Imaizumi Yoko, Nishida Etsuo
Department of Health Science, Graduate School of Medicine, Osaka University, Suita, Japan.
Twin Res Hum Genet. 2011 Apr;14(2):179-84. doi: 10.1375/twin.14.2.179.
The purpose of this study was to estimate the number of siblings in each Japanese family with multiple birth children using two sets of census data, from 1990 and 1995. The mean number of siblings for singletons was 2.3 in 1990 (2.4 in 1995), 2.9 (2.9) for one set of twins, 4.6 (4.5) for two sets of twins, and 3.5 (3.3) for one set of triplets. For birth order of multiples, the highest mean sibling number was 4.4 for one set of twins (the middle), 7.5 for two sets of twins (the middle-middle), and 4.3 for one set of triplets (the last). The mean sibling number was slightly higher for like-sexed twins and triplets than in unlike-sexed twins and triplets. The mean sibling number was highest in the Okinawa District, among nine districts (0.4 for singletons, 0.6 for one set of twins, 1.0 for two sets of twins and 0.6 for triplets). The current study of the number of siblings in each family with multiple birth children will help provide data for designing programs to help support multiple-birth families. The method of using census data on multiple births might result in a system to analyze nationwide data on multiple birth children if there is no national registry of multiple births after live births in any country.
本研究的目的是利用1990年和1995年的两组人口普查数据，估算每个有多个孩子的日本家庭中的兄弟姐妹数量。1990年单胎的平均兄弟姐妹数量为2.3（1995年为2.4），一对双胞胎为2.9（2.9），两对双胞胎为4.6（4.5），一对三胞胎为3.5（3.3）。对于多胞胎的出生顺序，一对双胞胎（中间出生）的平均兄弟姐妹数量最高为4.4，两对双胞胎（中间-中间出生）为7.5，一对三胞胎（最后出生）为4.3。同性双胞胎和三胞胎的平均兄弟姐妹数量略高于异性双胞胎和三胞胎。在九个地区中，冲绳地区的平均兄弟姐妹数量最高（单胎为0.4，一对双胞胎为0.6，两对双胞胎为1.0，三胞胎为0.6）。当前对每个有多个孩子的家庭中兄弟姐妹数量的研究将有助于为设计支持多胞胎家庭的项目提供数据。如果任何国家没有活产后多胞胎的国家登记处，使用多胞胎人口普查数据的方法可能会形成一个分析全国多胞胎儿童数据的系统。
