Understanding Non-Communicable Diseases: Causes, Types, and Prevention

Once dominated by infectious outbreaks, India’s health landscape has quietly shifted. Today, the bigger threat is not a virus passed from person to person but conditions that build up silently over decades, often linked to how we eat, move, and live. These are called non-communicable diseases, or NCDs, and they now account for the majority of deaths in the country. Understanding what they are, why they happen, and how they can be prevented is no longer just a medical concern, it is a life skill for every young adult.

What are non-communicable diseases? 🔗

Non-communicable diseases are long-duration health conditions that result from a combination of genetic, physiological, environmental, and behavioural factors and are not passed from one person to another. Unlike tuberculosis or influenza, they do not spread through germs. Instead, they develop slowly, often over many years, and tend to stay with a person for life.

NCDs are sometimes called “lifestyle diseases” because daily habits play such a big role in causing them. Globally, they kill more than 40 million people each year, which is about 74% of all deaths. In India, the picture is equally serious. According to the Indian Council of Medical Research, the proportion of deaths due to NCDs rose from 37.9% in 1990 to 61.8% in 2016, and more recent estimates push that figure to around 70%.

The four major types of NCDs 🔗

While dozens of conditions fall under the NCD umbrella, the World Health Organization focuses on four big categories that together cause the most damage. These four groups are responsible for the bulk of premature NCD deaths worldwide.

Cardiovascular diseases 🔗

Cardiovascular diseases (CVDs) affect the heart and blood vessels. They include heart attacks, strokes, hypertensive heart disease, and rheumatic heart disease. CVDs are the single biggest killer among NCDs, causing about 17.9 million deaths every year across the world.

India carries a particularly heavy share of this burden. Studies show that migrant Asian Indians have a 3-time higher prevalence of coronary artery disease than the native populations of the countries they move to, and Indians tend to be hospitalised for heart complications 2 to 4 times more frequently than other ethnic groups. The reasons range from genetics to diet to high stress levels in urban life.

Diabetes 🔗

Diabetes occurs when the body cannot properly regulate blood sugar, either because it does not produce enough insulin (Type 1) or because the cells stop responding to it (Type 2). Type 2 is by far the more common form and is closely linked to obesity, inactivity, and poor diet.

India has often been called the “diabetes capital of the world,” and the numbers explain why. The ICMR-INDIAB study found that the prevalence of hypertension is around 35.5%, with an estimated 315 million people having hypertension, while diabetes and pre-diabetes are spreading rapidly across both urban and rural areas. Awareness and control remain poor, with awareness, treatment, and control rates of diabetes in India at 46%, 36%, and 16% respectively.

Cancers 🔗

Cancer is a group of diseases where abnormal cells grow uncontrollably and can spread to other parts of the body. There are more than 100 known types, but in India the most common include oral, breast, cervical, lung, and colorectal cancers. Tobacco-related cancers, especially of the mouth and lungs, are particularly common because of widespread chewing and smoking habits.

What makes cancer especially tricky is that early stages often have no obvious symptoms. By the time many patients in India reach a hospital, the disease has already advanced, which is why screening and early detection programmes are now a major focus of public health policy.

Chronic respiratory diseases 🔗

Chronic respiratory diseases (CRDs) affect the airways and lungs over the long term. The two best-known examples are chronic obstructive pulmonary disease (COPD) and asthma. COPD makes breathing progressively harder and is strongly tied to smoking and exposure to polluted air or biomass smoke from traditional cooking fuels.

India’s high levels of indoor and outdoor air pollution contribute to roughly 6.7 million deaths globally, of which about 5.6 million are due to NCDs like stroke, ischaemic heart disease, COPD, and lung cancer. Rural women who cook on wood or dung stoves are especially vulnerable to chronic lung damage.

What causes NCDs? 🔗

The good news is that most NCDs are not random. They are driven by a set of risk factors that science has identified and that, in many cases, can be changed.

Behavioural risk factors 🔗

The WHO highlights four behaviours that account for the majority of NCD cases worldwide: tobacco use, physical inactivity, unhealthy diet, and the harmful use of alcohol. These four behaviours then trigger four key metabolic changes, namely raised blood pressure, overweight and obesity, raised blood glucose, and raised cholesterol, which directly damage the heart, blood vessels, and other organs.

Unhealthy diet: Modern Indian diets have become heavier in refined carbohydrates, sugar, salt, and ultra-processed foods, while servings of fruits, vegetables, and whole grains have shrunk. This dietary shift fuels diabetes, obesity, and heart disease.

Physical inactivity: Office jobs, two-wheelers, food delivery apps, and screen-based entertainment have made daily life dramatically less active. The ICMR-INDIAB data show that every second Indian individual is physically inactive, and less than 10% of the studied population engages in regular physical activity.

Tobacco use: Smoking and chewing tobacco are linked to cancers, heart disease, stroke, and COPD. India’s National Monitoring Framework has set a target of a 30% relative reduction in the prevalence of current tobacco use by 2025.

Harmful alcohol use: Beyond liver damage, alcohol contributes to hypertension, certain cancers, and accidents that add to the chronic disease burden.

Non-modifiable and other risk factors 🔗

Some risk factors cannot be controlled, such as age, gender, family history, and genetics. South Asians, for instance, are biologically prone to insulin resistance and central obesity, which raises diabetes and heart disease risk even at lower body weights than in other populations.

Environmental and social factors also matter. Air pollution, poverty, low education, inadequate healthcare access, and stressful urban living all increase NCD risk. Researchers point out that most NCD deaths can be prevented by eliminating the most important modifiable factors, especially the four behavioural ones.

Prevention and control of NCDs 🔗

Because NCDs build up slowly, there is usually a long window during which they can be prevented or delayed. Action is needed at three levels: the individual, the community, and the government.

Lifestyle changes at the individual level 🔗

Most prevention advice comes down to a few practical habits. Eating more fruits, vegetables, pulses, and whole grains while cutting back on sugar, salt, and fried foods makes a measurable difference. The WHO recommends at least 150 to 300 minutes of moderate physical activity per week for adults, which can include brisk walking, cycling, swimming, or sports.

Quitting tobacco in any form, limiting or avoiding alcohol, sleeping well, and managing stress through activities like yoga or meditation also lower risk substantially. For young people, building these habits in their 20s pays off massively in their 40s and 50s, the decades when NCDs typically begin to appear.

Early detection and screening 🔗

Many NCDs, especially hypertension, diabetes, and certain cancers, can be detected before they cause serious symptoms. Regular check-ups for blood pressure, blood sugar, and cholesterol from the age of 30 onwards are recommended, and earlier if there is a family history.

India has rolled out a population-based initiative for prevention, control and screening for common NCDs such as diabetes, hypertension and common cancers under the National Health Mission, integrated with the Comprehensive Primary Health Care system. This means basic screening is now meant to be available at the Health and Wellness Centres under Ayushman Bharat.

Treatment and management 🔗

For people already diagnosed, NCDs are usually managed rather than cured. This involves medication, regular monitoring, dietary changes, and follow-up care. India’s flagship programme for this is the National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS), implemented since 2010 as the national programme for prevention and control of major NCDs. It has set up NCD clinics at district and community health centre levels, district cardiac care units, and day care centres for cancer.

Policy and population-level action 🔗

Individual effort can only go so far if the environment around people pushes them towards unhealthy choices. That is why governments use policy tools such as higher taxes on tobacco and sugary drinks, warning labels on packaged foods, bans on smoking in public places, clean cooking fuel schemes, and urban planning that encourages walking and cycling. The WHO’s Global Action Plan for the Prevention and Control of NCDs aims for a 25% relative reduction in premature mortality from cardiovascular diseases, cancer, diabetes or chronic respiratory diseases through such measures.

Why this matters for young Indians 🔗

NCDs are no longer a problem only for the elderly. In India, heart attacks, diabetes, and certain cancers are increasingly being diagnosed in people in their 30s and even 20s. Premature deaths, those occurring between ages 30 and 70, are particularly damaging because they cut short productive years and put enormous financial strain on families, since chronic care is expensive and often out-of-pocket. Recognising NCDs as a slow-building threat, and acting early, is one of the most important health decisions a young person in India can make.

What do you think? Looking at your own daily routine, which one or two habits do you feel are quietly putting you at risk for an NCD in the future, and what small change could you start with this week? And do you think the responsibility for tackling NCDs lies more with individuals making better choices, or with governments shaping the environment in which those choices are made?

References

1. https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases
2. https://www.pib.gov.in/PressReleaseIframePage.aspx?PRID=1796435
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9572583/
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC6994761/
5. https://nmji.in/lessons-learnt-from-the-icmrindiab-study/
6. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(23)00298-X/fulltext
7. https://www.who.int/data/gho/data/themes/topics/topic-details/GHO/ncd-risk-factors
8. https://www.nhp.gov.in/healthlyliving/ncd2019
9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12187832/
10. https://www.physio-pedia.com/Non-Communicable_Diseases?lang=en