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Category: sex

Prevalence of Illicit Drug Detection in Out-of-Treatment People Who Inject Drugs

Among people injecting drugs and not engaged in medical care, nearly all tested positive for fentanyl and multiple other substances, with polysubstance and xylazine detection rates highest among unhoused and recently incarcerated participants.

This cross-sectional study used data from HPTN 094. Participants who met eligibility criteria were invited to participate in a baseline interview and were enrolled between June 2021 and September 2023. All participants completed written informed consent prior to participating in study procedures, and a single institutional review board (Advarra) provided ethical approval for HPTN 094; this cross-sectional analysis was exempt from additional IRB approval. The current study was conducted and reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.23

Participants were required to meet the following criteria: be at least 18 years of age, have a urine test positive for recent opioid use and evidence of recent injection drug use (visible venipuncture marks), meet diagnostic criteria for opioid use disorder, be able to give informed consent, be willing to start MOUD treatment, complete an assessment of understanding, have confirmed HIV seropositivity or self-reported sharing of injection equipment and/or condomless sex in the past 3 months with partners living with HIV or with unknown HIV status, and provide locator information. Participants were excluded if they self-reported being prescribed MOUD in the 30 days prior to screening, had a urine test positive for methadone (with the exception of verified hospitalization), or were enrolled in another study.

Sex Differences in Left Ventricular Remodeling for Aortic Regurgitation

In a multicenter cohort study of adults with moderate-severe AorticRegurgitation and preserved ejection fraction, women experienced higher mortality under medical management compared to men.

The optimal left ventricular end-systolic diameter index threshold associated with mortality was similar for both sexes (≥20 mm/m²), while volumetric thresholds differed: 40 mL/m² for women and 45 mL/m² for men.

These findings support the use of sex-specific thresholds to improve risk stratification and timing of intervention.

This cohort study evaluates sex differences in left ventricular remodeling among individuals with aortic regurgitation.

Scientists identify a brain region that differs between males and females and may influence social behavior

Scientists have uncovered a previously unknown cluster of brain cells that may help explain differences in social behavior between males and females. The small neural circuit appears to function like an on/off switch, showing a striking pattern of activity that differs sharply by sex, an unusually clear contrast compared with most known brain sex differences, which tend to be more subtle and overlapping. Researchers also found that the circuit’s activity shifts with social and reproductive status, suggesting the brain may use this mechanism to adapt behavior across key life stages.

The new study was led by Dr. Tamar Licht and Dr. Dan Rokni from the Institute of Medical Research Israel-Canada (IMRIC) at the Hebrew University of Jerusalem and is published in the Proceedings of the National Academy of Sciences.

Burden of Central Nervous System Cancer in the United States

While incidence rates for central nervous system cancer remained stable from 1990 to 2021, both mortality and disability-adjusted life-years (DALYs) declined. Disparities by geography, age, sex, and sociodemographic status highlight needs for targeted health policy reforms and resource redistribution.

Findings In this cross-sectional study, analysis of the Global Burden of Disease Study 2021 data on US CNS cancers revealed that although the incidence rate remained relatively stable, both disability-adjusted life-years and mortality rates declined. However, substantial disparities persisted across geographical location, age, sex, and sociodemographic profile.

Meaning The persistent disparity in CNS cancer burden highlights the urgent need to reevaluate public health policies and redistribute health care resources to better support marginalized and underserved populations.

Uniform Amyloid Thresholds Across Populations

This diagnostic study validates the biological comparability of brain amyloid thresholds used in AlzheimerDisease diagnostics across racial and ethnic subgroups of older adults, with no significant differences by sex or APOE4 status.

Further research should determine whether uniform thresholds yield comparable prognostic utility in clinical practice.

High-dose birth control pills linked to elevated fear in safe contexts

A new study published in Neuropsychopharmacology suggests that the use of oral contraceptives may influence how the brain regulates fear responses in safe environments. The research indicates that women who use birth control pills, particularly those with higher doses of synthetic estrogen, may experience elevated fear in safe contexts compared to women who have never used hormonal contraception. The findings also imply that these alterations in fear processing could persist for a significant period after an individual stops taking the medication.

Anxiety disorders and post-traumatic stress disorder are nearly twice as prevalent in women as they are in men. Biological factors likely contribute to this disparity, with sex hormones acting as potential mediators. Specifically, the hormone estradiol plays a significant role in how the brain manages fear and memory.

Effective fear regulation requires the ability to distinguish between a threat and a safety signal based on the surrounding environment. For example, seeing a snake in a forest might require a fear response, while seeing a snake in a zoo enclosure should not. This process is known as contextual fear regulation.

Psychopathic women are more likely to use physical aggression

New research provides evidence that women with high levels of psychopathy are more likely to engage in physical, verbal, and indirect aggression against other women. The study indicates that while women generally favor covert competitive tactics, those with specific dark personality traits may bypass these social norms to target rivals directly. These findings were published in Evolutionary Behavioral Sciences.

Evolutionary theory suggests that humans compete for access to romantic partners through a process known as intrasexual selection. This competition can manifest in various ways depending on the sex of the individual. For women, biological factors related to reproduction play a significant role in shaping these competitive strategies.

The theory of obligatory parental investment notes that women face higher biological costs in reproduction than men. Because women carry the fetus during gestation and often care for infants, they must protect their physical well-being to ensure the survival of their offspring. This biological reality implies that direct physical confrontation is a high-risk strategy for women.

Study links men’s higher intelligence to fewer abusive relationship behaviors

A new study published in the journal Personality and Individual Differences shows that men with higher general intelligence are less likely to engage in abusive or coercive behaviors toward their romantic partners. The findings suggest that cognitive ability may play a role in how men manage conflict and commitment in heterosexual relationships.

General intelligence is a broad mental capacity that influences reasoning, planning, and problem-solving. Psychology research has long established that people with higher general intelligence tend to experience better life outcomes. They generally achieve higher levels of education and earn more money. They also tend to live longer and suffer from fewer health issues.

But the relationship between intelligence and romantic success is less clear. Some data suggests that intelligent people are less likely to divorce. Other studies indicate they may have sex less frequently or choose to have fewer children. Evolutionary psychologists have debated why this might be the case.

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