Published online November 1, 2005
PEDIATRICS Vol. 116 No. 5 November 2005, pp. e662-e666 (doi:10.1542/peds.2005-0682)
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow P3Rs: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when P3Rs are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My File Cabinet
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Hille, E.T.M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hille, E.T.M.
Related Collections
Right arrow Premature & Newborn

ELECTRONIC ARTICLE

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

E.T.M. Hille, MSc, PhD*,{ddagger}, L. Elbertse, MD*, J. Bennebroek Gravenhorst, MD, PhD*, R. Brand, PhD*,§, S.P. Verloove-Vanhorick, MD, PhD*,|| on behalf of the Dutch POPS-19 Collaborative Study Group

* TNO Quality of Life, Leiden, the Netherlands
{ddagger} Department of Neonatology, Erasmus Medical Center-Sophia Children’s Hospital, Rotterdam, the Netherlands
§ Department of Medical Statistics, Leiden University Medical Center, Leiden, the Netherlands
|| Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands

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.

Design. The 19-year follow-up program was part of a large ongoing collaborative study in the Netherlands on the long-term effect of prematurity and dysmaturity on various medical, psychological, and social parameters. In the original cohort, 1338 infants (94%) with a gestational age of <32 weeks and/or a birth weight of <1500 g were enrolled. Neonatal mortality was 23% (n = 312), and another 67 children had died between the ages of 28 days and 19 years, leaving 959 survivors (72% of the original cohort) for follow-up at the present assessment. To study the effect of nonresponse, we divided the 959 survivors into 3 groups: full responders (596 [62.1%]), postal responders (109 [11.4%]), and nonresponders (254 [26.5%]). In the 3 groups we compared demographic and neonatal data, as well as outcome at the last available assessment.

Results. The odds ratios (ORs) for male versus female for the probabilities of nonresponse and postal response were statistically significant: 2.7 (95% CI: 1.9–3.9) and 1.6 (95% CI: 1.0–2.5), respectively. The same holds for the ORs for non-Dutch versus Dutch and low versus high maternal education for nonresponse: 2.0 (95% CI: 1.3–3.2) and 3.7 (95% CI: 2.0–6.7), respectively. Special education and severe handicap showed a statistically significant influence on nonresponse (OR: 1.6; 95% CI: 1.1–2.4 and OR: 2.6; 95% CI: 1.3–5.2) and postal response (OR: 2.0; 95% CI: 1.2–3.3 and OR: 4.4; 95% CI: 2.0–9.9), respectively. At the age of 19 years, primary school and special education were found significantly more frequent in the postal responders than in the full-response group (20% and 21% vs 6% and 12%). The full responders, on the other hand, were higher educated than were the postal responders.

Conclusions. In this follow-up study at the age of 19 years, boys, non-Dutch adolescents, and low maternal education were overrepresented in the nonresponse and postal-response groups. Nonresponse decreased the proportion of infants with adverse outcome in assessed children. To be able to present reliable results for the total group of survivors in long-term follow-up studies, the nonresponse bias needs to be quantified. Therefore, it is evident that more research using statistical methods such as imputation of missing data is needed.

Key Words: adolescents • bias • follow-up studies • outcomes of high-risk infants • preterm infants

Abbreviations: SGA, small for gestational age • AGA, appropriate for gestational age • OR, odds ratio • CI, confidence interval

Accepted Jun 1, 2005.




This article has been cited by other articles:


Home page
 Arch Gen PsychiatryHome page
K. Raikkonen, A.-K. Pesonen, K. Heinonen, E. Kajantie, P. Hovi, A.-L. Jarvenpaa, J. G. Eriksson, and S. Andersson
Depression in Young Adults With Very Low Birth Weight: The Helsinki Study of Very Low-Birth-Weight Adults
Arch Gen Psychiatry, March 1, 2008; 65(3): 290 - 296.
[Abstract] [Full Text] [PDF]

Home page
 Int J EpidemiolHome page
R. C Brown, T. Dwyer, C. Kasten, D. Krotoski, Z. Li, M. S Linet, J. Olsen, P. Scheidt, D. M Winn, and for the International Childhood Cancer Cohort Cons
Cohort Profile: The International Childhood Cancer Cohort Consortium (I4C)
Int. J. Epidemiol., August 1, 2007; 36(4): 724 - 730.
[Full Text] [PDF]

Home page
 Arch. Dis. Child. Fetal Neonatal Ed.Home page
S A Reijneveld, M J K de Kleine, A L van Baar, L A A Kollee, C M Verhaak, F C Verhulst, and S P Verloove-Vanhorick
Behavioural and emotional problems in very preterm and very low birthweight infants at age 5 years
Arch. Dis. Child. Fetal Neonatal Ed., November 1, 2006; 91(6): F423 - F428.
[Abstract] [Full Text] [PDF]