Ageing does not affect everyone in the same way. While some people remain relatively healthy into their later years, others develop several chronic illnesses despite being of a similar age. Scientists are investigating whether part of this difference can be traced to the way the immune system changes over a lifetime.

A study published in Immunity, offers a new clue. Researchers found that the balance between two populations of immune cells was associated with people’s long-term risk of disease and death. They also developed a way to estimate this balance using proteins circulating in the blood.

The findings could help scientists identify biological changes associated with unhealthy ageing before symptoms appear. Why do some people’s immune systems remain resilient while others develop patterns associated with declining health?

Ageing Leaves Marks on the Immune System

The immune system changes as people grow older. Its ability to respond to unfamiliar threats can weaken, while some immune cells become more prominent after years of exposure to infections and other stimuli. These changes can influence how the body responds to disease.

To investigate these differences, researchers examined approximately 12.4 million immune cells collected from 2,609 adults aged 20 to over 90 across eight study groups. Their analysis focused on two populations of T cells, which are white blood cells involved in identifying and responding to threats. The cells were distinguished by their production of granzyme K and granzyme B, proteins that help coordinate immune responses and destroy infected or abnormal cells.

The researchers found that older adults did not share a single pattern of immune ageing. Instead, their immune systems varied considerably, with some showing a greater presence of cells associated with granzyme B and others displaying a different balance.

That variation mattered when the team examined participants’ health outcomes. An immune profile dominated by granzyme B-producing cells was associated with a higher risk of several chronic conditions and death over the following years. The finding suggests that a person’s immune system may reveal aspects of their health trajectory that their age alone cannot capture.

What Blood Proteins Can Reveal

Counting specific immune cells requires specialised laboratory techniques. The researchers therefore investigated whether the proteins circulating in blood could offer an alternative way to estimate the same underlying pattern. They used a smaller dataset linking immune-cell measurements with blood-protein levels to develop a computer model. This model was then applied to data from approximately 50,000 participants in the UK Biobank, a long-running research resource that tracks health and biological information.

The team compared the predicted immune profiles with participants’ subsequent health records. Those whose profiles indicated a greater abundance of granzyme B-producing cells had higher risks of death and conditions including type 2 diabetes, hypertension, liver disease and kidney disease. The researchers followed health outcomes over an extended period, allowing them to investigate whether the blood-protein patterns were associated with future illness rather than simply reflecting differences observed at one point in time.

Could This Lead to an Early-warning Test?

One potential application is a blood test that helps identify people whose immune systems show signs associated with poorer long-term health. Many chronic diseases develop over years. Detecting biological changes before a person experiences noticeable symptoms could eventually give researchers and clinicians an additional way to assess risk and investigate preventive strategies.

The research team is working towards a simpler testing approach that could use standard laboratory equipment. At present, however, the findings represent a research advance rather than an established clinical test for healthy ageing. A useful test would need to do more than identify a statistical association. It would have to demonstrate that its predictions are sufficiently accurate for individual patients, work reliably across different populations and provide information that improves clinical decisions.

An Association That Needs Explanation

A greater abundance of granzyme B-producing cells could reflect underlying immune stress or other biological processes associated with disease. Researchers will need further investigation to establish whether these cells contribute directly to the development of chronic conditions or primarily act as indicators of changes occurring elsewhere in the body.

The results also require validation before the proposed protein signature can be used widely. A model developed from one set of participants may not perform equally well in people with different genetic backgrounds, lifestyles, environmental exposures or existing health conditions.

For ageing research, the larger opportunity lies in understanding why people follow different biological trajectories. A reliable marker could help scientists study these differences and identify when intervention might be most effective. The immediate achievement is a potential way to read some of those differences through blood. Whether that information can translate into longer, healthier lives will depend on the evidence that follows.

Around 170 million children and adolescents worldwide were living with obesity in 2024, including 70 million children aged five to nine and approximately 100 million adolescents aged 10 to 19, according to the World Health Organization (WHO). The prevalence of obesity among children and adolescents aged five to 19 has quadrupled since 1990, rising from 2% to 8%.

The scale of the problem extends beyond obesity alone. Around 400 million children and adolescents aged five to 19 were overweight worldwide in 2024, including those living with obesity. The prevalence of overweight, including obesity, in this age group increased from 8% in 1990 to 20% in 2024, according to WHO.

A separate analysis by the United Nations Children’s Fund (UNICEF) highlights a shift in the global burden of malnutrition. Its 2025 Child Nutrition Report found that, for the first time, the global prevalence of obesity among children and adolescents aged five to 19 had surpassed that of underweight, at 9.4% compared with 9.2%. UNICEF also reported that low- and middle-income countries accounted for more than 80% of children and adolescents living with overweight. The findings point to the growing importance of addressing unhealthy food environments alongside individual health needs.

In its first global guidelines on managing obesity in children and adolescents, WHO recommends comprehensive lifestyle interventions as the foundation of care, reserving medicines and surgery for selected cases. The guidelines emphasise that childhood obesity requires sustained medical support and broader action to create healthier environments.

WHO defines obesity as a chronic, relapsing disease characterised by excessive fat deposits that can be managed through effective treatment and care. Childhood obesity is associated with an increased risk of noncommunicable diseases, including type 2 diabetes and cardiovascular disease. Children may also experience stigma, discrimination and bullying, which can adversely affect their mental health and well-being.

Lifestyle changes and mental health at the centre of care

WHO strongly recommends dietary improvements, physical activity and other behavioural interventions as the primary approach to managing obesity in children and adolescents. Treatment should be tailored to individual needs, supported by long-term follow-up and designed to improve overall health and quality of life.

The agency does not recommend weight-loss medicines, bariatric surgery or weight-loss devices for children aged zero to nine. For adolescents aged 10 to 19, approved medicines, including glucagon-like peptide-1 (GLP-1) therapies, may be considered when supervised lifestyle interventions have failed to produce improvements. Bariatric surgery may be considered for adolescents with severe obesity under strict conditions.

“The foundation of obesity care for children and adolescents is not medicine or surgery, but access to comprehensive support that enables healthy eating, physical activity and sustainable behaviour change,” said Dr Luz María De Regil, director of WHO’s Department of Nutrition and Food Safety.

However, clinical treatment alone cannot reverse the growing burden of childhood obesity. WHO has called for policies that make nutritious food and opportunities for physical activity more accessible and affordable. These include regulatory and fiscal measures, alongside action in education, urban planning, transport and social protection.

UNICEF has similarly called for measures to improve school food environments, restrict unhealthy food marketing to children, strengthen food labelling and make nutritious foods more affordable.

The Union Health Ministry has asked all States and Union Territories to ensure that hospitals and other clinical establishments prominently display their service charges, including package rates for foreign patients travelling to India for medical or Ayush treatment. In a letter to State Chief Secretaries, Union Health Secretary Punya Salila Srivastava called for compliance with existing rules requiring rates to be displayed in English and the local language.

The directive places the focus on enforcement of healthcare price-disclosure requirements intended to help patients understand treatment costs before making decisions about their care.

Rules Mandate Display of Rates

The Ministry’s letter refers to the Clinical Establishments (Registration and Regulation) Act, 2010, and the Clinical Establishments (Central Government) Rules, 2012. Under these provisions, clinical establishments in States and Union Territories where the Act applies must display the rates charged for each type of service, along with details of available facilities, in a conspicuous place. The information must be provided in the local language as well as English.

Srivastava said the display of rates would help patients and their families understand likely treatment expenses, make informed healthcare decisions and plan their expenditure.

The Act does not apply uniformly across India. States and Union Territories that have not adopted the central legislation regulate clinical establishments under their own legal frameworks. Implementation therefore depends on the regulatory arrangements in each jurisdiction.

Displayed Rates and Final Bills

A hospital’s price list can give patients an initial estimate of expenses, but the final bill may include charges that depend on the course of treatment. Medicines, diagnostic tests, consumables, additional procedures and a longer hospital stay can increase the amount payable.

The usefulness of a displayed rate depends partly on whether patients can identify what it covers. A procedure package that includes the operating theatre and a specified period of hospitalisation may not be comparable with one that excludes medicines, follow-up consultations or other services.

Clear disclosures of package inclusions, exclusions and possible additional charges would help patients assess estimates more accurately. Such information is particularly relevant to families paying out of pocket, who may need to arrange funds or compare providers before planned treatment. In emergencies, however, patients may have little opportunity to shop around.

The Ministry’s latest communication does not provide figures on current compliance, inspections or penalties for establishments that fail to display rates. The extent to which patients encounter missing, outdated or unclear price information therefore remains difficult to establish from the announcement alone.

Enforcement Rests with State Authorities

The central legislation provides for regulatory oversight of clinical establishments, with implementation responsibilities assigned to the relevant authorities. States and Union Territories operating under separate laws have their own regulatory arrangements.

The Ministry’s request will need to translate into checks on whether establishments display the required information and whether authorities respond to violations. Public reporting on inspections, complaints and enforcement action would help establish how consistently the requirements are being implemented.

Patients also need accessible channels to report establishments that fail to display rates or provide unclear information. Without effective complaint handling, the existence of a legal requirement may offer limited practical recourse to someone trying to understand a hospital bill.

Package Rates for International Patients

The Ministry has also asked States and Union Territories to ensure prominent display of package rates for foreign patients travelling to India on medical or Ayush visas.

Published rates can help international patients assess treatment costs before travelling, but package terms need to be explicit. The quoted price should clarify which procedures and services are included and whether medicines, complications, additional investigations or follow-up care may incur separate charges. These details can be especially important for patients who may find it difficult to resolve billing disputes after returning to their home countries.

What Price Transparency can Achieve

Displaying service charges gives patients access to information they need, but it does not establish whether prices are affordable or ensure that the final bill matches an initial estimate. Those questions require clear billing practices and scrutiny of how establishments communicate additional costs.

The Ministry has asked State and Union Territory administrations to enforce existing requirements. Evidence of progress will depend on compliance checks, action against violations and whether patients can obtain clear information about the services they are paying for. A price list is useful only when its terms are understandable and the charges applied during treatment can be explained.