Analyzing weight evolution in mice infected by Trypanosoma cruzi
Acta sci., Health sci
;
42: e51437, 2020.
Article
in English
| LILACS
| ID: biblio-1372266
ABSTRACT
Concerning the specificities of a longitudinal study, the trajectories of a subject's mean responses not always present a linear behavior, which calls for tools that take into account the non-linearity of individual trajectories and that describe them towards associating possible random effects with each individual. Generalized additive mixed models (GAMMs) have come to solve this problem, since, in this class of models, it is possible to assign specific random effects to individuals, in addition to rewriting the linear term by summing unknown smooth functions, not parametrically specified, then using the P-splines smoothing technique. Thus, this article aims to introduce this methodology applied to a dataset referring to an experiment involving 57 Swiss mice infected by Trypanosoma cruzi, which had their weights monitored for 12 weeks. The analyses showed significant differences in the weight trajectory of the individuals by treatment group; besides, the assumptions required to validate the model were met. Therefore, it is possible to conclude that this methodology is satisfactory in modeling data of longitudinal sort, because, with this approach, in addition to the possibility of including fixed and random effects, these models allow adding complex correlation structures to residuals.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Trypanosoma cruzi
/
Biotherapics
/
Serum
/
Body-Weight Trajectory
Type of study:
Observational study
/
Risk factors
Limits:
Animals
Language:
English
Journal:
Acta sci., Health sci
Journal subject:
Medicina
/
Sa£de P£blica
Year:
2020
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Centro Universitário Ingá/BR
/
Universidade Estadual de Maringá/BR
/
Universidade de São Paulo/BR
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