Relationships between blood pressure and measures of dietary energy intake, physical fitness, and physical activity in Australian children aged 11-12 years.

STUDY OBJECTIVE: The aim was to examine associations between blood pressure and dietary energy intake, physical activity, and physical fitness in Australian children. DESIGN: The study was a survey of year 7 children attending schools in metropolitan Perth. SETTING: Survey schools were located in suburbs representative of the range of socioeconomic strata in metropolitan Perth. PARTICIPANTS: Data were obtained on 1311 out of 2045 eligible children (64%). The sample included 681 boys and 630 girls. Mean age was 12.0 (SD 0.4) years. MEASUREMENTS AND MAIN RESULTS: Triplicate blood pressure measurements were obtained using a Dinamap oscillometric recorder. Dietary energy intakes were computed from two week day 24 h records. Physical activity was assessed using questionnaires. Physical fitness was measured using a shuttle run test. Additional measurements included weight, height, and skinfold thickness at four sites. A previous observation of an inverse relationship between diastolic blood pressure and dietary energy intake in boys was confirmed. There was evidence of an inverse relationship in girls but not in boys between blood pressure and physical activity. There was little evidence of relationships between blood pressure and physical fitness. CONCLUSIONS: Compared with weight and body mass index, dietary energy intake and the chosen measures of physical activity and physical fitness are poor predictors of blood pressure in the population studied.