Environmental triggers of autoimmune hepatitis: a clinical perspective from Yemeni patients

Autoimmune hepatitis is a chronic inflammatory liver disease in which the immune system attacks liver tissue. While genetic predisposition plays a role, environmental factors are increasingly recognized as contributors to disease onset and progression. This study aimed to examine the association between environmental exposures and autoimmune hepatitis in a Yemeni population.

A case-control study was conducted, including 93 patients with clinically diagnosed autoimmune hepatitis and 280 age- and sex-matched healthy controls. Data was collected through structured interviews and laboratory analyses. Environmental exposures assessed included residence in different temperature zones, history of viral infections, medication use, pesticide exposure, and the habit of chewing Khat. Liver biopsy findings and vitamin D levels were evaluated to assess disease severity. Statistical comparisons were performed using odds ratios and confidence intervals to determine associations.

Khat chewing was significantly more common in autoimmune hepatitis patients than in controls (65.6% versus 42.1%, OR: 2.6; 95% CI: 1.6-4.3, p < 0.001). Exposure to medications known to induce autoimmune reactions, such as nitrofurantoin and minocycline, was also higher among patients (27.9% versus 1.8%, OR: 21.3; 95% CI: 7.9-57.7, p < 0.001). Living in warm temperature zones and exposure to pesticides (OR: 13.1; 95% CI: 2.7-62.8, p < 0.001) were both significantly associated with increased disease risk. Patients with these exposures also demonstrated higher liver enzyme levels and more advanced fibrosis on biopsy. Vitamin D deficiency was associated with greater disease severity.

These findings highlight the important role of environmental factors, particularly Khat chewing and pesticide exposure, in the development and progression of autoimmune hepatitis in Yemen. Public health interventions addressing these exposures may help reduce disease burden.