DISCONTINUITY INDEXES - A TOOL FOR EPIDEMIOLOGIC STUDIES ON BREAST-FEEDING

Background. The Discontinuity Index (DI), which measures the percentag e of infants who were exclusively breastfed gamma EBF) at the beginnin g of a given age interval and had abandoned this mode of feeding at it s end, and the relative weight of this discontinuation, was introduced and employed in the National Survey on Breast Feeding and Infant Feed ing Practices carried out in Cuba in 1990. The aim of this article is to illustrate, through a specific example, the quality of DI as a simp le procedure for assessing breastfeeding trends. Methods. The prevalen ce of EBF in the 14 provinces of Cuba at discharge from the maternity services and at 30, 60, 120, and 180 days of age, was obtained using d ata from a national sample of 6661 infants (4820 urban and 1791 rural) which were processed by means of a logistic regression model. Cumulat ive DI were calculated for the intervals 0-30, 0-60, 0-120 and 0-180 d ays, and partial DI for the terms 30-60, 60-120 and 120-180 days, for each province and for the whole country. Results. Cumulative DI show t he progress of cessation of breastfeeding and are strongly influenced by previous intervals. The Eastern provinces showed the lowest figures at most of the terms. Discontinuation during the first month of life was particularly high in two Western provinces. Partial DI are more sp ecific and allow discrimination of the intervals at which EBF disconti nuation is more frequent. The highest values were observed between 4 a nd 6 months. Conclusions. Discontinuity Indices are useful complements to prevalence rates in epidemiological studies of breastfeeding. The separate analysis of discontinuation in different periods can be highl y useful when comparing trends and in the study of the impact of breas tfeeding promotion programmes focused on different age intervals.