| 1. | Strachan DP. Hay fever, hygiene, and household size. BMJ 1989;299:1259–1260. |
| 2. | Koopman LP, Smit HA, Heijnen ML, Wijga A, van Strien RT, Kerkhof M, Gerritsen J, Brunekreef B, de Jongste JC, Neijens HJ. Respiratory infections in infants: interaction of parental allergy, child care, and siblings–The PIAMA study. Pediatrics 2001;108:943–948. |
| 3. | Hurwitz ES, Gunn WJ, Pinsky PF, Schonberger LB. Risk of respiratory illness associated with day-care attendance: a nationwide study. Pediatrics 1991;87:62–69. |
| 4. | Marbury MC, Maldonado G, Waller L. Lower respiratory illness, recurrent wheezing, and day care attendance. Am J Respir Crit Care Med 1997;155:156–161. |
| 5. | Celedon JC, Litonjua AA, Ryan L, Weiss ST, Gold DR. Day care attendance, respiratory tract illnesses, wheezing, asthma, and total serum IgE level in early childhood. Arch Pediatr Adolesc Med 2002;156:241–245. |
| 6. | Kramer U, Heinrich J, Wjst M, Wichmann HE. Age of entry to day nursery and allergy in later childhood. Lancet 1999;353:450–454. |
| 7. | Ball TM, Castro-Rodriguez JA, Griffith KA, Holberg CJ, Martinez FD, Wright AL. Siblings, day-care attendance, and the risk of asthma and wheezing during childhood. N Engl J Med 2000;343:538–543. |
| 8. | Nystad W, Skrondal A, Magnus P. Day care attendance, recurrent respiratory tract infections and asthma. Int J Epidemiol 1999;28:882–887. |
| 9. | Svanes C, Jarvis D, Chinn S, Omenaas E, Gulsvik A, Burney P. Early exposure to children in family and day care as related to adult asthma and hay fever: results from the European Community Respiratory Health Survey. Thorax 2002;57:945–950. |
| 10. | Nafstad P, Brunekreef B, Skrondal A, Nystad W. Early respiratory infections, asthma, and allergy: 10-year follow-up of the Oslo Birth Cohort. Pediatrics 2005;116:e255–e262. |
| 11. | Stein RT, Sherrill D, Morgan WJ, Holberg CJ, Halonen M, Taussig LM, Wright AL, Martinez FD. Respiratory syncytial virus in early life and risk of wheeze and allergy by age 13 years. Lancet 1999;354:541–545. |
| 12. | Mommers M, Swaen GM, Weishoff-Houben M, Creemers H, Freund H, Dott W, van Schayck CP. Childhood infections and risk of wheezing and allergic sensitisation at age 7–8 years. Eur J Epidemiol 2004;19:945–951. |
| 13. | Arshad SH, Kurukulaaratchy RJ, Fenn M, Matthews S. Early life risk factors for current wheeze, asthma, and bronchial hyperresponsiveness at 10 years of age. Chest 2005;127:502–508. |
| 14. | de Meer G, Janssen NA, Brunekreef B. Early childhood environment related to microbial exposure and the occurrence of atopic disease at school age. Allergy 2005;60:619–625. |
| 15. | Kusel MM, de Klerk NH, Kebadze T, Vohma V, Holt PG, Johnston SL, Sly PD. Early-life respiratory viral infections, atopic sensitization, and risk of subsequent development of persistent asthma. J Allergy Clin Immunol 2007;119:1105–1110. |
| 16. | Caudri D, Wijga A, Scholtens S, Kerkhof M, Gerritsen J, Ruskamp JM, Brunekreef B, Smit HA, de Jongste JC. 2008. Early daycare: more infections and asthma symptoms in infancy, no prevention of (allergic) asthma at 8 years [abstract]. ERS 2008 Berlin, abstract number 4418. (Accessed April 14, 2009, at http://www.ers-education.org/pages/default.aspx?id=1339&idBrowse=47778) |
| 17. | Asher MI, Keil U, Anderson HR, Beasley R, Crane J, Martinez F, Mitchell EA, Pearce N, Sibbald B, Stewart AW, et al. International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods. Eur Respir J 1995;8:483–491. |
| 18. | Burney PG, Luczynska C, Chinn S, Jarvis D. The European Community Respiratory Health Survey. Eur Respir J 1994;7:954–960. |
| 19. | Brunekreef B, Smit J, de Jongste J, Neijens H, Gerritsen J, Postma D, Aalberse R, Koopman L, Kerkhof M, Wilga A, et al. The prevention and incidence of asthma and mite allergy (PIAMA) birth cohort study: design and first results. Pediatr Allergy Immunol 2002;13:55–60. |
| 20. | Brunekreef B, van Strien R, Pronk A, Oldenwening M, de Jongste JC, Wijga A, Kerkhof M, Aalberse RC. La mano de DIOS…was the PIAMA intervention study intervened upon? Allergy 2005;60:1083–1086. |
| 21. | Kerkhof M, Schouten JP, De Monchy JG. The association of sensitization to inhalant allergens with allergy symptoms: the influence of bronchial hyperresponsiveness and blood eosinophil count. Clin Exp Allergy 2000;30:1387–1394. |
| 22. | de Schipper EJ, Riksen-Walraven JM, and Geurts SAE. Multiple determinants of caregiver behavior in child care centers. Early Child Res Q 2007;22:312–326. |
| 23. | Rubin D. Multiple imputation for nonresponse in surveys. New York: John Wily and Sons; 1987. |
| 24. | Schafer J. Analysis of incomplete multivariate data. London: Chapman & Hall; 1997. |
| 25. | van Buuren S, Oudshoorn K. MICE: Multivariate imputation by chained equations. R package version 1.15. Leiden, The Netherlands: TNO prevention and health 2005. (Accessed May 31, 2007, at http//web.inter.nl.net/users/S.van.Buuren/mi/hmtl/mice.htm). |
| 26. | van Buuren S, Oudshoorn K. Flexible multivariate imputation by MICE. Technical report. Leiden, The Netherlands: TNO prevention and health 1999. (Accessed February 27, 2008, at http://web.inter.nl.net/users/S.van.Buuren/mi/docs/rapport99054.pdf.). |
| 27. | Balemans WA, Rovers MM, Schilder AG, Sanders EA, Kimpen JL, Zielhuis GA, Ent CK. Recurrent childhood upper respiratory tract infections do not reduce the risk of adult atopic disease. Clin Exp Allergy 2006;36:198–203. |
| 28. | Hagendorens MM, Bridts CH, Lauwers K, van Nuijs S, Ebo DG, Vellinga A, De Clerck LS, Van Bever HP, Weyler JJ, Stevens WJ. Perinatal risk factors for sensitization, atopic dermatitis and wheezing during the first year of life (PIPO study). Clin Exp Allergy 2005;35:733–740. |
| 29. | Hagerhed-Engman L, Bornehag CG, Sundell J, Aberg N. Day-care attendance and increased risk for respiratory and allergic symptoms in preschool age. Allergy 2006;61:447–453. |
| 30. | Haby MM, Marks GB, Peat JK, Leeder SR. Daycare attendance before the age of two protects against atopy in preschool age children. Pediatr Pulmonol 2000;30:377–384. |
| 31. | Nicolaou NC, Simpson A, Lowe LA, Murray CS, Woodcock A, Custovic A. Day-care attendance, position in sibship, and early childhood wheezing: a population-based birth cohort study. J Allergy Clin Immunol 2008;122:500–506 e5. |
| 32. | Celedon JC, Wright RJ, Litonjua AA, Sredl D, Ryan L, Weiss ST, Gold DR. Day care attendance in early life, maternal history of asthma, and asthma at the age of 6 years. Am J Respir Crit Care Med 2003;167:1239–1243. |
| 33. | Ulrik CS, Postma DS, Backer V. Recognition of asthma in adolescents and young adults: which objective measure is best? J Asthma 2005;42:549–554. |
| 34. | Jones A. Asymptomatic bronchial hyperreactivity and the development of asthma and other respiratory tract illnesses in children. Thorax 1994;49:757–761. |
| 35. | Peat JK, Toelle BG, Salome CM, Woolcock AJ. Predictive nature of bronchial responsiveness and respiratory symptoms in a one year cohort study of Sydney schoolchildren. Eur Respir J 1993;6:662–669. |
| 36. | Forastiere F, Agabiti N, Corbo GM, Dell'Orco V, Porta D, Pistelli R, Levenstein S, Perucci CA. Socioeconomic status, number of siblings, and respiratory infections in early life as determinants of atopy in children. Epidemiology 1997;8:566–570. |
| 37. | Strachan DP, Harkins LS, Johnston ID, Anderson HR. Childhood antecedents of allergic sensitization in young British adults. J Allergy Clin Immunol 1997;99:6–12. |
| 38. | Kuyucu S, Saraclar Y, Tuncer A, Sackesen C, Adalioglu G, Sumbuloglu V, Sekerel BE. Determinants of atopic sensitization in Turkish school children: effects of pre- and post-natal events and maternal atopy. Pediatr Allergy Immunol 2004;15:62–71. |
