Tracking and Transition Probability of Blood Pressure From Childhood to Midadulthood.

Importance: Despite its relevance for pediatric blood pressure (BP) screening, the long-term predictive utility and natural progression of pediatric BP classification remain understudied.

Objective: To evaluate BP tracking from childhood to midadulthood using the American Academy of Pediatrics (AAP) thresholds and estimate transition probabilities among BP classifications over time considering multiple time points.

Design, setting, and participants: The analyses were performed in 2023 using data gathered from September 1980 to August 2018 within the longitudinal Cardiovascular Risk in Young Finns Study. Participants had BP examined 9 times over 38 years, from childhood (aged 6-12 years) or adolescence (15-18 years) to young adulthood (21-27 years), late young adulthood (30-37 years), and midadulthood (39-56 years).

Exposures: BP classifications (normal, elevated, hypertension) were based on AAP guidelines for children and adolescents and the 2017 American College of Cardiology/American Heart Association guidelines for adults.

Main outcomes and measures: Outcomes were BP classifications at follow-up visits. Tracking coefficients were calculated using generalized estimated equations. Transition probabilities among BP classifications were estimated using multistate Markov models.

Results: This study included 2918 participants (mean [SD] baseline age, 10.7 [5.0] years; 1553 female [53.2%]). Over 38 years, the tracking coefficient (odds ratio [OR]) for maintaining elevated BP/hypertension was 2.16 (95% CI, 1.95-2.39). Males had a higher probability than females of progressing to and maintaining hypertension and a lower probability of reverting to normal BP from childhood to midadulthood (transition probability: from normal BP to stage 2 hypertension, 0.20; 95% CI, 0.17-0.22 vs 0.08; 95% CI, 0.07-0.10; maintaining stage 2 BP, 0.32; 95% CI, 0.27-0.39 vs 0.14; 95% CI, 0.09-0.21; from stage 2 hypertension to normal BP, 0.23; 95% CI, 0.19-0.26 vs 0.58; 95% CI, 0.52-0.62. For both sexes, the probability of transitioning from adolescent hypertension to normal BP in midadulthood was lower (transition probability, ranging from 0.16; 95% CI, 0.14-0.19 to 0.44; 95% CI, 0.39-0.48) compared with childhood hypertension (transition probability, ranging from 0.23; 95% CI, 0.19-0.26 to 0.63; 95% CI, 0.61-0.66). The probability of maintaining normal BP sharply decreased in the first 5 to 10 years, stabilizing thereafter. Children with normal BP generally maintained this status into adolescence (male: transition probability, 0.64; 95% CI, 0.60-0.67; female: transition probability, 0.81; 95% CI, 0.79-0.84) but decreased by young adulthood (male: transition probability, 0.41; 95% CI, 0.39-0.44; female: transition probability, 0.69; 95% CI, 0.67-0.71).

Conclusion and relevance: Results of this cohort study reveal an enduring association of childhood and adolescent BP (AAP thresholds) with later BP. Although childhood normal BP tends to be maintained into adolescence, the probability of reverting to and sustaining normal BP decreases notably from adolescence to young adulthood. The findings of this study underscore the importance of prevention to maintain normal BP starting in childhood, suggesting adolescence as a potential critical period. The results suggest the potential for less frequent screenings for children with initially normal BP.