Characteristics of the sex ratio at birth in Chaoyang, Beijing from 2009 to 2019
LYU Xilin, TANG Youchi, ZHOU Yubo, LI Hongtian, LIU Jianmeng
Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health, Department of Epidemidogy and Biostatistics, School of Public Health, Peking University, Beijing 100191,China
摘要目的 分析近十年特别是全面两孩政策实施后北京市朝阳区出生人口性别比变化趋势,以及不同特征群体出生性别比分布情况。方法 研究资料为2009—2019年北京市朝阳区分娩出生登记信息,共534 376条记录,研究纳入分析变量主要包括新生儿性别、分娩方式、母亲产次,还有新生儿父母双方年龄、民族、籍贯和户籍。为比较不同特征群体出生性别比,采用χ2检验分析出生性别比例构成情况。采用中断时间序列模型,以2015年7月至2019年12月期间月度出生性别比为分析单位,研究全面两孩政策与出生性别比关系。为研究婴儿父母籍贯及户籍所在地与出生性别比的关系,将婴儿父母籍贯与户籍所在省份分为高出生性别比地区和中低出生性别比地区,前者指第六次人口普查出生性别比≥120的省份,后者指＜120的省份。结果 2009年出生性别比为113.0,2015年降至109.4,此后至2019年维持平稳,经中断时间序列分析未发现全面两孩政策显效后出生性别比的水平及趋势有所变化(P>0.05)。研究期间经产妇与初产妇(112.3 vs. 107.2)、剖宫产与阴道产(114.0 vs. 105.9)分娩婴儿性别比差异有统计学意义(P<0.05);父母籍贯均为高出生性别比地区婴儿的出生性别比显著高于父母至少一方籍贯为中低出生性别比地区的婴儿(114.2 vs. 108.4, P<0.05);对于父母籍贯均为高出生性别比地区的婴儿,其父母至少一方为北京户籍者出生性别比显著低于父母双方均为京外户籍者(107.7 vs. 118.0, P<0.05)。结论 近十年北京市朝阳区出生人口性别比呈现先降后稳的趋势,2016年全面两孩政策实施后,在考虑基线阶段变化趋势后,出生人口性别比无明显变化。经产妇及剖宫产分娩婴儿性别比偏高,籍贯均为高出生性别比地区且户籍均在京外的父母所生婴儿性别比偏高。
Abstract：Objective To investigate the temporal trends of sex ratio at birth (SRB) in Beijing over the past decade, especially after the implementation of the universal two-child policy, and to describe the characteristics of the SRB among different population subgroups.Methods The study was conducted based on birth records of Chaoyang district, a central area of Beijing, involving a total of 534,376 records during 2009 and 2019. The variables in the analysis included the sex of the newborn, the mode of delivery, the parity of the mother, as well as the age, ethnicity, birth place, and household registration of the parents. χ2 test was used to examine the differences in SRB among groups with different characteristics. The interrupted time series model was fitted to the data of monthly SRB between July 2015 and December 2019, with the aim of studying the impact of the universal two-child policy on SRB. In order to assess the relationship of the birth places of parents and their household registration with the SRB, provinces were classified into high SRB areas and low- to middle-SRB areas according to the sixth national census of China conducted in 2010.Results The overall SRB decreased from 113.0 in 2009 to 109.4 in 2015, and remained stable until 2019. The interrupted time series analysis identified no change in the level and trend of the SRB after the universal two-child policy took effect in 2016(P>0.05). During the study period, there were significant differences in the SRB between infants born to multiparous and primiparous mothers (112.3 vs.107.2) and between those delivered by cesarean section and vaginal delivery (114.0 vs.105.9) (P<0.05). The SRB was significantly higher for infants whose parents were both originated from high SRB areas than those whose one or both parents were originated from low- to middle-SRB areas (114.2 vs.108.4, P<0.05). Among infants whose parents were both from high SRB areas, the SRB was significantly lower for infants whose one or both parents had Beijing household registration than those whose both parents did not (107.7 vs.118.0, P<0.05).Conclusion The overall SRB in the study area decreases between 2009 and 2015 and remains stable thereafter, and there is no significant change in SRB after the implementation of the universal two-child policy. The SRB is relatively higher among infants born to multiparous mothers and delivered by cesarean section and among those whose parents are both originated from high SRB areas and do not have Beijing household registration.
吕希霖, 唐友池, 周玉博, 李宏田, 刘建蒙. 2009—2019年北京朝阳区出生人口性别比特征分析[J]. 中国生育健康杂志, 2023, 34(2): 114-119.
LYU Xilin, TANG Youchi, ZHOU Yubo, LI Hongtian, LIU Jianmeng. Characteristics of the sex ratio at birth in Chaoyang, Beijing from 2009 to 2019. Chinese Journal of Reproductive Health, 2023, 34(2): 114-119.
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