Nonresponse Bias in a Follow-up Study of 19-Year-Old Adolescents Born as Preterm Infants

Abstract
Objective. To assess the effect of demographic and neonatal risk factors and outcome at the last available assessment on the probability of full responders, postal responders (those who only responded to the mailed questionnaire), or nonresponders in a follow-up study of 19-year-old adolescents who were born as preterm infants.