Risk factors for non‐syndromic oral clefts: a matched case–control study in Hubei Province, China

Objective To explore the risk factors for CL/P in Hubei Province, China. Methods A hospital-based, matched case–control study was conducted. One hundred and eight cases with CL/P were matched by age and sex with 108 normal controls. Their parents were retrospectively interviewed using a questionnaire. Univariate and multivariate analyses were used to calculate the relative risk by odds ratio and 95% confidence interval. Results Univariate analysis identified ten factors as significantly related to CL/P (P < 0.05). Multivariate conditional logistic regression models showed that five of these factors were significantly associated with CL/P. Paternal occupational exposure (OR = 13.08, 95% CI: 2.35–72.86), first-trimester maternal illness (OR = 36.67, 95% CI: 5.37–250.36), first-trimester maternal bad mood (OR = 8.69, 95% CI: 1.35–55.84), first-trimester maternal diet of eggs or milk (≥5 meals per week, OR = 6.72, 95% CI: 1.23–36.69), and first-trimester maternal sexual activity (OR = 5.98, CI 95%:1.14–31.49) were risk factors for CL/P. Conclusions In our study, we identified that paternal occupational exposure, first-trimester maternal illness, first-trimester maternal bad mood, first-trimester maternal diet of eggs or milk (≥5 meals per week), and first-trimester maternal sexual activities were significantly associated with increased CL/P.