Alcoholism fuelling spread of tuberculosis in Kiambu County

A majority of people who tested positive for tuberculosis (TB) in Kiambu County from last November to January this year are men with alcohol use disorders (AUD).

This is according to findings from a new study published by the Kenya Medical Research Institute (Kemri).

Annfreshia Wangari, the lead researcher and a clinical epidemiologist at the Ministry of Health, noted that since last year, implementation of social contact invitations for TB screening by the ministry has yielded 25 patients, with the majority being men with AUD. According to the Kemri researchers, people who consume alcohol excessively are highly susceptible to TB.

The relationship between alcohol consumption and tuberculosis can be explained by two causal pathways.   First, alcohol consumption impairs the immune system, which increases susceptibility to tuberculosis infection, as well as to reactivation of latent TB. Second, alcohol consumption leads to presence in social environments that facilitate the spread of tuberculosis infection. Examples of such environments include bars, shelters, prisons and social institutions, which have been implicated in molecular-epidemiological studies, according to the US National Institute on Alcohol Abuse and Alcoholism.

The institute describes AUD as a medical condition characterised by an impaired ability to stop or control alcohol use despite adverse social, occupational or health consequences. AUD encompasses the conditions that some people refer to as alcohol abuse, alcohol dependence, alcohol addiction and the colloquial term, alcoholism. Considered a brain disorder, AUD can be mild, moderate, or severe. This means that a person’s risk for developing AUD depends in part on how much, how often, and how quickly they consume alcohol.

Alcohol misuse, which includes binge drinking and heavy alcohol use, over time increases the risk of AUD. Other factors that lead to AUD include drinking at an early age, genetics and family history of alcohol problems, mental health conditions and a history of trauma. Lasting changes in the brain caused by alcohol misuse perpetuate AUD and make individuals vulnerable to relapse.

Annfreshia highlights that over the years, TB contact tracing in Kenya has primarily focused on identifying household contacts for screening and investigating TB. However, the yield has not been optimal, especially among men in urban and peri-urban areas.

“Many of them live alone, with their families residing in villages, posing a challenge in reaching them for TB screening. Additionally, those residing in villages often spend their time with peers in town centers or workplaces, “the epidemiologist notes.

She adds that Mount Kenya region faces a significant challenge of high rates of unmarried men, particularly those with alcohol use disorder. According to data by the Health ministry,  in 2022, retreatment cases  in Kiambu County (a patient previously treated for TB who returns to treatment having previously lost to follow-up) accounted for 18 per cent (51 people out of a sample of 276), with 88 per cent (45/51) among men, and 24 per cent (12/51) identified as alcoholics.  The specialist emphasises the need to reach out to social contacts for TB patients, especially men.

Last year, retreatment cases decreased to 14 per cent (36/250), with 86 per cent (31/36) among males and 31 per cent (11/36) being alcoholics. Annfreshia highlights a new trend in Kiambu County that was observed by the researchers: “A concerning trend of TB was observed among a group of men associated with a specific night club in Kinoo and Muthure areas in Kabete and Kikuyu sub-counties testing positive.” This is why they are implemented a strategy to engage social contacts by educating TB patients about transmission modes and risk factors. All TB patients were tasked with bringing at least one social contact for screening after educating them on identifying symptoms in their social contacts.According to the lead researcher, community sensitiSation efforts were also conducted. 

Patients were informed about the risk of reinfection if they failed to recogniSe TB symptoms among their friends and family. 

“For those uncomfortable talking to their friends, they invited us to their social gathering areas for TB sensitisation and screening. By providing information on transmission and risk factors, we aimed to reduce stigma, a significant hindrance to social contact linkage,” she said. 

According to the epidemiologist, they have concluded that social contact invitation is an effective strategy to increase TB patient yield and enhance treatment adherence. 

The Health ministry is now of the view that proper implementation creates awareness, reduces stigma, and improves TB treatment uptake, thereby reducing community-level transmission.

“This strategy is also effective for active case finding , empowering clients with the knowledge to link others in their social network early for TB diagnosis, regardless of their TB status,” Annfreshia highlights. 

Frontiers, a global peer-reviewed immunology journal, notes that globally, an estimated 107 million people have AUD leading to 2.8 million premature deaths each year. 

TB is one of the leading causes of death globally and over eight per cent  of global TB cases are estimated to be attributable to AUD. 

Social determinants of health such as poverty and undernutrition are often shared among those with AUD and TB and could explain the epidemiologic association between them.
“
AUD has been shown to be an independent risk factor for TB, with a linear increase in the risk for TB with increasing alcohol consumption. 

While few studies have focused on potential biological mechanisms underlying the link between AUD and TB, substantial overlap exists between the effects of alcohol on lung immunity and the mechanisms exploited by Mycobacterium tuberculosis (Mtb) to establish infection,” the journal highlights. 

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