Prevalence and time trends of spina bifida in fourteen cities located in the Liaoning province of northeast China, 2006-2015

The present study sought to assess the time trends of spina bifida on the basis of cases identified by the Liaoning Birth Defects Registry in 14 cities from 2006 to 2015. We calculated the prevalence of spina bifida, percent and average change of time trends, and contribution rates of each city. Poisson regression model was used to find the line of best fit for spina bifida prevalence by year, with year as a continuous independent variable. From 2006 to 2015, a total of 2,029 spina bifida cases were identified from 3,248,954 live births (6.25/10,000 live births). We observed statistically significant decreasing trend of overall time trend (11.57% each year). Chaoyang, Fuxin, and Huludao were the top three leading cities, with 14.30/10,000 live births, 9.70/10,000 live births, and 9.20/10,000 live births, respectively. Inversely, the bottom three cities with lowest prevalence were Anshan (2.64/10,000 live births), Dandong (3.43/10,000 live births), and Dalian (3.45/10,000 live births). Of note, we observed significant decreasing trends in over half of these cities (n = 8). In addition, the decreasing trend of overall time trend could be mainly attributed to cities of Shenyang, Fushun, and Jinzhou which accounted for nearly one third. In summary, our study suggested a decreasing time trend of spina bifida during the past decade in the Liaoning province. The findings of this study provide evidence that the nationwide folic acid supplement program has been an effective strategy to prevent spina bifida.