University of Chicago study links birth order to life expectancy

A study published in the journal Nature Health suggests that birth order may significantly influence life expectancy and overall health. Researchers from the University of Chicago analyzed data from 5 million American families to investigate these correlations.

The findings indicate that second-born children may face higher mortality rates and a greater likelihood of developing certain health issues, such as gastrointestinal problems and infections like herpes zoster, often linked to lifestyle factors and substance abuse. Conversely, first-born children were found to have a higher prevalence of allergies and neurodevelopmental disorders, such as autism.

Researchers noted that these findings represent statistical associations rather than direct cause-and-effect relationships. The study is limited to families within the United States and does not account for variations in mortality across different cultures or countries. Additionally, scientists emphasized that healthy lifestyle choices can mitigate many of these statistical risks.