Several recent studies have examined biomarkers to predict Crohn’s disease.  A recent prospective study (W Turpin et al. Gastroenterol 2020; DOI: https://doi.org/10.1053/j.gastro.2020.08.005. Increased Intestinal Permeability is Associated with Later Development of Crohn’s Disease) sought to determine whether increased intestinal permeability, as measured by urinary fractional excretion of lactulose to mannitol ratio (LMR), is associated with future development of CD.

Methods: 1420 asymptomatic first-degree relatives (6–35 years old) of patients with CD (collected from 2008 through 2015) had LMR measured and were then followed for a diagnosis of CD from 2008 to 2017, with a median follow up time of 7.8 years. We analyzed data from 50 participants who developed CD after a median of 2.7 years during the study period, along with 1370 individuals who remained asymptomatic until October 2017

Key findings:

• An abnormal LMR (> 0.03) was associated with diagnosis of CD during the follow-up period (hazard ratio, 3.03; 95% CI, 1.64–5.63; P=3.97×10 ^-4).
• This association remained significant even when the test was performed more than 3 years before the diagnosis of CD (hazard ratio, 1.62, 95% CI, 1.051–2.50; P=.029).

My take:  It remains unclear whether abnormal barrier function primarily precedes or follows CD development.  The authors state that these findings support a model in which altered intestinal barrier function contributes to pathogenesis.