Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Time-ordering of the variables in the PROBIT study. Data were collected at baseline and six follow-up times. At each follow-up time point, breastfeeding status (At) and presence of infection over the past interval (Lt) were noted. Censoring occurring at time t (Ct = 1) indicates that later breastfeeding and infection status were not observed.
