The nature of disease in India has changed dramatically over the past three decades. Communicable diseases like diarrhoea, measles, tuberculosis and lower respiratory infections were the dominant causes of illness in the 1990s but these have now been surpassed by non-communicable diseases like heart disease and chronic obstructive pulmonary disorders that are more widespread in recent years.

However, this epidemiological transition has not been uniform across India largely because of big differences in the status of social development among its 1.34 billion people from 2,000 different ethnic groups. Therefore, states in India are at different stages of epidemiological transition. More developed states with better social indicators are at an advanced stage of transition, which means that they have less illness caused by infection and malnutrition but are dealing with higher burdens of non-communicable diseases. Less developed states are still battling the old problems like infections, anaemia and neonatal disorders. However, even among states with similar levels of development, there are striking differences in the burden of death and illness from major non-communicable diseases.

A new study by researchers from the Indian Council for Medical Research, the Public Health Foundation of India and the Institute for Health Metrics and Evaluation in the United States published in The Lancet and released on Tuesday estimates disease burdens and risk factors for disease in each state in India. The metrics used in the study are deaths, disability-adjusted life-years or DALYs, prevalence, incidence, and life expectancy for 333 disease conditions and injuries and for 84 risk factors.

Health is a state subject. Two-third of public spending on health across the country is made by individual states governments and one-third by the union government. State-specific disease data may help direct investment and frame specific policies to tackle the major diseases in each state, say the authors of the study.

“Rather than taking a more generic approach, these new estimates will be crucial to steering health policy to take account of specific health problems and risks in each state, and ultimately achieving the government’s vision of assuring health for all,” said Professor Lalit Dandona from the Public Health Foundation of India in a statement accompanying the release of the study.

The study shows that chronic diseases are now not only linked to better socio-economic standing. Conditions like heart disease and pulmonary disease are widely prevalent even among the poor and are linked to poverty. Meanwhile, even some advanced states have diseases of under development.

The study details the leading causes of disease and disability in India. Ischemic heart disease, which is heart disease caused by narrowing of blood vessels and thus restricting blood flow, is the major cause of illness followed by chronic obstructive pulmonary disorders, which is a group of non-communicable lung diseases characterised by poor air inflow and long-term breathing problems that get progressively worse. Diarrhoea and lower respiratory infections follow in third and fourth place.

DALYs: Disability-adjusted life-years is a measure of overall health expressed as the number of years lost due to ill-health, disability or early death.
DALYs: Disability-adjusted life-years is a measure of overall health expressed as the number of years lost due to ill-health, disability or early death.

So, what are the major diseases in each state of India?

Kerala is at the most advanced stage of epidemiological transition. The most common cause of illness here is ischemic heart disease. Other major causes of DALYs – an overall disease burden expressed as the number of years lost due to ill-health, disability or early death – are sense organ disorders like vision and hearing impairments, followed by diabetes and then lower back and neck pain.

Like Kerala, Himachal Pradesh, Punjab, Tamil Nadu and Goa have higher incidences of non-communicable lifestyle diseases than communicable, maternal, neonatal and nutritional diseases.

But there are some differences even among these states. For instance, Punjab has much higher rates of premature death and ill health due to diabetes and ischemic heart disease, but lower rates due to chronic obstructive pulmonary disease compared to neighbouring Himachal Pradesh.

In sharp contrast to states in an advanced stage of epidemiological transition is Bihar, the state which is at the earliest stage of epidemiological transition. Diarrhoeal diseases are the biggest causes of DALYs in Bihar. Lower respiratory infections are also a major cause of illness. However, Bihar also has a high rate of ischemic heart disease and chronic obstructive pulmonary disorders.

Diarrhoeal disease is the leading cause of illness in Jharkhand, Uttar Pradesh and Odisha, other states where epidemiological transition has been slow.

The leading risk factor for disease and death in India in 2016 was child and maternal undernutrition, which is largely a result of poverty. Bihar, Jharkhand, Uttar Pradesh, Rajasthan, Assam, Chhattisgarh and Madhya Pradesh, all states with lowest epidemiological transition levels, have the highest rate of disability caused by child and maternal undernutrition.

Not surprisingly, the second biggest risk factor is air pollution.

Half of all premature deaths caused by air pollution in the world occur in India. Air pollution contributes to India’s disease burden from cardiovascular disease, chronic respiratory disease, and lower respiratory infections. The disease burden due to air pollution is highest in states like Rajasthan, Uttar Pradesh, and Bihar. With air pollution from emissions and dust from the power, industrial, transport, and construction sectors projected to grow, it is likely to contribute to more disease across states in coming years.

“India needs an effective, coordinated response that immediately reduces the level of air pollution at it sources – crop burning, vehicles powered by internal combustion engines, coal fired power plants, among others,” said Michael Klag, dean of the Johns Hopkins Bloomberg School of Public Health and member Independent Advisory Committee for the Global Burden of Disease. “It is time to put regional differences and concerns within India aside and make choices to benefit everyone in India, especially children.”

Greater urbanisation will also pose a major challenge to Indian health systems in coming years, say the authors of the study. India is beset with ever increasing unplanned urbanisation and half of the population projected to be urban by 2050, up from a third at present.

A third challenge is an ageing Indian population. Increasing life expectancy will lead to more disability and a larger disease burden.

“Trying to deal with diseases and conditions that contribute to huge societal burdens of disease by treatment alone is like trying to keep a leaky boat afloat by bailing it out with a bucket,” said Klag. “In addition to treating disease, that is, bailing out the boat, one also has to stop up the leaks so water doesn’t come in – prevent the occurrence of new disease. Also, treatment is seldom perfect. It is seldom totally effective, except for certain infectious diseases, and has side effects. Prevention means that disease never occurs.”

With input from Mahim Pratap Singh.