title: 16-year incidence of ischemic heart disease in the NHLBI twin study. A classification of subjects into high- and low-risk groups.
abstract: Prospective data from the National Heart, Lung, and Blood Institute (NHLBI) Twin Study were used to investigate the relationship of risk factors measured in 1970 to 1971 to 16-year incidence of ischemic heart disease (IHD) in 905 males born between 1917 and 1927. A newly developed methodology, tree-structured survival analysis (TSSA), was used to classify subjects into discrete subgroups that differed significantly in profiles of risk factors and incidence of IHD. On the basis of five characteristics--systolic blood pressure (SBP), high-density-lipoprotein cholesterol (HDL-C), 1-hour postload glucose levels, forced expiratory volume in 1 second (FEV1), and a family history score for heart disease--the TSSA algorithm partitioned the cohort into six discrete subgroups that formed three clusters of individuals with distinct IHD experience. Highest IHD incidence rates were experienced by a subgroup of 56 men with baseline SBP above 134 mm Hg and HDL-C levels lower than 33 mg/dL. No IHD events were observed in a subgroup of 117 men who had low SBP, high FEV1, and a negative family history of heart disease. Relationships to the twinning condition showed that for both zygosities, cotwin-pair members were in the same risk subgroup more often than expected; however, the overall difference between the frequency of monozygotic (MZ) and dizygotic (DZ) cotwins was relatively small. The highest MZ/DZ ratios of observed to expected cotwin-pair membership occurred in subgroups with the highest and lowest incidences of IHD, suggesting that these extremes of incidence are most likely to be genetically determined.
authors.affiliation: Health Sciences Program, SRI International, Menlo Park, CA 94025.
authors.forename: D
authors.initials: D
authors.lastname: Carmelli
authors.forename: J V
authors.initials: JV
authors.lastname: Selby
authors.forename: J
authors.initials: J
authors.lastname: Quiroga
authors.forename: T
authors.initials: T
authors.lastname: Reed
authors.forename: R R
authors.initials: RR
authors.lastname: Fabsitz
authors.forename: J C
authors.initials: JC
authors.lastname: Christian
mesh_terms: D000368:Aged; D002423:Cause of Death; D015331:Cohort Studies; D003327:Coronary Disease / Q000453:epidemiology* / Q000235:genetics / Q000401:mortality; D003430:Cross-Sectional Studies; D004200:Diseases in Twins / Q000453:epidemiology* / Q000235:genetics; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics