Browsing by Subject "incidence"

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    HIV viral load as an independent risk factor for tuberculosis in South Africa: collaborative analysis of cohort studies
    (2017) Fenner, Lukas; Atkinson, Andrew; Boulle, Andrew; Fox, Matthew P; Prozesky, Hans; ZYrcher, Kathrin; Ballif, Marie; Furrer, Hansjakob; Zwahlen, Marcel; Davies, Mary-Ann; Egger, Matthias
    Introduction: Chronic immune activation due to ongoing HIV replication may lead to impaired immune responses against opportunistic infections such as tuberculosis (TB). We studied the role of HIV replication as a risk factor for incident TB after starting antiretroviral therapy (ART).
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    Incidence and Risk Factors for Influenza lower respiratory tract infection in a South African Birth Cohort
    (2026) Hapeela, Nchimunya; Zar, Heather; Nicol, Mark
    Background: Lower respiratory tract infection (LRTI) is a significant cause of morbidity and mortality in children under five years, particularly in low- and middle-income countries (LMICs). However, data on the incidence and risk factors for influenza-associated LRTI in young children in these settings are limited. This study prospectively investigated the incidence of and risk factors for influenza-associated LRTI from birth through early childhood, in a South African birth cohort, the Drakenstein Child Health Study (DCHS). Methods: Children enrolled in the DCHS between May 2012 to September 2015 were followed from birth up to 5 years of age. Data on socio-economic status, maternal and infant characteristics, and LRTI episodes were collected. Quantitative real-time polymerase chain reaction (qPCR) was used to identify respiratory organisms, including the influenza virus associated with each LRTI episode. Influenza-associated LRTI was defined as the presence of clinical LRTI symptoms with a laboratory-confirmed influenza infection (qPCR cycle threshold <40 for at least one influenza target gene). Generalized estimating equations (GEE) models were used to assess associations between potential risk factors and influenza-associated LRTI. Results: Among 1143 live births, 51% (586/1143) were male, 17% (189/1143) were born premature, and 22% (248/1143) were HIV-exposed uninfected, while two were living with HIV. The population experienced high levels of socio-economic disadvantages, with 61% (695/1143) of mothers having an education below secondary level, and 86% (982/1143) of households earning less than 5,000 South African rands per month. Maternal smoking and alcohol use during pregnancy were reported by 28% (323/1142) and 13% (137/1067) of mothers, respectively. None of the mothers received influenza vaccination during pregnancy, and no child was vaccinated against influenza through the study, although coverage for other routine childhood vaccines exceeded 98%. iv Overall, 47% (521/1108) of children experienced LRTI episodes (incidence rate of 22 episodes per 100 child-year, [95% CI 21, 23]). Among 472 children with qPCR results, 70 influenza-associated LRTI episodes occurred in 64 children (14%); incidence rate: 1.4 episodes per 100 child-year, [95% CI:1.1, 1.8] per 100 child-years. Of these 64 children with influenza-associated LRTI, 13% (9/70) required hospitalization, and one influenza-associated LRTI death was recorded among the hospitalized. Risk factors for all-cause LRTI included lower maternal education, maternal HIV, prenatal alcohol use, preterm birth, male sex, and winter birth. After adjusting for other factors, influenza-associated LRTI was significantly associated with older age (odds ratio for a one-month increase in age: 1.02, [95% CI: 1.00-1.04]) and winter season. Conclusion: Influenza remains a significant cause of LRTI, particularly among children affected by socio-economic disadvantages and maternal HIV exposure, and during the winter season. Expanding maternal and early childhood influenza vaccination programs, alongside broader public health interventions addressing underlying social vulnerabilities, could meaningfully reduce influenza-associated LRTI and improve child health outcomes.
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    The 8-year incidence of obesity and type 2 diabetes in five African-origin populations
    (2024) Conradie, Catharina Beatrix; Dugas, Lara
    Obesity and type 2 diabetes (T2D) have become worldwide pandemics, particularly in low middle-income countries and among African-origin populations. The Modeling of Epidemiological Transition Study (METS, 2009) enrolled 2,506 African-origin participants, aged 25-45, from five countries and its ancillary study; METS-Microbiome, continued yearly research visits in 2,085 participants (2018-2019). The countries represent the full epidemiological transition spectrum, represented by the Human Development Index: Ghana (low), South Africa and Jamaica, (middle), Seychelles (high) and the United States (US) (very high). Research visits included anthropometrics, body composition measurements, social history, socio-demographics and health questionnaires, physical activity by accelerometer and clinical measurements. Overall, 732 participants had complete measurements from both METS (baseline) and METS-Microbiome (follow-up). At baseline, the US participants had the highest obesity prevalence (61.0%) and Ghanaians the lowest (11.5%). However, the obesity prevalence increased significantly, most notably among the Ghanaians (125%; p<0.001), and Seychellois (60.7%; p<0.01). Significant obesity predictors included being females, waist circumference and fat mass (p<0.001). The interaction term for follow-up length and site was significant with higher odds of obesity compared to baseline; Ghana (OR 6.62, 95%CI 1.56-28.35), Jamaica (OR 4.57, 95%CI 1.06-8.88) and Seychelles (OR 4.31, 95%CI 1.12-16.57). The US participants had the highest T2D prevalence (10,0%) and Jamaicans (0%) at baseline. However, the Seychellois experienced a 600% increase in T2D prevalence (p<0.01) accompanied by the highest T2D and obesity incidence rate. The interaction term for follow up length and site was similarly significant with higher odds of T2D at follow-up; Seychellois (OR 10.00, 95%CI 1.83-54.52) and US (OR 2.33, 95%CI 1.17-4.66). Age (p=0.002) and waist circumference (p=0.016) were significant T2D predictors. In conclusion, the study underscores significant increases in obesity and T2D rates, not only in high-income countries but also in rapid transitioning settings, highlighting concerns about healthcare resources readiness for the growing global burden of non-communicable diseases.