Spatial cluster mapping and environmental modeling in pediatric inflammatory bowel disease

Area of Science:

• Environmental Epidemiology
• Pediatric Gastroenterology
• Spatial Analysis

Background:

• Geographical clusters of inflammatory bowel disease (IBD) suggest environmental influences, but pediatric IBD (PIBD) spatial patterns in North America remain uncharacterized.
• This study investigated geospatial clusters of PIBD in British Columbia (BC), Canada, hypothesizing associations with ethnicity and environmental exposures.

Purpose of the Study:

• To identify spatial clusters of pediatric IBD (PIBD) in British Columbia.
• To model the association between PIBD incidence patterns and population ethnicity, rurality, socioeconomic factors, and environmental exposures.

Main Methods:

• Utilized a clinical registry of 1,183 pediatric patients diagnosed with IBD (age ≤ 16.9 years, 2001-2016) with valid postal codes.
• Employed spatial cluster detection routines to identify high and low incidence areas.
• Conducted an ecological analysis using Poisson rate models, assessing IBD, Crohn's disease (CD), and ulcerative colitis (UC) incidence against ethnicity, rurality, family size, income, green space, air pollution (PM2.5), UV light, and pesticide applications.

Main Results:

• Identified PIBD, CD, and UC incidence hot spots in Metro Vancouver, southern Okanagan, and Vancouver Island, with cold spots in southeastern and northern BC.
• Novel risk factors for PIBD included fine particulate matter (PM2.5) air pollution and agricultural petroleum oil pesticide application.
• South Asian ethnicity was a risk factor, while Indigenous ethnicity, larger family size, and higher summer UV exposure showed protective effects for PIBD.

Conclusions:

• Spatial clusters of pediatric IBD (PIBD) were identified in British Columbia, associated with both known and novel environmental determinants.
• Fine particulate matter (PM2.5) air pollution and agricultural pesticide use emerged as significant novel risk factors requiring further investigation.
• The findings underscore the role of environmental exposures and ethnicity in pediatric IBD etiology.