Repeated high blood pressure at 6 and 11 years at the Pelotas 2004 birth cohort study.

Background: We evaluated the prevalence and the factors associated with repeated high systolic (SBP) and diastolic blood pressure (DBP) at 6- and 11-year follow-ups of children from the Pelotas (Brazil) 2004 Birth Cohort.

Methods: All live births to mothers living in the urban area of Pelotas were enrolled in the cohort. Blood pressure (BP) values were transformed into Z-scores by sex, age, and height. High SBP and DBP were defined as repeated systolic and diastolic BP Z-scores on the ≥95th percentile at the two follow-ups. Prevalence (95% confidence interval) of repeated high SBP, DBP, and both (SDBP) were calculated. Associations with maternal and child characteristics were explored in crude and adjusted logistic regression analyses.

Results: A total of 3182 cohort participants were analyzed. Prevalence of repeated high SBP, DBP and SDBP was 1.7% (1.2-2.1%), 2.3% (1.8-2.9%) and 1.2% (0.9-1.6%), respectively. Repeated high SBP was associated with males, gestational diabetes mellitus (2.92; 1.13-7.58) and obesity at 11 years (2.44; 1.29-4.59); while repeated high DBP was associated with females, family history of hypertension from both sides (3.95; 1.59-9.85) and gestational age < 34 weeks (4.08; 1.52-10.96). Repeated high SDBP was not associated with any of the characteristics investigated.

Conclusion: Prevalence of repeated high SBP, DBP, and SDBP were within the expected distribution at the population level. Nonetheless, gestational diabetes mellitus, obesity, family history of hypertension, and prematurity increased the risk of repeated high blood pressure measured at two occasions 5 years apart.