Predisposing factors of non-syndromic cleft lip and cleft palate in the northern Thai population: A 10-year retrospective case–control study

The most common congenital anomaly is orofacial cleft, which is categorized into two main types: cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). One of the most accepted etiologies is multifactorial (gene–environment). This study aimed to identify the amendable risk factors of an orofacial cleft in Northern Thailand. A retrospective case–control study in Maharaj Nakorn Chiang Mai Hospital was conducted from 2011 to 2020. One hundred and seventeen cases of CL/P and CPO were included. Forty-nine normal children were enrolled in a time-matched control group. Exploratory survey data on maternal exposures were collected. Multivariate logistic regression was used to estimate the adjusted association between maternal exposures and CL/P, and CPO occurrence. Multivariate analysis identified three predisposing factors that increased the risk of CL/P and CPO. The first factor was caffeine consumption with a total amount of 560 mg/week (adjusted OR: 7.59; 95% CI: 2.48–23.23; p < 0.001). The second factor was any smoker or passive smoking (adjusted OR: 8.47; 95% CI: 1.63–43.92; p = 0.011). The third factor was a low socioeconomic status (income of lower than 270 USD/month; adjusted OR: 4.05; 95% CI: 1.07–15.27; p = 0.039). From the 10-year study in Northern Thailand: caffeine consumption, exposure to cigarette smoke, and low socioeconomic status were identified as associated negative factors for orofacial clefts. We propose that preconceptional counseling for risk reduction should be emphasized in reducing the mother's exposure to these factors. Future investigations in large multicenter populations are suggested.