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PubMed1977

[Influence of sex on children's body measurements and indices of biological age (findings from a study of twins of different sexes)].

By antropometry and roentgenography methods in 52 twin pairs of different sex, body dimensions, the third metacarpal bone and the phalange of the third right hand finger, as well as the terms of permanent teeth eruption were studied. The investigation revealed no timely coincident periods in growth activity between girls and boys. During the first period (6,5--10 years), predominance of some dimentions is observed in boys, during the second (8,5--14 years)--in girls, and during the third (11--17 years)--in boys again. Somewhat different terms for permanent teeth eruption make it possible to distinguish two periods: 7 years when the boys surpass the girls in the number of permanent teeth (two teeth in average) and 8--14 years when the boys lag behind the girls in the number of permanent teeth.

Adolescent↗
PubMed1979

On the nature of difficulties in spatial-perceptual tasks: ethnic and sex differences.

The common claim that Africans exhibit a general weakness in handling spatial relationships is questioned, as is that of a general male superiority. The aim of the study was to identify some of the specific areas in which ethnic and sex differences may be located. A sample of 72 Ghanaian children evenly divided according to sex and early, middle and later stages of primary schooling were administered a series of tasks adapted from Piaget & Inhelder (1971); the same tasks were given to an equivalent group of Scottish children. On a block construction task involving memory the Ghanaians performed at the same level as the Scots when working from models, but not when the presentation consisted of photographs or line drawings (P less than 0.001). On two tasks requiring mental rotation of shapes and, subsequently, the actual assembly of shapes into regular figures, the Ghanaians again experienced more difficulty (P less than 0.001). Intercorrelation of scores on the various tasks suggested that the underlying structures of abilities may differ in Ghana and Scotland. The pattern of sex differences was exactly the same in both cultures. Girls did less well with the block construction (P less than 0.001), but there was no significant sex difference on mental rotation or shape assembly.

Adolescent↗
PubMedDate not supplied

Sex differences in daydreaming and related mental activity from the late teens to the early nineties.

Using the Imaginal Processes Inventory, aspects of daydreaming and associated mental activity were examined for sex differences in 1200 well educated middle and upper-middle class whites aged seventeen to ninety-two ninety-two years. Females reported higher levels of daydreaming and nightdreaming frequency and emotional reactions to daydreaming as well as more daydreams of a problem solving nature. Females also reported lower levels of daydreams of a sexual, bizarre-improbable, heroic and achievement-oriented nature. Most sex differences persisted over the life span with the difference for sexual daydreams increasing with increasing age level. Except for problem-solving daydreams, all daydreaming contents investigated decreased with increases in age. Across the lifespan problem-solving daydreams were the most likely for both sexes except for seventeen to twenty-nine year old males where such daydreams were second most likely; from age seventeen to twenty-nine sexual daydreams were most likely for males. After age forty, achievement oriented daydreams were relatively more important for females than for males. Females across the lifespan also reported more interpersonal curiosity than males while males exhibited more curiosity about things. Unexpectedly, male curiosity about things was equally as strong as their curiosity about people.

Adolescent↗
PubMed1979

Sex differences in response to hepatitis B virus. I. History.

Sex differences related to responses to hepatitis B infection are reviewed. In most human populations there is a higher prevalence of chronic carriers of hepatitis B virus (persistently HBsAg+) among males than females. Females are more likely than males to produce anti-HBs in response to infection. Diseases associated with increased frequencies of carriers are more prevalent among males. The response of parents to hepatitis B virus (HBV) infection appears to affect the sex ratio at birth of their offspring. Couples in which either parent is a carrier have higher sex ratios (higher proportion of males) compared with couples in which neither parent is HBsAg+. Couples in which the mother is anti-HBs+ have children with lower sex ratios than either carriers or uninfected couples.

Carrier State↗
PubMed1979

Sex differences in the utilization of health services for psychiatric problems in Saskatchewan.

Comprehensive data on all pscyhiatric patients in Saskatchewan show that women are substantially higher users of health services for psychiatric problems than are men. Women: 1) use up to twice as many services as men in the private sector, but use almost the same number of public sector services; 2) tend to be treated for psychosomatic and neurotic disorders on an outpatient basis; 3) have only a slightly greater chance than men of being hospitalized; and 4) are less likely than men to have organic or addictive diagnoses. These differentials in utilization cannot be explained by age, diagnoses and/or marital status. Sex is the best predictor of utilization. These results are largely consistent with utilization and epidemiological literature. It seems more likely that these sex differences in utilization result from the interaction of biology, sex roles, and the functioning and labelling processes of the health system rather than from any single factor. Combining Andersen's components of health behaviour with Freidson's lay-professional construction of illness continuum yields a possible framework for understanding sex differences in the utilization of psychiatric health services.

Adult↗
PubMed1977

Pubertal manifestation of sex difference in circadian rhythm of corticotrophin-releasing activity in the rat hypothalamus.

Post-natal development of the circadian rhythm of hypothalamic content of corticotrophin-releasing factor (CRF) was examined in male and female rats, separately. CRF activity was estimated by the intrapituitary injection technique. The circadian rhythm of the CRF content observed at the third week was without any noticeable sex difference: both male and female rats began their circadian rhythm with higher values in the afternoon than in the morning. Male rats maintained this pattern up to maturity. In contrast, female rats showed a marked change at ages of fifth to sixth week: the CRF rhythm in female rats changed to a female pattern, with higher values in the morning than in the afternoon. During this period, the vaginal opening occurred concurrently with a marked afternoon rise in the plasma corticosterone, characteristic of mature female rats. On the other hand, no essential difference could be observed between male and female rats in the developmental change in the circadian rhythm of locomotor activity. These results indicate that a sex difference in the CRF rhythm is not essentially related to the process of sex differentiation in the central nervous system, but is rather related to changes in ovarian activity following the onset of puberty.

Age Factors↗
PubMed1976

Sex differences in anaesthetic toxicity: fluroxene and trifluoroethanol in mice.

A sex difference in postanaesthetic mortality after fluroxene anaesthesia was found in Swiss Webster mice. More males succumbed than females. This toxicity was biotransformation-dependent and could be reversed by pretreatment with "opposite" sex hormones. The toxicity of the fluroxene metabolite trifluoroethanol also was more marked in male mice, but was only partially influenced by microsomal enzyme inhibitors or stimulators, or by sex hormones.

Animals↗
PubMed2022

Sex Differences in Human Immunodeficiency Virus Persistence and Reservoir Size During Aging.

BACKGROUND: Sex differences in human immunodeficiency virus (HIV) reservoir dynamics remain underexplored. METHODS: Longitudinal samples from virally suppressed midlife women (n = 59, median age 45 years) and age-matched men (n&#x2005;=&#x2005;31) were analyzed retrospectively. At each time point, we measured sex hormones (by means of enzyme-linked immunosorbent assay) and cellular HIV DNA and RNA (by means of digital droplet polymerase chain reaction). Number of inducible HIV RNA+ cells, which provides an upper estimate of the replication-competent reservoir, was quantified longitudinally in a different subset of 14 women, across well-defined reproductive stages. Mixed-effects models included normalized reservoir outcomes and sex, time since antiretroviral therapy (ART) initiation, and the sex-by-time interaction as predictors. RESULTS: At ART initiation, women and men had median (interquartile range [IQR]) CD4+ T-cell counts of 204/&#x3bc;L (83-306/&#x3bc;L) versus 238/&#x3bc;L (120-284/&#x3bc;L), respectively; median ages of 45 (42-48) versus 47 (43-51) years; and median follow-up times of 79.2/&#x3bc;L (60.5-121.1/&#x3bc;L) versus 66.2/&#x3bc;L (43.2-80.6/&#x3bc;L) months. We observed a significant decline of total HIV DNA over time in both men and women (P&#x2005;<&#x2005;.01). However, the rates of change differed significantly between the sexes (P&#x2005;<&#x2005;.01), with women having a significantly slower rate of decline than men, more pronounced with age. By contrast, the levels of inducible HIV RNA increased incrementally over time in women during reproductive aging (P&#x2005;<&#x2005;.01). CONCLUSIONS: In contrast to men, in whom the HIV reservoir steadily declines with aging, the HIV reservoir in women is more dynamic. Total HIV DNA (including intact and defective genomes) declines more slowly in women than in men, while the inducible HIV RNA+ reservoir, which is highly enriched in replication-competent virus, increases in women after menopause.

Aging↗
PubMed2026

Sex differences in sleep and alcohol consumption outcomes following a digital insomnia intervention.

BACKGROUND: Poor sleep is a well-established risk factor for heavy drinking, and evidence suggests that sleep could serve as a potential treatment target for reducing alcohol consumption. The relationship between poor sleep and problematic drinking appears to be stronger among females, but no studies to date have assessed sex differences in alcohol consumption following insomnia treatment. Here, we combine the samples from two clinical trials to investigate sex differences in the effects of a digital cognitive behavioral therapy for insomnia (Sleep Healthy Using the Internet; SHUTi) on sleep and alcohol outcomes. METHODS: 184 heavy drinking individuals with insomnia (weekly binge episodes: 4/5&#x2009;+ drinks in one sitting for females/males; AUDIT score >7; ISI score >14) were randomly assigned to either the SHUTi program (n&#x2009;=&#x2009;102) or an active control program (n&#x2009;=&#x2009;82). Participants completed self-report assessments at baseline, immediately following the 9-week intervention period, and at 3 and 6-months post-intervention. RESULTS: Linear mixed effects models showed that SHUTi effects over time were stronger among females than males for improved sleep outcomes and reduced frequency of total and heavy drinking days (ps &#x2264; 0.038). Follow-up comparisons of within-group effect sizes revealed consistently larger reductions in alcohol consumption among SHUTi females (Cohen's d range = 0.92-2.23) than SHUTi males (Cohen's d range = 0.65-1.95). CONCLUSIONS: Findings suggest that SHUTi may be more efficacious in improving sleep and reducing drinking among females with insomnia compared to males. These results could have important implications for sex-specific prevention and treatment efforts for heavy drinking individuals with insomnia.

Humans↗
PubMedDate not supplied

Sex differences in averaged visual evoked potentials during food intake in rats.

Averaged visual evoked potentials (AVEP's) were recorded in unrestrained male and female rats during alert wakefulness (baseline condition), feeding and drinking. The rats had been deprived of food and water for 23 hr prior to testing. Peak-to-peak amplitude of the AVEP's was measured between the slow negative and the preceding positive component. Under baseline conditions females had higher amplitude AVEP's than males. It is suggested that sex differences in adrenal steroid secretion could account for this observation. During feeding and drinking, AVEP's increased significantly in amplitude in both sexes, and high-voltage, slow EEG activity was observed to appear in most animals. During feeding, these increases in AVEO amplitude were significantly larger in males than in females. These findings support recent views on sex differences in the regulation of feeding behavior.

Animals↗
PubMed2026

An immune-associated mitochondrial DNA variant with sex differences reveals a putative novel microprotein called MASL.

The use of mitochondrial wide association studies (MiWAS) to link mitochondrial DNA variants (mtSNPs) to phenotypes of interest has uncovered important connections between mitochondrial genes and human health. The recent introduction of a re-annotated mitochondrial genome that accounts for small open reading frames (sORFs) with protein coding potential suggests the existence of mitochondrial-derived microproteins, many of which remain uncharacterized. Thus, considering the re-annotated mitochondrial genome when conducting genomic analyses such as MiWAS facilitates the mapping of mtSNPs back to microprotein-encoding sORFs and uncovers interactions between mitochondrial microproteins and biological systems. Here, we employ MiWAS of venous blood samples from the Health and Retirement Study (HRS) and identify a mtSNP associated with sex-specific changes to immune composition. After accounting for re-annotation, we map the identified mtSNP back to a sORF that encodes a novel microprotein, termed MASL (Mitochondrial Associated Small d-Loop peptide). Complementary phenome-wide association studies (PheWAS) in HRS and and UK Biobank confirm interactions between this mtSNP and immune phenotypes of interest, and our targeted RNA-Seq method (mitoSNP-seq) elucidates sex-differences in gene expression and functional pathways potentially altered by this mtSNP that may be relevant to the associated microprotein. Early characterization of the MASL microprotein shows sex-differences in circulating MASL levels in human plasma, and sex-specific interactions when comparing male and female mice treated with synthesized MASL. Together, the results of this study not only contribute to our understanding of mitochondrial dynamics in immunity, but also provide early characterization of a novel mitochondrial-derived microprotein with sex-specific modulatory effects.

Genomics↗
PubMed1977

Sex differences in response to hepatitis B infection among patients receiving chronic dialysis treatment.

Patients undergoing treatment at a community-based renal dialysis clinic were monitored monthly for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs). Of 160 patients who began treatment HBsAg(-)/anti-HBs(-), 77 subsequently became HBsAg(+). Once HBsAg(+), males were more likely to remain HBsAg(+) indefinitely, whereas females were more likely to convert to HBsAg(-) and develop anti-HBs. This was not due to a sex difference in exposure to hepatitis B virus because only patients who became infected while undergoing treatment were included in the analysis. These data are clear evidence of a sex difference in response to hepatitis B virus, which may partially explain the greater incidence of several chronic liver diseases, including primary hepatocellular carcinoma, in males.

Adolescent↗
PubMed1979

Sex differences in adrenocortical structure and function. V. The effects of postpubertal gonadectomy and gonadal hormone replacement on nuclear-cytoplasmic ratio, morphology and histochemistry of rat adrenal cortex.

Studies were carried out on adult rats of Wistar strain. Six weeks after postpubertal gonadectomy some of the orchiectomized rats were injected with a single dose of testosterone cypionate and ovari-ctomized rats with estradiol cypionate (17 beta-cyclopentyloproprionate esters of testosterone or estradiol). The control rats were sham operated. Investigations were carried out 8 weeks after surgery. Absolute and relative adrenal weight is lower in the male than in the female rat. Orchiectomy increases these weights while testosterone restores them to their normal level. Ovariectomy has no effect on the weight of adrenal, estradiol, however, increases the relative weight of the gland. The adrenal cortex of the adult female is wider than in the adult male rat and in female gland sudanophobic zone is lacking. Orchiectomy leads to the broadening of the adrenal cortex and testosterone replacement has an opposite effect. Ovariectomy has no effect on the structure of adrenal cortex and estradiol replacement resulted in the narrowing of zona glomerulosa. There were no differences in the nuclear-cytoplasmic ratio of zona glomerulosa cells in male and Female rats and neither gonadectomy nor gonadal hormone replacement has no effect on this parameter. The nuclear-cytoplasmic ratio of zona fasciculata cells in the male is markedly higher than in female. Orchiectomy lowers this ratio and testosterone restores it to the normal level. Neither ovariectomy nor estradiol replacement has effect on the nuclear-cytoplasmic ratio of zona fasciculata cells. Similar changes as those in the zona fasciculata were observed in zona reticularis cells. Among the oxidoreductases studied, the most marked sex differences were found in alpha-glycerophosphate dehydrogenase activity. In control female rats an intense reaction for this enzyme is observed in broad band of cells of the zona fasciculata interna, while in male rats only individual cells showed this reaction. In orchiectomized rats the reaction for this enzyme is similar as in control female rats and testosterone restores it to normal. Ovariectomy has no effect on localisation of reaction while after estradiol replacement reaction was more intense. Regarding the remaining oxidoreductases studied, in the adrenal cortex of rats of both sexes no marked differences were observed in localization, however, intensity of reaction depended upon applied experimental conditions. More distinct sex differences were observed in topochemistry of some hydrolases and intensity of reaction depended upon the applied experimental conditions.

Adrenal Cortex↗
PubMed2025

Permutation tests to assess sex differences in omics data.

It is common to sex-stratify analyses of omics data and to report effects as 'sex-specific' when they are significant in only one sex. However, when analysing hundreds or thousands of molecules, this approach will yield many spurious 'sex-specific' effects if not supported by significant interactions. I illustrate this problem using an RNA sequencing dataset showing almost no significant sex by treatment interactions, but where sex-stratified analyses yield hundreds of 'sex-specific' effects of treatment. These 'sex-specific' effects could be spurious or could be real but not show interactions due to low statistical power. To distinguish these possibilities, I describe permutation tests, which provide an intuitive way to determine if a pattern of observations differs from what would be expected due to chance. For this dataset, assigning sex at random often generates more 'sex-specific' effects than the real data, demonstrating that there is little evidence of sex differences. Next, I simulate an RNA sequencing dataset that includes genes modelled to have sex-specific effects of a condition. As expected, analysis of this simulated dataset yields both significant interactions and sex-specific effects in sex-stratified analyses. While stratified analyses detect a higher number of sex-specific effects than the analysis of interactions, they erroneously identify genes not modelled to show sex-specific effects more often than interactions. A permutation test confirms that the number of sex-specific effects observed in the simulated dataset is greater than expected due to chance. Permutation tests can be applied to omics studies of sex differences, simultaneously providing (i) a clear and simple demonstration of the problems of sex-stratified analyses, and (ii) additional evidence of sex-specific effects where these are present. R code is provided for permutations, simulations, and plots to visualize potential sex-specific effects, which can be adapted to other types of data.

Female↗
PubMed2024

Sex differences in MAGEL2 gene promoter methylation in high functioning autism - trends from a pilot study using nanopore Cas9 targeted long read sequencing.

BACKGROUND: MAGEL2 is an autism susceptibility gene whose deficiency has been associated with autism-related behaviors in animal models and in syndromic human autism spectrum disorders (ASDs) such as Schaaf-Yang syndrome, but has not been studied in the broader autism spectrum. Given the capabilities of long-read sequencing technologies, this pilot study used a targeted nanopore sequencing approach to simultaneously examine MAGEL2 DNA sequence and methylation in adults with high-functioning autism (HFA) compared to neurotypical controls (NC). METHODS: Using DNA extracted from peripheral blood, Cas9-targeted nanopore DNA sequencing was used to analyze MAGEL2, including its entire regulatory construct (chr15:23639316-23651466), for sequence variation and 5-methyl-cytosine (5mC) modification in a cohort of adults with HFA compared to sex- and age-matched NC. Given the known sex differences in ASD and MAGEL2 KO animal models, results were further analyzed by sex. RESULTS: 20 adults with HFA (10 males, 10 females) and 20 NC were included. While there were no overall differences in MAGEL2 DNA sequence and 5mC modification between HFA and NC, we found a significant difference in MAGEL2 gene promoter methylation between males and females with HFA and NC of both sexes, with HFA males tending to show hypomethylation in a 300&#xa0;bp long differentially methylated region (chr15:23647640-23647939) around the MAGEL2 transcription start site. CONCLUSIONS: In this pilot study utilizing nanopore Cas9 targeted DNA sequencing, significant sex-specific differences in MAGEL2 gene promoter methylation were identified in male adults with HFA in comparison to control groups, suggesting the potential for sex-specific epigenetic differences. However, further replication in larger cohorts is required to validate these findings.

Humans↗
PubMed2025

Sex differences in the developing human cortex intersect with genetic risk of neurodevelopmental disorders.

Autism is highly heritable and diagnosed more frequently in males than females. To identify neurodevelopmental processes that might present sex-biased vulnerability, we generated transcriptomic and epigenomic profiles of cell types present in the prenatally developing human cerebral cortex of 27 males and 21 females. By intersecting sex-biased molecular signatures and genes with de novo mutations in male and female autistic probands, we reveal two points of vulnerability contributing to the sex-biased penetrance in neurodevelopmental disorders (NDDs). First, we show that NDD risk genes are biased towards higher expression in females, identifying the NDD gene MEF2C as a critical transcription factor for female-biased expression. Second, we identify a significant contribution of X chromosome genes to NDD pathobiology. We construct a gene regulatory map of X-linked risk genes to enable functional studies of genetic variants that likely disrupt gene expression in the developing brains of autistic males. Together, these results point towards an outsized contribution of the X-chromosome to both the origin of sex differences in the developing human cortex and NDD vulnerability. We propose a model where female-biased vulnerability is driven by coding variation within genes while male-biased vulnerability is driven by noncoding variation in regulatory elements that affect gene expression.

Sex differences↗
PubMed1979

Sex differences in feelings attributed to a woman in situations involving coercion and sexual advances.

This study investigated sex differences of feelings attributed to a woman in situations involving varying degrees of coercion and sexual advances. Sixteen vignettes (12 dealing with sex and coercion, 4 dealing with coercion only) were rated on 17 semantic differential scales by 59 undergraduates (44 females, 15 males) and 45 graduate students (18 females, 27 males). The 16 vignettes yielded factors of Sexual Flattery/Overtures, Sexual Aggressiveness, and Violence. Factor analyses of the 17 semantic differential scales yielded factors of Helplessness, Aversiveness, and Threat. High agreement was found between males and females in both the graduate and undergraduate samples on the relative intensity of feelings attributed to the woman across the sex/coercion vignettes for the three dimensions of Helplessness, Aversiveness, and Threat. Even more importantly, systematic differences between males and females on intensity of attributed feelings across the semantic differential factors were independently replicated using the graduate and undergraduate samples. Analyses of variance revealed that males showed significantly greater attributions on the factors Helplessness and Threat on scenes mainly dealing with sexual flattery/overtures, whereas they showed significantly less attributions on the factor Aversiveness on scenes dealing with sexual aggressiveness and rape. In short, while there was strong agreement between men and women, there were also replicated significant systematic differences with men overestimating the psychological impact of less intense incidents and underestimating the psychological impact on women of more intense incidents.

Attitude↗