Tag: sex differences

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Smoking May Affect Fertility in Both Men and Women, New Study Finds

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New research has shed light on how exposure to cigarette smoke could affect reproductive health in both men and women, identifying changes in biological processes involved in ovarian function and sperm production.

The study, led by researchers from the Universities of Nottingham and Sheffield and published in Frontiers, provides new insight into potential mechanisms linking smoking with reproductive health.

Infertility affects a significant proportion of people of reproductive age worldwide. According to the World Health Organization, approximately one in six people globally experience infertility at some point during their reproductive years.

In this study, researchers used a mouse model to examine the effects of different levels of cigarette-smoke exposure on the ovaries and testes, focusing on changes to reproductive tissues and the activity of genes involved in their normal function.

In females, the number and structure of ovarian follicles showed relatively little change following exposure, even at higher levels. However, researchers identified clear changes in the activity of numerous genes.

Genes involved in cell division and metabolism became less active, while genes associated with protein production became more active. The pattern of gene activity showed similarities with biological processes previously associated with ovarian ageing and reduced ovarian function.

In males, higher levels of smoke exposure were associated with changes to structures within the testes, including enlargement of the seminiferous tubules. Researchers also identified changes in the activity of genes involved in sperm production, immune responses and cell signalling.

Some genes associated with sperm production became more active, while others involved in immune function became less active. The findings suggest that cigarette-smoke exposure may alter biological processes important for normal testicular function and sperm development.

The researchers say the findings add to existing evidence about the potential impact of smoking on reproductive health and highlight the need to better understand the biological mechanisms involved.

Professor Lucy Fairclough (School of Life Sciences, University of Nottingham), co-author, said: “Our study has identified potential biological mechanisms that could help explain the link between smoking and reproductive health in both men and women.

“In females, we identified changes in gene activity associated with biological processes that have previously been linked to ovarian ageing and reduced ovarian function. In males, we found changes in genes involved in sperm production and testicular function.

“These findings are important because they help us understand how exposure to cigarette smoke could affect reproductive health. Further research will be needed to establish how these biological changes relate to fertility in humans.”

Dr Adam Watkins (University of Sheffield) said: “While it is well-established that smoking is harmful for your reproductive health, the exact mechanisms are not fully understood. Our mouse study has enabled us to explore how the ovaries and testes respond following exposure to cigarette smoke. Interestingly, our study shows that the ovary and testis respond differently to the cigarette smoke. We observed that while the structure of the ovary was unaltered, the testis showed measurable changes in its morphology. Within the ovary, we identified changes in genes that regulate cell proliferation and the synthesis of proteins, while in the testis, genes regulating sperm production were altered.

“While our study only assessed the effects of cigarette smoke on the ovaries and testes, it does provide new mechanistic insight into how parental smoking shapes their reproductive health.”

Source: University of Sheffield

Categories : GeneticsTags :

How Sex Chromosomes Influence Health Throughout Life

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A new review published in Science brings together growing evidence that the X and Y chromosomes do much more than determining biological sex. They also shape how cells function, age and respond to disease. 

Differences in health between men and women have long been attributed mainly to sex hormones such as estrogen and testosterone. However, genes on the X and Y chromosomes also play a direct role, working both on their own and alongside hormones. 

The review was co-led by University of Arizona Cancer Center physician-scientist Dr. Dan Theodorescu and Dr. Dena B. Dubal of the University of California, San Francisco. It describes how sex chromosomes influence immunity, metabolism, brain aging, cancer and heart disease, and what this could mean for diagnosis, treatment and the design of clinical trials.

“X and Y chromosomes are often thought of as simple determinants for biological sex, but their role in human health is much larger,” said Theodorescu, one of the study’s corresponding authors and Nancy C. and Craig M. Berge Chair and Director of the Cancer Center. “Our review shows that these chromosomes carry genetic instructions that shape how our cells age and how our bodies defend against major diseases throughout our lives.”

The study shows that the genes on the X and Y chromosomes, rather than circulating hormone levels alone, determine disease risk, progression and therapeutic responses across key heath areas including aging, cancer, neurological conditions, immune system functions and cardiometabolic disease.

The review, which evaluated and synthesized existing evidence from human studies, mouse models and genomic technologies, describes several processes inside cells that shape health across the lifespan.

In women, one of the two X chromosomes is largely switched off early in development, but some of its genes stay active and others can switch back on with age, giving female cells extra doses of certain genes. Studies in mice suggest it also matters whether a cell’s active X came from the mother or the father. Men inherit their only X chromosome from their mother, while in women each cell uses either the mother’s or the father’s copy. In mice whose cells relied mostly on the mother’s X, faster brain aging and memory decline was observed. 

With age, some cells lose a sex chromosome. In women, loss of an X is linked to higher leukemia risk, though its broader effects remain largely unknown. In men, loss of the Y, most often measured in blood, is linked to cancers, heart disease, severe infections and Alzheimer’s disease. The loss of these chromosomes is being explored as both a biomarker of and potential contributor to age-related disease.

“When we look inside human cells, we see that X and Y chromosomes are participants in health and disease throughout a person’s life,” said Theodorescu, who is also a professor at the U of A College of Medicine – Tucson. “In cancer, for example, our laboratory has found that tumors that lose the Y chromosome can evade the immune system, yet may respond better to immunotherapy. Understanding this biology could help us tailor treatment.”

The review originated from discussions at the 2025 National institute on Aging Workshop: Sex Differences Impacting Human Health Across the Lifespan, especially with Francesca Duncan of the Northwestern University Feinberg School of Medicine.

“Our hope is that this review will stimulate further investigation and bring greater awareness to the significant potential of studying the X and Y chromosomes in cancer and other diseases, with far-reaching diagnostic and therapeutic implications,” said Theodorescu. “This would help ensure that treatments and diagnostics are tailored to match every patient’s unique profile. When clinical trials are designed to be sex-aware, researchers can turn these cellular differences into personalized medical care.”

Theodorescu’s previous related research focused on how the loss of the Y chromosome in T cells and cancer cells in men gave tumors the ability to evade the immune system, providing an explanation why the loss of the chromosome has been linked to increased mortality from carcinomas. Other recent Theodorescu group research showed how loss of the Y chromosome in normal-appearing tissues acts as an early warning sign and may mark a hidden zone of genetic risk for cancer to develop.

Original written by Phil Villarreal

Source: University of Arizona

Categories : Neurology PaediatricsTags :

Sex Differences in Attention are Present at Birth, Study Finds

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Cambridge scientists have shown that girls and boys show differences in what they pay attention to, even at birth. Since these differences are present so early, it is possible they emerge due to prenatal factors.

It’s nature and nurture, not nature or nurture

Simon Baron-Cohen

The findings suggest that some psychological differences between males and females (such the development of social skills) may be influenced by both prenatal biology as well as later experience.

The study, published today in Biology of Sex Differences, involved testing 130 newborn infants only hours after birth. It builds on previous research by the same lab and uses robust methods to demonstrate the differences.

For years, research has shown that girls, on average, learn to talk earlier and develop social skills faster than boys. Scientists have long debated whether these differences are due to culture or biology. One way to answer this question is to test if sex differences are present soon after birth, before society and culture have influenced a child’s development. 

A study from the University of Cambridge published in 2000 found girls at birth on average looked longer at faces, and boys on average looked longer at objects. Since then, scientists in the field called for a replication of this study. However, no research team has attempted this until now, since it is very challenging to carry out research on newborn infants.   

In this new study, infants were presented with side-by-side videos containing a social stimulus, namely a human face with natural movement, and a non-social object, namely a set of metallic balls swinging due to gravity and their mechanical properties (a Newton’s cradle). 

The team found that, regardless of sex, newborn infants generally preferred to look at the social stimulus. However, on average, female infants spent a greater proportion of the time looking at the social stimulus compared to male infants, while male infants spent a greater proportion of time looking at the non-social stimulus compared to female infants.

Since this is within hours of birth, before much postnatal experience (such as social expectations based on gender) has occurred, it is likely that prenatal biological factors that differ between the sexes during pregnancy (such as hormone levels and genetics) contribute to the observed on-average sex differences. 

Yumnah Khan, a PhD student at the Autism Research Centre, University of Cambridge and the lead researcher on the study, said: “Our recent research has also shown that on-average sex differences are present in brain structure at birth and emerge prenatally. This new study tells us that there are not only on-average sex differences in the brain but also in attention and behaviour.” 

Professor Sir Simon Baron Cohen, Director of the Autism Research Centre, University of Cambridge, who supervised the study, said: “This study addresses the age-old question of whether nature plays any role at all in shaping sex differences in the human mind and brain. The fact that we observe these differences within hours of birth, before extensive postnatal experience has occurred, suggests that prenatal factors play a role, and that these prenatal factors – sex hormones and/or genes – go on to interact with postnatal experience. In other words, it’s nature and nurture, not nature or nurture.”

The new study used more robust methods compared to the original 2000 study. In particular, it included more controlled experimental testing conditions as well as a more reliable method to monitor infant gaze. Crucially, the researchers who analysed the videos of the baby’s eyes were blind to the baby’s sex and whether the baby was looking at the social or the non-social stimulus, which ensured that they could not bias the results. 

Dr Alex Tsompanidis, Assistant Research Professor at the Autism Research Centre and a member of the research team, said: “Sex differences at birth are important as starting points, but we need to remember that they don’t fully determine how children learn and develop in later life. This is because biological and social factors always interact, contributing to the rich diversity of human societies.”

Professor Carrie Allison, Deputy Director of the Autism Research Centre and another member of the research team, said: “The differences we see don’t apply to all male or all female infants, and are only seen when you compare groups of male and female infants, on average. There’s a lot a variation within, and overlap between, each sex. Our future research needs to better understand that variation.” 

The team is now interested to find out if these early sex differences contribute to later differences in children’s minds, brains and behaviour. To test this requires a longitudinal (follow-up) study design, which is underway. The researchers hope that by understanding the origins of the earliest sex differences, scientists can better understand neurodiversity and conditions such as autism, which is diagnosed about twice as often in boys than in girls.

This research was supported by the Wellcome Trust, the Simon Foundation Autism Research Initiative (SFARI), and a PhD studentship from Trinity College, Cambridge and the Cambridge Trust. A follow-up study is funded by the K. Lisa Yang Centre for Autism Research at Cambridge, which is part of the Yang Tan Collective.

Reference

Khan, YT, Tsompanidis, A, Hymanson, E, Wickramanayake, S, APEX Consortium, Austin, T, Allison, C, & Baron-Cohen, S. Sex differences in social attention at birth. Biology of Sex Differences; 21 Sept 2026; DOI: 10.1186/s13293-026-00976-9

Republished from the University of Cambridge under a Creative Commons licence. Read the original article,

Categories : Metabolic DisordersTags :

Women with Type 2 Diabetes More Likely to Develop Mental Health Conditions

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Men, on the other hand, experience more cardiovascular and renal disease post-diagnosis

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In the years following type 2 diabetes diagnosis, women are more likely to develop mental health conditions, while men are more likely to develop cardiovascular and renal complications, according to a study published August 25th in the open access journal PLOS Medicine by Fabiola Eto from Queen Mary University of London, UK, and colleagues.

Type 2 diabetes, a metabolic disorder defined by high blood sugar, results from resistance to or insufficient production of insulin. Globally, type 2 diabetes affects about 536.6 million people between 20 and 79 years old, or 10.5% of the population; by 2045, this number is expected to rise to 700 million. Cardiovascular disease, end-stage renal disease, and mental health disorders like depression and anxiety are all associated with type 2 diabetes. Women and men are known to experience these conditions differently, but research has not yet described the disease trajectories according to sex and age in people with type 2 diabetes.

Eto and colleagues examined anonymized health records from 28,720 men and women in the UK who developed type 2 diabetes between 2010 and 2020. Men constituted 62% of the cohort with a median age of 54 at type 2 diabetes onset; women were on average older at diagnosis.

In the years following diagnosis, 39% of the participants experienced at least one significant health event. The events’ trajectory and timing differed by sex. For example: women were more likely to develop mental health conditions post-diagnosis (8.1% compared to 5.3%) and to experience trajectories culminating in death, while men showed higher proportions of cardiovascular disease (8.4% compared to 5.3%), end-stage renal disease, and hypertension (21.1% compared to 20.2%). The researchers noted that on average, women used more health services and long-term prescriptions than men, which may contribute to the increased diagnoses.

There were several similarities between the sexes as well. Both women and men who had a combination of type 2 diabetes and a mental health condition experienced premature mortality compared to other trajectories. Across all age groups and sexes, hypertension was the most frequent event following type 2 diabetes.

Current UK medical guidelines lack sex-specific prevention strategies and management for type 2 diabetes and comorbidities, especially mental health conditions. This study highlights the need for healthcare interventions differentiated by characteristics like sex and age.

The authors add, “One of the clearest signals in our data was the sex difference. Younger women with type 2 diabetes were showing mental health complications earlier and more often than we expected, which suggests routine psychological screening should be incorporated into standard diabetes care. For men, the pattern looked different: cardiovascular and kidney risks tended to emerge earlier, pointing to a need for earlier monitoring and stronger strategies to support men’s engagement with their treatment over time.”

Provided by PLOS

Categories : Gender NeurologyTags :

Neuroscience Reports of Sex-dependent Effects Often Lack Evidence

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Studies in the behavioural and brain sciences reporting a major sex-dependent effect – that a drug, treatment or other intervention is more effective in one sex than another – are supported by appropriate evidence less than 25% of the time, an analysis finds.

The Proceedings of the National Academy of Sciences (PNAS) published the analysis of 200 recent articles with a claim of a sex- or gender-dependent effect in the title. The articles included studies on human and non-human subjects and spanned six brain-related research areas: behavioural sciences, clinical neurology, neurosciences, psychiatry, psychology and substance abuse.

“We found that studies in psychology had the highest rate of appropriate evidence – 39% of the published papers included statistical evidence to support the claim of a sex difference,” says Donna Maney, corresponding author of the study and professor of psychology at Emory University. “Research in neuroscience had the lowest rate of appropriate evidence, at just 18%.”

The low rate of appropriate evidence in neuroscience is particularly troubling, Maney says. She notes that claims of sex-dependent effects are more numerous in neuroscience, where such reports are currently being published at triple the rate seen in any other field.

“The high number of reports seen in neuroscience may be due to bias – neuroscientists looking harder for sex differences than other scientists,” Maney says. “But most current evidence shows that the brain is one of the least sexually differentiated organs in the body.”

Maney’s team was particularly alarmed by the number of calls for changes in clinical approaches that were based on faulty analyses. Many of the 200 articles they reviewed, for example, called for sex-specific approaches to suicide prevention, stress-related psychiatric disorders, substance-use disorder and psychopathy – all without providing statistical comparisons of effects across sex.

First author of the PNAS paper is Madeline Olivier, who did the work as an Emory student and has since graduated with a BS in psychology. 
 

Summary of findings

  • In 24% of the 200 papers, the effect compared statistically across sex and the results supported the claim of a sex-dependent effect.
  • In 9%, the researchers tested for a sex difference, but the results were missing.
  • In 9.5%, the sex difference in the effect was reported as not statistically significant, which was incompatible with the claim in the title.
  • In 57.5%, the sexes were not statistically compared — the researchers did not test the claim in the title at all.


A logical error 

Maney is a neuroscientist who studies hormonal and genetic influences on behaviour. For more than a decade, she has also focused on investigating how sex differences are tested for and reported in biomedical research. 

One issue she emphasises is that, instead of comparing the sexes directly with each other, researchers often test for the effect in each sex separately. Although it might make sense on the surface, the practice reduces the number of subjects to the point where a real effect can be missed. If the effect is detected in one sex but missed in the other, researchers are vulnerable to a logical error: that the effect differs between the sexes, when they have not been directly compared. 

To show that the sexes differ, females and males must be directly compared with each other in a statistical test. Most of the articles analysed by Maney and colleagues for the current PNAS paper did not do that. Instead, the researchers relied on the individual, within-sex tests – an invalid way of comparing the sexes that produces the illusion of a difference up to 50% of the time. “It’s no better than flipping a coin,” Maney says.

It’s also easy to miss true sex differences with a subgroup approach. For example, men and women could respond differently to a treatment but when the sample is divided in half and tested separately, the effect could be missed in both.

Maney cites the classic example of a large clinical trial showing that aspirin significantly reduced mortality from heart attacks. To illustrate the problem with the subgroup error, cardiologist Peter Sleight reanalysed the data by dividing participants into subgroups according to their astrological signs. Once the trial was split into 12 zodiac groups, the benefit of aspirin was no longer statistically detectable among the Libras and Geminis.

Sleight’s “findings” demonstrated how dividing a large group into subgroups can make a real effect disappear in some of the groups, even when the treatment is clearly beneficial. 

“This problem is not new,” says Maney. “I made the error myself until I learned about it. “Many researchers don’t receive training in how to test whether an effect differs between two groups.”
 

A simple solution

To provide evidence that an effect differs by sex, the effect must be statistically compared between males and females, Maney emphasises. Only that approach can show sufficient evidence for a sex difference.

She designed an open-source tool, housed on the web at sexdifference.org, to help guide researchers to verify sex-specific effects.

Maney’s interests extend beyond statistical sex comparisons.

“Ultimately,” she says, “I would like to see researchers not treat sex as the most important variable in a biomedical study. Variation in participants’ weights, ages or habits, for example, likely explains variation in the effect of a treatment better than which sex category they are in.”

Original written by Carol Clark

Source: Emory University

Categories : UncategorizedTags :

Coffee’s Biological Benefits Linked to Metabolic Health and Sex Hormones

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Coffee is one of the world’s most widely consumed beverages, and previous research has linked its consumption to a lower risk of conditions such as type 2 diabetes and cardiovascular disease. However, the biological mechanisms behind these benefits remain unclear. A new Finnish study links habitual coffee consumption to healthier body composition and metabolic markers, while revealing distinct associations with sex hormones in men and women.

The study, conducted at the University of Oulu, analysed data from 2264 participants aged 46 in the Northern Finland Birth Cohort 1966. Researchers examined how habitual coffee consumption was associated with circulating metabolites, cardiometabolic risk markers and sex hormones.

Despite having a similar body mass index (BMI), individuals with higher coffee consumption had lower total and visceral fat and greater skeletal muscle mass than those who consumed less coffee.

In both men and women, higher coffee consumption was correlated with lower circulating levels of branched-chain amino acids, biomarkers that have previously been linked to insulin resistance and an increased risk of type 2 diabetes when chronically elevated.

The strongest sex-specific associations were observed in men. Higher coffee consumption was linked to a more favourable glucose–insulin profile, higher concentrations of total and bioavailable testosterone, and increased levels of sex hormone-binding globulin (SHBG). At the same time, free testosterone and the free androgen index were modestly lower. In women, hormonal associations were more limited and were primarily characterised by higher SHBG and lower measures of free androgens.

“Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones. What stood out in our findings was a distinct hormonal signature that didn’t disappear even after we took into account BMI and lifestyle factors, with several of these associations differing between men and women,” says Luca Verroest, lead author of the study and Doctoral Researcher at the University of Oulu.

The results suggest that hormonal pathways may partly explain the relationship between coffee consumption and metabolic health. However, as this was an observational study, the findings demonstrate associations rather than cause-and-effect relationships.

The study is particularly relevant in Finland, one of the world’s highest coffee-consuming countries, where annual consumption averages around 11.8 kilograms per person.

The researchers say the findings provide a foundation for future studies aimed at determining whether coffee itself drives these biological changes and identifying the compounds responsible. These questions are currently being investigated in animal models, with the long-term goal of progressing to human intervention studies. Further research will be needed before the findings could inform dietary recommendations.

The study, Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland Birth Cohort 1966 study, has been published in the European Journal of Nutrition on 16 July 2026.

Source: University of Oulu

Categories : CancerTags :

Uncovering Sex-specific Immune Differences in Glioblastoma

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Photo by Anna Shvets

Men and women experience many diseases very differently. Certain diseases present more commonly in one sex than in another. Some conditions like heart attacks may cause different symptoms in men and women. Some treatments work better or not at all for one sex over the other.

Cancer is no exception. There are major differences in male and female immune systems, a system critical for cancer’s growth and for successfully becoming cancer-free. For example, some immunotherapies work better in men than in women and vice versa.

Glioblastoma, the most common and fatal form of brain cancer, is more common and more deadly in men than in women. The reasons behind this difference and how the cancer’s biology differs between men and women remain largely unclear.

Now, a study has identified a cellular mechanism that differs between male and female laboratory models with glioblastoma. The study was published in the journal Nature Cancer and led by Defne Bayik, PhD, assistant professor of molecular and cellular pharmacology at the University of Miami Miller School of Medicine, and Asmita Pathak, PhD, a former postdoctoral fellow in the Bayik Lab.

“We have a growing appreciation that cancer doesn’t act the same way in men and women. There are differences in incidence rates. There are differences in treatment responses. There are differences in outcomes,” Dr Bayik said. “But we don’t really have a good, fundamental understanding of the mechanisms underlying these observational studies.”

Delving Into Immune Differences

To uncover that mechanism for glioblastoma, Dr Bayik and her colleagues focused on a certain class of immune cells in the brain known as myeloid-derived suppressor cells, or MDSCs. As their name suggests, these cells suppress other cells’ immune activity, especially that of T cells. In healthy contexts, their activity is important for regulating the immune system and keeping inflammation under control. But in the context of cancer, these cells are often recruited by tumours to suppress surrounding T cells and other immune cells, protecting cancerous cells from the rest of the immune system and allowing them to grow unchecked.

In previous work, Dr Bayik found sex-specific differences in the immune landscape of glioblastoma, with higher levels of monocytic myeloid-derived suppressor cells associated with disease in male laboratory models. Granulocytic MDSCs play a more prominent role in females. In studies of human glioblastoma tumours, she observed a similar pattern. Men tend to have more monocytic MDSCs within their tumours, Granulocytic MDSCs, or proteins associated with these cells, correlate with worse outcomes for women but not for men.

Women still constitute 40% of glioblastoma patients. By identifying these differences, we can better tailor treatments for both men and women.

Dr Defne Bayik

In the new study, Dr Bayik and her colleagues wanted to understand what drives this difference. How do granulocytic MDSCs act to promote cancer growth in female but not male laboratory models? In Dr Bayik’s previous study, she’d found several drug candidates that are predicted to act on granulocytic MDSCs. A few of these candidate drugs target proteins related to GABA, a brain signaling molecule also known as a neurotransmitter.

By exposing different populations of MDSCs to GABA in the lab, the scientists found that the neurotransmitter specifically affects cellular metabolism only in female granulocytic MDSCs. The process is unaffected in male MDSCs. They also found that this reprogramming of the cells’ metabolism by GABA made the granulocytic MDSCs more immunosuppressive. Finally, they found that blocking the GABA receptor in female laboratory models with glioblastoma improved their outcome. This had no effect on male laboratory models with the cancer.

Potential for treatment personalised by sex

Dr Bayik and her colleagues found that many of their lab findings held up in human samples donated by patients with glioblastoma. Tumour biopsies from women had higher levels of GABA and the GABA receptor in granulocytic MDSCs than did those from men. They also found that GABA reprograms granulocytic MDSC metabolism in women as it does in lab models.

These findings point to the potential for a sex-specific treatment for glioblastoma, Dr. Bayik said. She’s currently working to understand the basis for the difference in cellular metabolism in these immune cells between male and female laboratory models. Further uncovering the mechanism of this sex difference will help her and other scientists find new potential drug targets for the disease. MDSCs are involved in many other types of cance. Drugs that target these cells could have broader applications than just glioblastoma.

“Glioblastoma may be more common in men, but women still constitute 40% of patients,” said Dr Bayik. “By identifying these differences, we can better tailor treatments for both men and women.”

By Rachel Tompa, PhD

Source: University of Miami

Categories : Mental HealthTags :

Women Report Poor Sleep Despite a Good Night’s Rest – While Men Overestimate Their Own Sleep Quality

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Men reported sleeping better than they objectively did, while the opposite was true for women. Photo by Ketut Subiyanto on Pexels

Torbjörn Åkerstedt, Karolinska Institutet

Disturbed sleep is a common problem — and one that has many serious consequences beyond feeling tired the next day. Research has linked insomnia and poor sleep to early mortality and diseases including diabetes and cardiovascular disease.

Women often report experiencing disturbed sleep more frequently than men. They also constitute the majority of patients in sleep clinics. Yet strangely, some studies show worse objective sleep quality in men – a bit of a paradox.

To understand what might explain the paradox, my colleagues and I conducted a study that directly compared sleep quality ratings and objective sleep measures between men and women.

We found that women complained more of sleep problems – but slept objectively much better than men. We think this paradox can probably be explained by men overestimating their sleep quality as they’re less able to perceive how often they wake up at night.

A total of 238 randomly selected women participated in the study, plus 238 men who were matched on age and BMI with the women to ensure similar participants were compared against each other.

Sleep was recorded in each participant’s home using a recorder that measured brain waves (electroencephalography – EEG), muscle tension (electromyography – EMG) and eye movements (electrooculography – EOG). These devices tracked what stage of sleep a participant was in and for how long, how much time they spent awake and how quickly they fell asleep.

A researcher visited the participant’s home in the evening, mounted the recording equipment and left. The participant went to bed and awoke at their usual time.

In the morning, the participant rated the degree of difficulty they had falling asleep, if their sleep was restless, if they woke up early, how often they thought they’d woken up, how long it took them to fall asleep, how long they slept and their overall sleep quality.

The sleep recording was scored by a sleep technician based on visual inspection of the EEG, EOG and EMG recordings. The data was then analysed to understand the objective quality of each participant’s sleep and its relation to gender and age.

Analyses were also adjusted for factors such as gender, age and alcohol consumption and smoking, which may affect sleep.

Sleep quality

The results show that women subjectively reported significantly lower sleep quality than men. Yet women actually had considerably fewer nighttime awakenings, less stage one (superficial) sleep and higher sleep efficiency (they spent more time asleep while in bed). Women also experienced more stage three (deep) sleep and slept longer (400 minutes versus 382 minutes for men).

When women did wake up at night, they spent more time awake on average. Photo by Cottonbro on Pexels

The results suggest that women objectively had a good nights’ sleep, compared to men. The only variable that suggests worse sleep in women was that when they did wake up at night, they spent more time awake than men did – around nine minutes each time for women versus just under seven minutes for men.

It only takes around five minutes of being awake at night for a person to remember it the next morning. This may explain why women were better able to remember if they’d woken up the night before and estimate how many times they had. Men, on the other hand, grossly underestimated their number of awakenings (by 72% compared to women’s 37%).

For other quantitative measures, like time to fall asleep, sleep duration and time awake, men and women were equally good at estimating their objective values. And they were relatively correct.

We took this further and found that men who only woke up for a short period of time during the night (around eight minutes or so each time they woke up) often didn’t remember they had.

When this group of men was removed, no gender difference in subjective sleep quality remained. This suggests that men with short nighttime awakenings report better sleep quality than would be expected from their objective sleep measures as they didn’t remember they’d woken up.

It’s also noteworthy that men’s objective sleep deteriorated faster with age than women. This was particularly obvious for stage three sleep. While women aged over 65 got around 80 minutes of stage three sleep each night, men had only 53 minutes. Among those between 30 and 50 years of age, the amount was similar for men and women (around 70 minutes).

Sleep and wellbeing

A key reason women may complain of having a worse nights’ sleep than they objectively had may therefore be the amount of time they spent awake when they woke up, making it easier for them to notice. Likewise, men may overestimate their sleep quality because they’ve spent less time awake when they’ve woken up, so they don’t remember it happening.

Both findings would work towards reducing subjective sleep quality in women and increasing it in men. We assume then, that the experience of awakenings has an important influence on subjective sleep quality.

As our study was only conducted over one night, it will be important for future research to investigate whether these findings remain when participants are studied over longer periods of time.

Future studies may also want to explore the reasons for poor sleep in men – especially since common sources of disturbed sleep, such as alcohol, smoking and BMI, were all adjusted for in our analysis. Researchers may also want to investigate why men’s sleep becomes objectively worse as they get older.

Our research illustrates how sleep quality doesn’t just involve the physiological aspects of sleep. It also includes our own subjective experiences, which can impact our wellbeing and how rested we feel.

It also suggests that because many men overestimate their sleep quality, they may also overlook any sleep problems they’re experiencing. This could mean that some men aren’t getting help for conditions that could be affecting their health and wellbeing.

Torbjörn Åkerstedt, Senior Professor of Psychology, Department of Clinical Neuroscience, Karolinska Institutet

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Categories : ImmunologyTags :

Chimeric RNA Unique to Women Is an Important Controller of Health

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Strange “chimeric” RNA once thought to be the product of cancer is actually an important controller of women’s health, including influencing their susceptibility to infectious disease and autoimmune disorders, new University of Virginia School of Medicine research suggests.

UVA’s Hui Li, PhD, and colleagues have identified a chimeric RNA called UBA1-CDK16 that is found only in women. This RNA plays important roles in their blood cell development and in determining the severity of diseases such as COVID-19, the scientists found. The findings, published in Science Advances, could open the door to blood tests to help diagnose diseases or identify women at greatest risk for bad outcomes.

“Chimeric RNAs are RNA molecules composed of parts from different genes,” said Li, of UVA’s Department of Pathology and the UVA Comprehensive Cancer Center. “They were once believed to be cancer-specific. However, our research shows that they can also be part of normal physiology and play important roles in human health.”

Powerful Chimeras

RNA provides instructions for our cells, telling them what to do based on the genetic material, called DNA, that we inherit from our parents. Chimeric RNAs were long thought to be mistakes, as they are made up of instructions mashed together from different genes. This is why they were believed to be a byproduct of cancer; cancer itself is the result of cellular copying mistakes.

Li’s discovery, however, suggests that UBA1-CDK16  plays important roles in maintaining women’s health and in controlling their immune systems. This chimeric RNA is found only in women because women have two X chromosomes, while men have an X and Y. Normally, one of the two X chromosomes found in women’s cells are inactive. But Li found that the inactive X chromosome produces this peculiar chimeric RNA that he could identify in women’s blood.

Based on his findings, Li believes UBA1-CDK16 plays an important role in regulating blood cell formation. But his work also suggests the chimera may play an important role in the immune system’s response to infection. He found that the chimeric RNA was lost in 50% women who developed severe COVID-19 infections, while it was present in women who were asymptomatic. Further, the decrease in chimeric RNA correlated with the increasing severity of the infection.

Li suspects that the chimeric RNA may play an important role in governing the development of immune cells called neutrophils that act as the body’s first responders to infection. (Neutrophil count has already been identified as a way to predict how patients will fare against COVID-19.) 

“As humans share similar number of genes with fruit flies and worms, gene number does not explain why we are much more sophisticated than these lower organisms” Li said. “We believe chimeric RNAs are another means to expand the functional genome, without an actual increase in gene number.”

Li’s findings suggest that the chimeric RNA also may serve as a natural brake to protect women from excessive autoimmune activity. Women are far more likely to suffer autoimmune disorders than men, and Li is urging additional research to better understand the role chimeric RNA could be playing – and how it could be targeted to improve patient outcomes.

“This finding highlights there is another layer of control for gene expression,” Li said. “These chimeric RNAs may represent a hidden repertoire for biomarkers and therapy targets as well.”

Source: University of Virginia

Categories : CancerTags :

Age, Sex, and Cancer Type Influence Risk of Subsequent Cancers Among Survivors

On By ModernMedia

Findings may have implications for long-term cancer survivorship surveillance

Researchers assess the risk of developing a subsequent primary cancer based on demographic factors and cancer characteristics. Tara Winstead, Pexels (CC0, https://creativecommons.org/publicdomain/zero/1.0/)

Risk of developing a subsequent primary cancer varied significantly by age at initial diagnosis, sex, and type of first cancer, according to a study by Oxana Palesh and Susan Hong and colleagues at Virginia Commonwealth University, U.S., published April 28th in the open-access journal PLOS Medicine.

Advances in cancer detection and treatment have led to a growing population of cancer survivors. In the U.S., the number of cancer survivors is expected to grow by 22% over the next decade – from 18 million in 2025 to more than 22 million by 2035. Survivors remain at higher risk for developing new primary cancers distinct from their original diagnosis. This risk may be influenced by factors such as older age, exposure to radiation and/or chemotherapy and ongoing lifestyle factors like smoking, obesity and poor diet. Understanding who is at greater risk and how this risk changes over time can help to inform prevention and monitoring strategies.

Using retrospective data from more than 3 million cancer survivors in the U.S., researchers examined how demographic factors and cancer characteristics correlate with subsequent cancer risk. Several factors were associated with developing a subsequent cancer, including older age at initial diagnosis and male sex. In addition, survivors of lung, bladder, and skin melanoma were at higher risk of developing new cancer.

These findings reinforce the importance of long‑term survivorship care and risk‑based monitoring. By identifying survivor groups at heightened risk, studies like this can help to inform tailored prevention strategies, surveillance guidelines, and survivorship care planning as the cancer survivor population continues to grow.

First author Hui Cheng adds, “By examining nearly five decades of national data, we found population-level shifts in subsequent primary cancer risk, with several survivor groups experiencing rising risks. These findings can help design more tailored surveillance and prevention strategies.”

Provided by PLOS