Misclassification of self-reported exposures is a potential study limitation. We provided phone cards to encourage participants to contact their mothers or other relatives, but we did not ask whether they contacted relatives or consulted records before reporting early-life events. Response categories for some early-life exposures allowed for further uncertainty with reporting. Although not shown, associations with exposures reported as “definite” were generally similar or stronger than those with exposures reported as probable. However, analyses of infancy feeding are limited by the lack of adequate data on duration. For example, the null association with ever having been breastfed may have been influenced by the inclusion of those breastfed for a very short duration.
