PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 10474154

Multivariate linear mixed models for multiple outcomes.

M Sammel·X Lin·L Ryan
View original source ↗Export metadata ↓

Abstract

We propose a multivariate linear mixed (MLMM) for the analysis of multiple outcomes, which generalizes the latent variable model of Sammel and Ryan. The proposed model assumes a flexible correlation structure among the multiple outcomes, and allows a global test of the impact of exposure across outcomes. In contrast to the Sammel-Ryan model, the MLMM separates the mean and correlation parameters so that the mean estimation will remain reasonably robust even if the correlation is misspecified. The model is applied to birth defects data, where continuous data on the size of infants who were exposed to anticonvulsant medications in utero are compared to controls.

Explore related subjects

Abnormalities, Drug-InducedAnticonvulsantsCohort StudiesCongenital AbnormalitiesData Interpretation, StatisticalEpilepsyFactor Analysis, StatisticalFemaleHumansInfant, NewbornLinear ModelsMultivariate AnalysisPregnancyPregnancy ComplicationsComparative StudyJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M Sammel, X Lin, L Ryan. Multivariate linear mixed models for multiple outcomes.. https://doi.org/10.1002/(sici)1097-0258(19990915%2F30)18%3A17%2F18%3C2479%3A%3Aaid-sim270%3E3.0.co%3B2-f

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2001

Effects of maternal age on teratogenicity of di-n-butyltin diacetate in rats.

The present study was designed to assess changes in the teratogenic potency of di-n-butyltin diacetate (DBTA) with increasing maternal age in rats. Pregnant Wistar rats of 3, 7.5 or 12 months were treated orally with DBTA at 0, 7.5, 10, 15 or 22 mg/kg on day 8 of gestation. Cesarean sections were performed on day 20 of gestation. Maternal age had greater impact on litter size in the 7.5- and 12-month dams than the 3-month dams. The death of most of the fetuses of the 12-month dams made it difficult to evaluate the teratogenic potency of DBTA. In 3-month groups, fetuses with external malformation, such as cleft mandible, cleft lower lip, ankyloglossia and/or schistoglossia, which are malformations typical of DBTA, were observed at 15 and 22 mg/kg, while similar malformations were observed in 7.5-month groups at doses of 10 mg/kg and above. At 15 and 22 mg/kg, the incidences of these malformations in 7.5-month groups were similar to these from 3-month groups. In our previous studies, however, single DBTA-treatment at 10 mg/kg on day 8 of gestation has not produced such malformations from 3-month dams. The results suggest that the teratogenic potency of DBTA in 7.5-month dams may be greater than in 3-month dams.

Abnormalities, Drug-Induced↗
PubMed2001

Evidence of a common pathogenesis for foregut duplications and esophageal atresia with tracheo-esophageal fistula.

The pathogenesis of the alimentary tract duplications, including foregut duplications (FgD) remains speculative. The accidental finding of FgD in fetal rats with esophageal atresia and tracheoesophageal fistula (EA-TEF) induced by Adriamycin provided an animal model to investigate a possible relationship between these two entities. Timed-pregnant rats were intraperitoneally injected with Adriamycin (1.75 mg/kg) on gestational Days 6 to 9. Their embryos were harvested by Caesarean section from gestational Days 14 to 21. Forty-six of embryos were processed and serially sectioned in the transverse or sagittal planes. EA-TEF occurred in 43/46 (93%) embryos of which 11 (24%) were found to have an associated FgD located at the level where the esophagus was absent. Six FgDs communicated with the foregut or the trachea. Five noncommunicating FgDs were located between the foregut and the vertebral column. In the control embryo, the notochord was located in the centre of the vertebral column from Day 11 of the gestation. In Day 14, 15 and 16, however, embryos exposed to Adriamycin, an abnormal notochord or branch frequently was located within the mesenchyme of the maldeveloped foregut or attached to the duplication cyst. In some, it appeared that the notochord was drawing the cyst-like structure away from the foregut. The present study confirms that duplications adjacent to the esophagus arise from the foregut and that failure of the foregut to detach from the notochord at the normal time may contribute to the development of foregut duplications.

Abnormalities, Drug-Induced↗