Age-specific Sex Ratios Research Articles

Hierarchical Bayesian Integrated Modeling of Age- and Sex-Structured Wildlife Population Dynamics

AbstractBiodiversity of large wild mammals is declining at alarming rates worldwide. It is therefore imperative to develop effective population conservation and recovery strategies. Population dynamics models can provide insights into processes driving declines of particular populations of a species and their relative importance. But there are insufficient tools, namely population dynamics models for wild herbivores, for characterizing their decline and for guiding conservation and management actions. Therefore, we have developed a model which can serve as a tool to fill that void. Specifically, we develop an integrated Bayesian state-space population dynamics model for wildlife populations and illustrate it using a topi population inhabiting the Greater Mara-Serengeti Ecosystem in Kenya and Tanzania. The model integrates ground demographic survey with aerial survey monitoring data. It incorporates population age and sex structure and life history traits and strategies and relates birth rates, age-specific survival rates and sex ratios with meteorological covariates, prior population density, environmental seasonality and predation risk. It runs on a monthly time step, enabling accurate characterization of reproductive seasonality, phenology, synchrony and prolificacy of births, juvenile and adult recruitments. Model performance is evaluated using balanced bootstrap sampling and by comparing model predictions with empirical aerial population size estimates. The hierarchical Bayesian model is implemented using MCMC methods for parameter estimation, prediction and inference and reproduces several well-known features of the Mara topi population, including striking and persistent population decline, seasonality of births, juvenile and adult recruitments. It is general and can be readily adapted for other wildlife species and extended to incorporate several additional useful features. Supplementary materials accompanying this paper appear on-line.

Recent updates on treatment patterns in patients with treated attention-deficit/hyperactivity disorders from a nationwide real-world database in South Korea.

The prevalence of attention-deficit/hyperactivity disorder (ADHD) is steadily increasing across Korea. We analyzed ADHD patients with ADHD medications (Rx) characteristics and treatment patterns compared to patients without Rx and identified the differences between pediatric-/adult- and active-/transient-patients with Rx. Using a nationwide claims dataset from 2020 to 2021, we conducted a prevalence-based cross-sectional study and analyzed the recent patients' characteristics and patterns among ADHD patients. Among 132 017 ADHD patients with Rx, differences from 20 312 without Rx across all characteristics except sex. We found significant differences in characteristics and treatment patterns between pediatric-/adult- and active-/transient-patients with Rx. Age-specific sex ratios notably diverged in pediatric patients (61.2%), but remained similar in adults, revealing significant psychiatric comorbidities differences. Active-patients peaked at 6-11 years (41.4%), while transient-patients at 18-30 years (36.1%). Predominantly, methylphenidate (89.7%), atomoxetine (27.8%), and clonidine (2.8%) were prescribed, with 85% experiencing treatment changes within methylphenidate formulations. In pediatric patients, extended-release methylphenidate was preferred (56.1%), adults favored oral delivery system methylphenidate (71.5%), and active-patients had higher treatment rates than transient-patients across all patterns, with low monotherapy rates. This study provides epidemiologic insights into recent characteristics and treatment patterns of ADHD patients with Rx in Korea, providing valuable evidence for identifying those actively receiving ADHD treatment in future healthcare policy decisions.

Age-specific sex ratios: Examining rural–urban variation within low- and middle-income countries

The balance of men and women in society, captured by sex ratios, determines key social and demographic phenomena. Previous research has explored sex ratios mainly at birth and up to age five at national level, whereas we address rural–urban gaps in sex ratios for all ages. Our measures are based on the United Nations data on rural and urban populations by age and sex for 112 low- and middle-income countries in 2015. We show that rural sex ratios are higher than urban sex ratios among children and older people, whereas at working ages, urban areas are dominated by males. Our analysis suggests that the urban transition itself is not driving the gap in rural–urban sex ratios. Rather, internal migration seems to be key in shaping rural–urban sex ratio divergence in sub-Saharan Africa, while both internal migration and mortality differentials appear to be the predominant mechanisms driving sex ratio gaps in Latin America.

Global and national trends in the age-specific sex ratio of esophageal cancer and gastric cancer by subtype.

A male predominance was observed in esophageal and gastric cancers, though present limited data has revealed variations by age. We aim to investigate the global age‐specific sex differences in esophageal squamous cell carcinoma (ESCC), esophageal adenocarcinoma (EAC), gastric cardia cancer (GCC) and gastric noncardia cancer (GNCC). Data on esophageal and gastric cancers incidence by diagnosis year, sex, histology, subsite and age group were extracted from 171 registries in 54 countries included in the last two volumes (X and XI, 2003‐2012) of Cancer Incidence in Five Continents, which contributing to over 80% of the global burdens of these cancers. Age‐standardized incidence rates (ASIRs) and male‐to‐female ASIRs ratios were estimated for esophageal and gastric cancers, by histological subtype and subsite, globally and by country. We consistently observed a male predominance in esophageal and gastric cancers across the world from 2003 to 2012, with male‐to‐female ASIRs ratios of 6.7:1 for EAC, 3.3:1 for ESCC, 4.0:1 for GCC and 2.1:1 for GNCC. The sex differences were consistent across time periods but varied significantly by age across the life span. Across the four cancer types, the male‐to‐female incidence rate ratios increased from young ages, approaching a peak at ages 60‐64, but sharply declined thereafter. Similar “low‐high‐low” trends of age‐specific sex ratio were observed in other digestive cancers including liver, pancreas, colon and rectum with peak ages ranging from 50 to 65. Age‐dependent risk factors warrant further investigation to aid our understanding of the underlying etiologies of esophageal and gastric cancers by histological subtype and subsite.

Repeated experimental removals unveil sex and age-specific dispersal strategies in a social passerine bird

Context Sex and age are frequently proposed as drivers of a number of behavioural and demographic patterns that can have important consequences for population dynamics including access to mates, sexual selection, parental care and lifetime productivity. Sex and age might also be important in shaping the movement patterns and colonisation processes of social species moving into vacant habitat. Such information is critical for the management of strongly interacting species such as the noisy miner (Manorina melanocephala), which structure ecological communities through aggressive exclusion of other taxa from areas that they occupy. Aims In Manorina colonies, young females are usually dispersive, while males remain in the natal colony as the philopatric sex. Following removal of individuals from an area, we aimed to determine whether female-biased dispersal, particularly of young females, would result in a more equal sex ratio and a younger age structure in the recolonising population. Methods These predictions were tested by anatomically ageing and sexing 1856 noisy miners that had been experimentally culled in two regions of New South Wales, Australia, to reduce the aggressive impact of this species on other native species. Key results Prior to removal, noisy miner populations were significantly male-biased in both regions (57% and 60%); however sex ratios after each of two removal episodes no longer differed from parity. Immature birds were a dominant feature (65%) of recolonising populations in both regions, however, the age structure of recolonising populations was different in each region, mostly likely due to the respective timing of culls during the year. Furthermore, the culling response in terms of age-specific sex ratio varied between regions. After the final cull, the sex ratio of mature birds had fallen to parity in one region but had become even more male biased (68%) in the other region. There was no sex-ratio bias among immature birds before or after culling. Conclusion These results confirm the expectation that immature birds are more likely to be colonisers, but the expectation of greater female dispersal was equivocal. Implications The differences in response between regions may reflect variation in population density, landscape connectivity or seasonality, highlighting challenges when implementing culling programs for conservation management.

Development of Care for Orphans in Bohemia until 1918

"The article [provides] examples of error in the censuses and surveys and questions the reliability of age specific sex ratios in the 1990 Census of Turkey...[and derives] sex ratio at birth from census and survey results as well as from hospital records. Finally the 1990 population is reconstructed by surviving birth cohorts [from] 1900 until 1990 using historical trends of birth rates and cohort, age and time specific survival rates using the East Family of Coale-Demeny Model Life Tables." (SUMMARY IN ENG)

EVALUATING COMPOSITIONAL FIDELITY AND SOURCES OF MORTALITY OF SHORELINE FISH CARCASSES IN A FRESHWATER LAKE COMMUNITY IN WESTERN CANADA

ABSTRACT Taxonomic comparisons of death assemblages with extant communities continue to provide insight for ecological studies but whether demographic aspects such as age structure, sex ratio, and causes of mortality are accurately captured by the former remains little studied. At a 110 ha dystropic lake in western Canada, seasonal shoreline accumulations of fish carcasses were collected annually for 12 years (N=4499) during 95 full lake-circuits and analyzed for taxa, body size frequencies, sex ratio relative to live-captures and sources of mortality. Rank order of the four fish species (Gasterosteus aculeatus, Oncorhynchus clarki, O. keta, Salvelinus malma) was similar for live-captures and carcasses. Of the dominant species (G. aculeatus), modal adult body length (∼80 mm SL) was the same for carcasses and live-captures and shifted by about 10% over 30 years with parallel trends between the groups for both sexes. Age-specific body size was about 5% larger (P<0.001) in carcasses than live-captures. Carcasses were significantly female-biased (2:1) each year relative to a population sex ratio of 1:1 in the lake. There was a complete absence of juvenile fish (<30 mm) among carcasses but these constituted 70% of the live population. Estimated relative contributions to mortality for the carcasses include starvation (<1%), parasitism (3%), senescence (4%) and lethal injuries from predator attack (70–80%). If these carcasses are representative of a fossil series in freshwater lake sediments, then several demographic parameters including age-specific body size, age-class frequencies and sex ratio depart substantially from the live population. As well, the virtual absence of avian piscivores in the carcass assemblage, the major source of predation on the fish population, warrants additional attention in paleoecological studies.

Do Local Sex Ratios Approximate Subjective Partner Markets?

Sex ratios have widely been recognized as an important link between demographic contexts and behavior because changes in the ratio shift sex-specific bargaining power in the partner market. Implicitly, the literature considers individual partner market experiences to be a function of local sex ratios. However, empirical evidence on the correspondence between subjective partner availability and local sex ratios is lacking so far. In this paper, we analyzed how closely a set of different local sex ratio measures correlates with subjective partner market experiences. Linking a longitudinal German survey to population data for different entities (states, counties, municipalities), we used multilevel logistic regression models to explore associations between singles’ subjective partner market experiences and various operationalizations of local sex ratios. Results suggest that local sex ratios correlated only weakly with subjective partner market experiences. Adult sex ratios based on broad age brackets, including those for lower-level entities, did not significantly predict whether individuals predominantly met individuals of their own sex. More fine-grained, age-specific sex ratios prove to be better predictors of subjective partner market experiences, in particular when age hypergamy patterns were incorporated. Nevertheless, the respective associations were only significant for selected measures. In a complementary analysis, we illustrate the validity of the subjective indicator as a predictor of relationship formation. In sum, our results suggest that subjective partner availability is not adequately represented by the broad adult sex ratio measures that are frequently used in the literature. Future research should be careful not to equate local sex ratios and conscious partner market experiences.

Implications for Fisheries Management: Sex Ratio, Size at Sexual Maturity, and Reproductive Cycle of Saxidomus purpuratus (Bivalvia: Veneridae) in Korea

This study was performed to obtain information on the sex ratio, size at sexual maturity, and main spawning period of the butter clam Saxidomus purpuratus in Korea to contribute to the management of fisheries resources of this species. The age-specific sex ratios (female:male) of S. purpuratus were 1:2.20 (31.3% female) and 1:1.03 (49.2% female) in the 0+ and 1+ y classes, respectively, illustrating the initially higher percentage of males in the butter clam population. From the 2+ y class onward, however, the percentage of females in the population tended to increase with age. The shell length at sexual maturity was analyzed using a logistic regression model, and was determined to be 54.5 and 45.5mmfor females and males, respectively. The gonad index displayed a definitive pattern of seasonal changes, with high values in the spring and fall and low values in the summer and winter for both males and females. The butter clam S. purpuratus was found to have two spawning seasons per year, with the main spawning period being in May–June.

The association between uneven sex ratios and violence: Evidence from 6 Asian countries.

It has been hypothesized that uneven sex ratios in the population could lead to increased violence. The objective of this analysis is to explore the relationship between uneven sex ratios in the population and violence. This analysis uses data collected from men in six Asian countries about their experiences and perpetration of violence. We combine this with region- and age specific sex ratios calculated from Census data to explore the relationship between sex ratios and violence using multilevel models. We find that men from region-age brackets with higher ratios of men to women are significantly more likely to report ever having raped a woman, having perpetrated intimate partner violence, or having used a weapon. We find no evidence for an association between sex ratios and reports of ever having raped a man.

Age-specific sex difference in the incidence of hepatocellular carcinoma in the United States.

BackgroundHepatocellular carcinoma possesses a notable sex difference in incidence, and a protective role of estrogens has been hypothesized.MethodsUsing data from 13 cancer registries in the Surveillance, Epidemiology, and End Results Program, we describe the age-specific sex difference in the incidence of hepatocellular carcinoma in the United States during 1992-2013. We used a curve fitting by non-linear regression to quantitatively characterize the age-specific incidence rate of hepatocellular carcinoma by sex.ResultsA total of 44,287 incident cases of hepatocellular carcinoma (33,196 males and 11,091 females) were included, with an overall male-to-female ratio in age-standardized rate of 3.55. The sex ratio was below 2 at ages <25 years, increased with age from ages 25-29 years until peaking at 5.40 at ages 50-54 years, and declined thereafter. We also observed additional peaks in the age-specific sex ratio curves at ages 25-34 years across racial/ethnic groups. Modelling of age-specific incidence rates indicated a 15-year delayed increase with age in females compared with males in Asian and Pacific Islanders, and an 11-year delay in Hispanic whites.ConclusionsThe age-dependent patterns in the sex difference in the incidence of hepatocellular carcinoma support the hypothesis of a protective role of estrogens. The underlying reasons for the sex difference in hepatocellular carcinoma remain to be further explored in analytic epidemiological studies.

The Accuracy of Demographic Data in the Ethiopian Censuses

The quality of age-sex reporting and the presence of net undercount in the Ethiopian censuses were assessed using demographic analysis methods. First, to identify the presence of coverage errors, data organised by birth cohort for the three censuses (1984, 1994 and 2007) were graphically examined. Then age-specific sex ratios and cohort sex ratios were assessed. Second, to identify the pattern of digit preference, the two classical indices of heaping (Bachi's and Myers') were calculated. Third, to evaluate the overall accuracy of the data, the United Nations age-sex accuracy indices were calculated at the national and sub-national levels. Fourth, the relationship between quality of data and some socio-economic variables were analysed. The findings showed the presence of coverage and content errors in all of the three censuses. The results of all the indices suggested the inaccuracy of the data. The age-sex accuracy index declined from 66.5 in 1984 to 46.9 in 2007, suggesting a modest improvement in the accuracy but the qualification is still in the 'highly inaccurate' category. Finally, stressing the importance of better quality demographic data, some recommendations are made.

Population Sex Ratios and Violence Against Women: The Long-Run Effects of Sex Selection in India

This paper investigates the consequences of sex imbalance in India's population for violence against women. We match district level administrative crime data by category to age-specific sex ratios in census data across four decades and, to analyse mechanisms, we also use administrative data on marriage rates and household survey data on attitudes to violence against women and marriage quality. We estimate that the elasticity of violence against women with respect to the surplus of men age 20-24 is unity, and that this explains about 35% of the rise in gender-based violence since 1995. Although less robust, there is some evidence that the youth sex ratio also raises non-gendered forms of violence, but we find no discernible impact upon property and economic crime. In probing mechanisms we argue that men are more prone to crime than women, that the share of unmarried men is increasing in the youth sex ratio, that attitudes to violence against women are evolving as a function of the sex ratio at birth and marriage quality measures, including self-reported domestic violence, are negatively related to sex ratios.

Visualising the demographic factors which shape population age structure

1. IntroductionThe population pyramid is one of the most popular visual representations of data in demography. In its standard form it comprises two histograms rolled on their sides and placed back-to-back, with the youngest ages at the bottom of the diagram and the oldest at the top. Generally, the male population is placed on the left and the female population on the right. The populations of each age-sex group are shown either as absolute numbers or as a percentage of the whole population. As an example, Figure 1 presents a population pyramid for Australia at 31 December 2014.A population pyramid can be created in common spreadsheet or statistical software without much difficulty, and is easy to understand. It presents immediately digestible information on the age-sex structure of a population that would be less obvious in tabular form. This distribution is important for understanding the demand for the wide range of goods and services which vary by age and sex, such as baby products, childcare, education, housing for first home buyers, household appliances, recreational activities, aged care, and funeral services (Siegel 2002). Population age structure also affects government spending and taxation receipts (Australian Government 2015). A population pyramid additionally offers clues about a population's fertility history, mortality and migration, position in the demographic transition, and the likely influence of its age-sex structure on future demographic change. The shape of a population pyramid can hint at the economic or demographic role of the population in question, as might be apparent for a university town, a popular seaside retirement region, or an area with a communal establishment like a boarding school or prison. It can also be used to check for potential data problems, such as age heaping. Finally, population pyramids can also be quite entertaining, especially in dynamic form, as presented on some national statistical offices' and researchers' websites. Examples can be found* for Germany,* for Australia, and* for Moldova.Several variations on the standard pyramid have been created. Many involve disaggregating the bars into different categories of population, such as by marital status (e.g., Statistics Canada 2013), household living arrangement (e.g., van Imhoff and Keilman 1991), birthplace (e.g., Statistics Sweden 2009), educational attainment (e.g., Lutz, Cuaresma, and Sanderson 2008), labour force status (Statistics New Zealand 2015), ethnicity (e.g., Coleman 2010), and migrant status (e.g., Price 1998). Some display shadows on the bars of the pyramid where there is an excess number of one sex over another (e.g., Heenan 1965); others show age-sex structure with persons by age in one histogram and age-specific sex ratios in another (Haak 1942). Commonly, two or more population pyramids are overlaid on one another, often to compare age structure over time (e.g., The Economist 2011), to show the outcome of alternative future scenarios (e.g., Statistics Canada 2015), or to display probabilistic prediction intervals (e.g., Keilman, Pham, and Hetland 2002).However, population pyramids are not without their limitations. Because they display only the size of each age-sex group in the population, it is usually not possible to distinguish the relative contributions of different demographic processes to population age structure. For example, if there is an indentation at the young adult ages, is this more the result of a fertility decline two to three decades earlier or recent net out-migration? If age-specific populations at the upper end of the pyramid decline very rapidly with increasing age, is this just the result of mortality, or have past trends in births and migration also contributed?This paper presents a type of population pyramid that illustrates how births, deaths, and net migration have shaped a population's age structure. Termed the components-of-change pyramid, it is described and illustrated in section 2 following this introduction. …

Incidence and survival of retinoblastoma in Taiwan: a nationwide population-based study 1998–2011

ObjectiveTo study the epidemiology of retinoblastoma in Taiwan from 1998 to 2011.DesignThis was a retrospective population-based cohort study using the Taiwan National Health Insurance Research Database.ResultsThe present study included 154...

Age-Specific Sex Ratio Structure of the Administrative Population Improved for a Register-based Census: Evaluation and Challenge

본 연구의 목적은 등록센서스를 목적으로 작성된 2010년 센서스 시점의 보완행정인구를 센서스인구와 비교하여 연령대별 성비차이의 구조를 평가하는 것이다. 보완행정인구는 등록연령으로 작성되고, 센서스인구는 실제연령인 “조사연령”으로 작성되기 때문에, 센서스인구의 조사연령을 등록연령으로 변경하는 교차계수 방법론을 적용한다. 센서스인구의 조사연령구조와 등록연령구조 간 성비 차이는 사실상 무시할 정도이다. 한편, 연령대별 성비가 보완행정인구와 센서스인구에서 20세 이전까지 약간씩 증가하지만, 다만, 등록연령을 기준으로 센서스인구가 보완행정인구보다 15-24세에서는 성비가 약간 크지만 나머지 연령대 특히 25-34세에는 그 차이가 증가하며 35-44세에는 보완행정인구가 센서스인구보다 좀 많다가, 45세 이후부터 이런 차이가 다시 감소하면서 75세 이상에서는 역전되기도 한다. 보완행정인구는 센서스인구와 등록연령 기준으로 시도수준에서 성비를 비교할 때, 20-30세와 중장년층에서 미시적이기는 하지만 약간의 차이가 난다. 이 차이는 보완행정인구가 등록거주지를 기준으로 작성되어 있고, 센서스인구는 상주지 곧 조사거주지를 기반으로 작성되었기 때문이다. 물론, 센서스인구의 현장조사가 남녀를 차별적으로 파악함에 따라 생겨나는 차이도 있을 것이다. 2015년 인구주택총조사는 인구부문은 주민등록을 토대로 하는 보완행정인구를 기준으로 작성되기 때문에, 일정부분 센서스인구와 성비구조에서도 약간의 차이가 생겨날 것이다. 그러나 현재 통계청이 개발하고 있는 리지회귀식이나 사후조사 보정법의 일환으로 개발된 이원추정시스템을 이용한다면, 시계열 단절은 성비구조의 변동을 이해하는데 그리 심각한 문제가 되지는 않을 것이다.

Does the changing sex ratio of multiple sclerosis give opportunities for intervention?

In several international studies, an increasing women-to-men (w/m) ratio in patients with multiple sclerosis (MS) has been reported. Such sex ratios have been analysed by year of onset or by year of birth. In a Swedish study, data from the Swedish MS register (SMSreg) were used to analyse the w/m ratio in Sweden. The sex ratio was analysed both by year of birth (8834 patients) and by year of onset (9098 patients). No increased w/m ratio was seen in this study. The age-specific sex ratio did not demonstrate any significant changes. However, a new investigation of the sex ratio in Sweden, based on data from all available data sources (19,510 patients), showed a significantly increased w/m ratio of MS in Sweden from 1.70 to 2.67. Environmental factors such as cigarette smoking, hormonal factors and nutrition are of interest in this context, but the cause of the increasing w/m ratio in MS is yet not possible to explain.

Risky business: sex differences in mortality and dispersal in a polygynous, monomorphic lemur

Sexually selected traits and the use of strategies to enhance male reproductive success (e.g., competition and dispersal) can yield sex differences in metabolic requirements, rates and durations of growth and maturation, and the propensity for risky behavior, which are suggested to result in age-specific sex differences in mortality and life span. We investigated age-specific sex ratios, mortality, and dispersal in Propithecus edwardsi in Ranomafana National Park, Madagascar. We predicted that, due to similarities in growth rates and body sizes, male and female juvenile mortality rates would be comparable; because both sexes disperse and have intense intersexual competition and aggression, adult mortality would be similar; given similarities in dispersal frequency and distance, the timing of dispersal would not differ. We used 80 group-years births, deaths, and dispersals (N females = 41, N males = 34) collected over 23 years to calculate sex ratios and survival curves. Females lived longer than males (maximum 32 and 19 years, respectively). Sex ratios were male biased from sexual maturity through 17 years and female biased at birth and older ages. Infant survival probabilities were similar. Thus, differential development and maturation are unlikely explanations for longer female life span in this species. Males were more likely to survive from 2 to 18 years. However, male annual survival probability declined quickly around 13–18 years; males continued to disperse until their deaths, whereas females generally stopped dispersing after 11 years. We suggest that sex differences in the timing of dispersal and the unique challenges of risky behavior at older ages may be sufficient to yield differences in male and female life span.

Two-sex age structured dynamics in a fixed sex-ratio population

An age structured model is considered in order to analyze the growth of a two sex population with a fixed age-specific sex ratio. The model is intended to give an insight into the dynamics of a population where the mating process takes place at random and the proportion between females and males is not influenced by environmental or social factors, but only depends on a differential mortality or on a possible transition from one sex to the other (e.g. in sequential hermaphrodite species).First a basic model, asymptotically linear, is considered and its ergodicity is studied. Survival thresholds and their dependence on the sex ratio are then analyzed, in connection with the optimal sex ratio to guarantee survival.A further model including logistic effect is also considered and discussed in connection with existence and stability of steady states.

Epidemiologic features, seasonal variations and false positive rate of acute appendicitis in Shahr-e-Rey, Tehran

Introduction Appendicitis is the most common acute surgical condition of the abdomen. Age, sex and seasonal variations have been observed in many studies. To describe and find the possible differences in the epidemiology of acute appendicitis in Shahr-e-Rey, we carried out a retrospective study of all patients with acute appendicitis admitted to Shohadaay-e Haftom-e Tir hospital as it is the only hospital in this restricted part of Tehran. Methods Using hospital discharge abstract of patients who were admitted with the diagnosis of acute appendicitis from summer 1996 to spring 2004, we studied the demographic features, particularly age and sex, date of admission and final diagnosis of these patients. Results During the observation period, 1093 cases were admitted with the diagnosis of acute appendicitis. Of these, 74.4% were males and 6.1% were not actually an acute appendicitis. The age-specific incidence of acute appendicitis has different patterns in male and female. The incidence was highest in males aged 20–29 years whereas in females the highest incidence was observed in 10–19 years age group. A significant seasonal effect was also observed, with the rate of acute appendicitis higher in the summer months ( p < 0.006). The rate of false positive diagnosis was highest in the patients aged 0–9 years ( p < 0.0001). Of those correctly diagnosed, 85.5% had uncomplicated acute appendicitis; 8.3% had perforation; and others (6.2%) had acute appendicitis complicated with other situations. Conclusion Appendicitis is more common in males, in those aged 20–29 years, and during the summer months. The age-specific incidence and sex ratio of acute appendicitis give the impression that epidemiologic features of acute appendicitis are different with worldwide data. However, the seasonal variation and false positive rate of acute appendicitis are in a good agreement with other studies.