A Case–control Study on Risk Factors for Development of Tuberculous Meningitis in Adults

Abstract

Abstract Introduction: Tuberculous meningitis remains the most severe and devastating form of tuberculosis with relatively severe morbidity and mortality. Risk factors for TB meningitis have not focused on the role of the BCG vaccine or social and food insecurity which are known to have a role in pulmonary TB. Methods: We prospectively conducted a Case-Control study among 65 patients with TB meningitis and 41 controls with other forms of meningitis. We evaluated the role of the BCG vaccine, the Household Food Insecurity Access Scale (HFIAS) and the Social Readjustment Rating Scale (SRRS) to look for food and social stress respectively. We also evaluated the known risk factors for TB meningitis including age, HIV co-infection, alcoholism, malignancies, use of immunosuppression, head injury among others. A bivariate followed by multivariate regression analysis was performed. Results: The presence of BCG scar was seen in 64.6 percent of patients with Tuberculous meningitis and 61.0 percent of control (P= 0.71). There was no difference in the size of the scars (P= 0.45) . Household food insecurity using the Household Food Insecurity Access Scale (HFIAS) ( a positive answer in any of the 9 items) was present in 16.9% of the patients in the TBM group and in 14.6% of the patients in the control group. (P= 0.75). Social stress assessed using the Social Readjustment Rating Score (< 150 suggest no social stress, 150 – 300 moderate social stress,> 300 high social stress) showed that a majority of the patients in both the groups reports no social stress. Only 9.8% of patients in the TBM group and 18.5% in the control group reports moderate presence of social stress whereas none of the patients had severe social stress. Logistic regression analysis suggested that only higher BMI was associated with lesser incidence of Tuberculous meningitis, odds ratio 0.83 (95% confidence interval of 0.73 – 0.930) and individuals performing clerical and unskilled and under-skilled jobs- odds ratio 0.13 (95% confidence interval of 0.02 – 0.93) had lower risk for TB Meningitis. Conclusions: In our sample of TB meningitis patients the BCG vaccine, food insecurity nor social stress appear to be risk factors. Bigger BMI and certain occupations appear to be possibly protective.