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Analysis of correlated series of repeated measurements: application to challenge data
Author(s) -
Engel Bas,
van Reenen Kees,
Buist Willem
Publication year - 2003
Publication title -
biometrical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 63
eISSN - 1521-4036
pISSN - 0323-3847
DOI - 10.1002/bimj.200390055
Subject(s) - series (stratigraphy) , parametric statistics , mathematics , statistics , parametric model , variation (astronomy) , adrenal cortex , econometrics , biology , endocrinology , physics , paleontology , astrophysics
Data from an ACTH challenge experiment with veal calves, two short time series of cortisol measurements per animal at 6 and 27 weeks of age, are analysed. Interest is focussed on variation in cortisol profiles both within and between animals. Potential effects of an animals diet and housing system on the profiles are addressed as well. Fully parametric and semi‐parametric models, combining individual random effects with effects of diet and housing, were fitted using (approximate) restricted maximum likelihood (employing Laplacian integration). Eigenfunctions were utilized to describe the variation between profiles and the connection between profiles of the same individual. All calculations were performed with standard software. Results of the analysis provides empirical support for the existence of stable individual characteristics mediating reactivity of the adrenal cortex.