Printed in U.S.A. Relations of Plasma Fibrinogen Level in Children to Measures of Obesity, the (G^-^A) Mutation in the ^-Fibrinogen Promoter Gene, and Family History of

Higher plasma fibrinogen levels are associated with increased risk of myocardial infarction in adults, but little is known about factors that influence fibrinogen levels in childhood. The authors examined the associations of measures of obesity, presence of the (G^-^A) allele in the p-fibrinogen promoter gene, and family history of early onset of ischemic heart disease with plasma fibrinogen levels in children. Children (n = 299) were recruited during 1994-1997 from 276 families living in a racially mixed area of New York City. The mean age of the study children was 9.9 years; 79 % were Hispanic. The frequency of the ( G ^ ^ A) allele was lower in Hispanics than in non-Hispanic Whites (15.5 % vs. 28.3 % in children (p < 0.01) and 13.9 % vs. 28.3 % in parents (p < 0.001)). Graded relations of children's plasma fibrinogen levels were found with tertiles of body mass index (weight (kg)/height (m)2) and sum of skinfolds (tests for linear trend: p < 0.001). Plasma fibrinogen levels in the children were not related to race/ethnicity, presence of the (G^-^A) allele, or family history. Multiple linear regression analyses adjusting plasma fibrinogen levels for age, sex, race/ethnicity, the (G_4M->A) allele, and family history of early onset of heart disease showed a significant association with either body mass index or sum of skinfolds (p < 0.001 for both models) but not with the other variables. Am J Epidemiol 1999;150:737-46. atherosclerosis; cardiovascular diseases; child; fibrinogen; genetics; obesity The observation that fresh thrombus is often presen