Girls born extremely prematurely may have an increased risk of depression from childhood through young adulthood.
Using Finnish birth and health registries, researchers studied 37,682 people diagnosed with mild, moderate or severe depression, comparing them with 148,795 healthy controls. The children were born between 1987 and 2007, and their average age at diagnosis was 16.
After adjusting for parents’ age, depression, substance abuse, smoking, socioeconomic status and other factors, they found that in girls, but not boys, younger gestational age was strongly associated with a diagnosis of depression in childhood, adolescence or young adulthood. Girls born before 28 weeks’ gestation were at roughly three times the risk for depression as those born at full term. After 28 weeks gestation, the association was no longer significant. The study is in the Journal of the American Academy of Child & Adolescent Psychiatry.
The authors suggest that the limited age range in the study of 5 to 25 years means that it was primarily early onset depression that was detected, and this may underestimate the effect in boys, who are typically diagnosed with depression at older ages.
“This is a huge sample,” said a co-author, Dr. Andre Sourander, a professor of child psychiatry at the University of Turku in Finland, “and we had many covariates for both mothers and fathers.” Even after considering all these other factors that may contribute to depression, “the findings remained significant” he said.