Higher Sun Exposure is Associated With Lower Risk of Pediatric Inflammatory Bowel Disease

Abstract

Objectives:The incidence of pediatric inflammatory bowel disease (IBD) is increasing worldwide. Ecological studies show higher incidence in regions at higher latitude or lower ambient ultraviolet radiation; individual-level associations with sun exposure have not been assessed.Methods:We recruited children (0–17 years) with IBD from 2 large hospitals in Melbourne, Australia. Control participants were recruited from the day surgery unit of one of the same hospitals. Questionnaires provided data on demographics, past sun exposure, the likelihood of sunburn (skin sensitivity) or tanning following sun exposure, use of sun protection, physical activity, and parental smoking and education. Grandparent ancestry was used to determine participant ethnicity. Cases and controls were matched on age and sex. We used conditional logistic regression to test the association between being an IBD case and past sun exposure at different ages, adjusted for a range of other factors.Results:After matching, n = 99 cases and n = 396 controls were included in the analysis. In multivariable analysis, for each 10 min increment in leisure-time sun exposure in summer or winter there was a linear 6% reduction in the odds of having IBD (P = 0.002). Results were similar in sensitivity analyses including only the most recently diagnosed cases, only Caucasian cases and controls, only those with symptom onset within the year before study entry, or additionally adjusted for age or physical activity.Conclusions:Higher sun exposure in the previous summer or winter was associated with a reduced risk of having IBD. There are plausible pathways that could mediate this effect.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…A recent meta-analysis confirms a latitude gradient in the prevalence of MS which may be growing stronger; this provides further evidence of the importance of environmental factors in disease pathogenesis [ 115 ]. In children, higher sun exposure was associated with a lower risk of developing inflammatory bowel disease in an Australian study (adjusted OR 0.94, P = 0.002 for each additional 10 min outdoors) [ 116 ].…”

Incidence and Geographical Variability of Pediatric Inflammatory Bowel Disease in Croatia: Data From the Croatian National Registry for Children With Inflammatory Bowel Disease

“…15,36 The exact reasons for the IBD being more common in the Northern hemisphere have not been determined yet, but most commonly hypothesized and investigated are sunlight exposure, vitamin D levels, urbanization process, Mediterranean lifestyle, and so on. 37-39…”

“…15,36 The exact reasons for the IBD being more common in the Northern hemisphere have not been determined yet, but most commonly hypothesized and investigated are sunlight exposure, vitamin D levels, urbanization process, Mediterranean lifestyle, and so on. [37][38][39] With regard to the individual incidences of CD and UC, results of various studies show different proportions of IBD types in the overall IBD incidence. Studies from France, Germany, Czech Republic, Spain, and England have found a higher incidence of CD, 10,28,34,[40][41][42] which is inconsistent with our study.…”

Insolation and Disease Severity in Paediatric Inflammatory Bowel Disease—A Multi-Centre Cross-Sectional Study

“…This deficiency is thought to be related to malnutrition, inadequate dietary intake, lower bioavailability as well as reduced sunlight exposure. Higher sun exposure in the previous summer or winter was associated with a reduced risk of developing IBD [4].…”