Seasonal patterns of abdominal pain consultations among adults and children.

BACKGROUND AND AIM: Consultations for chronic abdominal pain are frequent in adults and children. A seasonal pattern of abdominal pain consultations with winter predominance was shown in previous pediatric studies; however, no studies have investigated whether such a pattern exists in adult patients. Understanding the differences in seasonal patterns of abdominal pain consultations among adults and children may indicate that either different mechanisms exist for common chronic pain conditions or triggering factors may vary by age. The aim of the study was to investigate whether a seasonal variation in abdominal pain consultation patterns exists among adults and children.
METHODS: The number of outpatient consultations among children (5-17 years) and adults (18 years or older) with a diagnosis of abdominal pain of nonspecified origin (International Classification of Diseases-9 code 789.0) from May 2000 to December 2008 was identified in an administrative claims database. The primary outcome measure was the rate of abdominal pain consultations (total number of abdominal pain consultations/total number of distinct patients by month×1000) by season in children and adults. Seasons were defined as follows: winter (December-February), spring (March-May), summer (June-August), and fall (September-November). A trend test was conducted to determine the degree of linearity in the patterns between the 2 groups. Among children, subanalyses by age 5 to 11 years and 12 to 17 years and sex were conducted.
RESULTS: A total of 172.4 million distinct patients (13.4% children, 87.6% adults) were identified in the database between May 2000 and December 2008. During the same time period, 15.6 million patient consultations for abdominal pain were identified (10.1% children, 89.9% adults). Children demonstrated a seasonal pattern in abdominal pain consultations, which best fit a quadratic regression curve, with consultations less common during the summer months. Abdominal pain consultations in adults were linear with no seasonal predominance. The trend in seasonal variation of abdominal pain consultations among children stratified by age and sex remained consistent with the overall child population.
CONCLUSIONS: Abdominal pain consultations in children are less common during summer months, whereas no evidence of seasonal pattern of consultation was found in adults. Factors involved in the pathogenesis of abdominal pain in adults and children may differ.