Importance — Orofacial cleft (OFC) is one of the most common congenital malformations, with a wide variation in incidence worldwide. However, population-based studies on the incidence of OFC in North America are lacking.
Objectives — To examine the incidence of OFC in Ontario, Canada, and to compare risk factors and mortality associated with children with OFC vs children without OFC.
Design, Setting, and Participants — This population-based retrospective cohort study used health administrative data from the province of Ontario, Canada. Children with OFC who were born from April 1, 1994, to March 31, 2017, in Ontario were each matched to 5 children without OFC based on sex, date of birth (±30 days), and mother’s age (±5 years). Analyses were conducted from September 2018 to January 2019.
Exposures — Children born with OFC.
Main Outcomes and Measures — Incidence of OFC over time and regional variation. Risk factors for OFC were assessed using 1-way analysis of variance for means, Kruskal-Wallis for medians, and χ2 tests for categorical variables. Adjusted Cox regression models were used to assess mortality.
Results — From 1994 to 2017, 3262 children were born with OFC in Ontario, Canada, and they were matched to 15 222 children born without OFC. Incidence of OFC in Ontario was 1.12 cases per 1000 live births, with wide geographic variation and a lower incidence from 2004 to 2017 compared with 1994 to 2003 (1.02 vs 1.13 cases per 1000 live births; P = .002), especially for the subgroup with cleft palate (0.52 vs 0.44 cases per 1000 live births; P = .006). Children with OFC, compared with children without OFC, were more likely to be born prematurely (406 children [13.3%] vs 1086 children [7.1%]; P < .001; standardized difference, 0.21) and had lower mean (SD) birth weight (3215.3 [687.6] g vs 3382.6 [580.0] g; P < .001; standardized difference, 0.26). The mortality rate among children with OFC was higher than among matched children without OFC (hazard ratio, 10.60; 95% CI, 7.79-14.44; P < .001). When mortality was adjusted for the presence of congenital or chromosomal anomalies, the risk of death was not significantly different between children with OFC and those without OFC (hazard ratio, 1.35; 95% CI, 0.73-2.72).
Conclusions and Relevance — These findings suggest that incidence of OFC In Ontario, Canada, decreased from 1994 to 2017. Mortality in children with OFC was high, especially in the first 2 years of life, and was predominantly associated with the presence of other congenital or chromosomal anomalies. Further research is required to better understand the causes of wide geographical variations of OFC incidence and improve the survival of these patients.
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