In South Africa, men are 70% more likely to develop TB and die from the disease, compared with women, write Mmamapudi Kubjane of Wits University and Leigh Johnson of the University of Cape Town in The Conversation.
They write:
We recently conducted research to establish the various factors that explain higher rates of TB among men in SA, which is ranked among the top six countries contributing to 60% of the global burden of TB.
Our main finding was that men are 70% more likely to develop TB and die from the disease, compared with women. We estimated that in 2019, 801 per 100 000 adult men developed TB while among women, the rate was 478 per 100 000.
Current TB interventions focus on biomedical approaches emphasising preventive TB medication, diagnosing TB patients and treating them with anti-TB drugs.
Our research demonstrates, however, that dealing with socioeconomic conditions and other determinants of TB is also important.
Men’s access to health facilities needs to be improved and there needs to be more effort to encourage men to seek medical care.
Our maths model
We used our Thembisa TB model, recently developed at the Centre for Infectious Disease Epidemiology and Research at the University of Cape Town, a mathematical model simulating the South African adult TB epidemic over time.
Because HIV is the most significant risk factor for TB and the primary driver of the epidemic, the TB model is combined with an existing Thembisa HIV model.
Approximately 60% of individuals with active TB are also living with HIV.
The model showed that between 1990 and 2019, South African men developed TB and died at consistently higher rates than women.
We estimated that in 2019 there were 1.6 times more new TB cases and 1.7 times more TB deaths in men than in women.
Our results are all the more startling because HIV is more prevalent in women than men.
The expectation would then be that women should have a higher TB incidence.
Some of the risks
Other factors contributing to the high TB epidemic among men included excessive alcohol use, smoking, diabetes and under-nutrition.
We estimated that of the 801 per 100000 adult men who developed TB in 2019, 51% were attributable to heavy alcohol use, 30% to smoking, and 16% to under-nutrition.
The numbers for women were much lower. Of the 478 per 100000 adult women who developed TB in 2019, 30% were attributable to heavy alcohol use, 15% to smoking, and just 11% to under-nutrition.
Low testing rates
We showed that lower testing rates and delays in starting TB treatment among men contributed to 7% higher mortality.
Previous research has found that men are more likely to have jobs and it was more difficult to take time off to go to the clinic or secure treatments, as it would affect their earnings.
Men were also often older and sicker when they sought healthcare, and were more likely to stop treatment.
Our analysis showed that women benefited more from accessing HIV healthcare services, including HIV testing and antiretroviral therapy initiation, which significantly reduced TB incidence and mortality.
We estimated that in 2019, mainly due to treatment for HIV, TB cases dropped by 38% in women, while there was also a 52% reduction in deaths.
In contrast, TB cases among men dropped by 18% and there was a 29% reduction in deaths.
Next steps
The higher TB incidence and mortality in men highlights the need to make health services more accessible to men and address the structural barriers to their retention in tuberculosis and HIV care. Mobile clinics could be circulated at places of work to provide testing for TB, HIV and other potential co-morbidities.
Additionally, there is a need for effective socio-economic interventions.
A review of studies conducted across the world has shown that anti-smoking programmes driven by health practitioners and family have achieved success rates of up to 82%.
Self-help programmes to stop excessive alcohol consumption need to be complemented by structural interventions, like increased alcohol taxation and stricter enforcement of the laws restricting the sale of alcohol.
A recent trial conducted in India showed that providing households with food baskets to improve nutrition could reduce TB by 50%.
Although biomedical approaches have led to declines in the TB epidemic, South Africa still remains classified as a high TB burden country.
Medical treatment needs to be complemented with measures to tackle socio-economic conditions. Only then will we make real progress in reducing the TB epidemic in South Africa.
Mmamapudi Kubjane: researcher, Wits Health Consortium, University of the Witwatersrand.
Leigh Johnson: associate professor, University of Cape Town.
Study details
Drivers of sex differences in the South African adult tuberculosis incidence and mortality trends, 1990–2019
Mmamapudi Kubjane, Morna Cornell, Muhammad Osman, Andrew Boulle & Leigh Johnson.
Published in Nature Scientific Reports on 10 June 2023
Abstract
Males have higher tuberculosis incidence and mortality rates than females. This study aimed to assess how sex differences in tuberculosis incidence and mortality could be explained by sex differences in HIV, antiretroviral treatment (ART) uptake, smoking, alcohol abuse, under-nutrition, diabetes, social contact rates, health-seeking patterns, and treatment discontinuation. We developed an age-sex-stratified dynamic tuberculosis transmission model and calibrated it to South African data. We estimated male-to-female (M:F) tuberculosis incidence and mortality ratios, the effect of the abovementioned factors on the M:F ratios and PAFs for the tuberculosis risk factors. Over the period 1990–2019, the M:F ratios for tuberculosis incidence and mortality rates persisted above 1.0, and the figures reached 1.70 and 1.65, respectively, by the end of 2019. In 2019, HIV contributed greater increases in tuberculosis incidence among females than males (54.5% vs. 45.6%); however, females experienced more reductions due to ART than males (38.3% vs. 17.5%). PAFs for tuberculosis incidence due to alcohol abuse, smoking, and under-nutrition, in men were 51.4%, 29.5%, and 16.1%, respectively, higher than females (30.1%, 15.4%, and 10.7%, respectively); the PAF due to diabetes was higher in females than males (22.9% vs. 17.5%). Lower health-seeking rates in males accounted for a 7% higher mortality rate in men. The higher burden of tuberculosis in men highlights the need to improve men’s access to routine screening and ensure earlier diagnosis. Sustained efforts in providing ART remain critical in reducing HIV-associated tuberculosis. Additional interventions to reduce alcohol abuse and tobacco smoking are also needed.
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