Lung problems persist in most adolescents even after TB treatment

This alarming finding was revealed in a new study by Stellenbosch University (SU) researchers, which was recently published in the prominent medical journal, The Lancet's series; eClinicalMedicine. This is the first study to have comprehensively assessed lung function in adolescents with TB during anti-TB treatment and after treatment completion.

“Little is known about post-TB lung disease in adolescents," explains study lead, Dr Marieke van der Zalm, with SU's Desmond Tutu TB Centre. “Our data suggests that a large proportion of adolescents have impaired lung function following successful TB treatment completion. Strategies are required to identify individuals at risk for respiratory morbidity and interventions are needed to improve lung health after TB."

Each year an estimated 850,000 adolescents develop tuberculosis disease, of which about 90% are living in low- and middle-income countries. Adolescence is an important period for lung growth and respiratory diseases, such as TB, can potentially interfere with normal lung development. Tuberculosis during adolescence could therefore negatively affect a person's ability to reach full lung potential.

“With the combination of the high TB burden, severity of TB disease, some behavioural aspects (including smoking), and the critical period in lung development, adolescents may have more TB-associated respiratory morbidity compared to adults," warns Van der Zalm. “With longer life expectancy after TB compared to adults, adolescents may contribute substantially to the overall disability burden caused by TB."

The study was conducted in Cape Town, South Africa, and enrolled 100 adolescents between the ages of 10 and 19 years. The study compared the lung function of 50 adolescents diagnosed with TB to that of 50 healthy adolescents who were exposed to TB but did not develop disease. The cohort diagnosed with TB conducted a battery of lung function tests (spirometry, plethysmography, diffusion capacity lung function and six-minute walking test) two months after starting anti-TB treatment, and again after the completion of treatment, on average a year later. Results from the first assessment (conducted two months into treatment) found abnormal lung function among 76% of adolescents, and 65% were still showing abnormal lung function at the second assessment conducted after successful completion of treatment.

“The fact that adolescents with TB after successful treatment have overall lower lung function compared to their peers is concerning because this might mean that they will not be able to reach their full potential when they reach adulthood, with subsequent risk developing chronic lung disease early on in life. Studies have shown that even mild impairment of lung function is associated with increased risk of heart and lung issues later in life, or even premature death. As a result, our data shows that adolescents that had TB are at risk of permanent long-term heart and lung problems," Van der Zalm and colleagues warn.

“Our results show that adolescents urgently need to be included in studies investigating prevention and treatment of tuberculosis-associated respiratory morbidity; this includes the need to assess lung health as an outcome within tuberculosis treatment trials in adolescents," they conclude.

Source: Stellenbosch University