Fighting TB: Not a one-way solution

After reviewing a number of studies that attempt to explain the historical decrease of tuberculosis (TB), I could argue that the decline of TB incidence and mortality was due to a combination of both improvement of general social conditions and targeted public health interventions.

After being one of the main causes of death in the United Kingdom in the late 17^th century, and reaching a peak in around 1780 when an estimated 1.25% of the population died each year from TB, its incidence started to decline at the beginning of the 19^th century. This declining was observed long before the discovery of M. tuberculosis and a century before the use of antibiotics and other specific therapies. Therefore it’s argued that general improvements in the conditions of living, including better sanitation and nutrition, contributed significantly to the decline in TB incidence and mortality.

One of the leader researcher towards this argument is Thomas McKeown. Since the 1960s he’s been promoting the idea that the decline in TB mortality is due to the incremental changes in people’s standard of living, mainly better nutrition, thus minimizing the impact and effectiveness of direct public health programs, such as sanitary reforms, vaccination and segregation of infected people. For him, “the main reasons for improvement in health in probable order of importance were: a decline in the birth rate; a rise in the standard of living, first in food supplies […]; removals of specific hazards in the physical environment; and specific measures of preventing and treating disease in the individual.” [1]

This idea was revolutionary and changed the way of studying population’s health determinants, putting more emphasis in socio-economic factors than in curative medicine.

Other authors promote the use of multifactorial models to explain the downward trend of TB and other diseases. For example, Szreter cites the “existence of inter-current infections and occupational hazards that weakened host resistance to TB and of overcrowding and poor ventilation in work and home environments that enhanced transmission of the disease”. And then suggests that “these factors were removed not only by rising real wages and better nutrition but by political and social action associated with the public health movement” [2].

For Newsholme, on the other hand, segregation was an effective measure against TB, and he embraced to the idea that “targeted public health actions –including housing policies and public education leading to behavioral changes- could effectively contribute toward the decline in TB incidence and mortality”, and that these programs were “politically feasible, unlike broader social reform affecting nutrition and poverty.” [2]

There’s also evidence that the practice of directly observed therapy (DOT) and DOT short course (DOTS) is effective to control TB incidence, mainly preventing antibiotics resistance. This practice was promulgated by the WHO as its strategy for TB control.

There are many other studies that give us different approaches to the matter, leading me to think that there’s no single formula to explain the evolution of TB, but a combination of factors. It’s true that income is a powerful means to improve people’s health, by providing access to better nutrition, sanitation, housing, and even medicines or treatments for medical conditions. Therefore, poverty and income inequalities are determinants of a population’s wellbeing. But as I said, income is a means, and what’s important is the use and benefits one could obtain with the disposable income. That’s why I believe that wages alone or GDP per capita don’t determine the wellbeing of a population. Money should be put to good use, from the individual point of view, but also from governments that are in charge of the health of the population.

Some articles draw a parallel between high income countries, high health expenditures and low TB incidence [3]. This could be true in part, but there’re countries with modest per capita incomes that show as good health indicators as much richer countries. As I said earlier, money should be spent wisely, meaning from the broadest policies such as education or sanitation, to targeted health programs and research. I believe that a combination of socio-economic improvements and targeted health interventions are applicable as determinants of the declining of TB incidence and mortality.

Do you think that the political environment has any influence in the population’s health? Which political system you believe provides a more favorable environment?

References

[1] McKeown, Thomas, “A Sociological Approach to the History of Medicine”

[2] Fairchild, Amy and Oppenheimer, Gerald. “Public health nihilism vs pragmatism: History, politics, and the control of tuberculosis”. In American Journal of Public Health; Jul 1998; 88, 7; ABI/INFORM Global, pg. 1105 http://www.collphyphil.org/APHA%20Readings/Day%202%20Readings/FairchildandOppenheimer.pdf

[3] Paul D. van Helden, “The economic divide and tuberculosis. Tuberculosis is not just a medical problem, but also a problem of social inequality and poverty”. http://www.nature.com/embor/journal/v4/n6s/full/embor842.html

Szreter, Simon. “Rethinking McKeown: The Relationship Between Public Health and Social Change.” http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1447152

Colgrove, James. “The McKeown Thesis: A Historical Controversy and Its Enduring Influence” http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1447153

Evans, Robert. “Thomas McKeown, meet Fidel Castro: Phisicians, Population Health and the Cuban Paradox.” http://www.longwoods.com/product.php?productid=19916

Rolling Back Malaria, really

Roll Back Malaria is a program launched back in 1998 by the World Health Organization, UNICEF, UNDP and the World Bank to coordinate interventions and funds aimed to reduce and eventually eliminate the burden of malaria. Malaria actually threatens nearly half percent of the entire population worldwide, and is responsible for the death of around 3,000 people every day, one million yearly, most of them children from African countries.

Malaria deaths are considered preventable and curable since the entire chain of transmission is well known, and treatment is also available. P. Falciparum parasite is transmitted to humans through the bite of infected mosquitoes, which reproduce in stagnant water. The Roll Back Malaria program has three main components: distribution of bed nets, combined treatment based on artemisinin, and use of insecticides inside the houses. Despite the resources and continuous efforts for more than 10 years, the incidence and mortality rates of malaria remain steady.

Some researchers like Jeffrey Sachs states that the resources put to work under this program are not enough, that there’s need for more money committed from the wealthiest countries and international agencies to fight this pandemic. This program has become unsustainable in economic terms, because when the funding stopped in some communities, the incidence and deaths caused by malaria rose up.

There’s also evidence that the implementation of the Roll Back Malaria program has been somewhat ineffective because it didn’t took in count cultural practices or beliefs or was introduced without empowering people of the communities. For example, in Brazil a community refused to have their houses sprayed with DDT because it stained the walls and people thought to be ineffective, but accepted another insecticide (lambdacyhalothin) because it didn’t tinted the walls and also killed cockroaches. Likewise, in Papua New Guinea people didn’t accept insecticide in their houses because it killed a wasp which controlled a caterpillar which ate roofs, in consequence roofs had to be replaced more often.

Regarding the use of bed nets, it’s estimated that only one in seven children in Africa sleep under a net, and only 2% of children use an insecticide-treated net. The reasons are many, ranging from lack of access, distribution of resources in the family, lack of knowledge of the benefits or past learnt behaviors.

Another critique to the program has been that it should include other elements besides bed nets, artemisinin and insecticides, like the control and drainage of stagnant water pools that are very common in the poorer, highly populated areas of Africa. Without removing this element from the cycle, the reproduction of mosquitoes P. Falciparium will continue to prevent any program centered on Malaria eradication to succeed.

The program should also incorporate the local internal and external environments to its strategy. The internal environment includes the strategies, staff, skills, style and culture, while the external environment takes in count the economic, social, institutional and political situation existing in the country.

For malaria control to be effective in the long term an integrated approach is required as well. There’s need to coordinate not only the efforts of the international agencies with the national governments, but also among different sectors in the country, such as the ministries of health, education and agriculture, local governments, NGOs and community based organizations, to promote the empowerment of all the agents in the fight against malaria.

Malaria is an example of a well known, preventable illness whose presence depends more on socioeconomic underpinnings, than in high-end curative medicine. Eradicating malaria is as difficult as eradicating poverty. But until all the magic happens and the world can really roll back malaria, still 3,000 die each day from this epidemic, that is more than 2 lives lost per minute.

References

http://apps.who.int/malaria/wmr2008/malaria2008.pdf

http://www.who.int/mediacentre/factsheets/fs094/en/index.html

http://www.who.int/inf-pr-1998/en/pr98-77.html

http://www.unicef.org/supply/index_8748.html

http://www.bmj.com/cgi/eletters/328/7448/1086#59115