Vitamin D receptor BsmI haplotype BB confers lower 25(OH)D levels during tuberculosis: a pilot cross-sectional study

Background: Adequate micronutrient absorption remains key for tuberculosis control. Objective: To evaluate the frequency of vitamin D receptor polymorphisms, FokI , TaqI , and BsmI , and their relationship with total vitamin D and cathelicidin levels in patients with pulmonary tuberculosis (PTB) and healthy controls (HC) in the province of Colon, Panama. Design: Pilot cross-sectional study, PTB ( n = 80) and HC ( n = 50). Methods: We measured total vitamin D (25-OH-vitamin D, 25(OH)D) and cathelicidin (LL-37) levels by enzyme-linked immunosorbent assays and analyzed vitamin D receptor (VDR) polymorphisms by PCR-RFLP. We compared the total 25(OH)D and cathelicidin levels across participant demographics and explored the associations with vitamin D receptor polymorphisms. Results: We observed no significant difference in vitamin D levels between PTB and HC (median (IQR) = 36.6 (27.6–48.7) ng/mL and 32.5 (18–46.3) ng/mL, respectively, p = 0.067). In terms of sex, vitamin D levels in women were higher in the PTB group compared to HC (median (IQR) = 33.9 (26.8–48.1) versus 19.5 (11.8–33.4) ng/mL, p = 0.002). Regarding LL-37, PTB unemployed participants showed higher levels compared to HC (median (IQR) = 59.4 (42.4–79.3) versus 28.2 (13.9–42.8) ng/mL, p = 0.048), as well as Hispanic PTBs (59.6 (48.2–71.41) versus 38.9 (19.5–49.2) ng/mL, p = 0.014). As for the treatment phase, vitamin D levels in PTB within 1 month of treatment were higher than HC (median (IQR) = 39.9 (28.5–50.51) versus 32.5 (18–46.3) ng/mL, p = 0.06). When stratifying by sex, these differences were observed only in women (median (IQR) = 41.4 (27.9–55.5) versus 19.5 (11.8–33.4) ng/mL for PTB and HC, respectively; p = 0.01). A statistically significant association was observed between the BsmI VDR polymorphism and serum 25-hydroxyvitamin D levels, with a significant difference between PTB and HC ( p = 0.004). Conclusion: The observed associations between VDR polymorphisms, vitamin D levels, and cathelicidin levels highlight the need for further studies to clarify the role of host genetic and sociodemographic factors in pulmonary tuberculosis susceptibility and immune response.