Is thin-fat India in trouble?

We are the diabetes capital of the world. That makes us high-risk TB contractors. Is thin-fat India in trouble?

First came the bad news: With 30 million Indians diagnosed with diabetes, this country holds the world's second largest population with the disease, and is likely to reach the top spot within 10 years. Add to this, India has the highest number of people with active tuberculosis (TB).

It doesn't get better.

Last week, a study commissioned by The Lancet, reported that the diabetes epidemic is closely linked with rising cases of TB. The study says diabetes is making an increasingly important contribution to India's TB epidemic, as it is in other diabetes prone nations. In the last three years, a 52 per cent increase in diabetes prevalence has been recorded in 22 countries with the highest number of TB cases.

What is it that links a non-communicable disease to a communicable one?

Immune crash
Dr Manoj Chaddha, consultant endocrinologist and diabetologist at Khar's Hinduja Healthcare Surgical, says, "High blood sugar levels weaken a person's immune system. So, diabetics are at high risk for all sorts of infection. Which is why even a common cold takes longer to cure in a diabetic."

It doesn't help that mycobacterium tuberculosis, the causative agent of most TB, is an air-borne microbe as opposed to a water-borne microbe, thus leaving us always exposed to the infection.

The Indian diet, high in starch, is not just making us prone to diabetes but also to TB, points out Dr Shashank R Joshi. "The Indian vegetarian diet, especially, is protein deficient. The TB microbe has been seen to thrive in a protein deficient environment," says the endocrinologist at Bandra's Lilavati Hospital, also the president of Association of Physicians of India.

Dr Joshi, who authored a 2009 study, along with Dr Tiyas Sen and Dr Zarir F Udwadia (both are consultant chest physicians at P D Hinduja Hospital and National Research Centre) titled, Tuberculosis and Diabetes Mellitus: Merging Epidemics, says that the lack of protein, a critical nutrient for a better immune system, also means that the body's muscle mass is low.

"This explains the high incidence of thin-fat Indians. It refers to someone who may appear lean, but his body mass percentage of fat is high, which makes him more susceptible to diabetes and thus, TB," Dr Joshi adds.

Reactivated TB
The rule of 10 applies to the interlinking of the two diseases, he explains. Ten per cent of all patients with diabetes will have TB and 10 per cent of all patients with TB will suffer diabetes.

While how diabetes makes a patient prone to TB is evident, the reverse is unclear.

The 2009 article states: Studies conducted after the introduction of the glucose tolerance test in the 1950s, have shown high prevalence of impaired glucose tolerance test in patients with tuberculosis with rates ranging from two per cent to 41 per cent. Why this happens, however, is not clearly understood yet.

Dr Vikas Oswal, a TB and chest consultant at Shatabdi Hospital and a consultant at Sunrise Hospital, who also has a practice at Chembur, says the diabetic-patients-with-TB he sees come in with the same symptoms - lethargy, fever and cough for two weeks that anti-biotics haven't helped cure. Not all however, need to have been recently exposed to the TB bacteria.

"In many cases, patients who may have had TB earlier, and have seen the bacterium lay dormant after medication, could develop active TB if they are detected with diabetes. The immune system is now unable to suppress the bacteria," he explains. In India, Dr Oswal says, three lakh people die of TB every year and 1.9 million Indians develop the condition annually.

In a 2013 editorial for Thorax, a peerreviewed medical journal, which Dr Udwadia co-wrote, he said that in almost a fifth (19%) of all cases, re-infection occurred with a different genotype of TB, indicating spread of the disease, "possibly from attendance by diabetics at clinics with high local TB prevalence. This confirmed again that healthcare settings should be considered high-risk environments for disease spread for our vulnerable patients".

Tougher to treat
Many physicians, Dr Oswal says, treat a patient for TB without confirming the diagnosis. "Only upon sputum examination should a patient be given TB medication. Otherwise, chances of the disease turning drug-resistant are high. Also, patients must complete the course without a break," he warns.

Dr Udwadia says not only are diabetics more prone to TB, but "once they develop it, they also fight it off more slowly." And so, the WHO standardised four-drug treatment won't work in patients with the dual diseases. Dr Chaddha says, "The patient is getting less support from his own body. While a regular TB patient can be cured within six months, a diabetic could take anywhere between 10 to 18 months."

And before you sign off thinking that as an urban middle-class Indian, you aren't the target reader for this story, here's a clarification from Dr Joshi: "Just as diabetes is no longer the rich Indian's disease, TB is no longer the poor man's burden. There are no class boundaries to these ailments anymore."

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