Factors Associated with Duration of Exclusive Breastfeeding

摘要

To estimate the probabilities of various factors at various time intervals for duration of exclusive breastfeeding, the present study was done at the well baby clinic. Mothers with infants below one year of age were selected and interviewed. The median duration of exclusive breastfeeding (EBF) was found 6 months. Relationship between duration of EBF and practice of breastfeeding (on demand or at fixed time) was studied and found statistically not significant (p>0.05) by log rank test. Other factors affecting EBF were also studied like literacy, type of family and monthly family income. Median duration of EBF was found more (7 months) for illiterate women than for literate (6 months) and statistically significant (p<0.05). On testing equality of survival prospects for duration of EBF as per type of family, log rank test was found not significant (p>0.05). A statistically significant difference was observed while testing two different groups based on total family income. Introduction The benefits of prolonged breastfeeding for mother and infant health are documented in a vast scientific literature. All women should be enabled to practice exclusive breastfeeding (EBF) and all infants should be fed exclusively on breast milk from birth to 4 to 6 months of age and thereafter, children should continue to be breastfed, while receiving appropriate and adequate complementary foods, for upto 2 years of age or beyond (1). Too early introduction of breast milk substitutes and too late introduction of semi solid complementary feeds are common and are responsible for rapid increase in the prevalence of under nutrition between 6-24 months (2). Exclusive breastfeeding defined by World Health Organization (WHO) as practice of feeding only breast milk (including expressed breast milk) and allows the baby to receive vitamins, minerals or medicines and water, breast milk substitutes, other liquids and solid foods are excluded. World Health Assembly of WHO in 2001 made resolution that exclusive breastfeeding for the first six months is the most appropriate infant feeding practice (3). Recent developments suggest full breastfeeding should continue to six months (4). There is good evidence that two more months of EBF from fourth to six months provides infants with additional protection against gastrointestinal and acute respiratory infections during that two months period (4, 5). This study was done to estimate the probability of exclusive breastfeeding since birth at various time intervals for a group of women incorporating some censored cases through survival analysis procedure. In survival analysis, censored cases are cases for which the second event is not recorded or simply does not occur before the end of the study. First event is time after birth of child when breastfeeding starts and second event refers to the end of EBF when some food supplements are introduced and breastfeeding becomes partial if continues. So, those women reporting continuance of EBF on the date of interview were considered as censored cases and for this situation, survival analysis technique, method of estimating time to event models in presence of censored cases is useful. As the study is based on interview of mothers, there remain some elements of subjectivity, recall lapses and digit preference. A variation of cohort study is the historically prospective design where a general sample (usually of women) from population is asked to recall their breastfeeding history (6). As this is a historically prospective study, it therefore introduces the recall bias which is a limitation of this study. The aim of this study was to analyze the observed data on duration of EBF of a group of women who had delivered a child within last one year from survey date. Survival analysis method using life table and Kaplan Meier methods was applied and conditional probability of survival (continuance of EBF), at monthly interval of time were obtained. The relationship between duration of EBF an