Variation In Prevalence Estimates Research Articles

Prevalence of alcohol and other drug use in patients presenting to hospital for fall-related injuries: a systematic review

BackgroundAlcohol and other drug (AOD) use is a key preventable risk factor for serious injuries. Prevention strategies to date have largely focused on transport injuries, despite AOD use being a...

Ways Forward in Preventing Severe Maternal Morbidity and Maternal Health Inequities: Conceptual Frameworks, Definitions, and Data, from a Population Health Perspective.

Ways Forward in Preventing Severe Maternal Morbidity and Maternal Health Inequities: Conceptual Frameworks, Definitions, and Data, from a Population Health Perspective.

Prevalence of horizontal violence of nurses in their first year of practice: A systematic review

<h2>ABSTRACT</h2><h3>Background</h3> ‘Horizontal violence' refers to hostile, aggressive, or harmful behaviour between peers. Nurse educators and managers who support newly qualified nurses should be aware of horizontal violence in the workplace when directed towards this professional group. The prevalence of horizontal violence in newly qualified nurses has not been subject to a systematic review. <h3>Aim</h3> The aim of this systematic review was to estimate prevalence of horizontal violence in newly qualified nurses in their first year of practice. <h3>Methods</h3> A systematic search was undertaken with the following databases on October 2018: AMED, CINAHL, CENTRAL, EMBASE, MEDLINE, ERIC and PsychINFO. An updated search was undertaken on August 12, 2020. Observational and experimental studies were included. Two researchers independently completed title, abstract and full-text screening. Nine studies were finally included in the review. Risk of bias was determined using the Joanna Briggs Institute critical appraisal tool. <h3>Findings.</h3> Included studies were cross-sectional in design and horizontal violence was determined using nine different self-report measures. Reported rates of horizontal violence ranged from 7% to 73%. All included studies were rated as having a moderate risk of bias. <h3>Discussion</h3> The broad range of prevalence estimates is likely explained by the use of different measures in included studies and the sources of bias. It is unclear if horizontal violence is common in nurses in their first year of practice. Further research that addresses the sources of bias we have identified is justified. <h3>Conclusion</h3> There is considerable variation in prevalence estimates of horizontal violence in nurses in their first year of practice

Prevalence of Calf Mortality in Ethiopia: A Systematic Review and Meta-Analysis.

Background Calf mortality has been a major cause of economic losses in the dairy industry in Ethiopia. The condition results in a significant drop in the number of replacing heifers and bulls for sustainable dairy business. Reports on calf mortality with a wide range of prevalence are rising in the country; however, a pooled prevalence of this condition has not been established. Thus, this systematic review and meta-analysis aimed to quantitatively estimate the pooled prevalence of calf mortality in Ethiopia. Methods Meta-analysis was carried out to obtain the pooled prevalence of calf mortality in Ethiopia. A comprehensive literature search was carried out on PubMed, African Journals Online, CAB, Web of Science Direct, and Google Scholar. Eligible studies were selected based on predefined inclusion and exclusion criteria. Moderators such as the study area, breed of calf, study design, agroecology, and year of study article published were used as a milestone of data extraction. The random-effect model was used to estimate pooled prevalence. Publication bias and the variation in prevalence estimates attributed to heterogeneity were also assessed. Results Twenty-five original research papers on the prevalence of calf mortality in various parts of Ethiopia were included. The reported prevalence of calf mortality was between 0.9% and 37%. The pooled prevalence of calf mortality in the country was 14.79%, and the pooled calf mortality estimate across studies for the entire period regarding 1991 to 2000, 2001 to 2010, 2011 to 2016, and 2017 to 2020 was 26.54%, 17.03%, 14.21%, and 11.23%, respectively. Analysis of study subgroups and location revealed significant variations in prevalence. High heterogeneity was observed in the pooled estimates and even after the subgroup meta-analysis. The funnel plots and Egger's regression asymmetry coefficient (b = −1.0434) (95% CI = −1.49, −0.59; p value of 0.012) did suggest the presence of publication bias. There was also an indication of missing studies that could be incorporated by Duval and Tweedie's trim and fill method where they might fall on a funnel plot and visualize them in an attempt to increase the plot's symmetry. Analyses also suggest that calf breed, sample size, and study location are likely to be moderators of calf mortality prevalence in Ethiopia. Conclusion This finding shows that calf mortality is widespread and could result in considerable economic losses for the dairy industry in Ethiopia. Inevitably, a significant reduction in calf mortality prevalence has been observed in recent years since 2010, but the reduction has not yet reached an economically tolerable level. Calf breed susceptibility contributed to the high prevalence. Therefore, interventions for increasing calf health and performance should be focused on minimizing calf mortality on farm and animal levels.

Examining Variations in the Prevalence of Diagnosed Mood or Anxiety Disorders Among Migrant Groups in Ontario, 1995-2015: A Population-Based, Repeated Cross-Sectional Study.

International evidence on the frequency of mood or anxiety disorders among migrant groups is highly variable, as it is dependent on the time since migration and the socio-political context of the host country. Our objective was to estimate trends in the prevalence of diagnosed mood or anxiety disorders among recent (<5 years in Canada) and settled (5-10 years in Canada) migrant groups, relative to the general population of Ontario, Canada. We used a repeated cross-sectional design consisting of four cross-sections spanning 5 years each, constructed using health administrative databases from 1995 to 2015. We included all Ontario residents between the ages of 16 and 64 years. We assessed differences in the prevalence of mood or anxiety disorders adjusting for age, sex, and neighbourhood-level income. We further evaluated the impact of migrant class and region of birth. The prevalence of mood or anxiety disorders was lower among recent (weighted mean = 4.10%; 95% confidence interval [CI], 3.59% to 4.60%) and settled (weighted mean = 4.77%; 95% CI, 3.94% to 5.61%) migrant groups, relative to the general population (weighted mean = 7.39%; 95% CI, 6.83% to 7.94%). Prevalence estimates varied greatly by region of birth and migrant class. We found variation in prevalence estimates over time, with refugee groups having the largest increases between 1995 and 2015. Our findings highlight the complexity of mood and anxiety disorders among migrant groups, and that not all groups share the same risk profile. These results can be used to help inform health service allocation and the development of supportive programs for specific migrant groups.

Systematic review of mental health symptoms in firefighters exposed to routine duty-related critical incidents.

Due to high rates of potentially traumatic exposure (PTE) within the firefighting profession, a large body of literature concerning firefighters’ mental health has developed over recent decades. However, given variable prevalence outcomes and the largely descriptive nature of most studies, it is unclear whether the prevalence of trauma-related mental disorders in firefighters is elevated in comparison with the general population. The present systematic review examined literature on prevalence of posttraumatic stress disorder, depression, and anxiety in firefighters exposed to routine, duty-related PTEs to synthesize prevalence outcomes across the literature. Systematic search of 6 databases was conducted to review eligible articles published between 1980 and 2017 in any language. In all, 40 articles concerned firefighters exposed to routine work-related PTE. We report that strong evidence exists to suggest that the prevalence of posttraumatic stress disorder and depression is elevated in firefighters compared with the general population of Canada, whereas moderate evidence exists for the elevated prevalence of anxiety disorders. However, measurement tool is a substantial source of variability in prevalence estimates across the literature, and few predictive factors bear consistent relationships to posttraumatic stress disorder across samples. Future work should focus on measurement variance and examine possible interactions between commonly assessed predictive factors for disorder risk in firefighters.

Using linked administrative data to determine the prevalence of intellectual disability in adult prison in New South Wales, Australia.

Studies of the representation of people with intellectual disability (ID) in custody report widely inconsistent findings that reflect variation in how ID is defined and the methods employed for identification. Using linked administrative data may be of utility in studies of the representation of people with ID in custody. However, this approach requires an understanding of the purpose of and factors influencing identification in disparate administrative datasets. This study uses linked administrative data encompassing disability, health and corrections data for the year 2014 to estimate the prevalence of ID in adult custody and explore how ID representation within administrative data impacts prevalence estimates and what patterns of identification reveal about support service access for this group. This study finds that 4.3% of the New South Wales adult custody population had an identified ID. Prisoners with ID were younger, more likely to have had a previous custodial episode and more likely to be Indigenous than the general prison population. Identification of ID across linked administrative datasets is uneven, which, if used in isolation, would result in variation in prevalence estimates according to source data. The utilisation of linkage data from a broad range of health and support services including custody offers a comprehensive identification methodology. Inconsistency in the identification of ID across datasets indicates a potential disjuncture between prisoners with ID and support services, which may have relevance for efforts to reduce reincarceration of those in this population.

Analysis of Daily Variation for 3 and for 30 Days of Parasite-Specific IgG in Urine for Diagnosis of Strongyloidiasis by Enzyme-Linked Immunosorbent Assay

Recent work has found urine analysis to be as sensitive as serology for diagnosis of strongyloidiasis. Here, we examined the daily variation of Strongyloides-specific IgG in urine by qualitative and quantitative ELISA and its effects on diagnostic accuracy and reliability. In the first part of the study, matched urine and fecal samples were collected from project participants in northeast Thailand for three consecutive days. Urine samples were analyzed for Strongyloides-specific IgG by ELISA using Strongyloides ratti as the antigen source. Performance of urine ELISA was compared with parasitological diagnosis by agar plate culture technique (APCT) and formalin-ethyl acetate concentration technique (FECT). In the second part of the study, urine IgG levels were compared daily for thirty consecutive days.The prevalence of Strongyloides infection, as measured by urine ELISA for three consecutive days, was significantly higher than that found using parasitological methods (63.1% vs. 22%). There was slight daily variation in prevalence estimates according to urine ELISA while there were significant variations according to parasitological examination methods over three consecutive days. For the 3-day experiment, urine ELISA had 83-86% diagnostic sensitivity when compared with the fecal examination method or with a composite standard (combined results from fecal examination methods (APCT or FECT) and/or urine ELISA). The levels of parasite-specific IgG in urine were stable throughout both the 3-day and the 30-day studies.In conclusion, diagnosis of strongyloidiasis by urine ELISA is more sensitive than by fecal methods, with minimal daily variation for qualitative and quantitative diagnosis. Urine ELISA has potential for clinical diagnosis and population screening of strongyloidiasis.

Trends in the Prevalence of Metabolic Dysfunction–Associated Fatty Liver Disease in the United States, 2011–2018

Nonalcoholic fatty liver disease (NAFLD) affects more than 25% of the adult population worldwide and is associated with significant clinical and economic burden.1 However, heterogeneous definitions and inaccurate terminology contribute to variations in prevalence estimates and may not comprehensively incorporate complex metabolic dysfunctions that exist. An international expert panel consensus proposed updated nomenclature, metabolic dysfunction-associated fatty liver disease (MAFLD), and associated criteria to more accurately capture this complex multisystem metabolic disorder.2 Although it has not replaced NAFLD, the term MAFLD has been positively received given it more comprehensively incorporates the metabolic derangements that contribute to risk of fatty liver and it may be more practical for clinicians to identify patients with fatty liver.3 We describe prevalence of MAFLD among US adults based on these recently proposed nomenclature and definition.2.

Prevalence of multimorbidity in South Africa: a systematic review protocol

IntroductionMultimorbidity has increased globally over the past two decades, due to ageing populations and increased burden of non-communicable diseases (NCDs). In a country like South Africa, with a growing burden...

Variability in Prevalence Estimates of Disability Among Children in the National Survey of Children’s Health

Variability in Prevalence Estimates of Disability Among Children in the National Survey of Children’s Health

What is the prevalence of loneliness amongst older people living in residential and nursing care homes? A systematic review and meta-analysis.

the number of older people living in residential and nursing care homes is rising. Loneliness is a major problem for older people, but little is known about the prevalence of loneliness amongst older people living in care homes. to undertake a systematic review of literature on the prevalence of moderate and severe loneliness amongst older people living in residential and nursing care homes. we systematically reviewed the databases Cumulative Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, PsycINFO, Embase, Scopus, Cochrane and Allied and Complementary Medicine Database (AMED) from inception to January 2019. We included all studies reporting data on the prevalence of loneliness amongst older people living in care homes. A random-effects meta-analysis was conducted on all eligible data. a total of 13 articles were included, representing 5,115 participants (age range of 55-102years, mean age 83.5years, 68% female). There was a significant variation between studies in estimates of prevalence. The prevalence of moderate loneliness ranged from 31 to 100%, and the prevalence of severe loneliness ranged from 9 to 81%. The estimated mean prevalence of 'moderate loneliness' was 61% (95% confidence interval (CI): 0.41, 0.80). The estimated mean prevalence of 'severe loneliness' was 35% (95% CI: 0.14, 0.60). the prevalence of both moderate loneliness and severe loneliness amongst care home residents is high enough to warrant concern. However, the significant variation in prevalence estimates warrants further research. Future studies should identify which interventions can address loneliness and promote meaningful social engagement to enhance quality of life in care homes.

Treating Individuals With Eating Disorders: Part 1.

According to the American Psychiatric Association, eating disorders (EDs) are characterized by a persistent disturbance of eating or eating-related behaviors that result in altered consumption or absorption of food and that significantly impair physical health and/or psychosocial functioning. EDs are chronic psychiatric illnesses and are notoriously difficult to treat. The etiology of eating disorders is unknown and thought to be a complex interplay among biological predisposition, environmental and sociocultural factors, neurobiological influences, and psychological factors. Moreover, prevalence of eating disorders is increasing despite variation in prevalence estimates across studies. Nurses are well-positioned to implement appropriate screening for and comprehensive assessment of EDs as well as offer patient-centered treatment options including referrals when indicated. As the first in a two-part series, this article provides an overview of the clinical characteristics of EDs and key areas for assessment and diagnostic considerations. The follow-up article in this series will focus on pharmacological treatment strategies. [Journal of Psychosocial Nursing and Mental Health Services, 58(3), 7-13.].

Generalizability and comparability of prevalence estimates in the wild bird literature: methodological and epidemiological considerations

Wild birds have been the focus of a great deal of research investigating the epidemiology of zoonotic bacteria and antimicrobial resistance in the environment. While enteric pathogens (e.g. Campylobacter, Salmonella, and E. coli O157:H7) and antimicrobial resistant bacteria of public health importance have been isolated from a wide variety of wild bird species, there is a considerable variation in the measured prevalence of a given microorganism from different studies. This variation may often reflect differences in certain ecological and biological factors such as feeding habits and immune status. Variation in prevalence estimates may also reflect differences in sample collection and processing methods, along with a host of epidemiological inputs related to overall study design. Because the generalizability and comparability of prevalence estimates in the wild bird literature are constrained by their methodological and epidemiological underpinnings, understanding them is crucial to the accurate interpretation of prevalence estimates. The main purpose of this review is to examine methodological and epidemiological inputs to prevalence estimates in the wild bird literature that have a major bearing on their generalizability and comparability. The inputs examined here include sample type, microbiological methods, study design, bias, sample size, definitions of prevalence outcomes and parameters, and control of clustering. The issues raised in this review suggest, among other things, that future prevalence studies of wild birds should avoid opportunistic sampling when possible, as this places significant limitations on the generalizability of prevalence data.

Profile of and risk factors for poststroke cognitive impairment in diverse ethnoregional groups.

ObjectiveTo address the variability in prevalence estimates and inconsistencies in potential risk factors for poststroke cognitive impairment (PSCI) using a standardized approach and individual participant data (IPD) from international cohorts in the Stroke and Cognition Consortium (STROKOG) consortium.MethodsWe harmonized data from 13 studies based in 8 countries. Neuropsychological test scores 2 to 6 months after stroke or TIA and appropriate normative data were used to calculate standardized cognitive domain scores. Domain-specific impairment was based on percentile cutoffs from normative groups, and associations between domain scores and risk factors were examined with 1-stage IPD meta-analysis.ResultsIn a combined sample of 3,146 participants admitted to hospital for stroke (97%) or TIA (3%), 44% were impaired in global cognition and 30% to 35% were impaired in individual domains 2 to 6 months after the index event. Diabetes mellitus and a history of stroke were strongly associated with poorer cognitive function after covariate adjustments; hypertension, smoking, and atrial fibrillation had weaker domain-specific associations. While there were no significant differences in domain impairment among ethnoracial groups, some interethnic differences were found in the effects of risk factors on cognition.ConclusionsThis study confirms the high prevalence of PSCI in diverse populations, highlights common risk factors, in particular diabetes mellitus, and points to ethnoracial differences that warrant attention in the development of prevention strategies.

Prevalence of Burnout Among Physicians

Burnout is a self-reported job-related syndrome increasingly recognized as a critical factor affecting physicians and their patients. An accurate estimate of burnout prevalence among physicians would have important health policy implications, but the overall prevalence is unknown. To characterize the methods used to assess burnout and provide an estimate of the prevalence of physician burnout. Systematic search of EMBASE, ERIC, MEDLINE/PubMed, psycARTICLES, and psycINFO for studies on the prevalence of burnout in practicing physicians (ie, excluding physicians in training) published before June 1, 2018. Burnout prevalence and study characteristics were extracted independently by 3 investigators. Although meta-analytic pooling was planned, variation in study designs and burnout ascertainment methods, as well as statistical heterogeneity, made quantitative pooling inappropriate. Therefore, studies were summarized descriptively and assessed qualitatively. Point or period prevalence of burnout assessed by questionnaire. Burnout prevalence data were extracted from 182 studies involving 109 628 individuals in 45 countries published between 1991 and 2018. In all, 85.7% (156/182) of studies used a version of the Maslach Burnout Inventory (MBI) to assess burnout. Studies variably reported prevalence estimates of overall burnout or burnout subcomponents: 67.0% (122/182) on overall burnout, 72.0% (131/182) on emotional exhaustion, 68.1% (124/182) on depersonalization, and 63.2% (115/182) on low personal accomplishment. Studies used at least 142 unique definitions for meeting overall burnout or burnout subscale criteria, indicating substantial disagreement in the literature on what constituted burnout. Studies variably defined burnout based on predefined cutoff scores or sample quantiles and used markedly different cutoff definitions. Among studies using instruments based on the MBI, there were at least 47 distinct definitions of overall burnout prevalence and 29, 26, and 26 definitions of emotional exhaustion, depersonalization, and low personal accomplishment prevalence, respectively. Overall burnout prevalence ranged from 0% to 80.5%. Emotional exhaustion, depersonalization, and low personal accomplishment prevalence ranged from 0% to 86.2%, 0% to 89.9%, and 0% to 87.1%, respectively. Because of inconsistencies in definitions of and assessment methods for burnout across studies, associations between burnout and sex, age, geography, time, specialty, and depressive symptoms could not be reliably determined. In this systematic review, there was substantial variability in prevalence estimates of burnout among practicing physicians and marked variation in burnout definitions, assessment methods, and study quality. These findings preclude definitive conclusions about the prevalence of burnout and highlight the importance of developing a consensus definition of burnout and of standardizing measurement tools to assess the effects of chronic occupational stress on physicians.

ADHD prevalence estimates in Italian children and adolescents: a methodological issue

BackgroundAttention deficit hyperactivity disorder (ADHD) is recognized as the most common, and most studied, developmental age disorder. Basic information, such as the most appropriate case definition and the best way to evaluate the disorder’s prevalence rate, however, remains an open issue.MethodsA comprehensive meta-analysis on the epidemiology of ADHD in Italy, which was lacking from the literature, was therefore performed to attempt to estimate the actual prevalence rate of ADHD, highlighting conceptual and quantitative differences between clinical-diagnosis and survey-based symptoms studies. The Medline, Embase, and PsycINFO databases, and the grey literature, were searched up to January 2018. The review was laid out in three main sections: an overall prevalence estimate, an epidemiological profile of ADHD symptoms, and an attempt to define the actual rate of ADHD diagnosis, as emerged from Italian studies.ResultsA total of 15 unique studies were included. These contributed to estimating the prevalence of ADHD in 67,838 subjects aged 5–17, representing 9 of the 20 regions (45%) of Italy. Overall, the pooled prevalence of ADHD was 2.9% (range: 1.1–16.7%). When distinguishing studies based on case definition, however, we found an average prevalence estimate, based on symptoms criteria, of 5.9% (range: 1.4 to 16.7%) and a best-estimate prevalence rate of 1.4% (range: 1.1 to 3.1%).ConclusionsFollowing the case definition for epidemiological studies of ADHD, counting only subjects with an ADHD diagnosis performed and confirmed by clinical assessment would reduce the wide variability in prevalence estimates, and, above all, would both describe the real rate of subjects suffering from ADHD disorder and avoid misdiagnosis.

A systematic review and meta-regression of the knowledge, practices, and training of restaurant and food service personnel toward food allergies and Celiac disease.

BackgroundUp to 3–5% of adults may be affected by food allergies, while approximately 1% are affected by Celiac disease (CD). Food allergy reactions can be severe and potentially fatal, while CD can result in various symptoms. Restaurant and food service establishment staff have an important role in helping to prevent food allergy and CD risks among affected customers.ObjectivesA systematic review was undertaken to identify, characterize, and synthesize published research on the prevalence of food allergy and CD knowledge, practices, and training among restaurant and food service personnel. The population of interest included any personnel in these settings who prepare, handle, or serve food. Outcomes included the prevalence of food allergy and CD knowledge, practices, and training.MethodsThe review was conducted using standardized methods, including: a comprehensive search strategy; relevance screening of abstracts; characterization of relevant articles; data extraction; and risk of bias assessment. Outcomes were stratified into comparable subgroups and descriptively analyzed to examine prevalence trends across studies. Meta-regression was conducted on selected outcomes to identify possible sources of variability in prevalence estimates across studies.ResultsThirty-eight relevant studies were identified; most were conducted in the United States (50%) and focused on food allergies (90%). Significant variability was identified across studies for most outcomes. Participants generally had a higher knowledge, self-efficacy, and use of practices related to preparing and serving allergen-free meals compared to food allergy emergency response. Participants’ reported use of various risk prevention and response practices was generally low. Most participants across studies had not received prior food allergy training (median prevalence of 65% across 12 studies).ImplicationsKey knowledge and practice gaps were identified that could be targeted by future training programs. Research gaps were also identified, including a need for more experimental studies to evaluate food allergy and CD training interventions.

Continuous deep sedation until death in patients admitted to palliative care specialists and internists: a focus group study on conceptual understanding and administration in German-speaking Switzerland.

Continuous deep sedation until death is increasingly used to treat intolerable suffering of terminally ill patients. One of the highest incidences and strongest increases has been observed in Switzerland. Variation in prevalence estimates indicates a potential effect of differences in sedation practice between care settings and professionals. To explore physicians' and nurses' conceptual understanding of continuous deep sedation and unravel decision-making processes in everyday clinical practice. Between June and October 2016, we conducted seven qualitative focus groups with 47 healthcare professionals (21 physicians and 26 nurses) involved in sedation decision and administration. Participants had on average 20 years (range 3-39) of clinical experience, 10 years (range 0-30) of self-reported palliative care experience, and a mean annual number of 5 patients (range 1-20) continuously deeply sedated until death. Continuous deep sedation until death covers a wide spectrum of practices: specialised palliative sedation induced through benzodiazepines to treat refractory symptoms as option of last resort, sedation as comfort therapy with benzodiazepines or opioids, and sedation taken into account as a side effect of gradually increased analgesia. We found substantial variation in terminology and definition, indication and medication used for continuous deep sedation until death. To provide optimal symptom management in terminally ill patients, early involvement of palliative care experts as well as financial and regulatory support should be provided to encourage multi-disciplinary collaboration and thus consensus for defining the distinct sedation practices.

Understanding variation in prevalence estimates of polycystic ovary syndrome: a systematic review and meta-analysis.

Polycystic ovary syndrome (PCOS) prevalence estimates vary when different diagnostic criteria are applied. Lack of standardization of individual elements within these criteria may contribute to prevalence differences. A systematic review of studies reporting prevalence of PCOS, using at least one of the National Institutes of Health (NIH), Rotterdam or Androgen Excess Society (AE-PCOS) criteria, was conducted. The aim was to investigate the impact on prevalence reporting of different definitions of the clinical elements for PCOS diagnosis. A systematic search of Ovid MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Emcare and BIOSIS was conducted. The search was limited to English language and studies published between January 1990 and January 2018. Included articles needed to define PCOS by at least one of the NIH, Rotterdam or AE-PCOS criteria, be of an unselected population and be published as a full text article. Risk-of-bias was assessed. A total of 21 studies met the inclusion criteria. The random-effects pooled prevalence of PCOS in studies that used the NIH criteria (7% [95% CI: 6-7%]), was significantly different from that identified in studies that used the Rotterdam criteria (12% [95% CI: 10-15%], P < 0.0001) but not studies that used the AE-PCOS criteria (10% [95% CI: 6-13%], P = 0.075). The pooled estimates for Rotterdam and AE-PCOS were not significantly different from each other (P = 0.201). Pooled prevalence estimates were compared between studies separated on the basis of: oligo-amenorrhoea vs oligo-amenorrhoea plus short cycles, clinical androgen excess requiring hirsutism vs any clinical androgen excess, use of different versions and cut-offs for the Ferriman-Gallwey (F-G) score, and inclusion vs non-inclusion of oral contraceptive users. There were no statistically significant differences for any of these comparisons. There was insufficient information to allow subgroup analyses of definitions of polycystic ovaries. Inclusion of ovarian morphology results in statistically significantly higher pooled prevalence estimates for PCOS. Heterogeneity in prevalence estimates for PCOS reflect the broad clinical spectrum of the condition, lack of standardization of the elements within each set of diagnostic criteria and the use of a range of diagnostic cut-offs, as well as potential differences between study populations. The use of different definitions for anovulation and clinical androgen excess did not appear to contribute to differences in the estimated prevalence of PCOS in this study. However, as the number of studies in most of the comparison groups was small, real differences may have been missed. Uncertainty surrounding the diagnosis of PCOS urgently needs to be addressed in order to provide clinicians and their patients with greater diagnostic certainty, and hence reduce inappropriate labelling and the potential psychological harm that may accompany misdiagnosis.