Determinants of pulmonary hypertension in young adults.

BACKGROUND: Risk factors of pulmonary hypertension (PH) are poorly understood. The objective of this study was to identify the determinants of PH in young adults.

METHODS: We analysed a limited access dataset from the CARDIA (Coronary Artery Risk Development in Young Adults) study provided by the National Heart, Lung and Blood Institute. Pulmonary arterial pressure was assessed by the Doppler pulmonary artery acceleration time (PAAT). Socio-demographic characteristics, self-reported clinical variables, echocardiographic variables, pulmonary function tests, systemic blood pressure and body mass index calculated from height and weight were used in multivariate analysis.

RESULTS: There were 4171 study subjects, mean age 24.9 ± 3.6 years, retained in year five with echocardiographic data available after five years of follow-up. The prevalence of severe PH (PAAT ≤ 70 ms) and mild to moderate PH (PAAT = 109.9-70.01 ms) was 1.1% and 14% respectively. Multivariate analysis revealed that body mass index (β = -1.09, p < 0.0001), female gender (β = 6.25, p < 0.0001), age (β = -0.30, p = 0.02), African American race (β = -2.57, p = 0.007), physical activity (β = 0.005, p = 0.002), current smoking (β = -3.42, p = 0.001), left atrial dimension (β = -2.97, p = 0.009) and diastolic dysfunction (β = -13.06, p = 0.006) were statistically significant variables predicting PH.

CONCLUSION: In this large, observational study of young adults, pulmonary hypertension, as assessed by echocardiography, is common. Diastolic dysfunction, obesity, physical inactivity and smoking are associated with elevated pulmonary arterial pressure in young adults.