Revising on the run or studying on the sofa: prospective associations between physical activity, sedentary behaviour, and exam results in British adolescents.

Background: We investigated prospective associations between physical activity/sedentary behaviour (PA/SED) and General Certificate of Secondary Education (GCSE) results in British adolescents.

Methods: Exposures were objective PA/SED and self-reported sedentary behaviours (screen (TV, Internet, Computer Games)/non-screen (homework, reading)) measured in 845 adolescents (14·5y ± 0·5y; 43·6 % male). GCSE results at 16y were obtained from national records.

Prospective associations between sedentary time, sleep duration and adiposity in adolescents.

Objective: The objective of this study was to investigate whether objectively measured sedentary time and sleep duration are associated with changes in adiposity from mid- to late adolescence.

Methods: Students (n = 504, 42% boys) were recruited from schools in Cambridgeshire, UK. At baseline (mean age 15.

Perceived family functioning and friendship quality: cross-sectional associations with physical activity and sedentary behaviours.

Background: This study examined the association of adolescent-reported family functioning and friendship quality with objectively-measured moderate to vigorous physical activity (MVPA), sedentary time, and self-reported sedentary behaviours.

Methods: Data are from the ROOTS study. MVPA and sedentary time were assessed using combined movement and heart rate sensing.

Breakfast consumption and physical activity in adolescents: daily associations and hourly patterns.

Background: The association between breakfast consumption and physical activity (PA) is inconclusive.

Objective: We aimed to investigate daily associations and hourly patterns of PA and breakfast consumption in British adolescents.

Design: Daily PA [accelerometry-derived moderate and vigorous physical activity (MVPA)] and breakfast consumption (diet diary) were measured simultaneously over 4 d in 860 adolescents (boys: 43.

Is wearing a pedometer associated with higher physical activity among adolescents?

Objective: To examine whether wearing a pedometer was associated with higher objectively-measured physical activity (PA) among adolescents independent of other behavior change strategies, and whether this association differed by sex or day of wear.

Method: In a parallel-group population-based cohort study, 892 adolescents (43.4% male, mean±SD age, 14.

The quality of midday meals eaten at school by adolescents; school lunches compared with packed lunches and their contribution to total energy and nutrient intakes.

Objective: To compare food and nutrient intakes from midday meals provided by schools with those from packed lunches and to estimate the contribution from food eaten at midday to the total daily energy and nutrient intakes of teenagers.

Design: Dietary data were recorded in 4 d estimated diaries of which 2 d were school days. The school day data were analysed for total and midday energy and nutrient intakes.

Physical activity awareness of British adolescents.

Objectives: To assess adolescent physical activity (PA) awareness and to investigate associations with biologic and psychosocial factors.

Design: Cross-sectional study from November 1, 2005, through July 31, 2007 (the ROOTS study).

Setting: Population-based sample recruited from Cambridgeshire and Suffolk schools (United Kingdom).

Physical Activity Awareness of British Adolescents.

Objective: To assess adolescent PA awareness and investigate associations with biological and psychosocial factors.

Design: Cross-sectional from November 2005 to July 2007 (ROOTS study).

Setting: Population-based sample recruited via Cambridgeshire and Suffolk schools (UK).

The subjective and cognitive effects of acute phenylalanine and tyrosine depletion in patients recovered from depression.

Although there is evidence for the involvement of dopamine (DA) in unipolar depression, no published study has yet used the technique of acute phenylalanine and tyrosine depletion (APTD), a dietary intervention that selectively lowers DA synthesis, in order to investigate the role of DA in mood disturbance. Tyrosine and phenylalanine depleted and placebo amino acid drinks were administered to 20 patients recovered from depression in a double-blind, placebo-controlled, crossover design. Measures included subjective effects, Hamilton Depression Rating Scale scores, and a comprehensive battery of well-validated computerized cognitive tests.

Development of a short leyton obsessional inventory for children and adolescents.

Objective: To develop a short, cost-effective screening measure for adolescent obsessive-compulsive disorder (OCD).

Method: The 20-item Leyton Obsessional Inventory-Child Version and the Mood and Feelings Questionnaire were completed by five groups of adolescents: those with a predominant diagnosis of OCD (n = 9), major depressive disorder with comorbid OCD ( n = 14), major depressive disorder without comorbid OCD ( n = 65), a community sample including subjects at high risk for psychopathology ( n = 253), and well controls ( n= 50). Leyton Obsessional Inventory scores for the community sample ( n= 253) were factor analyzed, whereas the remaining groups' scores served as validation.