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 17th 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 19th 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
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