As for many complex diseases, the incidence of inflammatory bowel disease (IBD) is higher among individuals born during certain seasons.
This difference could arise from seasonal variations in many factors, including exposure to sunlight, antibiotics, or infectious agents.
Dr Charles Bernstein and colleagues from Canada investigated the relationship between season of birth, early childhood exposure to antibiotics, and incidence of IBD.
The research team performed a nested case-control analysis using data from the University of Manitoba inflammatory bowel disease epidemiology database.
|Approximately 27% of cases were born from April through June|
|Clinical Gastroenterology & Hepatology|
The researchers compared seasons of birth among 11,145 individuals with IBD (cases) and 108,633 controls using conditional logistic regression models.
The team collected data on use of antibiotics in the first year of life for cases and controls from the Manitoba Drug Program Information Network—a comprehensive database of all prescriptions given to residents of Manitoba since 1995.
Approximately 27% of cases were born from April through June, compared with 26% of controls.
Comparisons made by sex and type of IBD showed statistical significance only for men with Crohn's disease.
The team found that at ages 6 months and older, cases and controls born from April through June received a significantly greater number of prescriptions for antibiotics than cases and controls born in other months.
Dr Bernstein's team concludes, "Men with Crohn's disease are more likely to have been born in the months of April through June."