Clin Gastroenterol Hepatol. 2024 Jul;22(7):1462-1474.e5. doi: 10.1016/j.cgh.2024.01.020.Epub 2024 Feb 1.

Nidah S Khakoo ¹, Ashley H Beecham ², Jiangnan Lyu ³, Maria A Quintero ⁴, Lissette Gomez ⁴, Maria T Abreu ⁴, Amar R Deshpande ⁴, David H Kerman ⁴, Jacob L McCauley ², Siobhan Proksell ⁴, Oriana M Damas ⁵

Author information

¹Department of Medicine, University of Miami School of Medicine, Miami, Florida; Division of Digestive Health and Liver Diseases, University of Miami Miller School of Medicine, Miami, Florida.

²John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida.

³Department of Biostatistics, University of Miami School of Medicine, Miami, Florida.

⁴Division of Digestive Health and Liver Diseases, University of Miami Miller School of Medicine, Miami, Florida.

⁵Division of Digestive Health and Liver Diseases, University of Miami Miller School of Medicine, Miami, Florida. Electronic address: odamas@med.miami.edu.

Abstract

Background and aims: Inflammatory bowel disease (IBD) develops from a combination of genetic and environmental factors. The aim of this study was to determine the contribution of established environmental risk factors and genetic risk on age of IBD diagnosis in a diverse cohort.

Methods: IBD patients in clinic completed detailed questionnaires. Blood was drawn for genetic analysis. Environmental risk factors and age of diagnosis were analyzed by ethnicity (Hispanic/Latinx or non-Hispanic White [NHW] individuals) and IBD subtype (ulcerative colitis or Crohn's disease [CD]). Weighted genetic risk scores and environmental risk scores were developed. We examined the relationship between environmental risk scores, genetic risk scores, and age of diagnosis.

Results: A total of 2952 patients were included: 58.9% had CD. A total of 46.83% were of Hispanic background. Early life exposures like cesarean delivery and being born in a developed country were associated with a younger age of IBD diagnosis. Childhood exposures such as frequent plastic water bottle use and having more than 1 bathroom at home were associated with a younger age of IBD. Hispanic and NHW individuals shared similar susceptibilities to environmental exposures. Environmental factors explained 21% of the variance in age of CD diagnosis and 39% in ulcerative colitis. In models incorporating genetic risk score and environmental risk score, the environment was the only significant factor associated with younger age of IBD diagnosis in all groups.

Conclusions: Early life and childhood exposures impact IBD diagnosis and influence Hispanic and NHW individuals similarly. A cumulative environmental risk score contributes more to age of IBD diagnosis than genetic risk.