Pollard R
Department of Public Health, Somerset Health Authority, Taunton, England.
Hum Biol. 1995 Dec;67(6):921-31.
A meaningful comparison of the twinning rates of different populations can be hindered by several factors that may influence the rates. Chief among these factors are the sources of data from which the rates are derived and the maternal age structure of the populations. The effects of such factors were minimal when the twinning rates of 14 ethnic groups in California were compared. After standardization for maternal age, twinning rates per 1000 maternities for the main ethnic groups were 13.20 for blacks, 10.05 for whites, and 7.18 for Asians. There were significant differences within the Asian group. The highest rate was for Cambodians (8.57). This rate compares with rates of approximately 6 for Koreans, Thai, and Vietnamese. These rates are similar to those found in Asia but lower than those for Californian Chinese, Japanese, and Filipinos, who have been established in the state for longer. In general, the results provide support for previous reports that twinning rates are modified by both migration and interethnic mixing. Rates for Indians from India were lower than those reported from the Indian subcontinent, whereas the twinning rates for Native Americans (10.15) and Pacific Islanders (10.60) were similar to the rate for US whites.
不同人群双胞胎出生率的有意义比较可能会受到几个影响出生率的因素阻碍。这些因素中最主要的是计算出生率所依据的数据来源以及人群的母亲年龄结构。在比较加利福尼亚州14个种族的双胞胎出生率时，这些因素的影响极小。在对母亲年龄进行标准化后，主要种族每1000次生育的双胞胎出生率中，黑人是13.20，白人是10.05，亚洲人是7.18。亚洲人群内部存在显著差异。柬埔寨人的出生率最高（8.57）。这个比率与韩国人、泰国人和越南人的比率（约为6）相比。这些比率与在亚洲发现的比率相似，但低于在该州定居时间更长的加利福尼亚华裔、日裔和菲律宾裔的比率。总体而言，这些结果为先前的报告提供了支持，即双胞胎出生率会受到移民和族裔间通婚的影响。来自印度的印度人的比率低于印度次大陆报告的比率，而美国原住民（10.15）和太平洋岛民（10.60）的双胞胎出生率与美国白人的比率相似。
