Indoor urban environment and conventional risk factors for paediatric tuberculosis among 1-12 years old children in a megacity in Pakistan: a matched case control study

<b>Introduction:</b> TB among children is less well-defined and its risk factors are less well-studied. Indoor environment may play a significant role particularly for childhood TB. <b>Objectives:</b> To determine the association of indoor urban environment and conventional risk factors for pulmonary TB among children aged 1 to 12 years. <b>Methods:</b> An age matched case control study was conducted in two hospitals (a large tertiary and a secondary level) of megacity Karachi, Pakistan. The study recruited pulmonary TB cases (n=143), diagnosed by trained physicians using Pakistan Paediatric Association Scoring Chart for Diagnosis of Tuberculosis (PPASCT), and two age matched (±1 year) controls for each respective case (n=286) during June 2015-May 2016. The conditional logistic regression was conducted to determine the risk of pulmonary TB due to exposure to second hand smoke (SHS) and other conventional risk factors. <b>Results:</b> Female child (mOR: 1.8), children belonging to minor communities in the city (mOR: 2.3 - 4.5), household TB contact (mOR: 7.5), use of open kitchen for cooking (mOR: 2.7), though insignificant but exposure to second hand smoke among under-5 year old children (mOR; 1.4), and time spent inside home (mOR: 1.1 per hour) increased the risk for TB. <b>Conclusions:</b> This study strengthens the evidence that indoor air environment including time spent indoors, SHS (though insignificant), and low socioeconomic condition and being female and belonging to minor communities increase the risk for childhood TB. Concerted efforts are needed to improve indoor air environment in urban areas for healthier future generations.