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Category: sex

It’s not just how many, it’s when: People judge a potential partner’s sexual history by timing, not total number

A major international study has found that when it comes to choosing a long-term partner, people across the globe consider not just how many sexual partners someone has had, but also when those encounters took place.

This is the first time researchers have explored the timing of sexual history alongside quantity—offering a fresh perspective on human mating psychology. The study is published in the journal Scientific Reports.

Led by Swansea University, the study surveyed more than 5,000 participants from 11 countries across five continents. It found that people were generally less willing to commit to someone with a high number of past sexual partners but were more open if those encounters had become less frequent over time, suggesting a shift away from casual sex.

Season of birth shows slight association with depression in men but not women

Males born in summer months reported higher depression symptom scores than males born during other seasons, according to a study from Kwantlen Polytechnic University. Anxiety symptoms showed no association with season of birth for either sex.

Anxiety and remain among the most common mental disorders worldwide, with both conditions contributing to long-term disability, physical comorbidities, and substantial economic losses. A range of factors shape mental health across the lifespan, including housing, income, education, and age. Research into early-life exposures remains limited, particularly exposures shaped by environmental seasonality.

During gestation, exposure to temperature shifts, maternal diet, seasonal infections, and variation in daylight may influence neurodevelopment. Birth season has previously been associated with risk for psychiatric conditions including schizophrenia, bipolar disorder, and schizoaffective disorder. Studies examining and depression have produced mixed results, often without stratifying by sex.

Sepsis criteria and kidney function: eliminating sex, age and economic status biases

In this Perspective article, the authors argue that current criteria for sepsis in adults and children fail to adequately consider one of the most common sepsis-related organ dysfunctions, acute kidney injury, which has important implications for diagnosis and patient outcomes.

Circadian disruption by night light linked to multiple cardiovascular outcomes

Flinders Health and Medical Research Institute researchers, along with colleagues in the UK and U.S., have linked brighter night-time light exposure to elevated risks of five major cardiovascular diseases.

Circadian rhythms govern fluctuations in blood pressure, heart rate, platelet activation, hormone secretion, and glucose metabolism. Long-term disruption of those rhythms in animal and human studies have produced myocardial fibrosis, hypertension, inflammation, and impaired autonomic balance. Previous research efforts relied largely on satellite-derived estimates or small cohorts using bedroom or wrist light sensors, leaving personal exposure patterns uncharted at population scale.

In the study, “Personal night light exposure predicts incidence of cardiovascular diseases in 88,000 individuals,” posted on medRxiv, researchers conducted a prospective cohort analysis to assess whether day and night light exposure predicts incidence of cardiovascular diseases and whether relationships vary with genetic susceptibility, sex, and age.

New research reveals how male and female brains process regret and change decisions

A traditionally overlooked type of RNA plays an important role in promoting resilience to depression—but only in females. According to a new study led by the Icahn School of Medicine at Mount Sinai, researchers have now discovered a novel role this molecule plays in how the female brain makes decisions. The authors revealed brain-region-specific and sex-dependent effects of this biomarker, translated from humans to animals, on how individuals make only certain types of choices. This study uncovered differences in how each sex decides whether to change their minds after making mistakes, including when to cut their losses and move on as well as how they process regrets about missed opportunities.

This research sheds important light on how specific types of decisions that could negatively impact mood engage the male and female brain in very different ways. The study, published July 11 in Science Advances, using laboratory animal models, helps uncover new biological and psychological mechanisms that may be linked to psychiatric vulnerabilities.

Women are twice as likely to develop depression than men. Furthermore, depression can manifest with different symptoms between the sexes, including alterations in negative rumination on the past. However, the neurobiological mechanisms underlying these differences remain unclear.

Known risk factors alone do not explain disease accumulation, finds study

As the population ages, multimorbidity, or when a patient has multiple diseases at once, is becoming increasingly common. The onset of one disease increases the risk of developing other diseases, making it necessary to investigate how a range of risk factors together affect such accumulation. Prior studies have focused on individual risk factors and related individual diseases.

A study explored how the risk factors measured from birth to middle age and unmeasured, or latent, factors covering the entire lifespan predict and explain the incidence of chronic diseases in eight organ systems from middle to old age: the cardiovascular, metabolic, gastrointestinal, musculoskeletal, respiratory, neurological and psychiatric systems, and the sensory organs.

The study, published in The Lancet Healthy Longevity journal, analyzed 22 risk factors, including age, sex, (e.g., size at birth, early childhood growth, childhood wartime evacuee status), socioeconomic factors (e.g., socioeconomic status in childhood, income in adulthood), lifestyle factors (e.g., smoking, , , diet), clinical measurements and biomarkers (e.g., body mass index, , blood glucose).

Adolescent health is at a tipping point, global analysis suggests

By 2030, there will still be over 1 billion of the world’s adolescents (aged 10–24 years) living in countries where preventable and treatable health problems like HIV/AIDS, early pregnancy, unsafe sex, depression, poor nutrition and injury collectively threaten the health and well-being of adolescents, suggests a new analysis from the second Lancet Commission on adolescent health and well-being.

Commission co-chair, Professor Sarah Baird, George Washington University (U.S.) says, The health and well-being of adolescents worldwide is at a tipping point, with mixed progress observed over the past three decades.

While tobacco and alcohol use has declined and participation in secondary and tertiary education has increased, overweight and obesity have risen by up to eight-fold in some countries in Africa and Asia over the past three decades, and there is a growing burden of poor adolescent mental health globally.

Hormone cycles shape the structure and function of key memory regions in the brain

“To date, there was little understanding of how the estrous cycle affects neurons in living mice,” said Nora Wolcott, the paper’s lead author. Now, thanks to advanced microscopy techniques, Goard’s team was able to measure the structure and activity of neurons across multiple estrous cycles, thereby gaining insight into sex hormones’ role in brain plasticity and memory. Other authors on the paper include William Redman, Marie Karpinska, and Emily Jacobs.

Researchers observe how fluctuations in ovarian hormones shape the structure and function in the mouse hippocampus, with implications for neural plasticity in humans.

Brain structure changes in people who work long hours

If you need an excuse to turn off the laptop over the weekend or rein in overtime, scientists have found that working extended hours actually changes parts of the brain linked to emotional regulation, working memory and solving problems. While we know the toll that “overwork” takes physically and mentally, the precise neurological impact has not been well understood.

An international team of researchers including scientists from Korea’s Chung-Ang University assessed 110 healthcare workers – 32 who worked excessive hours (52 or more per week) and 78 who clocked less than 52 hours per week, or what would be considered closer to standard hours in the field. Voxel based morphometry (VBM) to assess gray matter and atlas-based analysis was then applied to MRI scans of each individual’s brain, identifying volume and connectivity differences.

When the scientists adjusted the results to account for age and sex, they found that, in the overworked cohort, the imaging showed a significant difference in brain volume in 17 different regions of the organ – including the middle frontal gyrus (MFG), insula and superior temporal gyrus (STG). Atlas-based analysis identified that, in the overworked individuals, there was 19% more volume in the left caudal MFG. The MFG – part of the brain’s frontal lobe – is the heavy lifter when it comes to executive functioning like emotional regulation, working memory, attention and planning, while the STG’s main task is auditory and language processing. The insula, meanwhile, is key in pain processing and other sensory signaling.

Sex-based brain differences: Structure of a single neuron in C. elegans provides new insights

Is there a difference in brain structure between men and women? If we were to find such a difference in a single neuron, would it matter?

One of the most useful models for studying these questions is the nematode Caenorhabditis elegans (C. elegans). This tiny worm has several characteristics that make it an excellent research model, one of which is that every cell in its body has a predetermined identity and lineage.

Like humans, C. elegans has two sexes. However, instead of male and female, the two sexes of this worm are male and hermaphrodite—a self-fertilizing individual capable of producing both male and female gametes (sperm and eggs), allowing it to reproduce without a partner.

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