• Tuberculosis
• diabetes
• chronic kidney disease
• ethnicity
• immunodeficiency

Among UK residents of South Asian descent potential risk factors for pulmonary tuberculosis (PTB) and, possibly, also for its recurrence, include vitamin D deficiency (as proposed by Crofts et al),1 the population-attributable fraction (PAF) for PTB attributable to diabetes mellitus,2 and end-stage chronic kidney disease(CKD).3. The PAF for PTB attributable to diabetes mellitus can be as high as 19.6% (95% CI 10.9% to 33.1%) and 14.2% (95% CI 7.1% to 26.5%) for UK Asian men and women, respectively, versus 6.9% (95% CI 3.1% to 12.4%) and 8.2% (95% CI 3.0% to 15.6%) for their white male and female counterparts, respectively.2 Furthermore, in the presence of diabetes mellitus, recognition and treatment of PTB can be complicated by the fact that its radiographic stigmata can simulate those of lower lobe community-acquired pneumonia, and by the fact that median time to culture conversion may be significantly (p=0.03) longer in subjects with diabetes than in their counterparts without diabetes.4 Relative to their white counterparts, UK Asians also have a 13.66-fold higher risk of end-stage diabetic nephropathy,5 end-stage CKD itself being associated with an acquired immunodeficiency state characterised by a 10- to 25-fold increase in risk of PTB.3 When vitamin D deficiency complicates CKD6 this might, arguably, further compound the risk of PTB and its recurrence.