Live birth prevalence of Down syndrome in Tottori, Japan, 1980–1999

Abstract

One hundred sixty-four patients with Down syndrome (DS) were confirmed in Tottori Prefecture, Japan, from 1980 to 1999. The sex ratio of 1.52 (99 males and 65 females) was comparable to that reported in previous studies. The live birth prevalence per 1,000 was 1.52 (95% CI: 1.29-1.75) from 1980 to 1999, with a prevalence of 1.34 (95% CI: 1.05-1.63) recorded between 1980 and 1989, and 1.74 (95% CI: 1.37-2.11) between 1990 and 1999. There was no statistically significant change between these two decades (chi(2)-test). Live birth prevalence in these two decades showed a significant increase (chi(2)-test, P < 0.005) compared with that recorded in 1969-1978 in Tottori Prefecture (0.803, 95% CI: 0.677-0.929). Mean ages of mothers at the birth of a DS patient were 31.0 years in 1980-1989 and 32.4 years in 1990-1999 (t-test, no significant difference). Dispersion analysis on the mean age of mothers at birth for patients born between 1969-1978, 1980-1989, and 1990-1999 showed a significant difference (t-test, P < 0.005), while comparing the mean age of mothers in 1969-1978 to those in 1990-1999 also revealed a significant difference (t-test, P < 0.001). Live birth prevalence has increased due to the rise in fertility rates among older women, although maternal age-specific risk rates remain unchanged. The widespread introduction of induced abortion following prenatal diagnosis decreased live birth prevalence of DS largely in European (and a few Asian) countries after 1990, or kept prevalence steady, despite increasing fertility rates among women aged 30 and over. In contrast, all published studies have reported an increase in live birth prevalence of this syndrome in Japan, probably resulting from the fact that prenatal diagnoses are used only exceptionally in this country (due to the negative attitude toward selection of life in Japanese culture).

Retrospective analysis of live birth prevalence of children with Down syndrome in Denizli, Turkey

“…Gender distribution is fairly balanced in our registries (51.3% male), compared to 53.1% males among the Down's cases of Balkan et al (2010) and 54.6% males by Duarte et al (2004); however, Takeuchi et al (2008) reported a gender ratio of 1.55.…”

“…It was reported that DS prevalence was increased from 9.0 to 11.8 per 10,000 live births in 10 USA regions during a 25-year period (Olsen et al, 2003;Shin et al, 2009 The live birth prevalence of DS has been increasing in Japan since 1970; the increasing frequency of DS is attributed to advanced maternal age (Hoshi et al, 1999;Kajii, 2008;Takeuchi et al, 2008). In contrast, the live birth prevalence of DS has decreased (from 1.17 to 0.89/1000) over the years, from 1993 to 1998 in Singapore, due to antenatal diagnosis and elective abortion (Lai et al, 2002).…”

Intracranial Hemangiopericytoma and the Role of Radiation Therapy

“…However, Down syndrome is less common in the Japanese and black populations. [9][10][11] The fewer number of cases of concurrent moyamoya disease and Down syndrome in these ethnicities may be secondary to a lower proportion of patients with Down syndrome in these populations. The contribution of Down syndrome to moyamoya disease in patients $ 15 years of age decreases, and other factors such as hypertension and diabetes mellitus assume greater importance.…”

Aging in Down Syndrome: Morbidity and Mortality

“…Reported live birth rates vary greatly between countries from 0.23 per 1,000 in Taiwan (Jou et al., 2005), to 2.98 in Ireland (O'Nuallain, Flanagan, Raffat, Avalos, & Dineen, 2007), reflecting differences in maternal age, access to antenatal diagnosis, and social attitudes toward termination of pregnancy. While live birth rates with Down syndrome have declined in Taiwan (Jou et al., 2005), Singapore (Lai et al., 2002), and France (Khoshnood, De Vigan, Vodovar, Goujard, & Goffinet, 2004), live birth rates are increasing in Ireland (O'Nuallain et al., 2007), Japan (Takeuchi et al., 2008), and Hungary (Metneki & Czeizel, 2005). The overall prevalence of people with Down syndrome is expected to increase for some time due to dramatic increases in median and average life expectancy, even where there is a drop in live birth rates.…”