Mediating Role of Depression and Anxiety in the Association Between Food Insecurity and Delayed TB Treatment in Botswana.

Background: Delayed TB treatment remains a major challenge to tuberculosis (TB) control in low- and middle-income countries, where it contributes to prolonged infection, higher costs, and increased drug resistance. Food insecurity is an important determinant of health among people with TB and may contribute to delayed treatment through economic, physical, and psychosocial pathways. Depression and anxiety have also been associated with both food insecurity and delayed TB treatment, suggesting that they may mediate this relationship. This study examined the association between food insecurity and delayed TB treatment initiation and assessed the mediating roles of depression for this relationship among people newly diagnosed with TB in Botswana. Methods: We recruited 180 participants newly diagnosed with TB in Gaborone, Botswana. Food insecurity, depression, and anxiety were measured using the Household Food Insecurity Access Scale, PHQ-9, and Zung Self-Rating Anxiety Scale, respectively. Logistic regression was used to examine the association between food insecurity and delayed TB treatment. Mediation analysis using a counterfactual framework was conducted to assess the mediating roles of depression and anxiety. Results: Among the 180 participants, 45 (25%) experienced delayed TB treatment initiation. Participants with delayed TB treatment had higher mean scores for food insecurity (4.16 vs 2.99, p = 0.11), depression (10.1 vs 6.92, p = 0.001), and anxiety (37.1 vs. 33.9, p = 0.05). While standard regression analysis found insufficient evidence of an overall association between food insecurity and delayed TB treatment initiation (OR = 1.04, 95% CI: 0.98 - 1.11, p = 0.20), mediation analysis found evidence of total natural indirect effects through depression (OR = 1.04, 95% CI: 1.01-1.08, p<0.001, 99% mediated) and anxiety (OR = 1.03, 95% CI: 1.01 - 1.06, p<0.001, 38% mediated). Conclusion: Mediation analysis revealed that depression and anxiety may represent pathways linking food insecurity to delayed TB treatment. These findings highlight the importance of considering both socioeconomic and psychological factors in addressing delayed TB treatment. Further studies are needed to confirm these pathways.