Risk of Breastfeeding Cessation Over Time
Table 2 is a life table that includes the 12 discrete time intervals and corresponding risk sets, the number of women censored, hazard functions, and survival functions.
Birth(Time 0) represents breastfeeding initiation (n=309).
Because the first observable event time is Month 1, the survival function (proportion of women who continued breastfeeding from birth to the start of Month 1) is 1.0. By the end of the first month, 63 women stopped breastfeeding and 35 women were censored. Because censoring began at this point, the survival function was estimated indirectly.
The estimated hazard function for Month 1 means that 20% of the women who began breastfeeding at birth discontinued by the end of Month 1 survival function (proportion of women still breastfeeding at the end of the first month) was estimated indirectly at 80% At the breastfeeding of Month 2, the risk set was 211 women who were still breastfeeding(309-63-35).
During Month 2,25 of the 211 women stopped breastfeeding and four women were censored .
The estimated hazard function for Month 2 was only 12% meaning that 12% of the 211 women who were breastfeeding at the beginning of Month 2stopped breastfeeding by the end of Month 2, thus reducing the estimated survival function to 70%