A recent study suggests that people who donate blood regularly may have genetic changes in their blood that could in fact reduce the risk of developing cancer. It is conducted by the researchers at the Francis Crick Institute, and the study has now provided new insights into how and why blood cancers develop. The study is published in the journal Blood and was conducted by the scientists from Heidelberg and the German Red Cross blood donation center. There is yet a need for further research to confirm these findings.

What Did The Study Find?

The researchers examined the blood of two groups of healthy male donors in their 60s:

• One group had donated blood three times a year for 40 years.
• The other group had donated only about five times in total.

The goal was to analyze genetic mutations in their blood and assess whether frequent donation had any impact on their genetic makeup.

How Can Blood Donation Affect Stem Cells?

As and when people age, their blood and other cells naturally develop mutations and some of them can also increase the risk of cancer. When anyone donates blood, his or her body compensates by producing new blood cells, which can influence the genetic diversity of stem cells in the bone marrow. The study also found that both groups had a similar number of mutations. For instance the frequent donors had 217 mutations, while the irregular donors had 212 mutations.

However, the nature of these mutations differed. In the frequent donors, 50% of the mutations were of a type not associated with a high risk of blood cancers, compared to only 30% in the irregular donors.

Further laboratory analysis showed that these specific mutations behaved differently from those linked to leukemia, a type of blood cancer. When human blood stem cells with these mutations were injected into mice, they were found to be highly effective at producing red blood cells, which is considered a positive outcome.

Dr. Hector Huerga Encabo, one of the study authors, emphasized that these mutations do not indicate an increased risk of leukemia. The findings suggest that regular blood donation may influence how stem cells evolve, but whether this translates into a lower cancer risk remains uncertain.

Read More: Who Can Donate Blood To Whom?

Limitations

One notable disadvantage is the "healthy-donor effect"—because blood donors are often healthier than the general population, their lower cancer risk could be unrelated to blood donation.

Dominique Bonnet, senior researcher and head of a stem-cell laboratory at the Francis Crick Institute, stressed the need for larger studies with female volunteers to confirm the findings.

Despite ongoing research into potential health benefits for donors, the primary goal of blood donation remains saving lives. NHS Blood and Transplant emphasized that while the study is interesting, further research is required to draw firm conclusions. The organization also noted that blood supplies are currently critically low and encouraged eligible individuals to donate.

Also Read: How Long After a Tattoo or Piercing Can I Donate Blood?

As pollution levels rise in October, doctors warn that exposure to particulate matter can affect lung and heart health, aggravate existing respiratory conditions, and cause symptoms even in otherwise healthy individuals, particularly as winter approaches.

PM2.5 and PM10 can irritate the respiratory tract, while fine particles such as PM2.5 can penetrate deep into the lungs, with some entering the bloodstream.

Delhi woke up to poor air quality on Thursday, with the Commission for Air Quality Management’s (CAQM) AQI dashboard recording an Air Quality Index (AQI) of 226 across Delhi-NCR at 7 am.

As per the CAQM’s dashboard, some areas of the national capital recorded very poor air quality, with an average AQI of 307.

The Commission for Air Quality Management (CAQM) on Wednesday imposed Stage I of the Graded Response Action Plan (GRAP) across Delhi-NCR after the capital's air quality slipped into the 'poor' category.

According to the Air Quality Early Warning System, Delhi's air quality is likely to remain in the 'poor' category until October 23. The forecast for the following six days also indicates that pollution levels are likely to remain in the same category.

Also read: Delhi Air Pollution Is Back: What Days Of Poor AQI Can Do to Your Lungs

How Air Pollution Affects Lung And Heart Health

Dr. Amit Kumar Mandal, Senior Director - Pulmonology, Paras Health Panchkula, told HealthandMe that air pollution can cause inflammation in the airways and worsen asthma, chronic obstructive pulmonary disease (COPD) and other respiratory conditions. It can also increase the risk of cardiovascular complications.

The effects may not always be immediately noticeable. People may experience persistent coughing, throat irritation, wheezing or breathlessness. Repeated exposure over time can contribute to more serious health problems, even in people without pre-existing conditions.

Dr. A.S. Sandhya, Consultant, Pulmonary & Sleep Medicine, Kailash Hospital & Neuro Institute, told HealthandMe that October can mark the beginning of a prolonged period of poor air quality in Delhi-NCR.

When pollution combines with changing weather conditions, people with asthma, bronchitis and COPD may experience more frequent symptoms. However, healthy individuals can also develop eye irritation, coughing, throat discomfort and reduced exercise tolerance after exposure to polluted air.

How To Protect Yourself From Rising Pollution

Read More: Can Delhi’s Air Pollution Increase GI Cancer Risk? Doctors Report Patients As Young As 15

Doctors recommend monitoring daily AQI levels and limiting exposure when air quality is poor.

Dr. Mandal advises reducing prolonged outdoor activity and avoiding exercise near busy roads during high-pollution periods. Children, older adults, pregnant women and people with respiratory or heart conditions should take extra precautions.

Dr. Sandhya recommends limiting strenuous outdoor exercise when pollution levels are high and using a well-fitted N95 mask when outdoor exposure cannot be avoided.

Indoor air quality also matters, particularly for children and older adults who spend extended periods at home. Air purifiers with suitable filtration may help reduce indoor particulate matter, although they do not eliminate all pollutants.

When To Seek Medical Advice

People should not ignore persistent coughing, wheezing or unusual breathlessness. Those experiencing persistent breathing difficulties, chest discomfort or worsening respiratory symptoms should consult a doctor.

People with existing medical conditions should follow their treatment plans and seek medical advice if their symptoms worsen.

Taking preventive measures now, rather than waiting for pollution to peak in winter, can help reduce exposure and the risk of avoidable health complications in the months ahead.

Climate change is not just raising temperatures and intensifying extreme weather. It may also affect digestive health by disrupting food production, threatening water security and changing the spread of gastrointestinal infections, according to two leading gastroenterology experts from the World Gastroenterology Organization (WGO).

Climate change can contribute to heat-related illnesses and influence the geographic spread of infectious diseases, especially in countries like India.

A February 2025 review in The Lancet Planetary Health outlines how the combined effects of climate change could affect the human gut microbiome, including through food insecurity, malnutrition and exposure to disease-causing pathogens. These challenges could alter the composition of gut microbial communities worldwide.

Research suggests that heat stress may alter gut microbes, digestion and immune function. It may also increase intestinal permeability, potentially allowing toxins and pathogens to enter the bloodstream.

Climate-related drought can disrupt food production and reduce access to nutritious food, potentially affecting the gut microbiome. Environmental changes may also influence food- and waterborne pathogens, increasing infection risks where access to safe water and sanitation is limited.

Speaking to HealthandMe, Professor Geoffrey Metz, professor of medicine at the University of Melbourne, said climate change was becoming an increasing concern for gastrointestinal health.

“Certainly, with global warming, we're seeing a lot more infectious diseases in the gastrointestinal tract,” Metz said.

How Climate Change Can Affect Digestive Health

Also read: 'Humanity Can Still Act': Lancet Warns Of 17 Global Health Threats By 2100

Climate change can affect digestive health through several interconnected pathways, including water availability, food production and infectious diseases.

Metz said the consequences of global warming extend beyond rising temperatures.

“The other thing, of course, with global warming—and this is a major interest of the World Gastroenterology Organisation—is that it's not just making us hot, but it's also creating more drought, which interacts with food production. So there's less food available, impacting our nutrition.”

Drought can disrupt food production and reduce food availability, raising concerns about nutrition. Changes in water availability can also make safe food preparation and hygiene more difficult.

However, the extent to which these environmental changes contribute to specific gastrointestinal diseases requires further investigation.

Safe Water And Food Hygiene Remain Essential

Professor Carolina Olano, professor of gastroenterology in Montevideo, Uruguay, and president of the WGO, highlighted the role of environmental factors in digestive diseases.

“Well, I think it's a combination of many factors. You know that there are some things related to genetics, and we have genetic predispositions to some diseases. But there are also environmental factors related to different diseases, and climate change has an impact too. We are working very hard at the World Gastroenterology Organisation to understand how climate change is affecting different diseases.”

Olano also emphasised the importance of safe drinking water and food hygiene in preventing infections.

“It's also important to have a varied diet and to drink safe, clean water, making sure that the water we drink is safe. Food hygiene is also extremely important.”

She told HealthandMe that handwashing was another simple preventive measure.

“We learned from the COVID pandemic that handwashing before eating is extremely important. These are things we can do every day without spending anything, and they can help prevent many important diseases, especially those related to infections.”

Climate Change Has Wider Health Consequences

Read More: Climate Change Is Affecting Skin Health Worldwide, Warns Study

The effects of climate change may extend beyond the digestive system, affecting multiple aspects of health.

“Global warming is not just affecting how we feel; it's also having an effect on heart disease, lung disease, gastrointestinal disease, obstetrics and gynaecology,” said Metz, who is also the former president of the WGO.

Olano also pointed to population movements as a factor to consider when assessing environmental and health risks.

“As you know, it's not only about weather and climate change. It's also about how populations move from one country to another and what the impact of these movements is when people move from one region to another.”

“Because, as you know, it's not only about weather and climate change. It's also how populations move from one country to another and what the impact of these movements is when people move from one region to another.”

Understanding these connections is important as researchers investigate how climate-related environmental changes may influence disease patterns across regions.

What Can People Do To Protect Their Digestive Health?

While individuals cannot control climate-related changes, Olano highlighted everyday measures that can help prevent infections and support digestive health:

• Drink safe, clean water.
• Maintain food hygiene and handle food safely.
• Wash hands before eating.
• Follow a varied diet.
• Stay physically active.

She also stressed the importance of seeking medical advice about hepatitis prevention, vaccination and testing where appropriate, as well as colorectal cancer screening.

Climate change presents a broader public health challenge, but safe water, food hygiene and infection prevention remain important measures for reducing avoidable digestive health risks.

Depression affects millions of people worldwide, but not everyone responds equally well to treatment. Now, researchers at the University of Sydney have identified a new subtype called “circadian depression,” which is linked to the body’s internal clock and may help explain why conventional antidepressants work less well for some people.

The subtype was identified in nearly a quarter of participants with severe, recurrent or persistent depression in an Australian study. Researchers say recognizing its characteristics could help clinicians identify patients who may benefit from different treatment approaches.

“Our research has identified circadian depression as a new subtype, affecting around a quarter of people in our study into those with severe, recurrent or persistent depression,” said Dr. Emiliana Tonini from the Brain and Mind Centre at the University of Sydney.

“Depression is not a uniform illness and understanding the characteristics of different subtypes mean that we can give people earlier access to treatments that will be most effective for them,” she added.

Circadian Depression: What Are The Key Symptoms?

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Circadian depression is linked to the body’s 24-hour internal clock, which regulates the sleep-wake cycle. Researchers identified several symptoms and characteristics associated with this subtype, including:

• A seasonal pattern of illness

• Sleeping longer during depressive episodes

• Waking up feeling very tired

• Being a night owl

To investigate the subtype, researchers analyzed clinical and genetic data from more than 10,000 people with depression who participated in the nationwide Australian Genetics of Depression Study.

Of these, 2,604 participants, or nearly 25%, were identified as having circadian depression.

The researchers also found that people with this subtype were more likely to experience depression earlier in life and had more severe symptoms, including mania and higher levels of suicidal thoughts.

In addition, these participants had a higher genetic risk for inflammatory and cardiovascular health problems, as well as major neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD).

The findings, published in the British Journal of Psychiatry, offer insights into the genetic mechanisms associated with circadian depression and may help explain why conventional treatments, such as selective serotonin reuptake inhibitors (SSRIs), work less well for some people with this subtype.

How Does Circadian Depression Differ In Treatment Response?

Antidepressants such as SSRIs and serotonin-norepinephrine reuptake inhibitors (SNRIs) are commonly used to treat depression. However, the researchers reported that these medications were less effective and associated with more side effects in people with the circadian subtype.

Because circadian depression is linked to the body’s internal clock, treatments targeting circadian rhythms may be relevant for some patients. These include light therapy, melatonin and melatonin-targeted antidepressants.

“Because circadian depression is linked to people’s internal body clock, treatments targeting the circadian rhythm, such as light therapy and melatonin, may be much more relevant, and clinicians should reach for these much earlier in people with this presentation,” said Dr. Jacob Crouse, co-senior author of the study, from the Brain and Mind Centre.

“For those who find that antidepressants are not working for them, it is important to speak to your clinician for advice about your individual circumstances,” he added.

Professor Ian Hickie, co-director of the Brain and Mind Centre and a clinical psychiatrist, emphasized that failing to recognize circadian depression in young people could contribute to early treatment failures and more side effects.

“We really want young people to receive the most appropriate treatment early in their course of illness.

“Most young people will be offered SSRIs first up, but for at least a quarter there are better circadian-focused medical and behavioural options to help treat and manage their condition.”

The findings suggest that identifying circadian depression could help clinicians consider more tailored treatment approaches. However, the study does not establish that body-clock disruption causes depression or that every person identified with this subtype will respond better to circadian-focused treatments. Patients should consult their clinicians before making any changes to prescribed medication, the experts said.