Dehradun: More than a million new cases of TB every year in India are attributable to under-nutrition, according to a study published in The National Medical Journal of India that discusses a factor hitherto ignored in the epidemic.
More than half of all cases of TB every year – two-thirds of new cases in people 15-19 years old – could be prevented by ensuring that people get enough to eat in terms of calories and proteins, according to a statement.
Researchers from the Himalayan Institute of Medical Sciences, Jolly Grant, Dehradun, Uttarakhand, India, and the McGill International TB Centre, McGill University, Montreal, Canada, used data on undernutrition in India from the National Family Health Survey-3 to assess the impact of undernutrition in Indian adolescents and adults on TB incidence.
Undernutrition is endemic in India, with 34% of men and 36% of women 15-49 years in India undernourished, according to NFHS-3 estimates. These people are up to four times more likely to develop TB disease than healthy people are, as undernutrition the leading cause of immunodeficiency globally, weakens resistance to the TB bacillus.
According to the researchers, scheduled castes (SC), scheduled tribes (ST), other backward classes (OBC) and the poorest one-fifth of the population are at greatest risk of TB disease. Women are at greater risk than men.
India has the highest number of new cases of tuberculosis and number of TB-related deaths in the world, with 2.3 million new cases and an estimated 320,000 deaths annually.
The Revised National Tuberculosis Control Programme (RNTCP) has had little impact on decreasing the number of new cases, note the researchers. The growing number of drug resistant cases threatens treatment success, and an effective vaccine for TB is nowhere in sight.
“In India, an estimated 400 million people, a number larger than the entire population of the USA, are infected with the TB bacillus, are asymptomatic but at risk of developing active TB. This infection can be contained if the immune system functions normally. Undernutrition, which suppresses the immune system, is the major factor driving the progression of infection in these people to active tuberculosis in India — rather than HIV (which accounts for only 7% of new cases), diabetes or smoking, said lead author, Dr Anurag Bhargava, associate professor, department of internal medicine, Himalayan Institute of Medical Sciences, Jolly Grant, Dehradun.
Dr Bhargava further said, “In India endemic undernutrition in adolescents and adults plays a part in sustaining the TB epidemic, similar to that played by endemic HIV infection in Africa. It is time that undernutrition in adults (highest in global terms) is now addressed as part of the solution of TB in India.”
“We must strive to improve the quantity and quality of food that Indians — especially the poor, those in rural India, and those belonging to disadvantaged social groups – eat,” Dr Bhargava said.
According to Dr Bhargava, there is clear evidence that tuberculosis underwent a significant decline in the western world even before the first TB drugs or the BCG vaccine was introduced because of improvements in living conditions, particularly nutrition.
“The India Human Development Report 2011 of the Planning Commission has drawn attention to the decline in the per capita intake of calories as well as proteins in Indians, in successive nutritional surveys over the past 25 years, which is very worrisome,” added Dr Bhargava.
This paper was awarded the Research Paper of the Year award at the recent British Medical Journal India awards function on September 20, in New Delhi. It was awarded this after a 3-phase process consisting of 2 rounds of shortlisting and a final presentation before a jury on September 19.