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Comment by Dr. Krishna Kumari Challa on August 6, 2026 at 9:18am

Birth order may influence your disease risk later in life, study finds

Whether you are first-born or second-born may be associated with your risk of developing certain diseases, according to a new study published in Nature Health.

Previous research has found that younger siblings often have lower rates of allergies and asthma, which may be because their older brothers or sisters bring more microbes into the home. But it was unclear whether birth order was linked more broadly to health risks across the body.

In this study, scientists analyzed a health records database of more than 10 million individuals from more than 5 million two-child families. The data were collected over two decades from commercial insurance claims.

The team screened for 569 disease categories using two approaches. First, they compared 1.6 million first-borns with second-borns from different families who were matched by sex, birth year, location and similar parental ages. They also directly compared first-born and second-born siblings within the same household across all families. This helped account for shared genetics, parenting and home environments.

Of 418 diseases with enough cases to analyze, the scientists found that 150 showed significant birth-order associations. First-borns were more often diagnosed with neurodevelopmental and some mental health conditions, including autism and ADHD, tics and Tourette syndrome, depression and anxiety. They also had higher diagnosis rates for allergy-related conditions like asthma, allergic rhinitis and food allergies.

Meanwhile, second-born children more often had diagnoses of substance abuse, migraines, digestive issues like gastritis, shingles and some joint conditions. "Birth order is associated with disease risk more broadly than previously appreciated," the study authors wrote.

The researchers suggested several possible reasons birth order might influence disease risk. One possibility is that first-time parents may watch their first child more closely, leading to earlier diagnoses of conditions like autism and ADHD.

Second-borns may also be exposed to everyday microbes brought home by older siblings, which may help their immune systems develop greater tolerance and lower the risk of allergies. For behavioral risks like substance abuse, younger siblings may also be exposed to older peer groups at an earlier age.

"The most conservative interpretation is that neurodevelopmental associations probably reflect a mixture of pregnancy-order biology, parental surveillance, diagnostic timing, and residual confounding rather than one uniform mechanism."

The findings show that these statistical links are clear across millions of people, but the actual risk difference for any single child is quite small.

It is also worth noting that these are statistical associations and cannot be interpreted as direct evidence that birth order causes a particular disease.

Benjamin Kramer et al, Birth order and disease risk across the human phenome, Nature Health (2026). DOI: 10.1038/s44360-026-00177-z

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 10:21am

Brain scans reveal tau buildup in late-onset psychosis

Hallucinations and delusions that appear for the first time in midlife or later are often treated as psychiatric symptoms whose biological cause is unclear. The study, published in Molecular Psychiatry suggests that, for many patients, these symptoms may be linked to brain changes also seen in dementia.
Among 37 people with psychosis onset after age 40, 65% had tau PET positivity and 35% had amyloid positivity, versus 15% and 2% of 47 healthy controls. Tau patterns included amyloid-positive Alzheimer-type and amyloid-negative forms; greater parietal tau in amyloid-positive patients correlated with poorer executive function.
Using positron emission tomography, or PET, the research team found that about 65% of patients who developed psychosis after age 40 showed abnormal buildup of tau, a protein associated with Alzheimer's disease and other forms of dementia. By comparison, tau PET positivity was seen in about 15% of healthy older controls. The study also found amyloid PET positivity in 35% of patients, compared with 2% of controls.

The findings provide the first in vivo evidence that diverse tau-related brain changes may be involved in late-onset psychosis. Until now, earlier epidemiological and postmortem studies had suggested a possible relationship between late-life psychotic symptoms and neurodegeneration, but direct evidence in the living brain had been limited.

Patients can show the same symptoms, such as hallucinations or delusions, but their clinical course and response to treatment can be very different.

Manabu Kubota et al, High prevalence of tau pathologies in late-onset psychosis: A PET study, Molecular Psychiatry (2026). DOI: 10.1038/s41380-026-03749-3

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 9:17am

Social determinants of health linked to more fatalistic cancer beliefs

New research shows that greater cumulative exposure to adverse social determinants of health is associated with beliefs that cancer is unavoidable or a death sentence. This can influence whether people choose to be screened for common cancers or seek treatment after a diagnosis.
Among 1,400 respondents, greater cumulative exposure to adverse social determinants of health was associated with stronger fatalistic beliefs that cancer is unavoidable or inevitably fatal. Poverty, housing insecurity, lack of insurance, discrimination, and social isolation may contribute to reduced screening follow-up and treatment engagement.

Jaitri Joshi et al, Effect of social stressors and social determinants of health (SDOH) on cancer beliefs: Analysis of a cancer center catchment area, Journal of Psychosocial Oncology (2026). DOI: 10.1080/07347332.2026.2666535

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 9:13am

Like Zika, Oropouche virus can also affect the brains of unborn babies
Oropouche virus infected human neural stem cells and brain organoids, reducing proliferation, disrupting tissue organization, and increasing inflammatory and cell-death pathways. Historical and recent strains caused similar effects, suggesting inherent neurodevelopmental risk. Organoid results support biological plausibility for congenital abnormalities but do not establish pregnancy outcomes.

Gabrielle Brum et al, Microcephaly-like phenotype triggered by novel reassortant and prototypic Oropouche virus strains in brain organoids, eBioMedicine (2026). DOI: 10.1016/j.ebiom.2026.106408

original article.

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 9:04am

Forest floors reveal overlooked seed dispersers: Slugs, beetles and crabs spread viable seeds

A review by researchers has revealed that tiny ground-dwelling invertebrates are overlooked but important seed dispersers, challenging the traditional focus on birds and mammals and offering new insights into forest regeneration and biodiversity conservation.
A synthesis of 43 publications documented viable seed dispersal by at least 51 invertebrate species across 186 plant taxa. Slugs, earthworms, beetles, crickets and crabs can deposit seeds in favourable microsites, sometimes enhancing germination. This short-range dispersal may support regeneration where vertebrate dispersers decline.
The findings highlight an important but underappreciated pathway of seed dispersal that may help sustain plant regeneration, especially in fragmented or degraded ecosystems where larger animal dispersers are declining.

Si-Chong Chen et al, Invertebrate endozoochory: An overlooked pathway of seed dispersal, Trends in Plant Science (2026). DOI: 10.1016/j.tplants.2026.06.004

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 8:19am

Seaweed-derived coating keeps strawberries fresher than a fridge

Researchers have developed an edible, seaweed-derived coating that can keep strawberries fresh for at least four days at room temperature, outperforming uncoated berries stored in the refrigerator.

An edible agar–zinc–tannic acid coating reduced moisture loss, maintained firmness, and preserved vitamin C and antioxidants in strawberries. Coated berries remained mold-free for ≥4 days at room temperature and ≥6 days refrigerated, exceeding untreated fruit. The coating showed antibacterial activity, no intestinal-cell toxicity, and a lower estimated carbon footprint than refrigeration.
Published in the Journal of Agricultural and Food Chemistry, the findings offer a simple approach for extending produce shelf life and reducing reliance on refrigeration across the supply chain. Maintaining cold temperatures from farm to warehouse to truck to grocery store requires significant energy and infrastructure, especially for fresh produce transported over long distances.
The coating is made from agar, a substance derived from red seaweed that is widely used as a vegan alternative to gelatin and as a thickener in foods like puddings and jellies. On its own, agar forms a thick gel. But when researchers combined it with zinc, an essential nutrient, and tannic acid, a naturally occurring plant compound found in grapes and tea, the material transformed—self-assembling into tiny microparticles that create a thin protective layer around the fruit.

When dipped in the solution, strawberries, grapes and apple slices emerged with a thin, edible coating that dried completely clear.

The breakthrough could help address one of the food industry's most persistent challenges: reducing food waste.

Ivy Chiu et al, Self-Assembled Metal–Phenolic–Agar Microparticle-Derived Coatings Enable Scalable and Sustainable Fresh Produce Preservation, Journal of Agricultural and Food Chemistry (2026). DOI: 10.1021/acs.jafc.6c06531

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 7:27am

What's in the dust? Study finds hidden metals in city streets

If you're in an urban area with strong winds, chances are you are breathing in more than a little dust. You could be exposed to metals from cars, construction sites or pesticides used decades ago.

Road dust from cities contained toxic metals, including lead, arsenic, and cadmium, in one-third of samples. Metal concentrations varied with legacy industrial activity, pesticide use, and port operations. Average concentrations remained below health recommendations, but dry conditions may increase exposure.
These dust samples are not from the middle of the highway. They were collected at public spaces, such as parks, schools and downtown areas where residents are likely to be exposed.

Minh Tri Truong et al, Tracing spatial mid-size Eastern U.S. cities road dust pollution: insights from source apportionment and health risk assessment, Environmental Science and Pollution Research (2026). DOI: 10.1007/s11356-026-38034-x

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 7:23am

Reducing night lights in cities has ecological effects

Artificial light at night (ALAN) can cause plants to open their buds and sprout leaves earlier in the spring. ALAN can also cause trees to delay changing the colour of their leaves in the fall. These changes can ripple through ecosystems, affecting pollinators, herbivores and insects that lay eggs on plants. ALAN also disorients many migrating birds and other animals.
Some cities have attempted to reduce overall ALAN using techniques such as shielding fixtures, implementing adaptive dimming, reducing light output and choosing warmer colour temperatures.

Urban light-mitigation measures in New York City and Washington, D.C., reduced artificial light at night, particularly blue wavelengths, unlike nearby comparison cities. Reduced lighting was associated with less advanced spring green-up and less delayed autumn leaf coloration, indicating potential mitigation of ALAN-driven shifts in plant phenology.
The authors found that New York City and Washington, D.C., showed a reduction in ALAN after the policies were implemented, especially in the blue band, while Newark and Philadelphia did not.

Plant growth cycles also differed between the cities. ALAN typically advances the start of the growing season and delays the end of the season, but in cities with mitigation policies, the start of the season is several days less advanced than it would otherwise be, as measured by the emergence of new green growth visible in satellite images. Cities with mitigation policies also show a transition to fall colour that is less delayed than in cities without such policies.

According to the researchers, the findings demonstrate the feasibility of using high-resolution satellite images to identify relative differences in ALAN levels and point toward ways in which this tool could support urban ecological research.

Mitigating artificial light at night: effectiveness of policies and implications for plant phenology, PNAS Nexus (2026). DOI: 10.1093/pnasnexus/pgag237 academic.oup.com/pnasnexus/art … /5/8/pgag237/8750162

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 7:18am

Researchers uncover hidden mechanism behind congenital heart disease

Congenital heart disease affects approximately two in every 100 newborns globally. But why does it occur? An important part of the answer may lie in a previously unknown mechanism on the surface of our cells. Researchers identified this mechanism in a new study.
They have discovered a new communication system on the exterior of the cell that is crucial for the proper formation of the heart during embryonic development.

The mechanism is located in the primary cilium, a microscopic "antenna" that protrudes from most cells in the body. The cilium's role is to interpret the body's signaling molecules, enabling the cell to determine whether it should divide, move or die, for example.

In the study, the researchers show that three proteins, TAK1, TAB2 and PKA-Cα, function as a signaling hub within the cell's antenna and play a significant role in heart formation.

These proteins act as molecular instructions that tell stem cells when and how to develop into heart muscle cells. However, genetic alterations can disrupt this communication, causing 'antenna defects,' which may lead to congenital heart defects.

The researchers observed effects not only in the heart.

In the study, the rare genetic mutations were identified in patients with so-called syndromic congenital heart disease. Syndromic heart defects are caused by an underlying genetic syndrome that often also leads to defects and associated conditions in other organs.

At the same time, experiments in zebrafish and detailed studies of cilia in other tissues suggested that the mechanism is also important for the development of other organs.

When the ciliary mechanism fails, it typically affects the development of several other organs as well. This may explain why some patients with congenital heart disease also have defects and related conditions affecting the brain, kidneys and skeleton. The mechanism provides a unifying explanation for diseases that we have previously struggled to understand.
The researchers therefore think that the discovery could help improve the understanding and treatment of a wide range of diseases caused by defects in the primary cilium.
This new knowledge may eventually make it easier to identify patients early and develop targeted treatments.

TAK1 operates at the primary cilium in non-canonical TGFB/BMP signaling to control heart development, PLOS Biology (2026). DOI: 10.1371/journal.pbio.3003902

Comment by Dr. Krishna Kumari Challa on August 5, 2026 at 7:10am

The brain's electrical signatures shift as tinnitus becomes chronic

Ears are built to listen to sounds from the world around us, but for some people, the sound comes from within. Tinnitus causes people to hear ringing or other noises in one or both ears or in their heads, even when there is no actual sound outside. While tinnitus is frequently associated with hearing loss, a substantial proportion of individuals with clinically normal hearing thresholds still experience it, and the underlying mechanism remains murky to scientists. A recent study investigated how brain network patterns change as tinnitus progresses from a new condition to a long-term chronic one in people with clinically normal hearing.

After recording the electrical activity in the brains of people with acute and chronic tinnitus, the researchers found that the two conditions have very different neurophysiological profiles. People with recent-onset tinnitus showed an imbalance between two important brain networks: the salience network, which detects salient or potentially threatening signals, and the executive control network, which supports attention and decision-making. The brain significantly increases its focus on the former while decreasing the latter's activity. Those with chronic tinnitus showed much more balanced switching between these networks, meaning the brain began to adapt rather than worsen.

Meng-Fang Gong et al, EEG microstates and dynamic functional connectivity reveal stage-specific brain networks in subjective tinnitus, iScience (2026). DOI: 10.1016/j.isci.2026.116995

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