Study: Most adults born prematurely survive without developing major comorbidities

Most people born prematurely are likely to survive into adulthood without developing major chronic diseases or conditions like asthma, hypertension, diabetes, and other illnesses, Mount Sinai researchers report in a study published today in the Journal of the American Medical Association (JAMA).

This study provides the first population-based estimates of the prevalence of survival without major comorbidities in adults born prematurely. The relatively high prevalence of this positive outcome in the population studied reflects not only the treatment advances that have occurred over the past 50 years, but the apparent resilience of people who survived preterm birth in maintaining good health. While the results are promising, they call for further investigation to identify protective factors that will enhance the long-term health trajectory of people who were born prematurely."

Casey Crump, MD, PhD, corresponding author and Vice Chair for Research of the Alfred and Gail Engelberg Department of Family Medicine and Community Health, Icahn School of Medicine at Mount Sinai

The researchers studied the health of more than 2.5 million people in Sweden who were born from 1973 to 1997, all of whom were followed up for survival and comorbidities through 2015. Of this group, 55 percent who were born preterm (a gestational age less than 37 weeks), and 22 percent born extremely preterm (a gestational age of 22 to 27 weeks), were alive with no major comorbidities at ages 18 to 43 years, compared to 63 percent of people in Sweden who were born full-term (a gestational age of 39 to 41 weeks).

The findings were similar among men and women and were independent of birth year and other perinatal or maternal factors. In addition, co-sibling analyses suggested that the prevalence of survival without comorbidities was not due to shared genetic or environmental factors in families. Limitations of the study include the fact that detailed clinical data weren't available to validate health conditions and longer follow- up is needed to examine outcomes after the age of 43.

Prior studies of long-term health consequences of preterm birth have focused almost entirely on specific adverse outcomes, either physical, mental, or social. Such studies have reported that people born prematurely have increased risks of cardiometabolic, respiratory, and neuropsychiatric disorders; social adversity; and premature mortality in young adulthood. Potential positive outcomes or indicators of resilience have rarely been assessed.

Additional studies are needed to identify protective factors across life that enhance resilience and the long-term health of people who were born prematurely, particularly at the earliest gestational ages.

"A key strength of this study is its ability to assess an extensive range of comorbidities in a large cohort of people with follow-up into early to mid-adulthood, using birth, medical, and pharmacy registry data," says Kristina Sundquist, MD, PhD, Professor and Family Physician, Lund University, Sweden, a study author and co-investigator. "This study design minimized potential selection bias and enabled more robust estimates based on a national population."

The U.S. National Heart, Lung, and Blood Institute at the U.S. National Institutes of Health supported the study, as did the Swedish Research Council, the Swedish Heart-Lung Foundation and ALF project grant, Region Skane/Lund University, Sweden.