Blood pressure.

Up to three blood pressure measurements were taken, using the proper cuff size, during visits to Mobile Examination Center after participants had rested quietly in a sitting position for at least 5 minutes. In 1988–1994, 1999–2004, and 2005–2010, 78%, 76%, and 79% of adolescents, respectively, had three blood pressure measurements. We classified adolescents as having ideal (normal), intermediate (prehypertension), or elevated blood pressure (hypertension) based on the age-, gender-, and height-specific blood pressure percentiles using the 2000 CDC growth charts [22]. Ideal (normal) was defined as systolic blood pressure (SBP) and diastolic blood pressure (DBP) <90th percentile for age, sex, and height, intermediate (prehypertension) as SBP or DBP ≥90th but <95th percentile or observed BP levels ≥120/80 mmHg. Elevated blood pressure (hypertension) was defined as SBP and/or DBP ≥95th percentile.