Excess Of Males Research Articles

Ancestral Origins and Admixture History of Kazakhs.

Kazakh people, like many other populations that settled in Central Asia, demonstrate an array of mixed anthropological features of East Eurasian (EEA) and West Eurasian (WEA) populations, indicating a possible scenario of biological admixture between already differentiated EEA and WEA populations. However, their complex biological origin, genomic makeup, and genetic interaction with surrounding populations are not well understood. To decipher their genetic structure and population history, we conducted, to our knowledge, the first whole-genome sequencing study of Kazakhs residing in Xinjiang (KZK). We demonstrated that KZK derived their ancestries from 4 ancestral source populations: East Asian (∼39.7%), West Asian (∼28.6%), Siberian (∼23.6%), and South Asian (∼8.1%). The recognizable interactions of EEA and WEA ancestries in Kazakhs were dated back to the 15th century BCE. Kazakhs were genetically distinctive from the Uyghurs in terms of their overall genomic makeup, although the 2 populations were closely related in genetics, and both showed a substantial admixture of western and eastern peoples. Notably, we identified a considerable sex-biased admixture, with an excess of western males and eastern females contributing to the KZK gene pool. We further identified a set of genes that showed remarkable differentiation in KZK from the surrounding populations, including those associated with skin color (SLC24A5, OCA2), essential hypertension (HLA-DQB1), hypertension (MTHFR, SLC35F3), and neuron development (CNTNAP2). These results advance our understanding of the complex history of contacts between Western and Eastern Eurasians, especially those living or along the old Silk Road.

Incidence trend of neuroendocrine tumors and disparities by sex and race/ethnicity in adults from the United States, 2000-2020.

The incidence of neuroendocrine tumors (NET) has been increasing globally for several decades. The objective of the study was to examine the most recent trend in the incidence of NET as well as disparities by sex and race/ethnicity in adults in the USA. Patients with NET aged ≥20 years were identified from the SEER 22 Registries from 2000 to 2020. The age-adjusted incidence rate was calculated for overall NET and by primary site. The incidence trend was assessed by annual percent change. Disparities by sex and race/ethnicity were examined using the incidence rate ratio. Age-adjusted incidence rate of overall NET in adults was 9.39 per 100 000 in 2000-2020. The incidence rate increased from 2000 but reached a plateau with no significant change since 2015. The lung and bronchus, small intestine, and rectum were the most common primary sites. Sex and racial/ethnic disparities in NET incidence varied by primary sites. For example, there was a female excess in NET of the lung and bronchus, stomach, and appendix; and there was a male excess in the small intestine, pancreas, colon, rectum and other/unknown NET. Compared to non-Hispanic white, non-Hispanic black had higher incidences of stomach, small intestine, liver, pancreas, colon, rectum, and other/unknown NET; they had lower incidences of lung and bronchus, and appendix NET than non-Hispanic white. Age-adjusted incidence rate of overall NET has reached a plateau since 2015. However, there were sex and racial/ethnic disparities in such incidence, which varied depending on the primary site of NET.

The biology of Marchantia polymorpha subsp. ruderalis Bischl. & Boissel. Dub in nature.

Though used as the model liverwort in culture for several decades, the biology of Marchantia polymorpha subsp. ruderalis in nature has never been documented in detail in a single account. Here we synthesize routine field observations documented with hundreds of images of M. ruderalis colonies (or groups) showing sex differentiation over 3 years on two populations of M. ruderalis after major heathland fires in 2020. Initial post-fire establishment is from airborne spores rather than a spore bank but thereafter spread is via gemmae which have less exacting germination requirements. Young sporelings are highly gemmiferous but gemmae production becomes less frequent after sex organ formation. Over the course of a year there are up to three waves of carpocephalum production with the overwhelming majority of antheridiophores appearing 2-3 months ahead of the archegoniophores though no differences in growth rates were apparent between male and female thalli. Spermatozoids are produced almost continuously throughout the year, whilst sporophyte maturation is restricted to the summer months. Because of the asynchrony between antheridiophore and archegoniophore production a 1:1 sex ratio is only apparent over this period. The spring months see an excess of males with more females in the summer. An almost 100% fertilization rate, with fertilization distances of up to 19 m far exceeding those in all other bryophytes, is attributed to vast spermatozoid production for most of the year, dispersal on surface oil films between thalli and highly effective intra-thallus spermatozoid transport via the pegged-rhizoid water-conducting system. Archegoniophores do develop on female-only populations but have shorter stalks than those where fertilization has occurred. Eventual disappearance post fires is attributed to a fall in topsoil nutrient levels preventing new sporeling establishment and competition from Ceratodon purpureus and Polytrichum spp. A major drought in the summer of 2022 almost wiped out the heathland Marchantia populations but all the other bryophytes survived.

A cytogenetic Study of Down’s Syndrome in Iraqi Population

Down’s syndrome is the most common type of chromosomal abnormality found in neonates. It is associated with characteristic abnormal facial features and mental retardation. However, clinical diagnosis is not sufficient to confirm the disease. Classical karyotyping has long been used as diagnostic tool for confirming Down’s syndrome. The present study was conducted to confirm the cytogenetic composition of individuals suspected with Down’s syndrome after the preliminary clinical diagnosis in Basra, Iraq. Karyotype analysis was carried out for 249 suspected cases of Down’s syndrome. 249 patients were confirmed to have Down’s syndrome after cytogenetic tests. Nearly 90% of these patients had pure trisomy 21 and about 5% of cases had translocations. Less than 4% of cases were reported having mosaic trisomy and only 1.4% patients carried additional chromosomal abnormalities. In our study, the disease showed significant gender bias, with an excess of males than females (sex ratio was 1.39). The identification of specific chromosomal abnormalities in different variants of Down’s syndrome patients work as first step towards improving their quality of life. The study also provides the basic information required to forecast the various complications associated with Down’s syndrome.

Sex ratio at birth in Canada: a male excess in Quebec

Sex ratio at birth in Canada: a male excess in Quebec

Sex differences in hepatitis A incidence rates-a multi-year pooled-analysis based on national data from nine high-income countries.

Possible sex differences in hepatitis A virus (HAV) incidence rates in different age groups are not well documented. We aimed to obtain stable pooled estimates of such differences based on data from a number of high-income countries. We obtained data on incident cases of HAV by sex and age group over a period of 6-25 years from nine countries: Australia, Canada, Czech Republic, Finland, Germany, Israel, Netherland, New Zealand and Spain. Male to female incidence rate ratios (IRR) were computed for each year, by country and age group. For each age group, we used meta-analytic methods to combine the IRRs. Meta-regression was conducted to estimate the effects of age, country, and time period on the IRR. A male excess in incidence rates was consistently observed in all age groups, although in the youngest and oldest age groups, where the numbers tended to be lower, the lower bounds of the 95% confidence intervals for the IRRs were less than one. In the age groups <1, 1-4, 5-9, 10-14, 15-44, 45-64 and 65+, the pooled IRRs (with 95% CI) over countries and time periods were 1.18 (0.94,1.48), 1.22 (1.16,1.29), 1.07 (1.03,1.11), 1.09 (1.04,1.14), 1.46 (1.30,1.64), 1.32 (1.15,1.51) and 1.10 (0.99,1.23) respectively. The excess HAV incidence rates in young males, pooled over a number of countries, suggest that the sex differences are likely to be due at least in part to physiological and biological differences and not just behavioral factors. At older ages, differential exposure plays an important role. These findings, seen in the context of the excess incidence rates in young males for many other infectious diseases, can provide further keys to the mechanisms of the infection.

Clustering of the Adult Population According to Behavioural Health Risk Factors as the Focus of Community-Based Public Health Interventions in Poland.

Effective lifestyle health promotion interventions require the identification of groups sharing similar behavioural risk factors (BRF) and socio-demographic characteristics. This study aimed to identify these subgroups in the Polish population and check whether local authorities' health programmes meet their needs. Population data came from a 2018 question survey on a random representative sample of 3000 inhabitants. Four groups were identified with the TwoStep cluster analysis method. One of them ("Multi-risk") differed from the others and the general population by a high prevalence of numerous BRF: 59% [95% confidence interval: 56-63%] of its members smoke, 35% [32-38%] have alcohol problems, 79% [76-82%] indulge in unhealthy food, 64% [60-67%] do not practice recreational physical activity, and 73% [70-76%] are overweight. This group, with an average age of 50, was characterised by an excess of males (81% [79-84%]) and people with basic vocational education (53% [50-57%]). In 2018, only 40 out of all 228 health programmes in Poland addressed BRF in adults; only 20 referred to more than one habit. Moreover, access to these programmes was limited by formal criteria. There were no programmes dedicated to the reduction of BRF exclusively. The local governments focused on improving access to health services rather than on a pro-health change in individual behaviours.

The presence of a guard vicariously drives split sex ratios in a facultatively social bee.

Split sex ratios provide broad insights into how reproductive strategies evolve, and historically have special relevance to the evolution of eusociality. Yet almost no attention has been directed to situations where split sex ratios may potentially decrease the payoffs for worker-like behaviour, increasing selective thresholds for eusociality. We examined sex ratios in a facultatively social colletid bee, Amphylaeus morosus. Sex ratios in this bee vary strongly with the presence of a nest guard and in a pattern that does not conform to assumptions of previous models in which split sex ratios facilitate altruism. While the production of daughters was constant across social and solitary nests, mothers produced more brood when a non-reproductive guard was present, but these extra brood were all male. This leads to split sex ratios, vicariously driven by guards that are unable to manipulate sex ratios in their favour. Importantly, if guarding becomes more common in a population this would lead to an excess of males and lower the genetic value of these extra males to guards, effectively putting a brake on selection for worker-like behaviour.

Editors' Selections from Relevant Scientific Publications

Editors' Selections from Relevant Scientific Publications

COVID-19 onset reduced the sex ratio at birth in South Africa.

The sex ratio at birth (defined as male/(male+female) live births) is anticipated to approximate 0.510 with a slight male excess. This ratio has been observed to decrease transiently around 3-5 months following sudden unexpected stressful events. We hypothesised that stress engendered by the onset of the COVID-19 pandemic may have caused such a decrease in South Africa 3-5 months after March 2020 since in this month, South Africa reported its first COVID-19 case, death and nationwide lockdown restrictions were instituted. We used publicly available, recorded monthly live birth data from Statistics South Africa. The most recent month for which data was available publicly was December 2020. We analysed live births for a 100-month period from September 2012 to December 2020, taking seasonality into account. Chi-squared tests were applied. Over this 100-month period, there were 8,151,364 live births. The lowest recorded monthly sex ratio at birth of 0.499 was in June 2020, 3 months after March 2020. This June was the only month during this period where the sex ratio inverted i.e., fewer male live births occurred. The predicted June 2020 ratio was 0.504. The observed June 2020 decrease was statistically significant p=0.045. The sex ratio at birth decreased and inverted in South Africa in June 2020, for the first time, during the most recent 100-month period. This decline occurred 3 months after the March 2020 onset of COVID-19 in South Africa. As June 2020 is within the critical window when population stressors are known to impact the sex ratio at birth, these findings suggest that the onset of the COVID-19 pandemic engendered population stress with notable effects on pregnancy and public health in South Africa. These findings have implications for future pandemic preparedness and social policy.

Sex disparities in the incidence of 21 cancer types: Quantification of the contribution of risk factors.

Cancer incidence is higher in men than in women at most shared anatomic sites for currently unknown reasons. The authors quantified the extent to which behaviors (smoking and alcohol use), anthropometrics (body mass index and height), lifestyles (physical activity, diet, medications), and medical history collectively explain the male predominance of risk at 21 shared cancer sites. Prospective cohort analyses (n=171,274 male and n=122,826 female participants; age range, 50-71 years) in the National Institutes of Health-AARP Diet and Health Study (1995-2011). Cancer-specific Cox regression models were used to estimate male-to-female hazard ratios (HRs). The degree to which risk factors explained the observed male-female risk disparity was quantified using the Peters-Belson method. There were 26,693 incident cancers (17,951 in men and 8742 in women). Incidence was significantly lower in men than in women only for thyroid and gallbladder cancers. At most other anatomic sites, the risks were higher in men than in women (adjusted HR range, 1.3-10.8), with the strongest increases for bladder cancer (HR, 3.33; 95% confidence interval [CI], 2.93-3.79), gastric cardia cancer (HR, 3.49; 95% CI, 2.26-5.37), larynx cancer (HR, 3.53; 95% CI, 2.46-5.06), and esophageal adenocarcinoma (HR, 10.80; 95% CI, 7.33-15.90). Risk factors explained a statistically significant (nonzero) proportion of the observed male excess for esophageal adenocarcinoma and cancers of liver, other biliary tract, bladder, skin, colon, rectum, and lung. However, only a modest proportion of the male excess was explained by risk factors (ranging from 50% for lung cancer to 11% for esophageal adenocarcinoma). Men have a higher risk of cancer than women at most shared anatomic sites. Such male predominance is largely unexplained by risk factors, underscoring a role for sex-related biologic factors.

Sex-biased admixture and assortative mating shape genetic variation and influence demographic inference in admixed Cabo Verdeans.

Genetic data can provide insights into population history, but first, we must understand the patterns that complex histories leave in genomes. Here, we consider the admixed human population of Cabo Verde to understand the patterns of genetic variation left by social and demographic processes. First settled in the late 1400s, Cabo Verdeans are admixed descendants of Portuguese colonizers and enslaved West African people. We consider Cabo Verde’s well-studied historical record alongside genome-wide SNP data from 563 individuals from 4 regions within the archipelago. We use genetic ancestry to test for patterns of nonrandom mating and sex-specific gene flow, and we examine the consequences of these processes for common demographic inference methods and genetic patterns. Notably, multiple population genetic tools that assume random mating underestimate the timing of admixture, but incorporating nonrandom mating produces estimates more consistent with historical records. We consider how admixture interrupts common summaries of genomic variation such as runs of homozygosity. While summaries of runs of homozygosity may be difficult to interpret in admixed populations, differentiating runs of homozygosity by length class shows that runs of homozygosity reflect historical differences between the islands in their contributions from the source populations and postadmixture population dynamics. Finally, we find higher African ancestry on the X chromosome than on the autosomes, consistent with an excess of European males and African females contributing to the gene pool. Considering these genomic insights into population history in the context of Cabo Verde’s historical record, we can identify how assumptions in genetic models impact inference of population history more broadly.

Differences in sex ratio, tail autotomy, body size and body condition between suburban and forest populations of the cuban endemic lizard Anolis homolechis

Although growing evidence suggests that natural and sexual selection pressures may differ between natural and urban habitats, their consequences in terms of morphological differentiation, extent of sexual dimorphism and sex ratio remain poorly studied. Anolis lizards are an ideal model to study the phenotypic effects of urbanization, as they are well known for the existence of ecomorphs adapted to particular microhabitats. However, so far most studies of urban populations of anoles have considered invasive species and largely focused on males. Here, we compared morphological differentiation, sexual dimorphism and sex ratio between suburban and forest populations of the native A. homolechis, in western Cuba, based on large sample size (n > 800) and a balanced nested design. Overall, both male and female individuals from suburban populations were larger and in better body condition than individuals from forest populations. In addition, evidence of caudal autotomy was more than twice more frequent in suburban populations compared to forest ones, with no sex effect. Habitat type and season of the year had additive effects on sex ratios, with a significant excess of males in suburban habitats and during the non-reproductive season. Accordingly, the extent of sexual dimorphism in size was more pronounced in suburban populations compared to forest ones. Our results suggest that the shape and direction of natural selection may differ between urban and natural populations of anoles.

Patterning of Sexual Violence against Women across US Cities and Counties

Sexual violence against women is a global public health concern; yet, determining its patterning is still largely understudied. An excess of males has emerged as a central concern given that men are the primary perpetrators of violent behavior, particularly against women. However, it is increasingly unclear as to whether an excess or, rather, a shortage of men drives purported negative social outcomes. To address these conflicting expectations, we target data from the U.S. Census and the National Incident-Based Reporting System to explore the patterning of sexual violence against women across cities and counties in the United States. Through the use of generalized linear mixed models, we assess the role of adult sex ratio imbalance, along with measures of gender inequality, on sexual violence. Our results indicate mixed support for competing predictions. Violence does not simply increase by way of male surplus or shortage, but instead with increasing skew in the sex ratio. That is, balanced sex ratios exhibit the lowest rates of violence. However, rates of sexual violence against women increase more quickly with increasing male scarcity and are lowest at low levels of male excess (51%). Thus, our findings are particularly challenging to interpret from a ‘more males = more violence’ framework because violence increases more quickly with female excess and is rarest with a slight male bias in the population. We argue that these results highlight a need to target the specific types of violent behaviors expected to be motivated by partner availability, rather than overly simplistic predictions of male surfeit or deficit leading to an excess of violence.

Genetic assimilation and the evolution of direction of genital asymmetry in anablepid fishes.

Phylogenetic comparative studies suggest that the direction of deviation from bilateral symmetry (sidedness) might evolve through genetic assimilation; however, the changes in sidedness inheritance remain largely unknown. We investigated the evolution of genital asymmetry in fish of the family Anablepidae, in which males' intromittent organ (the gonopodium, a modified anal fin) bends asymmetrically to the left or the right. In most species, males show a 1 : 1 ratio of left-to-right-sided gonopodia. However, we found that in three species left-sided males are significantly more abundant than right-sided ones. We mapped sidedness onto a new molecular phylogeny, finding that this left-sided bias likely evolved independently three times. Our breeding experiment in a species with an excess of left-sided males showed that sires produced more left-sided offspring independently of their own sidedness. We propose that sidedness might be inherited as a threshold trait, with different thresholds across species. This resolves the apparent paradox that, while there is evidence for the evolution of sidedness, commonly there is a lack of support for its heritability and no response to artificial selection. Focusing on the heritability of the left : right ratio of offspring, rather than on individual sidedness, is key for understanding how the direction of asymmetry becomes genetically assimilated.

The Impact of COVID-19 on Mortality in Italy: Retrospective Analysis of Epidemiological Trends.

BackgroundDespite the available evidence on its severity, COVID-19 has often been compared with seasonal flu by some conspirators and even scientists. Various public discussions arose about the noncausal correlation between COVID-19 and the observed deaths during the pandemic period in Italy.ObjectiveThis paper aimed to search for endogenous reasons for the mortality increase recorded in Italy during 2020 to test this controversial hypothesis. Furthermore, we provide a framework for epidemiological analyses of time series.MethodsWe analyzed deaths by age, sex, region, and cause of death in Italy from 2011 to 2019. Ordinary least squares (OLS) linear regression analyses and autoregressive integrated moving average (ARIMA) were used to predict the best value for 2020. A Grubbs 1-sided test was used to assess the significance of the difference between predicted and observed 2020 deaths/mortality. Finally, a 1-sample t test was used to compare the population of regional excess deaths to a null mean. The relationship between mortality and predictive variables was assessed using OLS multiple regression models. Since there is no uniform opinion on multicomparison adjustment and false negatives imply great epidemiological risk, the less-conservative Siegel approach and more-conservative Holm-Bonferroni approach were employed. By doing so, we provided the reader with the means to carry out an independent analysis.ResultsBoth ARIMA and OLS linear regression models predicted the number of deaths in Italy during 2020 to be between 640,000 and 660,000 (range of 95% CIs: 620,000-695,000) against the observed value of above 750,000. We found strong evidence supporting that the death increase in all regions (average excess=12.2%) was not due to chance (t21=7.2; adjusted P<.001). Male and female national mortality excesses were 18.4% (P<.001; adjusted P=.006) and 14.1% (P=.005; adjusted P=.12), respectively. However, we found limited significance when comparing male and female mortality residuals’ using the Mann-Whitney U test (P=.27; adjusted P=.99). Finally, mortality was strongly and positively correlated with latitude (R=0.82; adjusted P<.001). In this regard, the significance of the mortality increases during 2020 varied greatly from region to region. Lombardy recorded the highest mortality increase (38% for men, adjusted P<.001; 31% for women, P<.001; adjusted P=.006).ConclusionsOur findings support the absence of historical endogenous reasons capable of justifying the mortality increase observed in Italy during 2020. Together with the current knowledge on SARS-CoV-2, these results provide decisive evidence on the devastating impact of COVID-19. We suggest that this research be leveraged by government, health, and information authorities to furnish proof against conspiracy hypotheses that minimize COVID-19–related risks. Finally, given the marked concordance between ARIMA and OLS regression, we suggest that these models be exploited for public health surveillance. Specifically, meaningful information can be deduced by comparing predicted and observed epidemiological trends.

Global variation in young adult central nervous system tumor incidence by region, age, and sex from 1988 to 2012

BackgroundCentral nervous system (CNS) tumors result in tremendous morbidity and mortality. Incidence of CNS tumors in young adults is less studied. It is unknown how young adult CNS tumor incidence has changed globally in recent decades. MethodsWe used Cancer Incidence in Five Continents (CI5) data (1988–2012) to estimate incidence rates (IR), average annual percent change in incidence (AAPC; 95% confidence intervals [95% CI]), and male-to-female incidence rate ratios (IRR; 95% CI) by six histologies and age at diagnosis (20–29years, 30–39years). Tumors were classified as astrocytic, medulloblastoma, ependymal, oligodendroglial, meninges, and other embryonal. Geographic regions were defined using the United Nations Statistics Division geoscheme. ResultsThere were 78,240 CNS tumor cases included. 20–29-year-old (yo) rates were lower than 30–39 yo in most regions for astrocytic, oligodendroglial and ependymal tumors. Globally, astrocytic tumor incidence decreased (20–29 yo AAPC: − 0.70; 95% CI: − 1.32, − 0.08) while incidence increased for oligodendroglial (20–29 yo AAPC: 3.03; 95% CI: 1.57–4.51; 30–39 yo AAPC: 2.67; 95% CI: 0.79–4.58), ependymal (20–29 yo AAPC: 1.16; 95% CI: 0.31–2.03; 30–39 yo AAPC: 2.29; 95% CI: 1.14–3.46), medulloblastoma (30–39 yo AAPC: 0.6; 95% CI: 0.04–1.24) and tumors of the meninges (20–29 yo AAPC: 1.55; 95% CI: 0.04–3.07). There was a 20–40% male incidence excess in all histologies except for meninge tumors (30–39 yo IRR: 0.71; 95% CI: 0.61, 0.84). ConclusionsIncidence of oligodendroglial and ependymal tumors increased globally in 20–39 yo suggesting better diagnoses or changes in risk factors. Males had a higher incidence of CNS tumors for most tumors studied and in most regions.

Evaluation of Additional Drosophila suzukii Male-Only Strains Generated Through Remobilization of an FL19 Transgene.

Drosophila suzukii (D. suzukii) (Matsumura, 1931; Diptera: Drosophilidae), also known as spotted wing Drosophila, is a worldwide pest of fruits with soft skins such as blueberries and cherries. Originally from Asia, D. suzukii is now present in the Americas and Europe and has become a significant economic pest. Growers largely rely on insecticides for the control of D. suzukii. Genetic strategies offer a species-specific environmentally friendly way for suppression of D. suzukii populations. We previously developed a transgenic strain of D. suzukii that produced only males on a diet that did not contain tetracycline. The strain carried a single copy of the FL19 construct on chromosome 3. Repeated releases of an excess of FL19 males led to suppression of D. suzukii populations in laboratory cage trials. Females died as a consequence of overexpression of the tetracycline transactivator (tTA) and tTA-activated expression of the head involution defective proapoptotic gene. The aim of this study was to generate additional male-only strains that carried two copies of the FL19 transgene through crossing the original line with a piggyBac jumpstarter strain. Males that carried either two chromosome 3 or a singleX-linked transgene were identified through stronger expression of the red fluorescent protein marker gene. The brighter fluorescence of the X-linked lines was likely due to dosage compensation of the red fluorescent protein gene. In total, four X-linked lines and eleven lines with two copies on chromosome 3 were obtained, of which five were further examined. All but one of the strains produced only males on a diet without tetracycline. When crossed with wild type virgin females, all of the five two copy autosomal strains examined produced only males. However, the single copy X-linked lines did not show dominant female lethality. Five of the autosomal lines were further evaluated for productivity (egg to adult) and male competition. Based on these results, the most promising lines have been selected for future population suppression experiments with strains from different geographical locations.

Young adult males have worse survival than females that is largely independent of treatment received for many types of central nervous system tumors: A National Cancer Database analysis.

Central nervous system (CNS) tumors rank among the top 5 cancers diagnosed in young adults aged 20 to 39 years at diagnosis and show a clear male excess in incidence. It is unknown whether sex differences in survival persist across histologic types and depend on the treatment received. From the National Cancer Database (2004-2016), young adults (aged 20-39 years) who had been diagnosed with CNS tumors were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated as measures of association between sex and death via Cox regression. An inverse odds weighting mediation analysis was performed with treatment received as a mediator. There were 47,560 cases (47% male). Males had worse overall survival than females for 9 of 16 histologic types, including diffuse astrocytoma, glioblastoma, and meningioma (all P < .05). Males had an increased risk of death after a brain tumor diagnosis overall (HR, 1.47; 95% CI, 1.41-1.53) and for 8 histologies. There was a significant association between male sex and death overall that was mediated by treatment received (indirect-effect HR, 1.17; 95% CI, 1.15-1.18), but no single histology had a significant indirect effect. All histologies examined in mediation analyses had significant direct effects for sex. The excess mortality due to sex was 20% for all CNS tumors combined and 34% among males with CNS tumors. Overall, treatment received may mediate a portion of the association between sex and death after a CNS tumor, but sex itself appears to be a stronger risk factor for death in this study.

Racial/ethnic and sex differences in young adult malignant brain tumor incidence by histologic type

BackgroundBrain tumors are among the top four cancers in young adults. We assessed important windows of tumor development and examined the interplay of race/ethnicity, age, and sex in young adult brain tumor incidence. MethodsUsing SEER 18 data (2000–2017), incidence rates were estimated by Poisson regression in individuals aged 20–39 years at diagnosis. Incidence rate ratios (IRR) and 95% confidence intervals (95% CI) were estimated by race/ethnicity, sex and age for 12 malignant histologies. ResultsWhite incidence for all histologies was higher (White vs. Black IRR: 2.09, 95% CI: 1.94, 2.24; White vs Asian Pacific Islander IRR: 1.88, 95% CI: 1.75, 2.03; White vs Hispanic IRR: 1.70, 95% CI: 1.62, 1.78; White vs American Indian IRR: 1.40, 95% CI: 1.14, 1.73). Minority groups had higher lymphoma incidence (White vs Black IRR: 0.32, 95% CI: 0.25, 0.40, White vs Hispanic HR: 0.55, 95% CI: 0.44, 0.68). Males had higher incidence than females for all histologies (IRR: 1.36, 95% CI: 1.31, 1.41). Male rates were highest for lymphoma (male-to-female [MF] IRR: 2.00, 95% CI: 1.65, 2.42) and glioblastoma (MF IRR: 1.61, 95% CI: 1.48, 1.75). The male excess in incidence was similar by race/ethnicity and increased with age (20–24-year-old IRR: 1.18, 95% CI: 1.07, 1.29; 35–39-year-old IRR: 1.44, 95% CI: 1.35, 1.54). ConclusionsA White race and male incidence excess was observed among brain tumors. ImpactThe male excess was similar by race/ethnicity and increased with age suggesting male sex may be an intrinsic risk factor for brain tumor development.