Seasonal Variation of Rectal Foreign Bodies: Data from Nationwide Inpatient Sample.

Background: Seasonality is noted in various aspects of human behavior and functioning which have led to an increasing interest in their seasonality in the recent years.

Aims: We aimed to examine the seasonal variation in the incidence of rectal foreign bodies in the US using a large inpatient database.

Methods: We used the Nationwide Inpatient Sample database to identify patients aged ≥18 years admitted with a primary diagnosis of the rectal foreign body from 2009 to 2011. We used the Edward's recognition and estimation of cyclic trend method to study the seasonal variation of the incidence of rectal foreign body and Z-test to compare the seasonal incidences.

Results: A total of 3359 hospitalizations with primary diagnosis of the rectal foreign body were reported from 2009 to 2011. The peak incidence of rectal foreign bodies was seen in October (peak/low ratio 1.20, 95% confidence interval [CI]: 1.10-1.32).

Conclusion: Data on seasonal variation of rectal foreign bodies are extremely limited. Further studies would be required to verify whether our findings of a higher incidence in the fall season are reflective of acute changes in the length of the days, climate, sleep-wake cycle, or decreased sexual intercourse at this time of the year. High suspicion at this time of the year may help promptly diagnose and avoid unnecessary investigations.