Objective: To explore the genetic and environmental factors related to the development of polydactyly and syndactyly, and to provide evidence for prevention on birth defects.
Methods: A hospital-based case-control study was conducted. 111 cases and 222 controls were interviewed with standardized questionnaires. Logistic regression models were used to select risk factors.
Results: Research data through univariate analysis showed that the occurrence of polydactyly and syndactyly were associated with educational level, annual average income per family member, meat and egg intake during early pregnancy, family heredity history, exposure to hazardous substance before pregnancy, serious pregnant reaction etc. of the pregnant women. As shown in multivariable logistic model, some factors, including annual average income of per family member (OR = 0.240), meat and egg intake during early pregnancy (OR = 0.182), could reduce the risk of the development of polydactyly and syndactyly. Other factors including family heredity history (OR = 10.187), exposure to hazardous substance before pregnancy (OR = 3.029), could increase the risk of developing polydactyly and syndactyly. The attributable risks (%) of family heredity history and exposure to hazardous substance before pregnancy were 90.18% and 66.99% respectively.
Conclusion: Genetic factor was the leading cause on the development of polydactyly and syndactyly. In addition, environmental factors, such as family economic condition, nutritional status during early pregnancy and working condition before pregnancy were associated with the development of polydactyly and syndactyly.