Dietary and lifestyle factors associated with blood pressure among US adolescents

Purpose: To identify modifiable lifestyle factors associated with blood pressure among U.S. adolescents. Methods: A cross-sectional study was conducted of 4508 12-19-year-old respondents of the 1999-2002 National Health and Nutrition Examination Survey. Systolic and diastolic blood pressure (SBP and DBP) were measured and adjusted for gender, age, and height using z-scores (SBPZ and DBPZ). Body mass index (BMI) was adjusted for gender and age (BMIZ). Questionnaires were used to measure nutrient intake (carbohydrate, protein, saturated and unsaturated fat, sodium, potassium, calcium, magnesium, fiber, and caffeine) and activities (physical activities and sedentary activities, including television watching). Results: In the adjusted model (R-2 = .115), SBPZ was higher by .022 standard deviation (SD) (95% confidence interval [CI]:.007-038, equivalent to similar to .2 mmHg) per 1-hour increments in sedentary activities; higher by .244 SD (.198 - .289, similar to 2.6 mmHg) per 1 SD of BMIZ; and lower by .099 SD (-.192 to -.006, similar to 1.1 mmHg) per 100 g of carbohydrate intake. Unexpectedly, BMIZ was negatively associated with DBPZ (-.078 per 1 SD, -.114 to -.043, similar to.9 mmHg). Conclusions: Among U.S. adolescents, sedentary activities and BMI are positively associated with SBP after adjustment for confounding factors and mediators, while BMI is negatively associated with DBP. If confirmed by further studies, population-based interventions aimed at sedentary activities may be practical approaches to decrease SBP and the risk of obesity among adolescents.) 2007 Society for Adolescent Medicine. All rights reserved.