Background and aimThere is a widely held and influential view that physical activity begins to decline at adolescence. This study aimed to identify the timing of changes in physical activity during childhood and adolescence.MethodsLongitudinal cohort study (Gateshead Millennium Study) with 8 years of follow-up, from North-East England. Cohort members comprise a socioeconomically representative sample studied at ages 7, 9, 12 and 15 years; 545 individuals provided physical activity data at two or more time points. Habitual total volume of physical activity and moderate-to-vigorous intensity physical activity (MVPA) were quantified objectively using the Actigraph accelerometer over 5–7 days at the four time points. Linear mixed models identified the timing of changes in physical activity across the 8-year period, and trajectory analysis was used to identify subgroups with distinct patterns of age-related changes.ResultsFour trajectories of change in total volume of physical activity were identified representing 100% of all participants: all trajectories declined from age 7 years. There was no evidence that physical activity decline began at adolescence, or that adolescent declines in physical activity were substantially greater than the declines during childhood, or greater in girls than boys. One group (19% of boys) had relatively high MVPA which remained stable between ages 7 and15 years.ConclusionsFuture policy and research efforts to promote physical activity should begin well before adolescence, and should include both boys and girls.

Moderate-to-vigorous-intensity physical activity (MVPA) is important for childhood obesity prevention and treatment, yet declines with age. Timing and magnitude of the decline in MVPA in children and adolescents are unclear but important for informing effective obesity intervention development. This systematic review aimed to determine and compare the year-to-year changes in MVPA among children and adolescents. Longitudinal studies were identified by searching 10 relevant databases up to December 2018. Studies were eligible for inclusion if they reported accelerometer-assessed MVPA (min day −1 ) separately for boys and girls and had follow-up duration of at least 1 year. After screening 9,232 studies, 52 were included representing 22,091 aged 3 to 18 year olds (boys=8,857;girls=13,234). Pooled-analysis of the relative change in MVPA per year showed a decline of −3.4% (95% CI, −5.9 to −0.9) in boys and −5.3% (95% CI, −7.6 to −3.1) in girls, across all age groups. There were notable declines in MVPA at age 9 for both boys (−7.8%, 95% CI, −11.2 to −4.4) and girls (−10.2%, 95% CI, −14.2 to −6.3). The relative decline in MVPA affects both sexes from an early age; however, it is greater among girls. Interventions to promote MVPA should start before adolescence.

Objectives: To measure health-related quality of life (HRQoL) in a clinical sample of obese children by child self-report and parent-proxy report; to compare quality of life assessments provided by obese children and their parents; to assess differences in quality of life between the obese clinical sample and healthy control children. Design: Pairwise comparison of obese children matched for age, gender and socio-economic status with non-obese controls. Subjects: One hundred and twenty-six obese children (body mass index (BMI) X98th centile) and 71 lean control children (BMI o85th centile). Controls were matched with 71 children from the obese clinical group (mean age 8.6, standard deviation (s.d.) 1.9 years; 33 M/38 F). Measurement: The Paediatric Quality of Life Inventory (UK) version 4 was self-administered to parents and to children aged 8-12 years and interview was administered to children aged 5-7 years. This questionnaire assessed physical, social, emotional and school functioning from which total, physical and psychosocial health summary scores were derived. Results: In the obese clinical group (n ¼ 126), parent proxy-reported quality of life was low for all domains. In the obese clinical group, parent-reported scores were significantly lower than child self-reported scores in all domains except physical health and school functioning. Parent-proxy reports were significantly higher for healthy controls than obese children in all domains (median total score 85.2 vs 64.7; 95% confidence interval (CI) 15.6, 24.1). For child self-reports, only physical health was significantly higher for healthy controls than obese children (median score 81.3 vs 75.0; 95% CI 3.1, 12.5). Conclusions: HRQoL is impaired in clinical samples of obese children compared to lean children, but the degree of impairment is likely to be greatest when assessed using the parent perspective rather than the child perspective.

BACKGROUND:Electronic cigarette (e-cigarette) use is common among youth, and there are concerns that e-cigarette use leads to future conventional cigarette use. We examined longitudinal associations between past-month cigarette and e-cigarette use to characterize the stability and directionality of these tobacco use trajectories over time.

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WHAT'S KNOWN ON THIS SUBJECT: Earlier adiposity rebound may increase fatness in later life; however, there is limited evidence from large cohorts of contemporary children with direct measures of fatness in adolescence or adulthood. WHAT THIS STUDY ADDS:Early adiposity rebound is strongly associated with increased BMI and fatness in adolescence. Future preventive interventions should consider targeting early childhood to delay timing of adiposity rebound. abstract OBJECTIVES: To investigate associations between timing of adiposity rebound (AR; the period in childhood where BMI begins to increase from its nadir) and adiposity (BMI, fat mass) at age 15 years in the Avon Longitudinal Study of Parents and Children (ALSPAC). METHODS:The sample consisted of 546 children with AR derived in childhood and BMI and fat mass index (FMI; fat mass measured by dual-energy radiograph absorptiometry/height in m 2 ) measured at 15 years. Multivariable linear regression models were based on standardized residuals of log BMI and log FMI to allow comparison of regression coefficients across outcomes.RESULTS: There were strong dose-response associations between timing of AR and both adiposity outcomes at 15 years independent of confounders. BMI was markedly higher in adolescence for those with very early AR (by 3.5 years; b = 0.70; 95% confidence interval [CI]: 0.33-1.07; P # .001) and was also higher for those with early AR (between 3.5 and 5 years; b = 0.34; 95% CI: 0.08-0.59; P = .009) compared with those with later AR (.5 years) after full adjustment for a range of potential confounders. Similar magnitudes of association were found for FMI after full adjustment for confounders (compared with later AR: very early AR b = 0.74; 95% CI: 0.34-1.15; P # .001; early AR b = 0.35; 95% CI: 0.07-0.63; P = .02).CONCLUSIONS: Early AR is strongly associated with increased BMI and FMI in adolescence. Preventive interventions should consider targeting modifiable factors in early childhood to delay timing of AR. Pediatrics

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PurposeTo systematically review lifestyle interventions for women with prior Gestational Diabetes Mellitus (GDM) to report study characteristics, intervention design and study quality and explore changes in 1) diet, physical activity and sedentary behaviour; 2) anthropometric outcomes and; 3) glycaemic control and diabetes risk.MethodsDatabases (Web of Science, CCRCT, EMBASE and Science DIRECT) were searched (1980 to April 2014) using keywords for controlled or pre–post design trials of lifestyle intervention targeting women with previous GDM reporting at least one behavioural, anthropometric or diabetes outcome. Selected studies were narratively synthesized with anthropometric and glycaemic outcomes synthesized using meta-analysis.ResultsThree of 13 included studies were rated as low bias risk. Recruitment rates were poor but study retention good. Six of 11 studies reporting on physical activity reported favourable intervention effects. All six studies reporting on diet reported favourable intervention effects. In meta-analysis, significant weight-loss was attributable to one Chinese population study (WMD = − 1.06 kg (95% CI = − 1.68, − 0.44)). Lifestyle interventions did not change fasting blood glucose (WMD = − 0.05 mmol/L, 95% CI = − 0.21, 0.11) or type 2 diabetes risk.ConclusionsLack of methodologically robust trials gives limited evidence for the success of lifestyle interventions in women with prior GDM. Recruitment into trials is challenging.