DESIGN: Food choice was assessed using the validated New Zealand Adolescent FFQ. Principal components analysis was used to determine dietary patterns. Trained research assistants measured participants' height and body mass. Cardiorespiratory fitness was assessed in a subset of participants using the multistage 20 m shuttle run. The level and stage were recorded, and the corresponding VO2max was calculated. Differences in mean VO2max according to sex and BMI were assessed using t tests, while associations between cardiorespiratory fitness and dietary patterns were examined using linear regression analyses adjusted for age, sex, school attended, socio-economic deprivation and BMI.
SETTING: Secondary schools in Otago, New Zealand.
SUBJECTS: Students (n 279) aged 14-18 years who completed an online lifestyle survey during a class period.
RESULTS: Principal components analysis produced three dietary patterns: 'Treat Foods', 'Fruits and Vegetables' and 'Basic Foods'. The 279 participants who provided questionnaire data and completed cardiorespiratory fitness testing had a mean age of 15·7 (sd 0·9) years. Mean VO2max was 45·8 (sd 6·9) ml/kg per min. The 'Fruits and Vegetables' pattern was positively associated with VO2max in the total sample (β=0·04; 95%CI 0·02, 0·07), girls (β=0·06; 95% CI 0·03, 0·10) and boys (β=0·03; 95% CI 0·01, 0·05).
CONCLUSIONS: These results indicate that increase in cardiorespiratory fitness was associated with a healthier dietary pattern, suggesting both should be targeted as part of a global lifestyle approach. Longitudinal studies are needed to confirm this association in relation to health outcomes in New Zealand adolescents.