Rothman K J, Fabia J J
Am J Epidemiol. 1976 Jun;103(6):560-4. doi: 10.1093/oxfordjournals.aje.a112260.
Prevalence rates at birth for Down's syndrome were compared for Massachusetts communities of different population densities. Overall, there was a small positive association between the rate of Down's syndrome and population density, entirely attributable to a strong association for the children of older mothers. An analysis for space and time clustering of births of 2469 children born in Massachusetts with Down's syndrome revealed no aggregation of cases, except for a slight seasonal peak in the summer.
对马萨诸塞州不同人口密度社区唐氏综合征的出生患病率进行了比较。总体而言，唐氏综合征患病率与人口密度之间存在微弱的正相关，这完全归因于高龄母亲所生子女中的强相关性。对马萨诸塞州出生的2469名患有唐氏综合征儿童的出生时空聚集性分析显示，除夏季略有季节性高峰外，病例并无聚集现象。
