Prevalence of latent tuberculosis infection and predictive factors in an urban informal settlement in Johannesburg, South Africa: a cross-sectional study.
South Africa has one of the highest burdens of latent tuberculosis infection (LTBI) in high-risk populations such as young children, adolescents, household contacts of TB cases, people living with HIV, gold miners and health care workers, but little is known about the burden of LTBI in its general population.



Using a community-based survey with random sampling, we examined the burden of LTBI in an urban township of Johannesburg and investigated factors associated with LTBI. The outcome of LTBI was based on TST positivity, with a TST considered positive if the induration was ≥5 mm in people living with HIV or ≥10 mm in those with unknown or HIV negative status. We used bivariate and multivariable logistic regression to identify factors associated with LTBI RESULTS: The overall prevalence of LTBI was 34.3 (95 % CI 30.0, 38.8 %), the annual risk of infection among children age 0-14 years was 3.1 % (95 % CI 2.1, 5.2). LTBI was not associated with HIV status. In multivariable logistic regression analysis, LTBI was associated with age (OR = 1.03 for every year increase in age, 95 % CI = 1.01-1.05), male gender (OR = 2.70, 95 % CI = 1.55-4.70), marital status (OR = 2.00, 95 % CI = 1.31-3.54), and higher socio-economic status (OR = 2.11, 95 % CI = 1.04-4.31).



The prevalence of LTBI and the annual risk of infection with M. tuberculosis is high in urban populations, especially in men, but independent of HIV infection status. This study suggests that LTBI may be associated with higher SES, in contrast to the well-established association between TB disease and poverty.
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. Jabulani.Ncayiyana@wits.ac.za.|Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 29 Princess of Wales Terrace, Johannesburg, 2193, South Africa. Jabulani.Ncayiyana@wits.ac.za.
Jabulani R
JR
Ncayiyana
Witkoppen Health and Welfare Centre, 105 William Nicol Drive, Fourways, Johannesburg, 2055, South Africa.
Jean
J
Bassett
Witkoppen Health and Welfare Centre, 105 William Nicol Drive, Fourways, Johannesburg, 2055, South Africa.
Nora
N
West
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
Daniel
D
Westreich
Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 29 Princess of Wales Terrace, Johannesburg, 2193, South Africa.
Eustasius
E
Musenge
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
Michael
M
Emch
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
Audrey
A
Pettifor
Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
Colleen F
CF
Hanrahan
Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
Sheree R
SR
Schwartz
Clinical HIV Research Unit, Department of Medicine, University of the Witwatersrand, Perth Road, Auckland Park, Johannesburg, 2092, South Africa.
Ian
I
Sanne
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.|Department of Epidemiology and Social Medicine, Faculty of Medicine and Health Sciences, University of Antwerp, Campus Drie Eiken, University Square, Wilrijk, Antwerp, 2610, Belgium.
Annelies
A
van Rie
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D005260:Female; D015658:HIV Infections / Q000453:epidemiology; D006801:Humans; D007223:Infant; D055985:Latent Tuberculosis / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014374:Tuberculin Test; D014504:Urban Health; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
ARI; LTBI; Prevalence; Risk factors; South Africa; Urban population