China’s congenital anomaly mortality fell as regional relative inequalities rose

Congenital anomaly mortality in China declined between 2008 and 2021, but a population-based surveillance study found that relative geographical inequalities increased for several cause groups among children younger than five. The national age-standardized mortality rate fell from 2.90 to 1.11 deaths per 100,000 population, with an average annual percentage change of −6.54% (95% confidence interval [CI], −8.74% to −4.29%). The study analyzed aggregate data from the China Cause of Death Surveillance System for 2008–2021.

It used Joinpoint regression to examine mortality trends and performed sensitivity analyses addressing the expansion of surveillance in 2013. Generalized additive models were used to analyze patterns in the data, while symmetric two-factor Das Gupta decomposition separated the contributions of population age structure and age-specific mortality to changes in crude mortality. For children younger than five, the researchers assessed geographical inequalities with the slope index of inequality (SII) and the relative index of inequality (RII).

The two measures captured different aspects of the disparities: the SII decreased for circulatory anomalies, from 8.36 to 7.05, whereas the RII increased from 1.42 to 4.25 over the study period. Thus, the national decline in age-standardized mortality did not mean that relative differences between regions disappeared. Das Gupta decomposition showed that population age structure and age-specific mortality contributed differently to the reduction in crude mortality.

Age structure contributed −0.23 deaths per 100,000, while age-specific mortality contributed −1.54 deaths per 100,000. The larger contribution from age-specific mortality indicates that changes within age groups accounted for most of the observed contribution to the crude-rate change. These results do not by themselves identify the causes of the decline.

Analyses that addressed this transition still indicated a decline in congenital anomaly mortality. The national trend therefore was not observed only in an analysis that ignored the surveillance expansion, although the study used aggregate surveillance data and could not establish the mechanisms behind the temporal change. Urban–rural comparisons were more sensitive to possible differences in death ascertainment.

The urban–rural SII was significantly negative from 2013 through 2018, indicating a changing pattern in the measured distribution of mortality across those areas. The authors assessed how additional under-ascertainment in rural areas could affect the estimates: assuming 20% additional rural under-ascertainment changed the 2015 RII for circulatory anomalies from 0.62 to 0.97, with a conditional 95% CI of 0.83 to 1.12. The analysis also tested whether residual ascertainment differences could account for the apparent increase in relative regional inequality.

In a scenario assuming a 30% residual ascertainment deficit at the disadvantaged rank endpoint in 2009 and no deficit in 2021, the 2021 RII for circulatory anomalies remained 2.10 times the 2009 value. The increase persisted under assumed initial residual deficits of 10–30%, although larger initial deficits could eliminate the increase. Overall, the findings separate two simultaneous patterns: a substantial decline in China’s age-standardized congenital anomaly mortality rate and persistent or increased relative inequality for several causes among children under five.

The surveillance analysis provides evidence about temporal trends and geographical disparities, but its deterministic bias scenarios and reliance on aggregate data limit conclusions about the causes of the regional differences. The authors reported that the national trend remained evident in sensitivity analyses, while the urban–rural reversal was more sensitive to differential ascertainment.

Subject of Research: Trends and geographical inequalities in congenital anomaly mortality in China, 2008–2021

Article Title: Temporal trends and geographical inequalities in congenital anomaly mortality in China, 2008–2021: a population-based surveillance study

Article References: Tai, M., Bai, Z., Lu, S., Zhang, Y., Patel, N., Yang, Z., & Mo, X. (2026). Temporal trends and geographical inequalities in congenital anomaly mortality in China, 2008–2021: a population-based surveillance study. BMC Public Health. https://doi.org/10.1186/s12889-026-30041-4

Image Credits: AI Generated

DOI: 10.1186/s12889-026-30041-4

Keywords: congenital anomalies, child mortality, China, health inequalities, cause-of-death surveillance, mortality trends, age-standardized rates, geographical disparities, Temporal, trends, geographical, inequalities