Coast-or Inland Residence and Differences in the Occurrence of Cleft Lip and Cleft Palate.

Objetive: To analyze if differences in lifestyle and environment between coastal and inland areas are associated with differences in frequency of orofacial cleft types.

Design: Populational cross-sectional study.

Setting: All live borns with orofacial cleft registered at Brazilian Live Birth Information System between 1999 and 2020.

Participants: 33,699 live borns with orofacial cleft.

Intervention: Data from borns with orofacial cleft were collected at Brazilian Live Birth Information System.

Main Outcome Measure: Differences in frequencies between the cleft types and covariates were determined using chi-square. Bivariate analysis was done to obtain the prevalence ratio of types of clefts by geographic origin. Multiple logistic regression analysis was used to determine adjusted odds ratios, controlling for covariates, establishing a significance level of p value <0.05.

Results: The frequency of cleft types was statistically significant different according to geographic origin (inland x coast). For syndromic clefts, the prevalence ratio for cleft lip with/without palate was 3.6 times higher inland (p value = 0.000). Regarding non-syndromics, the prevalence ratio for cleft lip with/without palate was two times higher inland (p value = 0.000). Logistic regression suggested cleft lip with/without palate was 6.33 more likely to occur in inland regions (p value = 0.000).

Conclusion: Geographic origin was associated with the type of cleft in Brazil, with a higher prevalence of cleft lip with/without palate in inland areas, compared to cleft palate, which was higher in the coast.