Risky behaviour and psychosocial correlates in adolescents - is there a link with tuberculosis?

OBJECTIVE: Reasons for the increase in incidence of tuberculosis (TB) in late adolescence are poorly understood. One hypothesis is that psychological and behavioural variables associated with adolescence may increase risk of developing TB. The study aimed to determine whether psychosocial and behavioural variables affect incidence of TB disease in adolescents. METHODS: A case-control study design was used in adolescents who were participants in a TB epidemiological study. Cases were adolescents diagnosed with TB disease. Approximately half of the controls had no TB disease but a positive TST indicative of latent TB. Half had neither TB disease nor latent TB. A self-administered questionnaire was completed by participants. The questionnaire consisted of a combination of standardised psychosocial instruments. RESULTS: Of 292 participants, 62 were cases, 112 had latent TB and 118 neither TB disease nor latent TB. There were no significant differences in instrument scores between cases and controls. There was a trend for certain adverse life events to be more common in the TB-disease group. CONCLUSION: In adolescents, a trend for association between TB incidence and psychosocial and behavioural variables was not statistically significant. Given the trend, research with larger samples, and more comprehensive assessment of the relationship between stressors and TB, is warranted.

The tuberculin skin test: a comparison of ruler and calliper readings.

BACKGROUND: The Mantoux tuberculin skin test (TST) is widely used to diagnose latent infection with Mycobacterium tuberculosis. TST skin induration may be measured either by a transparent ruler or by a pair of callipers. We hypothesised that the type of instrument used may affect the reading. OBJECTIVE: To determine whether variability in Mantoux TST measurement is affected by the type of reading instrument. METHOD: A TST (Mantoux method) was performed among healthy adolescents. The indurations were read with among ruler and calliper by two independent readers. Limits of agreement and Kappa (κ) scores at TST positivity cut-off points were calculated. A Bland-Altman graph was constructed. RESULTS: The 95% limits of agreement between instruments ranged from -5 mm to 3 mm. The limits of agreement between readers ranged from -5 mm to 4 mm. κ scores between instruments were respectively 0.7 and 0.8 at 15 mm and 10 mm cut-offs. CONCLUSION: The variability between readers of TST indurations is not influenced by changing the reading instrument.

Are adolescents ready for tuberculosis vaccine trials?

Tuberculosis (TB) vaccine trials are planned in adolescents in a high tuberculosis burden rural area near Cape Town, South Africa. To determine the knowledge and attitudes of adolescents about tuberculosis, vaccines and vaccine trials, a representative sample of adolescent learners was chosen from high schools in the trial area. A questionnaire was administered and focus group discussions held with the group and a sample of their parents. The questionnaire response rate was 65%. Knowledge of tuberculosis was fair 63.7% but knowledge of vaccines poor 41.9% based on a TB and vaccine knowledge score, respectively. Willingness to participate in vaccine trials will be influenced by the type of procedures involved (60% willing to answer questions, 43% willing to be examined, 32% willing to undergo skin tests and 39% willing to undergo blood draw). In general, better knowledge was statistically associated with greater willingness to participate in study procedures except for the blood draw. The focus group discussions showed that adolescents and their parents were positive about participating in vaccine trials but concerns about safety and the provision of adequate information should be considered when planning TB vaccine trials. This study suggests that TB vaccine trials would be acceptable amongst adolescents in this community with certain provisos.