Epidemiological and spatial factors for tuberculosis: a matched case-control study in Nagata, Japan

Setting and objective Several studies have found a significant association between tuberculosis (TB) and spatial factors. We wished to determine the effect of host-related factors and spatial factors associated with an increased risk of TB, and to assess spatial clustering. Design A hospital-based case-control study using medical records was conducted. A total of 103 age- and sex-matched TB patients (cases) and 299 patients without TB (controls) were recruited from January 2000 to December 2016 in a hospital in Nagata, Kobe, Japan. Logistic regression, kernel density estimation, Cross L function and a Poisson regression model were applied. Results The epidemiological factors associated with TB were being a health care worker (OR 10.1) and lower serum albumin level (OR 0.5). Spatial analyses revealed TB to be positively associated with population density (risk ratio [RR] 32.1), the proportion of single households (RR -1.85) and persons aged 65 years (RR 2.65) and one spatial clustering. Conclusion Our findings could help in the identification of high TB risk individuals and districts.