Increased risk of allergic rhinitis among children delivered by cesarean section: a cross-sectional study nested in a birth cohort.
Few studies have evaluated the association between delivery by cesarean section (CS) and asthma, allergic rhinitis and chronic rhinitis and whether this association is different in children with and without a family history of asthma. This study aims to investigate whether children born by CS have a higher chance to develop asthma, allergic rhinitis and chronic rhinitis and to evaluate the influence of parental history of asthma on these associations.



This is a cross-sectional study of 672 children nested in a birth cohort evaluated at 6-years of age. Asthma and chronic/allergic rhinitis were identified by means of the mother's responses to the ISAAC questionnaire. The association between CS, asthma, chronic rhinitis and allergic rhinitis was evaluated by multivariable logistic regression. The evidence of effect modification of parental history of asthma on the association CS and outcomes was examined by introducing interactions terms in the logistic regression models adjusting for confounders.



Asthma was not associated with birth by CS irrespective of parental history of asthma (odds ratio (OR) 1.03; 95 % CI 0.61-1.74). Chronic rhinitis and allergic rhinitis were both significantly associated with birth by CS but only in the subgroup of children with by parental history of asthma (OR 1.56; 95 % CI 1.04-2.34) and (OR 1.60; 95 % CI 1.01-2.55) respectively, after adjustment for confounders. The parental history of asthma was a effect modifier in the association between CS, chronic rhinitis and allergic rhinitis (p for effect modification = 0.10 and 0.02, respectively).



CS increases the risk of chronic rhinitis and allergic rhinitis in children at 6 years of age with parental history of asthma. Health professionals must be alerted with regard to the increased risk of allergic rhinitis and made aware this is another reason to avoid unnecessary CS.
Doctorate student of Escola Bahiana de Medicina e Saúde Pública, Salvador, Brazil. helivb.fsa@gmail.com.|, Rua Marechal Castelo Branco 597, Capuchinhos, Feira de Santana, Bahia CEP: 44076-020, Brazil. helivb.fsa@gmail.com.
Heli Vieira
HV
Brandão
Full Professor of Pediatrics, State University of Feira de Santana, Feira de Santana, Brazil.
Graciete Oliveira
GO
Vieira
Instructor of Pediatrics, State University of Feira de Santana, Feira de Santana, Brazil.
Tatiana
T
de Oliveira Vieira
Full Professor of Pediatrics, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Paulo Augusto
PA
Camargos
Associate Professor State University of Feira de Santana, Feira de Santana, Brazil.
Carlos Antonio
CA
de Souza Teles
Full Professor of Escola Bahiana de Medicina e Saúde Pública, Salvador, Brazil.
Armênio Costa
AC
Guimarães
Head of the Center of Excellence in Asthma of the Federal University of Bahia, Salvador, Brazil.
Alvaro Augusto
AA
Cruz
Adjunct Professor of Escola Bahiana de Medicina and Saúde Pública. Coordinator of Multidisciplinary Research of Hospital Santo Antonio, Obras Sociais Irmã Dulce, Salvador, Brazil.
Constança Margarida Sampaio
CMS
Cruz
D001249:Asthma / Q000209:etiology*; D002585:Cesarean Section / Q000009:adverse effects*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008487:Medical History Taking; D016017:Odds Ratio; D065631:Rhinitis, Allergic / Q000209:etiology*; D012221:Rhinitis, Allergic, Perennial / Q000209:etiology; D012307:Risk Factors
Allergic rhinitis; Asthma; Cesarean; Children