Using log-linear models to test for associations among congenital malformations

T. H. Beaty, P. Yang, M. J. Khoury, E. L. Harris, K. Y. Liang

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Log-linear models can be used to test for pairwise associations and higher order interactions among anatomically distinct birth defects or congenital malformations. A log-linear model, including terms for every possible pairwise association among seven severe and easily detectable congenital malformations, was examined using data on 16,217 infants registered in the Metropolitan Atlanta Congenital Defects Program between 1968 and 1986. The resulting model showed clear patterns of strong association between some congenital malformations and not others, and the presence of 3-way interaction terms where the association between two malformations depended on the presence of a third. Examining a more parsimonious log-linear model showed overlapping patterns of pairwise association involving anal-rectal atresia and omphalocele, anal-rectal atresia and limb deficiency, and anal-rectal atresia and tracheaesophageal fistula. A second common pattern involved a triangular cluster with a hierarchical relationship among the three malformations (where there was a strong association between the first and second malformations and between the first and third malformations, but the association between the second and third was only seen in the absence of the first). Three such overlapping triangular clusters were identified from these data: neural tube defects, oral clefts, and omphalocele; neural tube defects, oral clefts, and limb deficiency; and limb deficiency, diaphragmatic hernia, and neural tube defects. Some of these clusters correspond to known associations, but log-linear models offer a simple and systematic approach to searching for possible associations among anatomically distinct malformations.

Original languageEnglish (US)
Pages (from-to)299-306
Number of pages8
JournalAmerican journal of medical genetics
Issue number3
StatePublished - 1991


  • birth defects
  • defect registry
  • multiple malformations

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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