Clinical, social, and ethical implications of changing life expectancy in Down syndrome

Abstract

Between 1 and 4% of the populations of developed nations are diagnosed with learning disability*. 1,2 In Australia, an estimated 1.9% of the population exhibit learning disability either as a primary disability or as a secondary condition, and approximately half of these people require continuing support in daily living, including mobility, self-care, and socialization. 3 After improvements in basic public health measures, life expectancy in most developed nations increased over the course of the 20th century, and this trend included people with learning disability. Thus, by the end of that century, the survival estimates for people with mild learning disability living in developed countries was 70 years, and nearly 60 years of age for those with severe learning disability. 4,5 The estimates of increased life expectancy mirror improved access to medical treatment for those with learning disability, and a shift in public attitude during the past 20 to 30 years that has resulted in better care within the community. The increased availability of more appropriate medication, surgical intervention, and overall health care management strategies have led to a positive effect on general health and have decreased mortality. More recently, national and international agencies have strongly argued for further improvements in health care opportunities for individuals with disabilities, and for the narrowing of health differentials between people with learning disability and the general population. 6-9 However, this is a complex issue with challenging social, economic, and ethical ramifications, because many people with learning disability are affected by major adverse health issues throughout their lives. As a result, increased survival is not only associated with a longer period of care, but is also related to a longer period of more specialized needs. Here we discuss these issues with specific reference to the circumstances of people with Down syndrome, although it should be emphasized that to a large degree they equally apply to a wide range of inherited disorders resulting in learning disability. EpidemiologyDown syndrome is the most commonly inherited form of learning disability, with an incidence rate of 1 out of every 650 to 1000 live births, 10-12 and in developed countries it accounts for 12 to 15% of the population of those with learning disability. 4,13,14 The actual number of Down syndrome conceptions is unknown, but occurrence of the disorder increases significantly with advancing maternal age, 15 and there is some evidence that advanced paternal age might also be involved. 16 There is a high rate of spontaneous prenatal loss and, for example, in one study 43% of Down syndrome pregnancies detected by chorionic villus sampling at 10 weeks gestation failed to reach term. 17 The trisomy 21 karyotype is present in 93 to 95% of people with Down syndrome; a further 3 to 4% exhibit translocation anomalies, and 1 to 3% are mosaic. 18-20 Down syndrome is usually associated with moderate to severe levels of learning disab...

The functional fitness capacity of adults with Down syndrome in South Africa

“…This is also the case for DS individuals as 80% of this population lives past 30 years of age (Goodman et al, 1998). In fact, life expectancy for DS individuals has been increasing from an average age of 9 years in 1929, to 12 years in 1949, 35 years in 1982, and currently to 55 years (Bittles et al, 2004;Carmeli et al, 2004). Torr et al (2010) also found that the life expectancy of DS individuals increased vastly in the last three decades, which have led to an increased amount of DS adults living well into middle and old age.…”

“…This is of enormous importance as Bittles et al (2004) pointed out that the life expectancy for DS individuals has been increasing drastically in the last century. This could be problematic as increased life expectancy has been shown to be associated with increased health problems in DS individuals (Carmeli et al, 2004;Folin et al, 2003;Krinsky et al, 2002;Shamas-Ud-Din, 2002).…”

“…Therefore this individual has 47 chromosomes instead of the normal 46 (23 chromosomes from each parent). The second cause, responsible for 3 -4% of DS cases (Bittles et al, 2004), is known as nondisjunction, which occurs when one pair of chromosomes fails to divide during meiotic cell division, resulting in 24 chromosomes in one haploid cell and 22 in the other. A third and rare cause of DS is translocation (1 -3% of all cases), also referred to as mosaicism.…”

“…Trisomy 21 occurs in 93 -95% of all cases (Bittles et al, 2004) and is so named because of the presence of an extra number 21 chromosome. Therefore this individual has 47 chromosomes instead of the normal 46 (23 chromosomes from each parent).…”

“…Cowley et al (2010) and Baynard et al (2008) was of the opinion that the low aerobic capacities of DS individuals remind one of the frail and aged. It must be remembered that the life expectancy of DS individuals has increased dramatically in the last century (Torr et al, 2010;Bittles et al, 2004;Carmeli et al, 2002 b ), but that this increased life expectancy is associated with increased health problems in DS individuals (Carmeli et al, 2004;Folin et al, 2003;Krinsky et al, 2002;Shamas-Ud-Din, 2002). Moreover, researchers have also shown that any further decline in the functional capacity of DS individuals, either as a result of ageing or living a sedentary life, could result in a shift from independence to a physical disability (Carmeli et al, 2003 b ).…”