Many large studies have implemented wrist or thigh accelerometry to capture physical activity, but the accuracy of these measurements to infer activity energy expenditure (AEE) and consequently total energy expenditure (TEE) has not been demonstrated. The purpose of this study was to assess the validity of acceleration intensity at wrist and thigh sites as estimates of AEE and TEE under free-living conditions using a gold-standard criterion. METHODS: Measurements for 193 UK adults (105 men, 88 women, aged 40-66 years, BMI 20.4-36.6 kg m-2) were collected with triaxial accelerometers worn on the dominant wrist, non-dominant wrist and thigh in free-living conditions for 9-14 days. In a subsample (50 men, 50 women) TEE was simultaneously assessed with doubly labelled water (DLW). AEE was estimated from non-dominant wrist using an established estimation model, and novel models were derived for dominant wrist and thigh in the non-DLW subsample. Agreement with both AEE and TEE from DLW was evaluated by mean bias, root mean squared error (RMSE), and Pearson correlation. RESULTS: Mean TEE and AEE derived from DLW were 11.6 (2.3) MJ day-1 and 49.8 (16.3) kJ day-1 kg-1. Dominant and non-dominant wrist acceleration were highly correlated in free-living (r = 0.93), but less so with thigh (r = 0.73 and 0.66, respectively). Estimates of AEE were 48.6 (11.8) kJ day-1 kg-1 from dominant wrist, 48.6 (12.3) from non-dominant wrist, and 46.0 (10.1) from thigh; these agreed strongly with AEE (RMSE ~12.2 kJ day-1 kg-1, r ~ 0.71) with small mean biases at the population level (~6%). Only the thigh estimate was statistically significantly different from the criterion. When combining these AEE estimates with estimated REE, agreement was stronger with the criterion (RMSE ~1.0 MJ day-1, r ~ 0.90). CONCLUSIONS: In UK adults, acceleration measured at either wrist or thigh can be used to estimate population levels of AEE and TEE in free-living conditions with high precision.

Physical activity energy expenditure and cardiometabolic health in three rural Kenyan populations.

OBJECTIVES: Physical activity is beneficial for metabolic health but the extent to which this may differ by ethnicity is still unclear. Here, the objective was to characterize the association between physical activity energy expenditure (PAEE) and cardiometabolic risk among the Luo, Kamba, and Maasai ethnic groups of rural Kenya. METHODS: In a cross-sectional study of 1084 rural Kenyans, free-living PAEE was objectively measured using individually-calibrated heart rate and movement sensing. A clustered metabolic syndrome risk score (zMS) was developed by averaging the sex-specific z-scores of five risk components measuring central adiposity, blood pressure, lipid levels, glucose tolerance, and insulin resistance. RESULTS: zMS was 0.08 (-0.09; -0.06) SD lower for every 10 kJ/kg/day difference in PAEE after adjustment for age and sex; this association was modified by ethnicity (interaction with PAEE P < 0.05). When adjusted for adiposity, each 10 kJ/kg/day difference in PAEE was predicted to lower zMS by 0.04 (-0.05, -0.03) SD, without evidence of interaction by ethnicity. The Maasai were predicted to have higher cardiometabolic risk than the Kamba and Luo at every quintile of PAEE, with a strong dose-dependent decreasing trend among all ethnicities. CONCLUSION: Free-living PAEE is strongly inversely associated with cardiometabolic risk in rural Kenyans. Differences between ethnic groups in this association were observed but were explained by differences in central adiposity. Therefore, targeted interventions to increase PAEE are more likely to be effective in subgroups with high central adiposity, such as Maasai with low levels of PAEE.

Health-related correlates of psychological well-being among girls and boys 6-8 years of age: The Physical Activity and Nutrition in Children study.

AIM: Due to limited knowledge on the differences in the correlates of psychological well-being (PSWB) between girls and boys, we compared the correlates of PSWB between primary school girls and boys. METHODS: A population sample of 412 children participated in the Physical Activity and Nutrition in Children study. Parents completed a questionnaire that included 19 questions on the components of PSWB, and a PSWB score was computed. We assessed correlates of PSWB, including physical activity, sedentary behaviour, cardiorespiratory fitness, diet quality, body fat content, sleep duration, sleep disordered breathing, prevalent diseases and parental characteristics. We used logistic regression to analyse the risk of being in the lowest third of the PSWB scores. RESULTS: Low parental education was associated with increased risk (odds ratio (OR) 2.34, P = 0.039) and high cardiorespiratory fitness with decreased risk (OR 0.26, P = 0.006) of poor PSWB in girls. At least 2 h of screen-based sedentary behaviour per day (OR 1.93, P = 0.037), daily parental smoking (OR 2.10, P = 0.034) and sleep disordered breathing (OR 4.24, P = 0.003) were related to increased risk of poor PSWB in boys. CONCLUSIONS: There are large differences in the correlates of PSWB between girls and boys. Most of these correlates are modifiable and related to the health behaviour of children and their parents.

Dietary cost associated with adherence to the Mediterranean diet, and its variation by socio-economic factors in the UK Fenland Study.

High cost of healthy foods could be a barrier to healthy eating. We aimed to examine the association between dietary cost and adherence to the Mediterranean diet in a non-Mediterranean country. We evaluated cross-sectional data from 12 417 adults in the UK Fenland Study. Responses to 130-item FFQ were used to calculate a Mediterranean diet score (MDS). Dietary cost was estimated by matching food consumption data with retail prices of five major supermarkets. Using multivariable-adjusted linear regression, we examined the association of MDS and individual foods with dietary cost in absolute and relative scales. Subsequently, we assessed how much the association was explained by education, income, marital status and occupation, by conducting mediation analysis and testing interaction by these variables. High compared with low MDS (top to bottom third) was associated with marginally higher cost by 5·4 % (95 % CI 4·4, 6·4) or £0·20/d (95 % CI 0·16, 0·25). Participants with high adherence had higher cost associated with the healthier components (e.g. vegetables, fruits and fish), and lower cost associated with the unhealthy components (e.g. red meat, processed meat and sweets) (P for trend<0·001 each). In total, 20·7 % (95 % CI 14·3, 27·0) of the MDS-cost association was explained by the selected socio-economic factors, and the MDS-cost association was of greater magnitude in lower socio-economic groups (P interaction<0·005). Overall, greater adherence to the Mediterranean diet was associated with marginally higher dietary cost, partly modified and explained by socio-economic status, but the potential economic barriers of high adherence might be offset by cost saving from reducing unhealthy food consumption.

Socioeconomic position and sedentary behavior in Brazilian adolescents: A life-course approach.

Socioeconomic position (SEP) is a potential correlate of sedentary behavior in adolescents. The aim of this study was to examine the associations between SEP and self-reported and objective measures of sedentary behavior in adolescents, using a life-course approach. Data from the 1993 Pelotas (Brazil) Birth Cohort Study were analyzed (N=5249). Cross-sectional and longitudinal associations between multiple SEP indicators (maternal education, family income, SEP composite, cumulative family income) at birth, 11, 15 and 18years, and five sedentary behavior outcomes (≥4h/day screen time; ≥4h/day TV; ≥2h/day computer; ≥2h/day video game; ≥12.7h/day objectively measured sedentary time) at 11, 15 and 18years, were examined. In cross-sectional analyses, higher SEP was positively associated with more screen time at ages 11 and 15years. There was a consistent and positive association between higher SEP with time spent using a computer, and with sedentary time assessed through accelerometry. SEP at birth had a positive and direct effect on screen, computer and total sedentary time at 18years. Participants in the highest cumulative income group had higher odds of high sedentary behavior in screen (OR: 2.40; 95% CI: 1.50-3.54), computer (OR: 7.35; 95% CI: 4.19-12.89) and total sedentary time (OR: 5.40; 95% CI: 3.53-10.35), respectively, compared with their counterparts with lower cumulative income. Our findings showed that SEP is an early determinant of sedentary behavior in adolescents.

Interplay of Socioeconomic Status and Supermarket Distance Is Associated with Excess Obesity Risk: A UK Cross-Sectional Study.

U.S. policy initiatives have sought to improve health through attracting neighborhood supermarket investment. Little evidence exists to suggest that these policies will be effective, in particular where there are socioeconomic barriers to healthy eating. We measured the independent associations and combined interplay of supermarket access and socioeconomic status with obesity. Using data on 9702 UK adults, we employed adjusted regression analyses to estimate measured BMI (kg/m²), overweight (25 ≥ BMI < 30) and obesity (≥30), across participants' highest educational attainment (three groups) and tertiles of street network distance (km) from home location to nearest supermarket. Jointly-classified models estimated combined associations of education and supermarket distance, and relative excess risk due to interaction (RERI). Participants farthest away from their nearest supermarket had higher odds of obesity (OR 1.33, 95% CI: 1.11, 1.58), relative to those living closest. Lower education was also associated with higher odds of obesity. Those least-educated and living farthest away had 3.39 (2.46-4.65) times the odds of being obese, compared to those highest-educated and living closest, with an excess obesity risk (RERI = 0.09); results were similar for overweight. Our results suggest that public health can be improved through planning better access to supermarkets, in combination with interventions to address socioeconomic barriers.

Sociodemographic, lifestyle and behavioural factors associated with consumption of sweetened beverages among adults in Cambridgeshire, UK: the Fenland Study.

OBJECTIVE: We aimed to identify sociodemographic, lifestyle and behavioural determinants of consumption of sugar-sweetened beverages (SSB) and artificially sweetened beverages (ASB) among adults in Cambridgeshire, UK. DESIGN: Cross-sectional data were obtained from a cohort of 9991 adults born between 1950 and 1975. An FFQ was used to assess consumption of beverages and other dietary factors. Multivariable logistic regression was used to examine potential determinants of consuming SSB and ASB (≥1 serving/d). SETTING: Recruitment from general practice surgeries to participate in the ongoing population-based Fenland Study. SUBJECTS: Adults (n 9991) aged 30-64 years from three areas of Cambridgeshire, UK. RESULTS: Prevalence estimates for daily SSB and ASB consumption were 20·4 % (n 2041) and 8·9 % (n 893), respectively. SSB consumption (OR; 95 % CI) was more common in men than women (1·33; CI 1·17, 1·50) and among those reporting lower income (£40 000/year; 1·31; 1·09, 1·58). In contrast, daily ASB consumption was more common among women than men (1·62; 1·34, 1·96), those on weight-loss diets than those who were not (2·58; 2·05, 3·24) and those reporting higher income than lower income (1·53; 1·16, 2·00). Factors associated with higher consumption of each of SSB and ASB included being a younger adult, being overweight/obese, having shorter education, eating meals or snack foods while watching television, and skipping breakfast (P<0·05 each). CONCLUSIONS: Frequent consumers of SSB and ASB differ by several sociodemographic characteristics. However, increased BMI, younger age and unhealthy eating behaviours are common to both groups.

Large Scale Population Assessment of Physical Activity Using Wrist Worn Accelerometers: The UK Biobank Study.

BACKGROUND: Physical activity has not been objectively measured in prospective cohorts with sufficiently large numbers to reliably detect associations with multiple health outcomes. Technological advances now make this possible. We describe the methods used to collect and analyse accelerometer measured physical activity in over 100,000 participants of the UK Biobank study, and report variation by age, sex, day, time of day, and season. METHODS: Participants were approached by email to wear a wrist-worn accelerometer for seven days that was posted to them. Physical activity information was extracted from 100Hz raw triaxial acceleration data after calibration, removal of gravity and sensor noise, and identification of wear / non-wear episodes. We report age- and sex-specific wear-time compliance and accelerometer measured physical activity, overall and by hour-of-day, week-weekend day and season. RESULTS: 103,712 datasets were received (44.8% response), with a median wear-time of 6.9 days (IQR:6.5-7.0). 96,600 participants (93.3%) provided valid data for physical activity analyses. Vector magnitude, a proxy for overall physical activity, was 7.5% (2.35mg) lower per decade of age (Cohen's d = 0.9). Women had a higher vector magnitude than men, apart from those aged 45-54yrs. There were major differences in vector magnitude by time of day (d = 0.66). Vector magnitude differences between week and weekend days (d = 0.12 for men, d = 0.09 for women) and between seasons (d = 0.27 for men, d = 0.15 for women) were small. CONCLUSIONS: It is feasible to collect and analyse objective physical activity data in large studies. The summary measure of overall physical activity is lower in older participants and age-related differences in activity are most prominent in the afternoon and evening. This work lays the foundation for studies of physical activity and its health consequences. Our summary variables are part of the UK Biobank dataset and can be used by researchers as exposures, confounding factors or outcome variables in future analyses.

Impact of sit-stand desks at work on energy expenditure and sedentary time: protocol for a feasibility study.

BACKGROUND: Prolonged sitting, an independent risk factor for disease development and premature mortality, is increasing in prevalence in high- and middle-income countries, with no signs of abating. Adults in such countries spend the largest proportion of their day in sedentary behaviour, most of which is accumulated at work. One promising method for reducing workplace sitting is the use of sit-stand desks. However, key uncertainties remain about this intervention, related to the quality of existing studies and a lack of focus on key outcomes, including energy expenditure. We are planning a randomised controlled trial to assess the impact of sit-stand desks at work on energy expenditure and sitting time in the short and longer term. To reduce the uncertainties related to the design of this trial, we propose a preliminary study to assess the feasibility and acceptability of the recruitment, allocation, measurement, retention and intervention procedures. METHODS: Five hundred office-based employees from two companies in Cambridge, UK, will complete a survey to assess their interest in participating in a trial on the use of sit-stand desks at work. The workspaces of 100 of those interested in participating will be assessed for sit-stand desk installation suitability, and 20 participants will be randomised to either the use of sit-stand desks at work for 3 months or a waiting list control group. Energy expenditure and sitting time, measured via Actiheart and activPAL monitors, respectively, as well as cardio-metabolic and anthropometric outcomes and other outcomes relating to health and work performance, will be assessed in 10 randomly selected participants. All participants will also be interviewed about their experience of using the desks and participating in the study. DISCUSSION: The findings are expected to inform the design of a trial assessing the impact of sit-stand desks at work on short and longer term workplace sitting, taking into account their impact on energy expenditure and the extent to which their use has compensation effects outside the workplace. The findings from such a trial are expected to inform discussions regarding the potential of sit-stand desks at work to alleviate the harm to cardio-metabolic health arising from prolonged sitting. TRIAL REGISTRATION: ISRCTN44827407.