TUESDAY, Sept. 20 (HealthDay News) -- Young adults who were born
prematurely may not give the circumstances of their birth much
thought, but a new study finds that health problems may re-emerge
decades later and raise their risk of death for some time.
From 18 to 36 years of age, people who were born preterm face up
to twice the risk of death compared to young adults born at a
normal gestational age, the researchers found. They also noted that
preemies have an increased risk of death from birth until age 5
years, but that association was less surprising.
"We found that people who were born preterm had a higher risk of dying than people born full-term. Even [those born] a couple of weeks early had an increased mortality in young adulthood," said the study's lead author, Dr. Casey Crump, a clinical assistant professor of medicine at Stanford University in California.
"In young adulthood, each additional week of pregnancy resulted in a 4 percent reduced risk of dying as a young adult," he added.
However, any individual's risk of dying was still low. Even
those who were born between 22 and 27 weeks' gestation had less
than a 1 percent risk of dying as a young adult, according to the
study, published in the Sept. 21 issue of the
Journal of the American Medical Association.
Dr. Kenneth Bromberg, chairman of pediatrics at the Brooklyn
Hospital Center in New York City, said that on an individual level,
those who might be more at risk may already be aware of that risk.
"Some of these kids with congenital anomalies, like heart defects,
are already aware of their problems. What we can't tell from this
kind of large population data is if there are other ill-defined
problems," he said.
Besides congenital abnormalities, the association was seen with
deaths from respiratory, cardiovascular and endocrine problems, but
not cancer, neurological disorders or accidents, the authors
Any birth that occurs before 37 completed weeks of pregnancy is
considered preterm, according to the study. Preterm births are the
leading cause of infant mortality, but more and more preterm babies
are surviving, the study authors noted. Yet, little information is
available on what happens as these babies reach adulthood, they
The current finding comes from a Swedish study of al;most
675,000 people born between 1973 and 1979. Of these, nearly 28,000
were born preterm. The study followed the babies through 2008, when
they were between 29 and 36 years old.
A total of 7,095 deaths occurred in the entire group. The
researchers found a strong inverse association between each week of
pregnancy and the risk of death for two age groups: children
between 1 and 5 years old, and young adults (aged 18 to 36 years).
No association was found between risk of death and the number of
weeks of pregnancy for children between the ages of 6 and 17
For the younger group, each additional week of pregnancy was
associated with an 8 percent decreased risk of dying. For the young
adults, that number was 4 percent for each additional week of
The incidence of death for young adults was 0.94 per 1,000
person-years for babies born between 22 and 27 weeks' gestation.
For babies born between 28 and 33 weeks' gestation, the rate was
0.86 per 1,000 person-years. At 34 to 36 weeks' gestation, the rate
was 0.65 and at normal gestation (37 to 42 weeks), the rate was
0.46 per 1,000 person-years, according to the study.
The researchers don't know exactly why there's an increased risk
of death in adulthood, after a relatively long period where death
risk isn't increased. "There is an increased risk of health
problems in premature infants. Maybe some of these conditions have
a long latency or period of development," suggested Crump.
Bromberg also noted that some of the life-saving interventions
done to premature babies might cause problems as the children get
The management of premature infants has changed over the years,
but Crump said it isn't clear how, or even if, newer therapies
might change these findings.
"There needs to be better awareness of the long-term health effects of preterm birth. The early health effects are well-known, but it's important to be aware of long-term risks of preterm birth," said Crump.
Learn more about why babies are born prematurely from the
March of Dimes.