RESEARCH ARTICLE Epidemiology of Peripheral Lymph Node Tuberculosis and Genotyping ofM. tuberculosis Strains: A Case-Control Study

Background This study examined potential risk factors of lymph node tuberculosis (LNTB), including phylogenetic lineages ofMycobacterium tuberculosis (MTB), in comparison to pulmonary tuberculosis (PTB) in a setting with an ethnically diverse population. Methods We conducted a case-control study at a major tuberculosis clinic in Sydney, Australia, which included all patients with peripheral LNTB seen at the clinic between 2000 and 2012. Controls were randomly selected patients with PTB seen at the same clinic during the study period. Epidemiological data were extracted from the hospital electronic database and med-ical records. Associations between LNTB and age, sex, ethnicity, comorbidities and phylo-genetic lineages of MTB in comparison to PTB were examined using logistic regression in univariate and multivariate analyses. Results There were 212 cases with LNTB and 424 randomly selected controls with PTB. Among patients with LNTB, 74 % were female and the mean age (standard deviation, SD) was 42 (16) years. Among patients with PTB, 43 % were female and the mean age was 44 (22) years. Females, 45 to 64-year-olds and Southern Asians had an increased risk for LNT