Study Links Birth Order to 150 Conditions in 10 Million U.S. Siblings
Updated
Updated · Fox News · Aug 13
Study Links Birth Order to 150 Conditions in 10 Million U.S. Siblings
3 articles · Updated · Fox News · Aug 13
Summary
Researchers analyzing 10 million U.S. siblings over two decades found birth order was significantly associated with 150 of 569 disease categories, according to a study published in Nature Health.
First-born children showed higher rates of autism, ADHD, Tourette's, OCD and food allergies, while second-borns were more prone to migraines, shingles, substance use disorders and gastritis.
The study points to birth order as a modest population-level risk marker, with possible drivers including differences in parental attention, early microbial exposure and biological changes between pregnancies.
Insurance-claims data and family differences such as parental age and sibling age gaps limit the findings, and the researchers said the correlations do not prove birth order causes any condition.