Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sex difference”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1981

[The measurement of individual differences in interpersonal cognitive structure (6): Age and sex differences of perceivers (author's transl)].

The purpose of the present study was to examine age and sex differences in "implicit personality theories (IPT)." Forty-four undergraduates and 77 junior high school students served as subjects in personality perception as obtained by the Repertory Grid method. Responses were analyzed by means of Carroll and Chang's INDSCAL model. The results were: (a) The dimensional structure of IPT for the older subjects were more complicated than that for the younger ones; and (b) for the younger subjects, males perceived role persons in less differentiated manners than did females.

Adolescent↗
PubMed1993

[Sex differences in the grooming parameters in rat ontogeny].

The analysis of sex differences in the total amount of grooming movements showed that sex differences first appeared in the 2nd month of rats' life because of great increase of grooming movements in females. During the 1st month of immature rat life sex differences were observed in the rate of increase of frequency of grooming movements and of their duration.

Aging↗
PubMed2006

Sex differences in morphine-induced analgesia of visceral pain are supraspinally and peripherally mediated.

Increasing evidence suggests there is a sex difference in opioid analgesia of pain arising from somatic tissue. However, the existence of a sex difference in visceral pain and opioid analgesia is unclear. This was examined in the colorectal distention (CRD) model of visceral pain in the current study. The visceromotor response (vmr) to noxious CRD was recorded in gonadally intact male and female rats. Subcutaneous injection of morphine dose-dependently decreased the vmr in both groups without affecting colonic compliance. However, morphine was significantly more potent in male rats than females. Because systemic morphine can act at peripheral tissue and in the central nervous system (CNS), the source of the sex difference in morphine analgesia was determined. The peripherally restricted mu-opioid receptor (MOR) antagonist naloxone methiodide dose-dependently attenuated the effects of systemic morphine. Systemic administration of the peripherally restricted MOR agonist loperamide confirmed peripherally mediated morphine analgesia and revealed greater potency in males compared with females. Spinal administration of morphine dose-dependently attenuated the vmr, but there was no sex difference. Intracerebroventricular administration of morphine also dose-dependently attenuated the vmr with significantly greater potency in male rats. The present study documents a sex difference in morphine analgesia of visceral pain that is both peripherally and supraspinally mediated.

Analgesics, Opioid↗
PubMed2005

No sex difference in yolk steroid concentrations of avian eggs at laying.

Yolk steroids of maternal origin have been proposed to influence genetic sex determination in birds, based on sex differences in yolk steroid concentrations of peafowl eggs incubated for 10 days. More recent reports dispute this proposal, as yolk steroids in eggs incubated for 3 days do not show such sex differences. To date, research examining this phenomenon has only analysed incubated eggs, although sex in avian species is determined before incubation begins. This may be a serious methodological flaw because incubation probably affects yolk steroid concentrations. Therefore, we investigated sex differences in yolk steroid concentrations of unincubated avian eggs. We withdrew yolk for steroid analysis from fresh, unincubated Japanese quail (Coturnix japonica) eggs by biopsy, and then incubated those eggs for 10 days, after which we harvested the embryonic material for genetic sexing and the incubated yolk for further steroid analysis. We found no sex differences in fresh Japanese quail eggs; however, sex differences were apparent in yolk steroids by day 10 of incubation, when female eggs had significantly more oestrogen in relation to androgen than male eggs. Concentrations of all yolk androgens decreased dramatically between laying and day 10 of incubation, whereas oestradiol (E2) concentrations increased marginally. Thus, yolk concentrations of androgens and E2 do not appear critical for avian sex determination.

Animals↗
PubMed1986

A hormonal basis for sex differences in the self-grooming of rats.

The self-grooming behavior of prepubescent male and female rats is described. Sex differences were observed in components of grooming addressed to the genitals, but not in other aspects of grooming. A hormonal basis for the sex difference was examined in two experiments. When females were injected with testosterone propionate (TP) on the day of birth, their subsequent grooming was found to be no different from that of control-treated females. However, males and females gonadectomized at weaning and treated daily with TP each performed significantly more genital self-grooming than oil-treated controls. There were no sex differences in gonadectomized, oil-treated rats, and sex differences in response to TP were limited to greater responsiveness of females to a 50-micrograms, but not 200-micrograms, TP dose. These results lead to the conclusion that sex differences in self-grooming can be accounted for primarily by differences in testosterone availability during the peripubertal period.

Animals↗
PubMed1998

Examining sex differences in the impact of anticipated and actual life events.

To examine for sex differences in anticipated and actual impact of pleasant and unpleasant life events in a non-clinical group, a cohort of 164 subjects was initially assessed in 1978 in their last year of teacher training. They were asked to participate in the life events study in 1979, and 97 subjects complied, providing us with ratings of impact of 'anticipated' life events. In 1983, the original cohort assessed the 'actual' impact of events experienced over the previous year. They also completed measures of neuroticism, state and trait depression, self-esteem, parental bonding and dependency in 1978, and gender roles in 1983. Some analyses for sex differences were undertaken for the entire cohort, with more extensive analyses for the 97 who had completed the 1979 (as well as 1978 and 1983) assessments. There were no sex differences in the scores for 'anticipated' or 'actual' impact of pleasant life events, or for 'anticipated' unpleasant life events. However, there was a statistically significant sex difference between 'actual' unpleasant life event scores, with females rating events as being either more pleasurable or unpleasant than males at both collection points. The actual impact of pleasant events was associated with higher dependency and masculinity scores, whilst unpleasant events was associated with higher dependency for females and higher parental overprotection and dependency scores for males.

Affective Symptoms↗
PubMed2004

Sex differences in performance over 7 years on the Wechsler Intelligence Scale for Children--Revised among adults with intellectual disability.

BACKGROUND: The aim of this study was to explore changes related to sex differences on the Wechsler Intelligence Scale for Children - Revised (WISC-R) subtest performance over a 7-year interval in middle-aged adults with intellectual disability (ID). Cognitive sex differences have been extensively studied in the general population, but there are few reports concerning individuals with ID. Sex differences are of current relevance to actively debated issues such as cognitive changes during menopause and risk for Alzheimer's disease. Given that hormonal effects on cognition have been observed in the general population, particularly in areas such as visuospatial processing, and individuals with Down's syndrome (DS) have been reported to be hormonally and reproductively atypical, we analysed our data to allow for the possibility of an aetiology-specific profile of sex differences for these adults. METHODS: The WISC-R subtests were administered in a longitudinal study, as part of a more comprehensive test battery, at least twice within 7 years. Participants were 18 females with ID without DS [age at first test time (time 1): mean = 40.5; IQ: mean = 59.3], 10 males with ID without DS (age at time 1: mean = 42.4; IQ: mean = 59.4), 21 females with DS (age at time 1: mean = 37.9; IQ: mean = 51.6), and 21 males with DS (age at time 1: mean = 40.3; IQ: mean = 54.3). All participants were in the mild to moderate range of ID and were displaying no changes suggestive of early dementia. RESULTS: Females, regardless of aetiology of ID, exhibited a robust superiority on the coding subtest, which parallels the widely reported difference among adults in the general population. Additionally, there was a decline in overall performance during the 7-year study interval, particularly on the verbal subscale subtests, but there was no evidence of sex-differentiated decline. There were also marginal sex by aetiology interactions on the object assembly and block design subtests, suggesting that males with unspecified ID might perform better than their female peers, but among adults with DS, females might do better than males. CONCLUSIONS: This study supports the presence of cognitive sex differences in the population with ID as indicated by female superiority on the WISC-R coding subtest. Extending this observation to adults with ID has implications for explanations of female advantage on this task, which now have to account for its presence among individuals with a broader range of intellectual capabilities, more atypical developmental histories and more varied genotypes than previously considered. Trends towards sex by aetiology interactions on the two visuoconstructive subtests, while marginal, were sufficient to warrant continued consideration of the idea of a distinct profile of sex differences for adults with DS and to justify looking at the effects of sex separately within different aetiologies of ID.

Adult↗
PubMed2003

Sex differences in rabbit masseter muscle function.

The proportions of fibers of different phenotypes in the rabbit masseter muscle differ strikingly in adult males and females. Muscles from females contain similar proportions of small fibers that express both the slow/beta and cardiac alpha myosin heavy chain (MyHC) isoforms and larger fibers containing the IIa MyHC isoform. In muscles from males, nearly 80% of fibers are of the IIa phenotype. To evaluate the functional significance of these sex differences, we used finely graded intramuscular microstimulation to study the contractile properties of masseter motor units in >6-month-old male and female rabbits. Twitch forces and torques in males were significantly greater in magnitude than those of females. Greater proportions of units that produced larger forces/torques were encountered in the males. The same motor units produced force or torque more rapidly in males than in females, principally because units in which twitch rise times were >22 ms were found only in females. The forces applied to the mandible and the torques generated about the right mandibular condyle were studied during cortically evoked rhythmic activation of the masticatory muscles. The overall range of torque rise times and the magnitudes of the peak torques did not differ between sexes. The mean rise time was significantly shorter and the mean peak torque was significantly greater in males. We conclude that sex differences in fiber phenotype proportions are reflected in sex differences in motor unit properties and in the function of these motor units during rhythmic activation.

Animals↗
PubMed2002

Sex differences in jealousy: evolutionary mechanism or artifact of measurement?

Two studies are presented that challenge the evidentiary basis for the existence of evolved sex differences in jealousy. In opposition to the evolutionary view, Study I demonstrated that a sex difference in jealousy resulting from sexual versus emotional infidelity is observed only when judgments are recorded using a forced-choice response format. On all other measures, no sex differences were found; both men and women reported greater jealousy in response to sexual infidelity. A second study revealed that the sex difference on the forced-choice measure disappeared under conditions of cognitive constraint. These findings suggest that the sex difference used to support the evolutionary view of jealousy (e.g., D. M. Buss, R. Larsen, D. Westen, & J. Semmelroth, 1992; D. M. Buss et al., 1999) likely represents a measurement artifact resulting from a format-induced effortful decision strategy and not an automatic, sex-specific response shaped by evolution.

Adult↗
PubMed2005

A meta-analysis of sex differences prevalence, incidence and severity of osteoarthritis.

OBJECTIVE: To resolve uncertainty regarding sex differences in osteoarthritis (OA) by performing a meta-analysis of sex differences in OA prevalence, incidence and severity. METHODS: Standard search strategies for population-based studies of OA providing sex-specific data. Random effects meta-analysis to provide pooled male vs female risk and rate ratios for prevalent and incident OA, and standardized mean differences (SMD) for OA severity. Meta-regression was used to investigate sources of heterogeneity. RESULTS: Males had a significantly reduced risk for prevalent OA in the knee [Risk Ratio (RR) 0.63, 95% CI 0.53-0.75] and hand [RR 0.81, 95% CI 0.73-0.90] but not for other sites. Males aged <55 years had a greater risk of prevalent cervical spine OA [RR 1.29, 95% CI 1.18-1.41]. Males also had significantly reduced rates of incident OA in the knee [Incidence Rate Ratio (IRR) 0.55, 95% CI 0.32-0.94] and hip [IRR 0.64, 95% CI 0.48-0.86], with a trend for hand [IRR 0.65, 95% confidence interval (CI) 0.35-1.20]. Females, particularly those > or = 55 years, tended to have more severe OA in the knee but not other sites. Heterogeneity in the estimates of sex differences in prevalence was substantially explained by age and other study design factors including method of OA definition. CONCLUSIONS: The results demonstrate the presence of sex differences in OA prevalence and incidence, with females generally at a higher risk. Females also tend to have more severe knee OA, particularly after menopausal age. The site differences indicate the need for further studies to explore mechanisms underlying OA.

Age Factors↗
PubMed2004

Exposure to bisphenol A during gestation and lactation causes loss of sex difference in corticotropin-releasing hormone-immunoreactive neurons in the bed nucleus of the stria terminalis of rats.

It has been suspected that endocrine disrupters induce abnormal differentiation and development of reproductive organs. In the present study, we examined whether exposure to bisphenol A (BPA), a known endocrine disrupter, during gestation and lactation affects sex difference in the number of corticotropin-releasing hormone-immunoreactive neurons (CRH neurons) in the preoptic area (POA) and the bed nucleus of the stria terminalis (BST). For that purpose, pregnant female Wistar rats (n=8-11 per treatment group) were treated with either 0.1% ethanol (control group) or 10 mg/l BPA (BPA group) dissolved in their drinking water until their offspring were weaned. In the control group, we confirmed a previous report that the POA of female rats contained significantly more CRH neurons than that of male rats (p<0.05). This significant sex difference was also evident in the BPA group, indicating that BPA exposure used in the present study had no effect on the sex difference in CRH neurons in the POA. We also found in the control group that the BST of female rats contained significantly more CRH neurons (p<0.05) than that of male rats. However, this significant sex difference was not observed in the BPA group (p>0.05), suggesting that BPA exposure affected the sex difference in CRH neurons in the BST. Since there was no statistically significant difference in the number of CRH neurons between the control and the BPA group, irrespective of the sex, the results suggested that a loss of sex difference in CRH neurons was due to both an increase in CRH neurons in male rats and a decrease in CRH neurons in female rats. The present study indicates that there is a significant sex difference in the number of CRH neurons in the BST as well as in the POA and that exposure to BPA during gestation and lactation causes a loss of this sex difference in the rat BST, but not in the POA. We suggest that CRH neurons in the BST are more susceptible to endocrine disrupters than those in the POA, irrespective of the sex.

Animals↗
PubMed1988

Susceptibility to sensitization. I. Sex differences in the enduring effects of chronic D-amphetamine treatment on locomotion, stereotyped behavior and brain monoamines.

There are sex differences in a number of behavior elicited by amphetamine (AMPH). The purpose of the present experiment was to determine if there are also sex differences in the sensitization of the locomotor activity and stereotypy produced by repeated intermittent AMPH treatment, and whether this is accompanied by sex differences in dopamine (DA) metabolism. It was found that female rats showed greater and more rapid sensitization of locomotor activity and stereotyped behavior than males. In addition, prior exposure to AMPH was associated with an elevation in resting striatal dihydroxyphenlacetic acid (DOPAC) to DA ratios in female, but not male rats, suggesting a sex difference in one neurochemical correlate of sensitization. As a group, males were more variable and heterogeneous in their response to repeated AMPH treatment, because they were divisible into two neurochemically distinct subgroups on the basis of their change in behavior and females were not. This heterogeneity may make it more difficult to identify neurochemical correlates of sensitization in males. It is suggested that there is a sex difference in the responsiveness of brain DA systems to repetitive activation, and this contributes to individual variation in the susceptibility to sensitization.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Sex differences in human brain morphometry and metabolism: an in vivo quantitative magnetic resonance imaging and positron emission tomography study on the effect of aging.

BACKGROUND: There are significant age and sex effects in cognitive ability and brain disease. However, sex differences in aging of human brain areas associated with nonreproductive behavior have not been extensively studied. We hypothesized that there would be significant sex differences in aging of brain areas that subserve speech, visuospatial, and memory function. METHODS: We investigated sex differences in the effect of aging on human brain morphometry by means of volumetric magnetic resonance imaging and on regional cerebral metabolism for glucose by positron emission tomography. In the magnetic resonance imaging study, we examined 69 healthy right-handed subjects (34 women and 35 men), divided into young (age range, 20 to 35 years) and old (60 to 85 years) groups. In the positron emission tomography study, we investigated 120 healthy right-handed subjects (65 women and 55 men) aged 21 to 91 years. RESULTS: In the magnetic resonance imaging study, age-related volume loss was significantly greater in men than women in whole brain and frontal and temporal lobes, whereas it was greater in women than men in hippocampus and parietal lobes. In the positron emission tomography study, significant sex differences existed in the effect of age on regional brain metabolism, and asymmetry of metabolism, in the temporal and parietal lobes, Broca's area, thalamus, and hippocampus. CONCLUSIONS: We found significant sex differences in aging of brain areas that are essential to higher cognitive functioning. Thus, our findings may explain some of the age-sex differences in human cognition and response to brain injury and disease.

Adult↗
PubMed1981

Special capabilities of the sexes: differences in the molecular repertoire of mammal brain, heart and skeletal muscle.

World records for men's and women's (anaerobic) 200 meter dash are 19.67 and 21.9 seconds respectively. Here the transphosphorylation mechanisms are operative and not the glycolytic anaerobic and aerobic ones. The purpose of this paper is to try to find molecular differences during the neuro-muscular sexual differentiation in the Wistar rat. Creatine kinase (CPK: EC 2.7.3.2) as model transphosphorylase and the protein synthesis pattern, determined from the post 125,000 x g cytosol fraction of the brain, heart and masseter muscle, were chosen as molecular monitors. The CPK specific activity profiles showed differences among tissues and sexes. In rats with similar weights between 200 and 320 g, the epigenetic control of protein synthesis in the studied tissues, reflected genome differential activation depending on sex and age. The electrophoretograms differed in regard to the number and position of the protein bands of homologous tissues of different sexes. As an original finding, against the generally accepted criterion (the brain fundamentally synthesizes BB-CPK isoenzyme), MB-CPK and MM-CPK isoenzymes appeared in the brain of both sexes. The molecular sexual differences in the studied tissues determine functional and anatomical differences.

Animals↗
PubMed1995

Initial sex differences in neuron growth and survival within an avian song nucleus develop in the absence of afferent input.

Only male zebra finches (Poephila guttata) sing, and nuclei implicated in song behavior exhibit marked sex differences in neuron number. In the robust nucleus of the anterior neostriatum (RA), these sex differences develop because more neurons die in young females than in males. However, it is not known whether the sexually dimorphic survival of RA neurons is a primary event in sexual differentiation or a secondary response to sex differences in the number of cells interacting trophically with RA neurons. In particular, since sexual differentiation of the RA parallels the development of dimorphisms in the numbers of neurons providing afferent input from the lateral magnocellular nucleus of the anterior neostriatum (IMAN) and the high vocal center (HVC), it has been hypothesized that sex differences in the size of these afferent populations trigger differential RA neuron survival and growth. To test this hypothesis, we lesioned either the IMAN or both the IMAN and HVC unilaterally in 12-day-old male and female zebra finches. Subsequently, RA cell death and RA neuron number and size were measured. Unilateral IMAN lesions increased cell death and decreased neuron number and size within the ipsilateral RA of both sexes. However, even in the IMAN-lesioned hemisphere, these effects were less pronounced in males than in females, so that by day 25 the volume, number, and size of neurons were sexually dimorphic in both the contralateral and ipsilateral RA. Similarly, the absence of both IMAN and HVC afferents did not prevent the emergence of sex differences in the number and size of RA neurons by 25 days posthatching. We conclude that these sex differences within the RA are not a secondary response to dimorphisms in the numbers of IMAN or HVC neurons providing afferent input.

Afferent Pathways↗
PubMed1983

Sex differences in strength - some observations on their variability.

One hundred and twelve datasets, which allowed a direct comparison of the strengths of men and women, were located in the published literature. For each of these, three indices of sex difference were calculated: the ratio of the mean female strength to the mean male (F/M), the proportion of the total variance in strength attributable to sex (R(2)) and the "percentage of chance encounters between members of the opposite sex in which the female is stronger" (%CEFS). Sex difference was shown to be very variable, the values of these indices being both task and population specific. An experiment was conducted in which male and female subjects gripped and turned knurled cylindrical handles of 10, 30, 50 and 70 mm diameter. Maximum isometric torques were recorded. Sex differences became more pronounced as handle size increased. The optimal handle-size was 50 mm for both male and female subjects. Data concerning whole body exertion (Pheasant et al, 1982) were also analysed for sex differences. It was concluded that very similar tests of strength could exhibit very different levels of sex difference. The task or equipment designer should not make assumptions about sex differences in strength for a particular action, but should rely on empirical investigation.

Journal Article↗
PubMed2006

Sex differences in outcome and recovery for schizophrenia and other psychotic and nonpsychotic disorders.

OBJECTIVE: It is generally believed by the field of psychiatry that women with schizophrenia have better outcomes and higher rates of recovery than their male counterparts, because many studies on the topic support this finding. Fewer data are available to assess potential sex differences among individuals with other psychotic disorders. This study used longitudinal data on sex differences previously unavailable to the field to examine long-term global outcome, potential recovery, course of illness, and rehospitalization for schizophrenia, other psychotic disorders, and nonpsychotic disorders. METHODS: A total of 239 young psychiatric patients (mean age of 23.4 years) were assessed prospectively at the index hospitalization and then followed over 15 years at five follow-up points (at a mean of two, 4.5, 7.5, ten, and 15 years). The sample consisted of 69 patients with schizophrenia, 56 with other psychotic diagnoses, and 114 with nonpsychotic psychiatric disorders. RESULTS: Sex differences in outcome were found for both patients with schizophrenia and those with other psychotic disorders, with women consistently showing better functioning over time, more frequent periods of good functioning and periods of recovery, less likelihood of uniformly poor outcome, and fewer and shorter rehospitalizations. Unlike both groups of patients who were psychotic, the patients with nonpsychotic disorders showed no significant sex differences in outcome. CONCLUSIONS: Both longitudinally and at each individual follow-up point, the data suggest that women with schizophrenia and with other types of psychotic disorders generally show better outcome than men with similar diagnoses. The sex differences in outcome for patients with schizophrenia were consistent over time. However, these sex differences were only moderate in size compared with the much larger difference in outcome between the diagnostic groups. The longitudinal data add a new dimension to previous research and suggest that sex differences in outcome are not specific to patients with schizophrenia but rather occur among patients with psychotic disorders in general.

Adult↗
PubMed1997

Sex differences in posttraumatic stress disorder.

BACKGROUND: Epidemiologic surveys in the general population documented a higher rate of posttraumatic stress disorder (PTSD) in women than in men. To date, the finding has received little scientific attention. This study examines the extent to which sex differences in PTSD might be explained by previously identified risk factors and whether the sex difference in PTSD varied by age at exposure to traumatic events. METHODS: The NIMH-DIS (NIMH Diagnostic Interview Schedule, Version III Revised) was used to measure DSM-IIIR disorders in a random sample of 1007 young adults. Cox proportional hazards models were used to estimate changes in the hazards ratio for PTSD associated with sex when potential risk factors were included. RESULTS: Lifetime prevalence of exposure to traumatic events and number of traumatic events did not vary by sex. The prevalence of PTSD was higher for women than for men exposed to traumatic events (hazards ratio, 2.3; 95% confidence interval, 1.5-3.6). Preexisting anxiety disorders or major depressive disorders played a part in the observed sex difference in PTSD. Family history of anxiety disorder and early separation from parents, although significant risk factors for PTSD in subjects of both sexes, were unrelated to the sex difference in PTSD. The sex difference in PTSD was markedly greater if exposure occurred in childhood than later on. CONCLUSIONS: Posttraumatic stress disorder is more likely to develop in females than in males after exposure to a traumatic event. Susceptibility to PTSD in females might be greater in childhood than after age 15 years. Explanations of the sex difference might involve characteristics of individuals and of the traumatic experiences.

Adult↗