Background: Seasonal fluctuations in outdoor temperature have been shown to affect blood pressure in adults. We have asked whether or not there is either a seasonal variation or an influence of outdoor temperature on blood pressure measurements in children and adolescents in middle Europe. Methods: Blood pressure was routinely measured in healthy and sick children and adolescents in outpatient clinics and during hospitalisation in a total of 6714 subjects (3,497 boys/3,237 girls), age 3 to 21 years, with a median of 10.6 years. Results: Cross-sectional analysis showed a significant seasonal variation in blood pressure measurements. The mean increase of systolic and diastolic blood pressure was 4.45/2.42 mmHg during winter. A significant correlation between average outdoor temperatures and systolic blood pressure was found (ρ=-0.074 p<0.001). However, the effect was only detectable at an average temperature below 0° C/32° F and above 10° C/50° F. For each degree Celsius increase in average outdoor temperature, the systolic blood pressure fell by 0.12 mmHg. Conclusion: Blood pressure measurements in children and adolescents, even in a temperate climate, are influenced by temperature and seasonal variation. Considering seasonal variations in blood pressure could be of clinical interest. / Background: High blood pressure is a major risk factor for cardiovascular disease. Blood pressure tracking could help to identify individuals with potential hypertension. Therefore, we have asked whether or not tracking was of predictive value for the development of hypertension in early life. Methods: Blood pressure was routinely measured in 13,261children and adolescents in outpatient clinics as well as during hospitalization. In a sub-analysis 568 individuals with normotensive and elevated blood pressure were compared after three follow-up periods (two, four and six years) and 2,157 normotensive individuals were compared in a paired t-test. Results: The follow-up analysis showed a significant tracking effect. However, the Pearson correlation coefficients of the systolic and diastolic blood pressure SDS decreased over time. Upon the follow-up after six years 35.6% of the children and adolescents with elevated blood pressure values remained in the elevated range group. Of the children within the normotensive blood pressure range 80.4% remained normotensive after six years. Children with normotensive blood pressure showed a stronger tracking than those who had had one hypertensive blood pressure reading. Children with high body weight gain left their SDS track to higher blood pressure values. Conclusion: Blood pressure tracking in children and adolescents is moderate. We conclude that the predictive power of a single hypertensive blood pressure measurement during a single visit is rather small, and thus repetitive measurements across several consecutive visits are necessary.

Background: Seasonal fluctuations in outdoor temperature have been shown to affect blood pressure in adults. We have asked whether or not there is either a seasonal variation or an influence of outdoor temperature on blood pressure measurements in children and adolescents in middle Europe. Methods: Blood pressure was routinely measured in healthy and sick children and adolescents in outpatient clinics and during hospitalisation in a total of 6714 subjects (3,497 boys/3,237 girls), age 3 to 21 years, with a median of 10.6 years. Results: Cross-sectional analysis showed a significant seasonal variation in blood pressure measurements. The mean increase of systolic and diastolic blood pressure was 4.45/2.42 mmHg during winter. A significant correlation between average outdoor temperatures and systolic blood pressure was found (ρ=-0.074 p<0.001). However, the effect was only detectable at an average temperature below 0° C/32° F and above 10° C/50° F. For each degree Celsius increase in average outdoor temperature, the systolic blood pressure fell by 0.12 mmHg. Conclusion: Blood pressure measurements in children and adolescents, even in a temperate climate, are influenced by temperature and seasonal variation. Considering seasonal variations in blood pressure could be of clinical interest.:Inhaltsverzeichnis......................................................................i Widmung .................................................................................. iii Bibliographische Beschreibung ................................................. iv I. Abkürzungen ......................................................................... i 1. Einführung ........................................................................... 1 1.1. Bedeutung von Blutdruckmessungen im Allgemeinen ................................................................................................. 1 1.2. Bedeutung und Durchführung von Blutdruckmessungen bei Kindern und Jugendlichen ................................................................................................ 2 1.3. Tracking ................................................................................................ 4 1.4. Innere und äußere Einflussfaktoren des Blutdrucks ................................................................................................ 5 1.5. Zweck der Studie ................................................................................................ 7 2. Publikationsmanuskript ................................................................................................ 10 2. 1. Influence of seasonal variation on blood pressure measurements in children, adolescents and young adults ................................................................................................ 10 Abstract .................................................................................. 11 Introduction ................................................................................................ 12 Subjects and methods ................................................................................................ 13 Results .................................................................................... 15 Discussion ................................................................................................ 18 Conclusion ................................................................................................ 21 Acknowledgements ................................................................................................ 22 References............................................................................... 23 Tables ..................................................................................... 27 Figure legends ................................................................................................ 29 Figures ................................................................................... 30 2.2. Blood pressure tracking in children and adolescents ....... 33 Abstract .................................................................................. 34 Inhaltsverzeichnis Subjects and methods ................................................................................................ 35 Results .................................................................................... 39 Discussion ................................................................................................. 42 Conclusion ................................................................................................. 44 Acknowledgements ................................................................................................. 45 References................................................................................ 46 Legends to figures .................................................................................................. 53 Figures ...................................................................................... 55 3. Zusammenfassung der Arbeit ................................................................................................... 62 4. Literaturverzeichnis ............................................................... 68 II. Erklärung über die eigenständige Abfassung der Arbeit ........ ii III. Lebenslauf ............................................................................ iii IV. Danksagung .................................................................................................... iv / Background: High blood pressure is a major risk factor for cardiovascular disease. Blood pressure tracking could help to identify individuals with potential hypertension. Therefore, we have asked whether or not tracking was of predictive value for the development of hypertension in early life. Methods: Blood pressure was routinely measured in 13,261children and adolescents in outpatient clinics as well as during hospitalization. In a sub-analysis 568 individuals with normotensive and elevated blood pressure were compared after three follow-up periods (two, four and six years) and 2,157 normotensive individuals were compared in a paired t-test. Results: The follow-up analysis showed a significant tracking effect. However, the Pearson correlation coefficients of the systolic and diastolic blood pressure SDS decreased over time. Upon the follow-up after six years 35.6% of the children and adolescents with elevated blood pressure values remained in the elevated range group. Of the children within the normotensive blood pressure range 80.4% remained normotensive after six years. Children with normotensive blood pressure showed a stronger tracking than those who had had one hypertensive blood pressure reading. Children with high body weight gain left their SDS track to higher blood pressure values. Conclusion: Blood pressure tracking in children and adolescents is moderate. We conclude that the predictive power of a single hypertensive blood pressure measurement during a single visit is rather small, and thus repetitive measurements across several consecutive visits are necessary.:Inhaltsverzeichnis......................................................................i Widmung .................................................................................. iii Bibliographische Beschreibung ................................................. iv I. Abkürzungen ......................................................................... i 1. Einführung ........................................................................... 1 1.1. Bedeutung von Blutdruckmessungen im Allgemeinen ................................................................................................. 1 1.2. Bedeutung und Durchführung von Blutdruckmessungen bei Kindern und Jugendlichen ................................................................................................ 2 1.3. Tracking ................................................................................................ 4 1.4. Innere und äußere Einflussfaktoren des Blutdrucks ................................................................................................ 5 1.5. Zweck der Studie ................................................................................................ 7 2. Publikationsmanuskript ................................................................................................ 10 2. 1. Influence of seasonal variation on blood pressure measurements in children, adolescents and young adults ................................................................................................ 10 Abstract .................................................................................. 11 Introduction ................................................................................................ 12 Subjects and methods ................................................................................................ 13 Results .................................................................................... 15 Discussion ................................................................................................ 18 Conclusion ................................................................................................ 21 Acknowledgements ................................................................................................ 22 References............................................................................... 23 Tables ..................................................................................... 27 Figure legends ................................................................................................ 29 Figures ................................................................................... 30 2.2. Blood pressure tracking in children and adolescents ....... 33 Abstract .................................................................................. 34 Inhaltsverzeichnis Subjects and methods ................................................................................................ 35 Results .................................................................................... 39 Discussion ................................................................................................. 42 Conclusion ................................................................................................. 44 Acknowledgements ................................................................................................. 45 References................................................................................ 46 Legends to figures .................................................................................................. 53 Figures ...................................................................................... 55 3. Zusammenfassung der Arbeit ................................................................................................... 62 4. Literaturverzeichnis ............................................................... 68 II. Erklärung über die eigenständige Abfassung der Arbeit ........ ii III. Lebenslauf ............................................................................ iii IV. Danksagung .................................................................................................... iv