title: The influence of age and gender on the relationship between birth weight and blood pressure in childhood: a study using 24-hour and casual blood pressure.
abstract: This study investigates the influence of age and gender on the relationship between birth weight and blood pressure in childhood, using casual and 24-h blood pressure measurements. Casual and 24-h blood pressure were measured on 976 normal schoolchildren (550 girls) aged 6 to 16 years. There was no significant association between birth weight and casual systolic blood pressure (regression coefficient (ss)=-0.30; 95% CI -1.79, 1.19). There was a significant negative correlation between birth weight and mean 24-h systolic blood pressure (ss=-2.13; 95% CI -3.35, -0.90). Subgroup analysis by gender revealed a significant relation for girls (ss=-2.88; 95% CI -4.44, -1.32) but not boys (ss= -1.02; 95% CI -2.99, 0.95). ). Subgroup analysis by age group revealed a significant relation for > or =11 years old (ss= -3.17, 95% CI -4.86, -1.48) but not children <11 years old (ss= -0.88; 95% CI -2.63, 0.88). Interaction tests demonstrated a statistically significant different relationship between birth weight and blood pressure for boys and girls ( P=0.021) and for children <11 and > or = 11 years of age ( P=0.036).
  
  
  CONCLUSIONS
  this study demonstrates that gender and age have an important influence on the relationship between birth weight and blood pressure in childhood. The observed differences between boys and girls and the different age groups remain unexplained.
authors.affiliation: Department of Paediatric Cardiology, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK. John.O'Sullivan@nuth.northy.nhs.uk
authors.forename: John
authors.initials: J
authors.lastname: O'Sullivan
authors.forename: Charlotte
authors.initials: C
authors.lastname: Wright
authors.forename: Mark S
authors.initials: MS
authors.lastname: Pearce
authors.forename: Louise
authors.initials: L
authors.lastname: Parker
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000704:Analysis of Variance; D001724:Birth Weight / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D012044:Regression Analysis; D012606:Scotland; D012727:Sex Characteristics; D013599:Systole; D013997:Time Factors