Changes in the Incidence of Congenital Anomalies in Henan Province, China, from 1997 to 2011
Fig 2
Factors associated with congenital anomalies.
A. The incidence of congenital anomalies in males and females was calculated each year. Logistic regression analysis showed a significant downward trend in females (p < 0.0001, OR = 0.95, 95% CI 0.95–0.96), but not in males (p = 0.212, OR = 0.99, 95% CI 0.99–1.00). The difference in incidence between 1997 and 2011 was analyzed by the chi-square test in both genders, and a significant difference was observed in females (p < 0.0001) but not in males (p = 0.883). The difference in incidence between the genders in 1997 and 2011 was analyzed with the chi-square test, and a significant difference was observed in 1997 (p < 0.0001) and in 2011 (p = 0.001). B. The incidence of congenital anomalies at different maternal ages was calculated each year. Logistic regression analysis showed significant downward trends in all the age groups during the surveillance period (p < 0.0001). C. The incidence of congenital anomalies in the four different quarters was calculated each year. Significant reductions were seen in all seasons except the second quarter (p < 0.001), but no overall differences were seen between the seasons.