Medical Bulletin 21/September/2026 - Video

Here are the top medical news for today:

Loss of Y Chromosome May Provide Early Warning of Cancer in Men: Study

Loss of the Y chromosome in men may create a hidden zone of genetic vulnerability in normal tissue, potentially allowing cancer to develop, according to a new study.

Published in JCI Insights, the research found that Y chromosome loss was present not only in cancer cells but also in normal-appearing tissue surrounding tumours. Researchers described this as a possible “pre-neoplastic field effect”, where seemingly healthy tissue carries changes that may make it more vulnerable to cancer.

Men typically have one X and one Y chromosome in each cell. Loss of Y, a genetic change that becomes more common with age, has previously been linked to disease risk and poorer outcomes in men with cancer.

Researchers analysed 1,000 tissue samples from 405 men, examining more than 4.3 million individual cell nuclei. They measured the ratio of X and Y chromosomes across normal, pre-cancerous and cancerous tissues from 11 major organs.

In bladder tissue removed during cancer surgery, researchers mapped Y chromosome loss across different areas. They found a gradual increase in Y loss from normal tissue through early abnormal changes and into established cancer.

Higher levels of Y chromosome loss in normal-appearing tissue were particularly observed around cancers of the colon, rectum, oesophagus, pancreas and lung.

The researchers described this pattern as a gradient, with Y chromosome loss increasing closer to a tumour. They suggested that, in the future, this pattern could potentially help doctors identify hidden cancer-related changes in biopsy samples that may not contain the tumour itself.

However, the study does not establish that Y chromosome loss directly causes cancer. It shows an association and suggests that the genetic change may be an early marker of tissue vulnerability.

Further studies are needed to determine whether detecting Y chromosome loss can improve cancer diagnosis or risk assessment.

REFERENCE: Arkadiusz Gertych, Dr. Huihui Ye, et al.; Human Y chromosome pan-organ mapping reveals progressive mosaic loss from normal to cancer; JCI Insight; DOI: 10.1172/jc.insight.201996

Study Links Reading for Pleasure to Better Mental Health and Cognitive Function

Reading for pleasure may support mental wellbeing, cognitive function and brain health across the lifespan, according to a review by researchers at the University of Cambridge and The Queen’s Reading Room.

Published in Psychological Medicine, the review examined evidence linking leisure reading with cognitive, psychological and social benefits. Researchers noted that reading is associated with better attention, memory and executive function, particularly among children and adolescents.

A study involving more than 10,000 young people found that those who started reading for pleasure earlier in life showed better cognitive performance and academic achievement, fewer mental health problems and healthier lifestyle patterns, including more sleep and less screen time.

In adults, reading has been associated with lower stress, improved relaxation, greater empathy and a better understanding of different perspectives. Shared reading through book clubs or reading with children may provide additional benefits by increasing social interaction and reducing feelings of isolation.

The potential benefits may also extend to older adults. Studies have linked leisure activities such as reading with slower cognitive decline and a lower risk of cognitive impairment and dementia. One study of nearly 5,500 adults aged 55 years and older found that people who frequently participated in cognitively stimulating activities, including reading, were less likely to develop cognitive impairment during five years of follow-up.

Brain imaging research has also associated reading with structural and connectivity differences in regions involved in language, learning, emotional regulation and executive control. Some intervention studies suggest that improvements in reading ability may be accompanied by changes in brain structure.

However, researchers emphasised that much of the available evidence is observational and demonstrates associations rather than proving that reading directly prevents mental health disorders or dementia.

The review suggests that encouraging enjoyable reading from childhood, including through comics and graphic novels, may offer a simple way to support cognitive and psychological wellbeing throughout life.

REFERENCE: Sahakian, B. J., et al. (2026) Reading and associations with brain health, cognition, wellbeing and mental health. Psychological Medicine. DOI: 10.1017/S0033291726105625.

Sex-Specific Biological Clocks Reveal How Aging Differs Across Women and Men: Study

Biological ageing may differ substantially between men and women and across organs, according to a study published in Nature Medicine.

Researchers developed 38 sex-specific biological ageing clocks covering 15 organ systems using genetic, proteomic, metabolomic, MRI and clinical data. They also analysed longitudinal data and outcomes from the A4 clinical trial of solanezumab.

Unlike chronological age, biological age reflects physiological changes that can vary between individuals and organs. The researchers found that several biological ageing measures showed different genetic patterns and disease associations in males and females.

Some metabolic ageing signals related to Alzheimer’s disease, sleep disorders and psychiatric traits were stronger in females. Hepatic and digestive metabolic ageing measures were also associated with cardiometabolic outcomes in females. In males, immune and endocrine ageing measures showed stronger associations with metabolic syndrome, lipid abnormalities, hypertension, diabetes-related changes and coronary interventions.

The ageing clocks also showed associations with future disease. In females, higher heart MRI-derived biological age was linked with hypertension, while higher immune and digestive metabolic age measures were associated with cardiometabolic conditions including hypercholesterolaemia and type 2 diabetes. Similar associations were identified in males involving endocrine and metabolic ageing measures.

Brain biological age was particularly associated with Alzheimer’s disease progression. Among people with mild cognitive impairment, each standard-deviation increase in brain age was associated with a 74% higher hazard of progression to Alzheimer’s disease in men and a 125% higher hazard in women. The clocks did not significantly predict progression from normal cognition to mild cognitive impairment.

The researchers also identified sex-specific protein signatures associated with brain and spleen ageing.

However, the study has important limitations. Much of the genetic data involved European-ancestry participants, several disease datasets were sex-pooled, and the models did not account for hormonal status, pregnancy history or social factors. External validation is also needed.

The findings suggest that sex-specific biological ageing measures could potentially improve future disease-risk assessment.

REFERENCE: The MULTI Consortium., Song, Z., Feng, D. et al. (2026). Sex-specific biological aging clocks across organs and omics. Nature Medicine, DOI: 10.1038/s41591-026-04662-6, https://www.nature.com/articles/s41591-026-04662-6

Saliva Cortisol May Serve as Early Indicator of Cognitive Decline: Study

Abnormal daily patterns and higher overall levels of the stress hormone cortisol may be associated with faster cognitive decline in older adults, according to a study involving nearly 3,900 people.

Researchers analysed data from the Chicago Health and Aging Project, including 2,503 Black and 1,392 White participants with an average age of 76.7 years. Participants were followed for up to 11 years.

Salivary cortisol was measured at three points over a 24-hour period—morning, afternoon and evening—to assess both overall cortisol levels and changes throughout the day.

The researchers found differences in cortisol patterns between Black and White participants. Black participants had lower overall cortisol levels, less variation across the day and a flatter morning-to-evening pattern.

Despite these differences, the relationship between cortisol patterns and cognitive decline was similar in both groups. Participants whose cortisol levels showed greater variation during the day tended to experience slower cognitive decline. In contrast, those with higher overall cortisol levels had faster cognitive decline.

Cortisol is released as part of the body's response to stress and can cross the blood-brain barrier, where it interacts with receptors in brain regions involved in cognition. The findings suggest that long-term changes in stress-related hormonal patterns may be associated with later changes in cognitive function.

However, the researchers did not find evidence that cortisol patterns predicted who would develop Alzheimer’s disease during the follow-up period.

The study also cannot establish that higher cortisol or chronic stress directly causes cognitive decline. Cortisol levels can vary because of multiple factors, and measurements taken at only three time points may not fully capture long-term hormonal patterns.

Longer-term research is needed to determine whether cortisol patterns can help identify people at higher risk of cognitive decline and whether interventions targeting chronic stress could support healthy brain ageing.

REFERENCE: Ng TKS et al. Salivary cortisol and cognitive decline and Alzheimer disease in older adults. JAMA Netw Open. 2026;9(7):e2622955.

New Blood Thinners Could Help Slow Cognitive Decline in Alzheimer’s, Study Finds

Newer blood thinners may be associated with slower cognitive decline in people with both Alzheimer’s disease and atrial fibrillation (AF), according to a study published in the European Heart Journal.

Researchers from Karolinska Institutet analysed data from the Swedish Registry for Cognitive Disorders and included 7,308 people diagnosed with both conditions. Participants were matched according to treatment with newer non-vitamin K oral anticoagulants (NOACs), the older anticoagulant warfarin, or no anticoagulant treatment.

Cognitive function was assessed using the standardised Mini-Mental State Examination (MMSE).

People treated with NOACs experienced significantly slower cognitive decline than those receiving warfarin or no anticoagulants. The difference was slightly more than 0.2 MMSE points per year. Although modest over one year, the researchers said the difference could become more relevant if sustained over several years.

NOAC treatment was also associated with lower risks of stroke, blood clots, fractures and death compared with no anticoagulant treatment. Warfarin was similarly associated with lower risks of stroke, blood clots and death, but was linked with a higher risk of major bleeding.

Researchers said anticoagulation could potentially influence cognition by reducing stroke and small-vessel brain damage or by improving cerebral blood flow. However, these mechanisms were not directly established by the study.

The findings do not prove that NOACs prevent or slow Alzheimer’s disease. The study was observational, meaning treatment was not randomly assigned. Differences in patients’ health, treatment decisions and other factors may therefore have influenced the results. Some participants may also have changed anticoagulant treatment during follow-up.

Further randomised studies are needed to determine whether NOAC treatment has a direct effect on cognitive decline in people with Alzheimer’s disease and AF.

The researchers said the findings add to evidence that anticoagulant treatment may have effects beyond stroke prevention, while emphasising that treatment decisions should consider individual risks and benefits.

REFERENCE: Nanbo Zhu, Hong Xu, Sara Garcia-Ptacek, Sumonto Mitra, Maria Eriksdotter. Oral anticoagulants, cognition, and clinical outcomes in atrial fibrillation and Alzheimer’s disease: a Swedish nationwide study. European Heart Journal, 2026; DOI: 10.1093/eurheartj/ehag584