In response to a question from my friend, Lisa... what contributes to the life expectancy of an individual with Down syndrome?
1929 - Life expectancy of an individual with Down syndrome was 9 years
Today - 55-60 years
What has caused the increase? Answer: primarily medical care (though I would also like to add that back in 1929, most individuals with Down syndrome were institutionalized, and I'm sure that environment would play a role in someone having a shorter life expectancy)
Specifically, intestinal surgery, heart surgery, infections and leukemia treatment. Approximately 50% of individuals with Down syndrome are born with a CHD (congenital heart defect). Approximately 12% are born with some sort of digestive issue. And children with Down syndrome are 10-15 times more likely to develop leukemia (though their response to treatment, I've heard, is usually better than a "typical" child who develops leukemia). Additionally, children with Down syndrome are 62 times more likely to develop pneumonia. And they are 12 times more likely to die from infectious diseases, if left untreated. They tend to get more ear infections than the general population, primarily due to VERY narrow ear canals.
If he had been born 50 years ago, Micah would have died soon after birth due to his duodenal atresia. And if it hadn't been the intestinal blockage, it would have been his heart defect. He went into heart failure around 5 weeks of age. It was managed through medications up to his surgery at 4 months (he's still on a medication, due to leakage in both his mitral and transcuspid valves... he'll likely be on that medication for life... most kids who have that same repair do not have to stay on a medication and they get cleared by their cardiologists quickly... Micah still sees a cardiologist every 6 months).
Anyway... one huge benefit to the life expectancy increasing is that they have found additional health issues that hadn't been studied in the past. The most major one is that the incidence of Alzheimer's in individuals with Down syndrome is significantly higher than the general population, and its onset is typically earlier. Why is that a benefit? A lot of the current Alzheimer's research is focusing on the 21st chromosome.
So to answer Lisa's question about life expectancy... yes, the lower life expectancy is related to health issues, whether that's intestinal obstruction, cardiac defects, or leukemia in the early years, or Alzheimer's/dementia in the later years. Micah's duodenal atresia won't lower his life expectancy at this point. But he's at a bit higher risk for pulmonary hypertension later in life, I think.