A new proportional hazard model with applications to breastfeeding data.

The World Health Organization recommends exclusive breastfeeding for the first 6 months of life, but several factors influence its cessation. Changes in breastfeeding behavior have been reported in the literature among infants at 0, 1, 3 and 5 months. The purpose of this paper is to introduce a new proportional hazards model based on the transformed-transformer method, employing the Weibull and piecewise exponential distributions as baseline models, with the aim of setting the partitions at the time when most weaning occurs. Some properties of the model, including monotonicity and quantile functions, are discussed in detail. Additionally, a regression model for censored data is presented. The parameters of the proposed distribution are estimated using the maximum likelihood approach. Some numerical illustrations of the estimators are presented with a discussion of the obtained results. Finally, two real applications related to breastfeeding in Brazil and the USA are provided to illustrate the usefulness of our proposal.