Most people are aware of type 1 and type 2 diabetes, but did you know there is a type 3 diabetes as well! It is a more obscure term. Although it is not an accepted medical diagnosis, type 3 diabetes has been discussed in the literature as a possible relationship between insulin resistance in the brain and Alzheimer's disease. This link has been described to help explain how metabolic disorders impact brain health, causing cognitive decline and dementia.

What is Type 3 Diabetes?

Type 3 diabetes is more of a misnomer because it should not be confused with type 3c diabetes, which relates to pancreatic dysfunction. The term "type 3 diabetes," on the other hand, has been loosely used by some scientists to analogously propose that Alzheimer's disease is strongly implicated with insulin resistance in the brain.

This concept was conceptualized by Dr. Suzanne de la Monte and Dr. Jack Wands of Brown University in the year 2008. This hypothesis postulated that Alzheimer's disease may be called type 3 diabetes for it bears many similarities with glucose metabolism disorder type 2 diabetes. Their concept arises from the basic principle that insulin is fundamental to blood sugar regulation, but it is also the case with the brain. When brain cells become insulin-resistant, they lose access to glucose, impairing their function.

Research published in the Journal of Diabetes Science and Technology supports this hypothesis by indicating that insulin resistance can be a significant contributor to the occurrence of dementia, also referred to as Alzheimer's. The symptoms of memory loss and diminished reasoning are associated with impaired glucose metabolism in the body, especially in the cerebral tissue.

Symptoms of Type 3 Diabetes

Although type 3 diabetes is not a "medical term," its symptoms correlate well with Alzheimer's diseases that are known to reduce the ability to think in an efficient manner and bring down brain health. These signs are:

- Loss of memory, especially short-term.

- Poor judgment and judgment ability

- Failure in recognizing people or places familiar once.

- Failure in the process of reading, writing or processing numbers

- Anxiety, agitation, or mood changes.

- Disorganized thoughts or confusion

- Lack of impulse control

As the disease advances, patients may be afflicted with severe complications including an inability to swallow or control their bodily functions. In the final stages, most patients die from fatal complications such as aspiration pneumonia.

Causes of Type 3 Diabetes

This may not be well understood with regards to type 3 diabetes, or the exact link between insulin resistance and Alzheimer's disease. Some identified contributing factors include the following:

1. Insulin Resistance

Insulin acts as an important regulatory mechanism of brain functions such as memory and cognition. The reduction in insulin signaling may impair metabolism of brain cells, thus bringing about neurodegeneration.

2. Type 2 Diabetes

These diseases show a strong relationship and those individuals diagnosed with type 2 diabetes have double chances of getting Alzheimer's. In the two, the main causes can be chronic inflammation, oxidative stress, and a defect in glucose metabolism.

3. Environmental and Lifestyle Factors

Insulin resistance associated with obesity, stress, and an unhealthy diet is considered a cause that may increase the chances of Alzheimer's disease.

Researches in Frontiers in Neuroscience and The Lancet Neurology have also highlighted that drugs used for antidiabetic medication may be crucial for the prevention or at least slowing down the course of Alzheimer's.

Treatments for Type 3 Diabetes

In 2022, in a study in Pharmaceuticals, researchers studied biomarker uptake in brain regions implicated in the faulty uptake and metabolism of blood sugar in Alzheimer’s patients.

Emerging Therapies

Research into such treatments as intranasal insulin has also been promising. Intranasal delivery of insulin directly to the brain has been reported to enhance glucose uptake by brain cells, improve memory, and boost cognitive performance. While such clinical trials have been shown to be successful, additional research is needed for safety and efficacy.

Medications

For patients being aggressive or agitated, antipsychotic drugs may be prescribed; however, therapies such as cognitive rehabilitation as well as cognitive stimulation therapy serve to preserve memory and executive function.

Lifestyle Interventions

Diet, exercise, and stress management are critical in preventing and managing insulin resistance. A review in the Journal of Alzheimer's Disease also highlighted the benefits of Kirtan Kriya meditation, which can regulate genes involved in insulin and glucose metabolism, improve sleep, and reduce inflammation.

Can Type 3 Diabetes Be Prevented?

Although type 3 diabetes is not officially recognized, its connection to Alzheimer’s disease underscores the importance of proactive measures for brain health. Some prevention strategies include:

1. Healthy Diet

Consuming a balanced diet rich in antioxidants, whole grains, and healthy fats may support brain health.

2. Regular Exercise

Physical activity improves insulin sensitivity, reduces inflammation, and enhances overall metabolic health.

3. Stress Reduction

Mindfulness practices, including meditation, have been shown to lower stress levels, which can reduce the risk of cognitive decline.

The term type 3 diabetes brings out the complex relationship between metabolic disorders and brain health. Even though it is not a recognized medical condition, the concept emphasizes the crucial role of insulin in brain function and its possible contribution to Alzheimer's disease. Continued research will hopefully provide hope for therapies such as intranasal insulin and lifestyle modifications.

She came to the hospital because of a cough that would not go away. The cough was eventually found to be nothing serious. But her CT scan revealed something unexpected — a 12 mm nodule in the outer part of her right lung.

She had never smoked. She felt completely well.

Yet that tiny shadow raised a big question: was it an old tuberculosis scar, a harmless growth, or an early lung cancer?

A CT scan can show us that a nodule is there. It cannot always tell us what it is.

This is an increasingly familiar situation. As CT scans have become more widely used, particularly after the COVID-19 pandemic, doctors are finding small lung nodules in people being scanned for entirely different reasons. Most turn out to be benign. Some, however, need closer assessment.

India has another challenge. Tuberculosis and its scars are common, and a lung shadow can sometimes be attributed to TB without tissue confirmation. While treating tuberculosis promptly is important, assuming that every suspicious nodule is TB can occasionally delay the diagnosis of something else, including cancer.

The answer, when appropriate, is to obtain a tissue sample.

Traditionally, a small nodule deep in the lung could be difficult to reach. A needle biopsy through the chest can be effective but carries a risk of a collapsed lung. Conventional bronchoscopy is excellent for the larger airways but becomes more challenging as the target gets smaller and farther towards the edge of the lung. Surgery may sometimes be necessary.

Newer techniques are changing the picture.

Navigation bronchoscopy uses the patient's CT scan to create a three-dimensional map of the airways and guide a thin catheter towards the nodule. Cone Beam CT adds real-time three-dimensional imaging during the procedure, allowing the doctor to check where the instruments are in relation to the lesion before taking the biopsy.

In simple terms, navigation helps us find the way; Cone Beam CT helps us confirm we are there.

The tissue can then be examined immediately where appropriate, helping determine whether the sample is adequate and whether additional material is needed for advanced testing.

Importantly, not every nodule needs a biopsy. Many are best managed through carefully planned follow-up scans. The decision depends on the nodule's size and appearance, previous scans, and the patient's overall risk.

For patients, the message is reassuring: a lung nodule does not mean cancer. But it should not be ignored either.

Keep previous scans. Ask what the likely possibilities are. Understand why your doctor recommends surveillance or biopsy — and make sure the follow-up happens.

Today, advanced bronchoscopy is helping doctors turn a worrying shadow into something much more useful: an answer.

(By Dr Shyam Krishnan, Intervention Pulmonologist, CMRI)

Second-hand smoke increases the risk of lung cancer in people who have never smoked because it contains harmful chemicals, including known cancer-causing agents. When someone who does not smoke is around a person who is smoking they breathe in smoke from the burning cigarette and the smoke that the smoker breathes out. This mix of smoke is called second-hand smoke or environmental tobacco smoke.

How Second-Hand Smoke Damages Lung Cells And DNA

Also read: From Occasional to Long-Term Smoking, Experts Explain How Much Lung Damage Can Actually Reverse After Quitting?

Even though the non-smoker does not light a cigarette they still take in dangerous substances. These chemicals can irritate the lungs. Cause inflammation. They also create stress, which means the body’s natural defenses are overwhelmed by harmful molecules. Over time this damage can harm the DNA inside lung cells.

When DNA is damaged the cells may start to change in ways. These abnormal cells can grow out of control. Turn into cancer. The longer and more intense the exposure to second-hand smoke the higher the risk becomes. For example, people who live with a smoker or work in places where smoking is allowed may get exposure over time.

Second-hand smoke also makes it harder for the body to fix cells. It keeps the lungs in a state of inflammation. This ongoing irritation helps create a condition where cancer can start and grow.

There is no level of exposure to tobacco smoke. Even small amounts can add to the risk. Some people are especially at risk like children, pregnant women and those with asthma or other breathing problems.

How Can Non-Smokers Reduce Their Exposure?

The best way to prevent lung cancer from second-hand smoke is to reduce exposure. This means keeping homes, cars and workplaces completely smoke-free. It also means supporting smoke- policies and encouraging people to quit smoking. Protecting non-smokers from second-hand smoke is a step, in reducing lung cancer rates.

Dr Saket Kumar, Senior Consultant – Physician & Pulmonology, Sterling Hospitals, Bhayli, Vadodara

Dry cough and breathing difficulty aren’t always caused by asthma, COPD, or infections. They can also be signs of interstitial lung disease (ILD), a group of lung conditions that can cause inflammation and scarring and, in some cases, progressive loss of lung function.

ILD can go unnoticed in its early stages because its symptoms are often mistaken for more common respiratory conditions. By the time a patient undergoes a CT scan and reaches an ILD clinic, significant lung scarring may have already developed — and some of that damage may be irreversible.

Millions May Be Living With ILD Worldwide

A Global Burden of Disease Study 2023 analysis, published in December 2025, estimated that 4.58 million people were living with ILD and pulmonary sarcoidosis worldwide in 2023, with 112,650 deaths attributed to the conditions that year.

“The true global burden of ILD is higher than currently reported, particularly in underserved populations and low- and middle-income countries,” Prof. Marlies Wijsenbeek-Lourens, Pulmonologist and Head of the Center for Interstitial Lung Diseases and Sarcoidosis at Erasmus University Medical Center, Netherlands, told HealthandMe.

The global expert said most available epidemiological data come from Europe, North America, Japan, South Korea and Australia, where access to specialist care, multidisciplinary diagnosis and high-resolution CT imaging is generally more available.

“As a result, large parts of Africa, South America, South and Southeast Asia remain underrepresented in current estimates. In these regions, more limited access to diagnostic facilities, fewer ILD specialists and under-recognition of disease undoubtedly result in substantial underdiagnosis.”

Even in high-income countries, she added, some patients with ILD likely remain undiagnosed because symptoms such as breathlessness and cough are often attributed to more common conditions.

Also read: From Occasional to Long-Term Smoking, Experts Explain How Much Lung Damage Can Actually Reverse After Quitting?

What Is Interstitial Lung Disease?

ILD is not a single disease but a group of more than 200 lung conditions. The disease affects the interstitium, the tissue surrounding and supporting the lungs’ air sacs, or alveoli. In ILD, this tissue can become inflamed and/or scarred.

As scarring progresses, the lungs can become stiffer, making it harder for them to expand and reducing the efficiency of oxygen transfer. As the disease progresses, the lung shrinks, making it difficult for the patient to breathe.

According to Prof. Marlies, there is a rise in ILD diagnoses due to several factors, such as:

• Better awareness
• More HRCT scans
• Better diagnosis
• Ageing populations
• Autoimmune disease
• Environmental and occupational exposure.

When Should Doctors Suspect ILD?

Some forms of ILD can be treated more effectively when identified early, before permanent lung damage occurs.

“Unfortunately, many patients still reach an ILD specialist late. Breathlessness and cough may initially be treated as asthma, infection or sometimes even tuberculosis. By the time a CT scan is done and the patient reaches an ILD clinic, significant scarring may already have developed,” Dr Asmita Mehta, Professor and Head, Department of Respiratory Medicine at Amrita Institute of Medical Sciences, Kochi, told HealthandMe.

“A dry cough and gradually progressive breathlessness lasting for more than three months, particularly breathlessness while walking or climbing stairs, should raise suspicion of ILD rather than simply being attributed to asthma, infection or ageing,” she added.

Read More: US Cancer Death Rates Fall For Men, Women: Lung Cancer Progress Drives Decline

Doctors should think of ILD especially when these symptoms do not improve with usual treatment, when fine crackling sounds are heard in the lungs, or when oxygen levels fall during walking.

It is also important to ask about joint pain, skin changes, dry eyes or mouth, and exposure to birds, mould, biomass smoke or occupational dust. Sometimes the clue to ILD is outside the lungs, the expert said.

ILD And COVID-19

Pre-existing ILD was associated with worse outcomes during COVID-19. Now, six years later, some patients who had severe COVID-19 also continue to show persistent lung abnormalities.

“The reassuring part is that not every abnormal CT after COVID means progressive lung fibrosis. In many patients, the lung changes gradually improve or remain stable. Some patients who had very severe COVID, prolonged ICU admission, or required ventilation may be left with persistent scarring and may need longer follow-up,” Dr Asmita said.

What Does ILD Look Like In India?

Common ILD diagnoses seen in India include connective tissue disease-associated ILD (CTD-ILD), hypersensitivity pneumonitis (HP), idiopathic pulmonary fibrosis (IPF), sarcoidosis and idiopathic nonspecific interstitial pneumonia (NSIP).

Dr Asmita said that, apart from idiopathic pulmonary fibrosis, ILD related to autoimmune diseases and environmental exposures is also commonly seen in India. These exposures can include birds, mould, biomass smoke and certain occupations.

Epidemiological reviews estimate the overall prevalence of ILD in India to range between 49.0 and 98.1 per 100,000 people, with an annual crude incidence rate of 10.1 to 20.2 per 100,000 population.

India is also building a larger national evidence base through the ICMR-led Indian Network of Pulmonary Fibrosis (INPF) registry.

Biggest Challenges For ILD Patients In India

• Delayed diagnosis: Symptoms can be mistaken for asthma, infections, or tuberculosis.
• Limited specialist access: ILD specialists and advanced diagnostic facilities are concentrated in larger centres.
• High treatment costs: Medicines, investigations, oxygen, and pulmonary rehabilitation can be expensive.
• Limited transplant access: Lung transplantation remains available only to a limited number of eligible patients.
• Low awareness: Many patients and families are unfamiliar with ILD and its long-term nature.

“We therefore need not only earlier diagnosis, but better awareness, affordable treatment, wider access to ILD specialists and stronger advanced-care and transplant programs,” Dr Asmita said.