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.

India has a target to eliminate dog-mediated rabies by 2030. It has strengthened access to post-exposure prophylaxis for people exposed to rabid animals, but controlling transmission among dogs still remains a challengge.

India's National Action Plan for dog-mediated rabies elimination rests on human-health component, which focuses on post-exposure prophylaxis and awareness among bite victims, and the animal-health component, which focuses on vaccinating and sterilising stray dogs.

In a conversation with HealthandMe, Dr Hanul Thukral, Veterinary Epidemiologist, South Asia Field Epidemiology & Technology Network (SAFETYNET), formerly with the Centre for One Health, National Centre for Disease Control (NCDC), Ministry of Health & Family Welfare, Government of India, says that the human-health side of the programme is strong. The bigger challenge lies in giving the animal-health side enough resources, coordination and accountability.

The Gap Of Animal Health Component In Rabies

Dr Thukral talks about an unusual problem at the heart of India's rabies-control efforts. He speaks about the ownership of stray dogs and that they do not fall under any single ministry.

“Stray dogs also do not come under a particular ministry. They do not come under the animal husbandry ministry, the health ministry or the wildlife ministry. They are under the purview of local bodies, including municipal corporations and rural local bodies,” he said.

This is a larger issue as the animal-health component of rabies elimination depends on sustained vaccination and sterilisation campaigns. Dr Thukral said the country currently lacks dedicated funding and resources for this part of the effort.

For India to move faster towards the 2030 goal, he said local bodies need to be given greater financial and operational support, including resources to capture rabid dogs, sterilise stray dogs and vaccinate them.

He added, “There should be an incentive-based model for local bodies like Swachh Bharat. Financial or non-financial incentives could be offered to local bodies for their rabies efforts, including recognition for those that prevent the majority of deaths.”

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Treatment Is Available But The Patient May Seek Treatment Late

India's human-health response is strong. Dr Thukral said the health ministry has increased access to rabies vaccination and rabies immunoglobulins, with a goal of making vaccines available up to the PHC level and immunoglobulin available up to the CHC level.

Yet the first break in the prevention chain can occur before the health system even knows a bite has happened.

“The prevention chain breaks down where it actually starts. It starts with the awareness of dog-bite victims,” Dr Thukral said. “A person bitten by a dog has to recognise the danger and seek care before the health system can intervene. According to a recent estimate cited during the interview, only around 20-25% of dog-bite victims receive post-exposure prophylaxis, while 60-65% do not. Of those who receive it, only 50% complete it.”

Dr Thukral stressed that these are not definitive figures. “These are just estimates based on a subset of the population,” he said.

That gap can lead to delayed treatment. “In rabies, time is everything,” he said, adding, “If we don't get post-exposure prophylaxis immediately after the dog bite, after 10 hours or after 24 hours, it has virtually no use.”

The 70% Dog-Vaccination Challenge

Human treatment can prevent death after exposure, but elimination requires the transmission cycle to be interrupted among dogs. Around 70% vaccination coverage among dogs is needed to interrupt the transmission chain.

The problem, Dr Thukral said, is that India does not have reliable nationwide data showing what proportion of its stray-dog population is actually vaccinated.

He said, “A nationwide stray-dog census was only recently conducted, counting almost 1 crore 50 lakh stray dogs across the country. Local bodies and panchayats conduct surveys and organise vaccination campaigns within their jurisdictions, but the current effort is very scattered and very non-uniform.”

He added, “If I achieve 70% vaccination in a particular block, the dogs of that block are protected. But there is always a chance that unvaccinated dogs from the periphery or neighbouring blocks can enter that block.”

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Treatment Alone Can Prevent Deaths, But Not Eliminate Rabies

Dr Thukral says saving people from rabies and eliminating rabies are not the same goal. He said, “One estimate suggests that if India continues increasing post-exposure prophylaxis coverage while carrying out suboptimal dog vaccination, around 400 deaths could be prevented over the next 10 years.”

Another estimate cited by Dr Thukral puts the figure at about 400-500 deaths over the next 10 years, with spending about 5 to 10 crores. But preventing those deaths would still fall short of elimination. “That’s it. We cannot achieve elimination,” Dr Thukral said.

“Humans are not the source of the infection,” he explained. “In this case, dogs or other animals are the source of infection. Unless we target them, we do not move closer to elimination.”

India Does Not Have Reliable Data For Vaccinated Stray Dogs

The same data problem extends to the Animal Birth Control programme, which combines sterilisation with anti-rabies vaccination. The expert says that there is no nationwide figure showing how many stray dogs have been vaccinated or sterilised. The information exists, but it sits across individual municipal corporations and panchayats rather than in one comprehensive national dataset.

“Vaccinating stray dogs doesn't come under the purview of the health ministry or the animal husbandry ministry,” he said. That makes it difficult to answer a seemingly basic question: what proportion of India's stray dogs is vaccinated at any given time? “We do not have nationwide data,” Dr Thukral said.

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Reliable 'One Health' Approach

Rabies is not a problem that can be solved by hospitals alone. At the district level, Dr Thukral said an effective One Health system would require health departments, municipalities, animal husbandry authorities, veterinary services and welfare bodies to have clearly defined responsibilities, adequate resources and a mechanism to coordinate.

He said, “The health department would focus on post-exposure prophylaxis, animal-bite management and awareness. Local bodies would handle dog vaccination, sterilisation and solid-waste management. The animal husbandry department could provide technical support, while welfare bodies could promote responsible dog ownership. Let every department do its job and establish coordination among them.”

That coordination also becomes important after an individual bite. Municipal or animal-health authorities need to communicate with the health department because one reported bite may indicate that additional people have been exposed.

How To Recognise A Rabid Dog?

Another challenge is recognising rabid animals. Dr Thukral said that after a dog is bitten by another rabid dog, it can take up to three months for symptoms to develop. However, he stressed that this does not mean the animal transmits the virus throughout that entire period.

“It will transmit the virus about 10 days before it starts showing symptoms,” he said. He also described several behavioural and neurological changes that can raise concern.

A dog that suddenly becomes aggressive, unusually quiet, or behaves differently from its normal pattern may warrant attention. Other signs described by Dr Thukral include seizures, excessive drooling, and changes in vocalisation.

“The basic thing we need to look out for if we get a dog bite or exposure from a potentially rabid animal is, most importantly, change in the animal's behaviour,” he said.

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India’s Surveillance Gaps

India's surveillance recorded 54 rabies deaths in 2024, according to the Press Information Bureau. But an independent study cited during the discussion put the number at more than 5,700, and estimated that India may have between 3,000 and 7,000 deaths annually.

Dr Thukral said that India's human rabies surveillance system is well equipped to detect, diagnose and report suspected and confirmed cases. But the bigger vulnerability, he said, may occur before a suspected case enters the health system.

“If there are scattered cases, such as one bite or a couple of bites, unless that patient reports to a health facility for potential post-exposure prophylaxis, the health system will most probably fail to capture it,” he said.

In other words, surveillance can only record what comes into contact with the system. Community awareness and care-seeking behaviour therefore remain critical.

The Biggest Challenge In India’s Rabies Elimination Goal

Dr Thukral believes the health component of India's rabies programme is comparatively strong. Post-exposure prophylaxis is accessible, almost free and cost-effective, he said. But it becomes more difficult when the focus shifts to dogs.

“Sterilising and vaccinating a dog currently takes around Rs 1,500 per stray dog to vaccinate it and sterilise it,” he said.

With a stray-dog population of around 1.5 crores, the scale of resources required becomes enormous. According to Dr Thukral, local bodies generally do not have that kind of money to dedicate to rabies control.

“So, yes, our system is very much in place and very strong to detect human rabies cases and treat them and provide them with the necessary care,” Dr Thukral said. “But for elimination, we need to target the source of the infection, which is obviously these stray dogs.”

For India to reach its 2030 goal, he said, the pace needs to pick up in terms of resources, manpower and political intention.

India's rabies challenge is therefore not confined to what happens after a person is bitten. It begins much earlier. With awareness, timely care-seeking, dog vaccination, sterilisation, waste management, reliable data and coordination between agencies working across the human and animal-health systems.

The country can continue expanding access to post-exposure prophylaxis and prevent more deaths. But, as Dr Thukral emphasises, that alone cannot deliver elimination. The question for the next four years is whether India can move from responding to individual exposures to systematically interrupting transmission at its source. As the expert said, “We need to target the source.”

You can feel fine and still have a heart that is slowly changing. Researchers at Imperial College London and the MRC Laboratory of Medical Sciences say millions of people could be living with hidden inflammation that does exactly that. They say the changes can start years before any symptoms show up.

"Our study, which is the largest of its kind, suggests that millions of people could be living with hidden inflammation, which is slowly changing their heart and causing long-term damage," said Professor Declan O'Regan, British Heart Foundation Chair of Cardiovascular AI at Imperial College London.

What The Study Found

The study was published in the European Journal of Preventive Cardiology. The team looked at data from nearly 480,000 adults in the UK Biobank, a large health database, Imperial says. They measured a blood marker called glycoprotein acetyls, or GlycA for short, which the paper uses to measure chronic inflammation. They also used heart scans and genetic data.

People with the highest levels of inflammation, the top 20%, had a 43% higher risk of heart attack and stroke than those with the lowest levels, the bottom 20%, according to Imperial.

Imperial adds that higher levels also went with changes in the heart itself. These included thicker heart walls, smaller heart chambers and poorer filling of the heart. The researchers say such changes can build quietly for years before possibly leading to heart failure.

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Where The Inflammation Comes From

Chronic inflammation is a long-term, low-level activation of the immune system, Imperial explains. It has been linked to cancer and diabetes, and is increasingly seen as a driver of heart disease.

According to Imperial, higher inflammation was strongly linked to poorer social and economic circumstances and to mental distress, as well as to smoking and excess body fat.

"The surprising thing was how much social factors and mental health are linked to inflammation and damage to the heart, as well as more well-known risk factors like smoking and inactivity," O'Regan said. He added that there was also a strong genetic factor, "with some people being naturally more resilient or susceptible to the inflammatory damage that comes from different lifestyles."

What Could Come Next

The study named proteins from the interleukin-1 and TNF families as likely drivers of the damage, Imperial says. Several are already targeted by drugs in clinical trials, which Imperial says raises hopes that anti-inflammatory treatments could help prevent heart disease before symptoms begin. The researchers say combining inflammation blood tests with genetic risk scores could help find the people who would benefit most from early action.

There is earlier proof that this idea can work. In the 2017 Canakinumab Anti-inflammatory Thrombosis Outcomes Study, or CANTOS trial for short, led by Paul Ridker and published in the New England Journal of Medicine, 10,061 people who had already had a heart attack, and had high inflammation, were given canakinumab or a placebo. The paper concluded that at the 150 mg dose, given every three months, canakinumab led to fewer repeat cardiovascular events than the placebo, independent of any drop in cholesterol. But those were heart attack survivors, not people without symptoms.

What to keep in mind

The study reports links, and the researchers describe inflammation as one possible pathway to heart damage. They also stress that being genetically susceptible, or living in hard circumstances, does not mean a person will develop heart disease, and that much can be done to prevent long-term inflammation.

A few floaters, a brief flash of light or mild blurring across your vision may seem harmless at first. But when these changes appear suddenly without any probable cause, they may signal a bigger problem. On World Retina Day, experts explain when your retina needs urgent medical attention.

The retina is the light-sensitive layer at the back of the eye, which plays a crucial role in maintaining healthy eyesight. Some retinal conditions may develop without obvious symptoms in early stages, while others can present suddenly and threaten your eyesight if treatment is delayed.

“Retinal health is fundamental to maintaining clear vision and preserving quality of life, yet many retinal conditions can develop silently, without obvious warning signs in their early stages,” Dr Rajesh Kapoor, Medical Director, Suruchi Eye Hospital, Navi Mumbai told HealthandMe.

“By the time a person begins to notice blurred or distorted vision, dark spots, flashes, floaters, or other visual changes, the condition may already require urgent medical attention. This is why we need to shift our approach from waiting for symptoms to prioritizing awareness, regular comprehensive eye examinations and timely consultation with an ophthalmologist.”

What Are Floaters And Flashes?

Floaters can look like tiny dots, lines, specks or cobweb-like shapes moving across your field of vision. They are easier to notice when looking at a bright background.

Flashes, on the other hand, can look like brief streaks or bursts of light. They may occur even when there is no actual source of light around you.

Occasional floaters can occur for reasons that are not always serious. However, a sudden increase in floaters or the sudden appearance of flashes should not be dismissed, especially if there are other changes in vision. One of the conditions doctors want to rule out in such situations is retinal detachment.

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What Is Retinal Detachment?

“Retinal detachment is a serious condition which requires urgent medical attention and occurs when the retina, the light sensitive layer at the back of the eye pulls away from its normal position,” Dr Mudit Tyagi, Scientific Chair, VRSI and Head, Smt Kanuri Santhamma Center for VitreoRetinal Diseases, L V Prasad Eye Institute, Hyderabad told HealthandMe.

There are several possible causes of retinal detachment. According to Dr. Tyagi, they include injury to the eye, high myopia and certain eye diseases.

When the retina separates from its normal position, its ability to function properly can be affected. The longer the condition remains untreated, the greater the concern about permanent vision loss.

Sudden Flashes And A Curtain Or Shadow Over Your Vision

The symptoms of retinal detachment can vary, but certain changes should warrant immediate medical attention.

A dark curtain or shadow across the field of vision is concerning because it can represent a portion of the visual field being lost.

Dr. Tyagi said, “The urgency of recognising retinal detachment can’t be overstated. If you have sudden flashes of light, a dramatic increase in floaters, or a dark shadow or curtain across your field of vision, don’t ignore it, even if there is no pain.”

The absence of pain should not be misconstrued as a non-emergency. A retinal problem can occur without the kind of discomfort people usually associate with an eye emergency.

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Timing Is Key

Retinal detachment is not a condition where it is advisable to wait and see whether symptoms settle on their own. “Retinal detachments, if detected in time and operated early enough can result in a good recovery of vision,” Dr Tyagi said.

He added, “It is important, therefore, to be vigilant and see an eye care specialist as early treatment can help avoid preventable loss of vision. So, timely recognition and diagnosis followed by right treatment can help save vision.”

This is why sudden visual changes deserve attention even if they seem minor initially.

Who Is At Risk?

Some people may need to be particularly proactive about retinal health. Dr. Kapoor said individuals with diabetes, increasing age, a family history of retinal disease or other risk factors that may affect retinal health should be more careful and alert.

Diabetes can affect the blood vessels supplying the retina and lead to diabetic retinal disease. Regular eye examinations can help identify changes before vision is significantly affected. Dr Kapoor also stressed that screening should not necessarily wait until symptoms appear.

“Advances in retinal imaging, diagnostics and treatment today provide ophthalmologists with valuable opportunities to identify and manage several retinal conditions at an earlier stage. However, technology can make its greatest impact when people seek eye care at the right time.”

A sudden change in vision does not automatically mean that a person has retinal detachment. But because some retinal conditions can progress rapidly, it is important to have sudden symptoms assessed rather than trying to determine their cause on your own.

Dr Kapoor said: “Through greater public awareness and proactive screening, we can encourage people to take retinal health more seriously. Protecting sight begins with understanding that healthy vision should never be taken for granted—because when it comes to the retina, we should not wait for a problem to become noticeable before taking action.”