Although an increasing number of children and adolescents are becoming obese, the psychological morbidities associated with obesity are not well established. Existing reviews report modest associations between obesity and global self-esteem. However, none have examined how this affects multi-component assessments of self-esteem and quality of life in young people with defined obesity. A literature search identified 17 self-esteem and 25 quality of life studies of cross-sectional, longitudinal or intervention design published since 1994. Child-completed and parent-proxy assessments were consistent in showing significant reductions in global self-esteem and quality of life in obese youth. Competences particularly affected were physical competence, appearance and social functioning. There were no clear differences in effects between children and adolescents, and evidence on gender and ethnicity was lacking. Competency improvements occurred in the presence and absence of weight loss, suggesting their value as intervention outcomes and the need for further investigation.

Epidemiological studies of bone mineral determinants rely heavily on measurements made with absorptiometric techniques such as single-photon absorptiometry and dual-energy x-ray absorptiometry. In general, absorptiometric data are expressed as areal densities (bone mineral density, BMD), obtained by dividing bone mineral content (BMC) by bone area or width (BA, BW). This size correction assumes that BMC and BA (BW) are directly proportional to one another, such that a 1% change in BA (BW) is matched by a 1% change in BMC. This is rarely the case, and the exact relationship depends on the population group, skeletal site, body size, instrumentation, and scanning conditions. Size adjustment determined by using predefined indexes, such as BMD and body mass index (BMI, wt/ht2), may fail to correct BMC fully for bone and body size, and may lead to spurious associations with other size-related variables such as calcium intake, energy expenditure, and grip strength. A general approach to size adjustment is described, in which BA (BW), weight, and height are incorporated in all regression models of BMC. Although BMD plays a valuable role in fracture-risk assessment and clinical management, we advocate that its use in epidemiological research be discontinued.

Objectives To determine the influence of birth weight on body mass index at different stages of later life; whether this relation persists after accounting for potential confounding factors; and the role of indicators of fetal growth (birth weight relative to parental size) and childhood growth. Design Longitudinal study of the 1958 British birth cohort. Setting England, Scotland, and Wales.

Objectives To understand how device-measured sedentary behaviour and physical activity are related to all-cause mortality in older men, an age group with high levels of inactivity and sedentary behaviour. Methods Prospective population-based cohort study of men recruited from 24 UK General Practices in 1978 -1980 . In 2010 surviving men were invited to a follow-up, 1655 (aged 71-92 years) agreed. Nurses measured height and weight, men completed health and demographic questionnaires and wore an ActiGraph GT3x accelerometer. All-cause mortality was collected through National Health Service central registers up to 1 June 2016. results After median 5.0 years' follow-up, 194 deaths occurred in 1181 men without pre-existing cardiovascular disease. For each additional 30 min in sedentary behaviour, or light physical activity (LIPA), or 10 min in moderate to vigorous physical activity (MVPA), HRs for mortality were 1.17 (95% CI 1.10 to 1.25), 0.83 (95% CI 0.77 to 0.90) and 0.90 (95% CI 0.84 to 0.96), respectively. Adjustments for confounders did not meaningfully change estimates. Only LIPA remained significant on mutual adjustment for all intensities. The HR for accumulating 150 min MVPA/week in sporadic minutes (achieved by 66% of men) was 0.59 (95% CI 0.43 to 0.81) and 0.58 (95% CI 0.33 to 1.00) for accumulating 150 min MVPA/week in bouts lasting ≥10 min (achieved by 16% of men). Sedentary breaks were not associated with mortality. Conclusions In older men, all activities (of light intensity upwards) were beneficial and accumulation of activity in bouts ≥10 min did not appear important beyond total volume of activity. Findings can inform physical activity guidelines for older adults.Nearly all epidemiological evidence used to estimate the shape of the dose-response curve between physical activity (PA) and mortality is based on self-reported PA.1 Moderately active compared with inactive adults have 20%-30% reductions in all-cause mortality, with greater reductions in older (>65 years) than middle-aged adults.2 PA is a key determinant of longevity globally.3 Current activity guidelines suggest accumulating ≥150 min moderate to vigorous PA (MVPA) per week in bouts lasting ≥10 min.4 5 The 10 min bout requirement was based on trial data for cardiometabolic risk factors only, not clinical end points. 5 In order to test whether the accumulation of MVPA in ≥10 min bouts affects risk of mortality, prospective cohort studies with device-measured physical activity (which can provide minute by minute data for calculation of bouts) and mortality data are required, but few studies have such data. Such data can also inform whether accruing sedentary time in prolonged bouts is associated with adverse effects on mortality, as this has been identified as an important research gap. Many studies report that higher levels of self-reported sedentary time are associated with mortality, [6][7][8][9] although self-reported sedentary behaviours may suffer from measurement error or recall bias.10-14 Experimental studies suggest benefits...

BackgroundOlder adults have low physical activity(PA) and high sedentary behaviour(SB) levels. We investigate how total volume and specific patterns of moderate to vigorous PA(MVPA), light PA(LPA) and SB are related to adiposity and metabolic syndrome (MS). Then, with reference to physical activity guidelines which encourage MVPA in bouts > =10 min and avoiding “long” sedentary bouts, we investigate whether accumulating PA and SB in bouts of different defined durations are differently associated with these outcomes.MethodsCross-sectional study of men (71–91 years) recruited in UK primary care centres. Nurses made physical measures (weight, height, bio-impedance, blood pressure) and took fasting blood samples. 1528/3137 (49 %) surviving men had ≥3 valid days (≥600 min) accelerometer data. 450 men with pre-existing chronic disease were excluded. 1009/1078 (93.6 %) had complete covariate data.ResultsMen (n = 1009, mean age 78.5(SD 4.7) years) spent 612(SD 83), 202(SD 64) and 42(SD 33) minutes in SB, LIPA and MVPA respectively. Each additional 30 min/day of SB and MVPA were associated with 0.32 (95 % CI 0.23, 0.40)Kg/m2 higher Body Mass Index (BMI) and −0.72(−0.93, −0.51) lower BMI Kg/m2 respectively. Patterns for waist circumference (WC), fat mass index (FMI), fasting insulin and MS were similar. MVPA in bouts lasting <10 min or ≥10 min duration were not associated differently with outcomes. In models adjusted for total MVPA, each minute accumulated in SB bouts lasting 1–15 min was associated with lower BMI −0.012 kg/m2, WC −0.029 cm, and OR 0.989 for MS (all p < 0.05), and coefficients for LPA bouts 1–9 min were very similar in separate models adjusted for total MVPA. Minutes accumulated in SB bouts 1–15 min and LPA bouts 1–9 min were correlated, r = 0.62.ConclusionsObjectively measured MVPA, LPA and SB were all associated with lower adiposity and metabolic risk. The beneficial associations of LPA are encouraging for older adults for whom initiating MVPA and maintaining bouts lasting ≥10 min may be particularly challenging. Findings that short bouts of LPA (1–9 min) and SB (1–15 min), but that all MVPA, not just MVPA accumulated in bouts ≥10 min were associated with lower adiposity and better metabolic health could help refine older adult PA guidelines.