A review of seasonality of cleft births - The Brazil experience.
OBJECTIVE
Evaluate the seasonal influence in nonsyndromic cleft lip and/or palate (NSCL/P) in Brazilian patients.


METHODS
A case-control study, with 361 unrelated patients with NSCL/P and 481 healthy individuals, was done on a reference service for craniofacial deformities in Minas Gerais State, Brazil. Information was collected from clinical records considering gender, month of birth, as well as with the seasons.


RESULTS
Nonparametric tests did not show a seasonal variation in month of birth and in seasons of year of NSCL/P compared to a control group (p = 0.902 and p = 0.679, respectively). A difference in births between the groups was identified only in January, however, was not significant. Moreover, among the control group there were more births in the months of February and August, and for the cleft group, more in July and August. The males were more affected by cleft lip with or without palate (CLP) and the females by isolated cleft palate (CP) manifestation. The ratio of CL:CLP:CP indicated that CLP was predominant when compared with CL and CP, CLP was more frequent in male patients, and CP predominance was seen in females.


CONCLUSIONS
This study did not show seasonal differences in births on NSCL/P in a Brazilian group, emphasizing that environmental factors may be related to oral clefts. These results provide a basis for further epidemiological studies of orofacial clefts in Brazil.
School of Dentistry, Federal University of Juiz de Fora, Governador Valadares, Minas Gerais, Brazil.
Sibele Nascimento
SN
de Aquino
Department of Oral Diagnostic, Piracicaba Dental School - State University of Campinas, Piracicaba, São Paulo, Brazil.
Renato Assis
RA
Machado
Health Science Program, State University of Montes Claros, Montes Claros, Minas Gerais, Brazil.
Lívia Máris R
LM
Paranaíba
Health Science Program, State University of Montes Claros, Montes Claros, Minas Gerais, Brazil.
Daniella Reis B
DR
Martelli
Health Science Program, State University of Montes Claros, Montes Claros, Minas Gerais, Brazil.
Daniela Araújo Veloso
DA
Popoff
Center for Rehabilitation of Craniofacial Anomalies, Dental School, University Jose Rosário Vellano, Alfenas, Minas Gerais, Brazil.
Mário Sérgio O
MS
Swerts
Health Science Program, State University of Montes Claros, Montes Claros, Minas Gerais, Brazil; Center for Rehabilitation of Craniofacial Anomalies, Dental School, University Jose Rosário Vellano, Alfenas, Minas Gerais, Brazil.
Hercílio
H
Martelli-Júnior
Brazil; Cleft lip; Cleft palate; Seasonal Variations