Breakfast consumption and physical activity in British adolescents.

Studies show an inverse relationship between breakfast frequency and weight gain. This may reflect poor eating habits generally and associated low physical activity (PA) or direct impacts of breakfast on mechanisms leading to lethargy and reduced PA. The relationship between breakfast frequency and PA is inconclusive. We aimed to determine whether breakfast frequency is associated with PA levels in British adolescents independent of body composition and socio-economic status (SES). Habitual breakfast frequency (self-report questionnaire) was assessed in 877 adolescents (43% male, age 14·5 (SD 0·5) years old). PA was measured over 5 d (accelerometry, average counts/ min; cpm). Associations between daily PA and breakfast frequency were assessed using linear regression adjusted for body fat percentage and SES. Effect modification by sex and associations with PA during the morning (06.00-12.00 hours) were explored. For boys, there were no significant associations between breakfast frequency and PA. For girls, less frequent breakfast consumption was significantly associated with lower PA (cpm) during the morning (occasional v. frequent b - 6·1 (95% CI - 11·1, -1·1), P = 0·017) when adjusted for body fat percentage and SES. There were no associations between PA and breakfast consumption over the whole day; however, for girls, less frequent breakfast consumption may be associated with lower PA levels during the morning, suggesting that breakfast consumption should perhaps be taken into consideration when aiming to promote PA in adolescent girls.

Altered respiratory function is associated with increased metabolic risk, independently of adiposity, fitness and physical activity.

AIMS: Reduced lung function is associated with an adverse metabolic risk profile, even after adjusting for body fatness. However, previous observations may have been confounded by aerobic fitness and physical activity. This study aimed to examine the association between lung function and both metabolic risk and insulin resistance in a cohort of White British adults with a family history of Type 2 diabetes, and to explore the extent to which these associations are independent of body fatness, aerobic fitness (VO(2max)) and objectively measured physical activity. METHODS: Adults (n = 320, mean age 40.4 +/- 6.0 years) underwent measurement of physical activity energy expenditure (PAEE), spirometry [forced expiratory volume in 1 s (FEV(1))] and forced vital capacity (FVC), aerobic fitness (predicted VO(2max)), and anthropometric and metabolic status at baseline and again after 1 year (n = 257) in the ProActive trial. Clustered metabolic risk was calculated by summing standardized values for triglycerides, fasting insulin, fasting glucose, blood pressure and the inverse of high-density lipoprotein-cholesterol. A cross-sectional analysis using linear regression with repeated measures was performed. RESULTS: Both FEV(1) and FVC were inversely and statistically significantly associated with metabolic risk and insulin resistance after adjusting for age, sex, smoking status, height, PAEE and fitness. The associations with metabolic risk remained significant after adjusting for measures of body fatness, but those with insulin resistance did not. CONCLUSIONS: Reduced lung function was associated with increased metabolic risk in this cohort of carefully characterized at-risk individuals. This association was independent of overall and central body fatness, objectively measured physical activity and aerobic fitness.