P9.15 The Role of Lung Function on Adolescents’ Blood Pressure Trajectories in a Multi-Ethnic Cohort: The Determinants of Adolescents Social Wellbeing and Health (Dash) Study

Objectives To investigate the relationship between baseline lung function (LF) and changes in blood pressure (BP) in multi-ethnic adolescent schoolchildren. Methods A multi-ethnic cohort (the DASH study) of 2525 children (80% ethnic minorities), aged 11–13y at baseline, were followed-up two years later (14–16y). Demographic details of ethnicity, socio-economic position and smoking were collected via self-completed questionnaires. Trained nurses measured BP (mean of last 2 of 3 readings) and anthropometry at both waves and spirometry (interpreted using Global Lungs Initiative reference equations) at baseline only. Associations between change in systolic and diastolic BP(ΔsBP, ΔdBP in mmHg) and lung function (LF) z-scores were assessed in multivariable linear regression models. The influence of correlates (age, room temperature, ethnicity, change in Z-scores of: body mass index, height, trunk length) on the LF-BP relationship was investigated. Results In males, adjusted for age and room temperature, one Z-score increase in FEV1 was associated with lower BP change between 11–13y and 14–16y (ΔsBP -1.09 (p<0.001) and ΔdBP −0.46 (p=0.03)); FVC was associated with ΔsBP only (−0.475, p=0.004). In females, similar patterns were seen for FEV1, with FVC associated with ΔdBP only. Adjustment for FEV1 (and to a lesser extent FVC) attenuated ethnic differences in BP changes for some groups (e.g. abolishing differences for Black Africans compared to Whites), but not others (e.g. South Asians), while other covariates did not. Conclusions FEV1, and to a lesser extent FVC, are correlates of BP changes in adolescence. Differences in adolescent LF may contribute to ethnic differences in BP trajectories during youth.