Primary Prevention of Crohn's Disease in High-Risk Individuals
Given your constellation of genetic risk factors (CARD9, IL23R variants), family history, extra-intestinal manifestations (uveitis, axial spondyloarthritis), and positive anti-CBir1 antibody, you should immediately adopt a Mediterranean diet rich in fruits, vegetables, and lean proteins while minimizing ultraprocessed foods, as this dietary pattern has been associated with reduced IBD risk and may represent your best evidence-based preventive strategy.
Dietary Modification as Primary Prevention
The most actionable evidence-based intervention available is dietary modification:
Adopt a Mediterranean diet emphasizing variety of fresh fruits and vegetables, monounsaturated fats (olive oil), complex carbohydrates, and lean proteins while minimizing ultraprocessed foods, added sugar, and salt 1.
Specifically reduce or eliminate red and processed meats, as decreased intake has been associated with lower risk of developing IBD 1.
Avoid sugar-sweetened beverages, which have been linked to both increased IBD risk and more severe disease course in prospective studies 1.
Breastfeeding history (if applicable to future children) is associated with lower childhood IBD risk, though this is not directly applicable to your current situation 1.
Understanding Your Risk Profile
Your risk constellation is particularly concerning and warrants close monitoring:
CARD9 variants are associated with both axial spondyloarthritis 2 and impaired anti-fungal immune responses, potentially linking your SpA and future IBD risk through innate immunity dysfunction 3.
IL23R genetic variants independently confer significant CD risk (OR 2.05-2.97 in pediatric studies) and interact cumulatively with CARD9 variants 4, 5.
Anti-CBir1 antibody positivity is independently associated with complicated Crohn's disease phenotypes (small-bowel, internal-penetrating, fibrostenosing disease) and predicts more active disease course 6, 7.
Your extra-intestinal manifestations (uveitis and axial spondyloarthritis) suggest systemic immune dysregulation that commonly precedes or accompanies IBD, with shared pathogenic mechanisms involving IL-23 signaling 3, 2.
Current Limitations in Pharmacologic Prevention
No pharmacologic agents are currently approved or recommended for primary prevention of Crohn's disease in asymptomatic high-risk individuals, even with your compelling risk profile:
Current IBD guidelines focus exclusively on treatment of established disease, not prevention 1, 8.
IL-23 inhibitors like risankizumab show excellent efficacy in established moderate-to-severe CD (OR 2.22 for clinical remission, 4.11 for endoscopic remission) 9, 10, but no studies have evaluated their use in disease prevention.
The theoretical rationale for IL-23 blockade in your case is strong given your IL23R variants and the drug's mechanism, but this remains entirely speculative without clinical trial data.
Monitoring Strategy
Given the absence of preventive therapies, vigilant monitoring is essential:
Regular assessment for GI symptoms including abdominal pain, diarrhea, rectal bleeding, or weight loss.
Consider periodic fecal calprotectin testing (every 6-12 months) to detect subclinical intestinal inflammation before symptoms develop, though this is not standard practice and lacks formal guideline support.
Maintain close follow-up with gastroenterology given your high-risk profile, allowing for rapid intervention if symptoms emerge.
Critical Caveats
The evidence linking Mediterranean diet to IBD prevention comes from observational studies, not randomized trials in high-risk individuals 1.
Your anti-CBir1 positivity predicts complicated disease behavior if CD develops 6, making early detection and aggressive treatment crucial should symptoms appear.
The cumulative effect of multiple genetic risk variants (CARD9, IL23R) substantially increases your baseline risk beyond single-gene carriers 5.
Some research suggests fungal involvement in spondyloarthritis pathogenesis 3, but antifungal therapy remains investigational and is not recommended for prevention.