Cohort reconstruction: which infants can be restudied at school age?

Abstract

Longer-term follow-up of infants with specific health concerns, such as low birthweight, is critical to assessing the effect of medical interventions. This report examines the approach of reconstructing previously studied cohorts in terms of the factors discriminating between respondents and non-respondents. Follow-up was attempted during 1987-1988 for 1875 children born during a 6-month period in 1978 in three geographically defined regions in the United States, for whom 1-year assessments of health and developmental status were obtained at 1 year of age as part of a previous study. For a 25% sample, participation involved a clinic visit for developmental assessments; for the remainder an interview by telephone or home visit. Follow-up was obtained for 72.5% of the cohort. Refusal rates were low (7%); most non-response was due to an inability to locate the families. Predictors of non-response reflected primarily low socio-economic status; completion rates were not influenced by mode of assessment. The role of a tracing agency is discussed. We conclude that cohort reconstruction is feasible with response rates comparable to some prospective studies with ongoing cohort maintenance.

Characteristics of childhood cancer survivors predicted their successful tracing

“…Difficulties experienced when tracing children include the breakup of families and the placement of the child with one parent or with another relative. Additionally, surname differences, possibly due to changes in the parents' marital status, add to the difficulty of tracing [5,6]. In our study, we found that parental information at the time of registration was generally accurate, and tracing was necessary only 15% of the time.…”

“…The type of information used to trace subjects varies depending on the tracing method. Many studies employ credit agencies to find lost participants, where the full name of the subject and social security number is helpful for a successful search [5,6,10]. State and local vital records offices, departments of motor vehicles, and the National Death Index can also be used in tracing efforts [6,[10][11][12][13].…”

“…Hospital records represent one possible source for assembling a cohort. In this situation, however, the research team is dependent on the information available from existing sources [5,6]. Because most of the information contained in hospital records is not collected with the objective of long-term follow-up, key pieces of information that facilitate tracing and the successful location of the eligible subject are often lacking.…”

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

“…Castro et al 14 and McCormick et al, 4 on the other hand, found that compared with children who were lost to follow-up, those who were compliant with follow-up had more adverse outcomes. It seems that the adolescents with higher completed or current education are overrepresented in the full-response group at the age of 19 years.…”

“…Some authors suggest that nonresponse increases the proportion of infants with adverse outcomes in the remaining study population, and others have described the reverse. 4,5 We therefore used the opportunity presented to assess the influence of complete response, partial response, and nonresponse on the outcome measures of our follow-up study of 19-year-old adolescents who were born as preterm infants. …”