Comparison between results of a cohort under prospective and historical approaches: breastfeeding in the first year of age

Author(s)

Gizelton Pereira Alencar

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR)
• Defense date: 2003-05-23

Examining board members

Jose Maria Pacheco de Souza; Maria do Rosario Dias de Oliveira Latorre; Antonio Carlos Pedroso de Lima

• Advisor: Jose Maria Pacheco de Souza

Abstract

Objective. A cohort of children was observed under two approaches: prospective cohort and retrospective (historical) cohort and the objective was to compare the estimates of the hazard ratio from Cox model between the two approaches and do the same comparison using the complementary log-log model. Moreover, to compare the estimates of the hazard ratio from the two models to each one of the approaches, separately. Methods. When the survival time for breastfeeding is studied without the covariates, the comparison between the results of actuarial technique and the complementary log-log model has been made for the recorded information. The Kaplan-Meier technique has been used with the daily notebook measures. The Cox and complementary log-log models can estimate the risk rate of covariates categories to both approaches. Results. Without the covariates, the comparison between the two information resources showed that retrospective measures give lower estimates than that from the prospective measures. With covariates, the estimates are not so different and led to the same results. Conclusions. The estimates of each one of the comparisons were too close. Just the variable mothers smoking during the pregnancy stayed in the final models for every techniques used, with close estimates, reinforcing likeness between the several approaches. (AU)