Abstract
BackgroundUndernutrition impairs immunity to Mycobacterium tuberculosis and is a risk factor for tuberculosis disease (TB). We aim to investigate if severe undernutrition affects the tuberculin skin test (TST) response among household contacts (HHCs) of pulmonary TB cases.MethodsWe analyzed data from HHCs (> five years) of pulmonary TB cases in Southern India. Undernutrition was defined as per World Health Organization based on body mass index (BMI) for adults (undernutrition 16–18.4 and severe undernutrition <16 kg/m2) and BMI relative to the mean for children (undernutrition 2SD-3SD and severe undernutrition < 3SDs below mean). Univariate and multivariate models of TST positivity (> five mm) were calculated using logistic regression with generalized estimating equations.ResultsAmong 1189 HHCs, 342 were children (age 5–17 years) and 847 were adults. Prevalence of TST positivity in well-nourished, undernourished and severely undernourished children was 135/251 (53.8%), 32/68 (47.1%), and 7/23 (30.4%) respectively; among adults, prevalence of TST positivity was 304/708 (42.9%), 43/112 (38.4%) and 12/26 (46.2%), respectively. Severe undernutrition in children was associated with decreased odds of TST positivity (adjusted odds ratio 0.3; 95%CI 0.1–0.9).ConclusionSevere undernutrition in children was associated with decreased odds of TST positivity. False-negative TSTs may result from undernutrition; caution is warranted when interpreting negative results in undernourished populations.
Highlights
Tuberculosis (TB), the leading infectious cause of death worldwide, affected 10 million people in 2017 [1]
Severe undernutrition in children was associated with decreased odds of TST positivity
In 2014, an estimated 1.7 billion individuals worldwide were infected with Mycobacterium tuberculosis (Mtb) infection; South-East Asia, Western-Pacific, and Africa regions had the highest prevalence of infection and accounted for ~80% of those infected [4]
Summary
Tuberculosis (TB), the leading infectious cause of death worldwide, affected 10 million people in 2017 [1]. Aerosolized droplets generated by an individual with active TB are the primary mode of spread After inhaling such droplets, persons who become infected are largely able to control the infection and prevent progression to primary disease [2]. Persons who become infected are largely able to control the infection and prevent progression to primary disease [2] This Mycobacterium tuberculosis (Mtb) infection or “latent tuberculosis infection” is diagnosed by a positive tuberculin skin test (TST) or interferon gamma release assay (IGRA) in the absence of clinical signs or symptoms of disease [3]. Several factors are linked to the progression of Mtb infection to disease, which occurs in 5–15% of infected individuals over their lifetime [5]. We aim to investigate if severe undernutrition affects the tuberculin skin test (TST) response among household contacts (HHCs) of pulmonary TB cases
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