Cohort Study

PMC: PMC4176007

/PMC/2026

Why It Matters

This caught my attention because vitamin D is one of the most measurable and modifiable immune factors we can track. The data suggests maintaining adequate vitamin D levels (>20 ng/mL, ideally >30 ng/mL) might matter for immune defense beyond just bone health. That said, this is observational — it shows association, not causation. We don't know if low vitamin D causes TB susceptibility or if TB infection depletes vitamin D.

Key Findings

  • 70% of TB patients had vitamin D deficiency (<20 ng/mL) versus 43% of healthy controls
  • Patients with vitamin D deficiency showed 2.9-fold increased odds of active TB disease (95% CI: 1.9-4.4)
  • Mean vitamin D levels were 18.2 ng/mL in TB patients compared to 24.6 ng/mL in controls, a 26% difference
  • The association remained significant after adjusting for age, sex, BMI, and socioeconomic factors
  • No intervention data provided — this is observational only, so causation cannot be established