Objective: To establish the rate of bleeding disorders amongst women with confirmed endometriosis and clarify predictive features on history. Methods: Eight-two women with confirmed diagnosis of endometriosis were recruited from a tertiary womens hospital. General bleeding tendency was evaluated with a modified internationally standardised questionnaire, and a bleeding score was calculated. Menstrual loss was evaluated by obtaining current and heaviest-ever menses profile using Pictorial Blood loss Assessment Chart(PBAC). Forty-one women satisfied criteria for a significant bleeding tendency and underwent coagulation tests including Prothrombin time(PT), activated partial thromboplastin time(aPTT), Platelet Function Analyser-100(PFA-100) and von Willebrand factor(vWF)/Factor VIII(FVIII) studies. Results : The prevalence of abnormal screening haemostasis tests for the population was 17.72% (95% CI 10.04-27.94) for all tests, 8.54%(95% CI 3.50-16.80) for vWF tests, and 12.99%( 95% CI 6.41-22.59) for PFA-100. Receiver Operator Characteristic curve analysis demonstrated a very good performance of the bleeding score as a diagnostic test for haemostatic abnormalities for nulliparous women with endometriosis. Bleeding symptoms individually were not predictive. Logistic regression suggested the combination of mittleschmerz, cutaneous bleeding symptoms, heavy menstrual bleeding and prolonged bleeding from minor wounds as predictive for haemostatic abnormalities (p=0.0197). Conclusion: The prevalence of abnormal bleeding tests in women with endometriosis on preliminary testing was higher than the population rate of bleeding abnormalities and thus people with histologically proven endometriosis warrant a higher index of suspicion with respect to testing for mild bleeding disorders.

BACKGROUND:We examined the association between unwanted sexual experiences and cervical cancer, cervical intraepithelial neoplasia 3, adenocarcinoma in situ, diagnosed ≤25 years of age.METHODS:A case-control study of women ≤55 years who attended gynecological hospitals in Australia between 1983 and 2007. Cases were ≤25 years when diagnosed with disease, control group 1 were "older women" >25 years at diagnosis; control group 2 were "well women" ≤25 years attending preventive health clinics. A self-administered postal survey was utilized. The main outcome measures were prevalence of childhood sexual abuse (<16 years) and unwanted adolescent sexual experiences (between 16 and 18 years) in cases compared to controls.RESULTS:Of 400 contactable subjects, 251 participated (62.8%). Prevalence of childhood sexual abuse in cases (26.6% [25/94]) was similar to other groups. Prevalence of childhood genital contact abuse in cases with cervical cancer was 45.5% [5/11], compared to older women (20% [10/50], p = 0.08) and well women (13.8% [8/58], p = 0.01), and was marginally more common compared to well women when adjusted for other lifestyle factors (odds ratio [OR]: 4.7 [1.0-22.6], p = 0.05). Prevalence of unwanted adolescent sexual experiences in cases was 28.9% [33/114]. Prevalence of adolescent penile-genital contact experiences in cervical cancer cases was 46.7% [7/15], compared to older women (9.4%, [6/64], p < 0.001) and well women (13.7%, [10/73], p = 0.003), and was more common compared to well women when adjusted for lifestyle (OR: 5.9 [1.4-24.9], p = 0.02) and sexual health risk factors (OR: 5.6 [1.4-22.1] p = 0.01).CONCLUSIONS:Unwanted sexual experiences with genital contact were a risk factor for invasive cervical cancer ≤25 years, likely due to a complex interplay of biological and environmental factors.

Background: Australia was the first country to implement a government-funded National Human Papillomavirus (HPV) Vaccination Programme. We assessed HPV vaccine uptake comparing self-reported and Register validated estimates, and the knowledge and attitudes of young women with regards to HPV vaccination post-implementation of the programme.Methods: Females, aged 16-25 years living in Victoria, Australia, were recruited using targeted advertising on Facebook from May to September 2010, to complete a web-based questionnaire.Results: Geographic distribution, Indigenous and socio-economic status of the 278 participants were representative of the target population. Overall, 210/278 (76%) had heard of HPV vaccines, with 1621278 (58%) reporting receipt of at least one dose of vaccine, and 54(19%) unsure. Verification of HPV vaccination status of 142 consenting participants (51%) showed 71% had received at least one dose. Main reasons for vaccination were for protection against HPV infection and cervical cancer (96%) and because it was free (87%), whereas unvaccinated women were uncertain of their eligibility (50%), concerned about adverse reactions (32%), or perceived that vaccination was not needed if they were monogamous (32%).Conclusion: The potential utility of a vaccination register in the context of a national programme is apparent from the large proportion of young women who were unsure of their vaccine status. HPV vaccine knowledge among participants was relatively high suggesting the national programme has successfully communicated to the majority of eligible women, the purpose and limitations of the vaccine. Vigilance is needed to ensure that young women follow through with Pap testing in vaccine eligible cohorts. The ongoing vaccination programme for pre-adolescent girls and boys should communicate to parents that those with one sexual partner can still acquire HPV and that the safety of the vaccine is now well demonstrated. (C) 2014 Elsevier Ltd. All rights reserved.

Concurrent sexual partnerships, or sexual partnerships that overlap in time, have been associated with HIV and sexually transmitted infections (STI). How best to measure concurrency and the personal characteristics and predictors of concurrency are not yet well understood. We compared two frequently used concurrency definitions, including a self-reported measure based on participant response regarding overlapping sex with partners, and the UNAIDS measure based on overlapping dates of last sex and intention to have sex again. We performed multivariable logistic regression analyses to identify socio-demographic, behavioral, and structural predictors of concurrency among 1,542 patients at an urban STI clinic in Jackson, Mississippi. Nearly half (44 %) reported concurrency based on self-reported sex with other partners, and 26 % reported concurrency according to the UNAIDS concurrency measure. Using the self-reported concurrency measure, the strongest predictors of concurrency were perceived partner concurrency, drug use at last sex, having more than 10 lifetime partners, and being recently incarcerated. Strongest predictors of concurrency using the UNAIDS measure were lifetime number of partners and perceived partner concurrency. Concurrency is highly prevalent in this population in the Deep South and social, structural and behavioral factors were important predictors of concurrency for both measures. Future research should use time anchored data collection methods and biomarkers to assess whether both definitions of concurrency are associated with HIV outcomes.

Purpose: To compare social and emotional adjustment including educational attainment and substance use in women who had a child, pregnancy termination, or miscarriage by young adulthood.Methods: Data were from a population-based longitudinal study of the health and well-being of 1,943 young Australians (Victorian Adolescent Health Cohort Study) followed from 15 to 24 years of age. The sample was restricted to female participants and based on pregnancies reported by age 24 years. Analyses were adjusted for early teenage depressive symptoms, cigarette smoking, alcohol use, cannabis use, and parent socioeconomic context.Results: A total of 208 pregnancies (in 170 women) were reported from a sample of 824 young women by 24 years of age. Compared with those who had never been pregnant, those who had a child had lower tertiary education completion and a higher risk of nicotine dependence; those who terminated a pregnancy were more commonly single and had a higher risk of smoking and alcohol use as well as nicotine and alcohol dependence; and those who had a miscarriage had a higher risk of depressive symptomatology and binge drinking as well as nicotine and cannabis dependence.Conclusions: Young women who have been pregnant by their mid-twenties report a range of difficulties in social and emotional adjustment that vary across the different pregnancy outcomes. Broad-based psychosocial health care is essential not only for young women whose pregnancies proceed to live birth, but also for those whose pregnancies end with miscarriage or induced abortion. (C) 2014 Society for Adolescent Health and Medicine. All rights reserved.

Knowledge regarding the natural history of human papillomavirus (HPV) infection and its clinical sequelae in adolescents has increased significantly over the last decade; as a result, there have been world-wide recommendations for less aggressive Pap screening and management of cervical dysplasias in young women. It is important that adolescent health providers understand these issues, as knowledge of HPV and its sequelae in the Australian community is limited, despite the introduction of a national immunisation programme. Parents and young women have expressed a desire for further information to make informed choices. This paper reviews the natural history of HPV infection in adolescents and the evidence behind new conservative guidelines for cervical screening, plus prophylactic vaccination in young women.

Background: Chlamydia (Chlamydia trachomatis) is the commonest bacterial sexually transmissible infection worldwide and contributes to significant morbidity in females. We examined potential barriers and facilitating factors for screening in young Victorian women, using the social networking site, Facebook to recruit participants. Methods: This was part of a larger study on young women's health that assessed the feasibility of using social networking sites for recruitment. An advertisement was placed on Facebook between May and September 2010, and was visible to eligible women. Women who clicked on the advertisement and expressed their interest in participating were invited to complete a questionnaire either at a study site or online. Results: In total, 278 participants completed the survey, with 76% reporting willingness to participate in chlamydia screening by recruitment via an online system. Overall, 73% of participants indicated they were comfortable providing a urine sample collected at home for chlamydia screening, with older participants less comfortable with this method (P = 0.02, odds ratio (OR) = 0.09, 95% confidence interval (CI) = 0.01-0.7). Participants expressed comfort with their Pap smear and chlamydia screening being performed together (92.7%), especially those who were aware of human papillomavirus (P < 0.01, OR= 2.5, 95% CI = 1.3-4.7). Conclusions: This study demonstrated willingness by young Victorian women using Facebook to participate in screening for chlamydia. There was strong acceptance of self-collected sampling, and of combined chlamydia and cervical cytology screening. Facebook may therefore be a feasible way for improving screening coverage at a population level.

Objectives Human papillomavirus (HPV) is the commonest sexually transmitted infection. Despite the significant morbidity and mortality associated with HPV-related diseases, previous studies have demonstrated low HPV knowledge in the general population. The objectives of this study were to assess knowledge of cervical cancer and HPV among young women and investigate predictors of high knowledge.Methods Female subjects, aged 16-25 years living in Victoria, Australia, were recruited using targeted advertising on Facebook from May to September 2010. A web-based questionnaire was used in a cross-sectional pilot study for a large longitudinal study on women's health, The Young Female Health Initiative.Results A total of 278 women completed the questionnaire. The geographic region, indigenous status and socio-economic status of participants were representative of the target population. Overall, 63% knew what HPV was, but only 48% knew it was a common virus. Predictors of high HPV knowledge on multivariate analyses were older age (adjusted OR (aOR) 2.78, 95% CI 0.77 to 10.04), higher socio-economic status (aOR 1.39, 95% CI 0.66 to 2.95), being Australian-born (aOR 3.10, 95% CI 1.15 to 8.36), older age at first vaginal intercourse (aOR 1.84, 95% CI 0.66 to 5.14), awareness of HPV vaccines (aOR 2.16, 95% CI 0.68 to 6.85) and chlamydia (aOR 2.57, 95% CI 1.11 to 5.94), and self-reported HPV vaccination status (aOR 1.83, 95% CI 0.76 to 4.41).Conclusions HPV and cervical cancer knowledge among participants were relatively high compared with other studies conducted both worldwide and in Australia. However, deficits in knowledge exist and warrant address in educational initiatives.

Objective. This study aimed to estimate and compare the validity of high-risk human papillomavirus DNA (HR-HPV DNA) testing using Hybrid Capture II with and without Pap cytological examination in the detection of incident high-grade cervical intraepithelial neoplasia (CIN 2+) after treatment.Materials and Methods. A total of 1,608 women undergoing ablative or excisional treatment were recruited to the study between May 2001 and June 2005, of whom 985 women were treated for CIN 2+. High-risk HPV DNA tests and Pap smears were performed once in every 6 months for 24 months after treatment.Results. A total of 888 women were eligible for analysis. High-grade cervical intraepithelial neoplasia was detected in 22 women (2.5%) for the 24 months after treatment. The sensitivity for CIN 2+ detection with cytological diagnosis ranged from 43% to 100%, from 67% to 100% for HR-HPV DNA test, and from 67% to 100% for both tests combined. The specificity of cytological diagnosis ranged from 94% to 97%, from 75% to 84% for HR-HPV DNA test, and from 80% to 82% for both tests combined. The positive predictive value for cytological diagnosis ranged from 8% to 30%, from 4% to 14% for HR-HPV DNA test, and from 4% to 11% for both tests combined. The negative predictive value was 99% or greater for cytological diagnosis alone, HR-HPV DNA test alone, or for both tests combined.Conclusions. As histologically proven CIN 2+ after treatment for this group of women was low, adding HR-HPV DNA testing to Pap smear did not increase the detection of CIN 2+ or enhance the negative predictive value of cytological diagnosis alone.

Cervical cancer is the third most common cancer in women worldwide. Persistent infection with an oncogenic human papillomavirus (HPV) is necessary, but not sufficient, for its development. Over many years, only a small proportion of women with chronic HPV infection progress to develop disease. The role of host genes and environmental factors in the pathogenesis of, or predisposition to, cervical cancer is still unclear. We conducted a systematic review of published literature in MEDLINE–PubMed to identify studies of cervical cancer susceptibility that used a twin study design. We used standard MeSH terms (controlled vocabulary) as well as specific free-text terms and combinations of terms related to cervical cancer, with no restriction on publication date. We performed a full text review to ensure the identified articles met our inclusion criteria and, if so, extracted information on demographics, sample size, study definitions, and key statistical findings. Of the 285 articles identified, three utilized a classical twin design and reported results specific to cervical cancer. The studies were based on cancer registry data from Scandinavia, with sample sizes ranging from 312 to 710 twin pairs. The findings from one study were consistent with a genetic mechanism for the causation of carcinoma in situ. Future research studies using the strength of the classic twin design, together with incorporation of HPV DNA status, are indicated to determine whether there is a potential role for genetic factors in the development of cervical cancer or high-grade cervical dysplasia from chronic oncogenic HPV infection.

Background: Recruitment of young people for health research by traditional methods has become more expensive and challenging over recent decades. The Internet presents an opportunity for innovative recruitment modalities.Objective: To assess the feasibility of recruiting young females using targeted advertising on the social networking site Facebook.Methods: We placed an advertisement on Facebook from May to September 2010, inviting 16- to 25-year-old females from Victoria, Australia, to participate in a health study. Those who clicked on the advertisement were redirected to the study website and were able to express interest by submitting their contact details online. They were contacted by a researcher who assessed eligibility and invited them to complete a health-related survey, which they could do confidentially and securely either at the study site or remotely online.Results: A total of 551 females responded to the advertisement, of whom 426 agreed to participate, with 278 completing the survey (139 at the study site and 139 remotely). Respondents' age distribution was representative of the target population, while 18- to 25-year-olds were more likely to be enrolled in the study and complete the survey than 16- to 17-year-olds (prevalence ratio = 1.37, 95% confidence interval 1.05-1.78, P = .02). The broad geographic distribution (major city, inner regional, and outer regional/remote) and socioeconomic profile of participants matched the target population. Predictors of participation were older age, higher education level, and higher body mass index. Average cost in advertising fees per compliant participant was US $20, making this highly cost effective.Conclusions: Results demonstrate the potential of using modern information and communication technologies to engage young women in health research and penetrate into nonurban communities. The success of this method has implications for future medical and population research in this and other demographics.

African Americans are disproportionately infected with HIV/AIDS. Despite Centers for Disease Control and Prevention (CDC) guidelines recommending routine opt-out testing for HIV, most HIV screening is based on self-perceived HIV risks. Philadelphia launched a rapid HIV testing program in seven public health clinics in 2007. The program provides free rapid oral HIV tests to all patients presenting for health services who provide informed consent. We analyzed demographic, risk behavior, and HIV serostatus data collected during the program between September 2007 and January 2009. We used multivariable logistic regression to estimate the association between behavioral and demographic factors and newly diagnosed HIV infection. Of the 5871 individuals testing for HIV, 47% were male, 88% were African American, and the mean age was 34.7 years. Overall HIV prevalence was 1.1%. All positive tests represented new HIV diagnoses, and 72% of individuals reported testing previously. Approximately 90% of HIV-positive individuals and 92% of individuals with more than five recent sex partners never, or only sometimes, used condoms. Two thirds of individuals testing positive and 87% of individuals testing negative assessed their own HIV risk as zero or low. Individuals reporting cocaine use and ever having a same sex partner both had 2.6 times greater odds of testing positive. Condom use in this population was low, even among high-risk individuals. Philadelphia's program successfully provided HIV testing to many underserved African Americans who underestimate their HIV risk. Our results nevertheless suggest greater efforts are needed to encourage more individuals to undergo HIV testing in Philadelphia, particularly those who have never tested.

OBJECTIVE:To estimate human papillomavirus (HPV) clearance of women with cervical abnormalities after treatment.METHODS:Women attending dysplasia clinics between 2001 and 2007 with a new diagnosis of high-grade dysplasia or persistent low-grade dysplasia requiring treatment by excision or laser ablation were invited to participate. Cervical cytology, histology of biopsies collected at colposcopy, and HPV DNA detection and genotyping of 37 HPV genotypes on specimens collected at treatment and subsequent routine visits were examined. A log-rank test was used to compare the survival distribution between groups.RESULTS:Of the 1,649 women eligible at treatment (baseline), 1,207 (73%) were included in the analysis; 96% (n=1,159) had three or more posttreatment visits. At baseline and the subsequent three follow-up visits, the prevalence of women with HPV DNA detected was 84%, 53% (on average, 6.3 months after baseline), 44% (on average, 15.7 months after baseline), and 45% (on average, 24.3 months after baseline). The median time to HPV clearance was approximately 6 months for either HPV 16 (n=387) or HPV 18 (n=96), irrespective of concurrent detection of other types. On average, HPV 16 or HPV 18 types cleared faster than other types (P<.001). This association remained significant after adjustment for age, preoperative histology, number of preoperative histology results, and treatment type.CONCLUSION:Clearance times of HPV 16 and HPV 18 infections were similar to each another but shorter than other HPV types.LEVEL OF EVIDENCE:III.

BACKGROUND:Chlamydia trachomatis is a common bacterial sexually transmitted infection in men who have sex with men (MSM), although little is known about its distribution in Australian MSM communities.METHODS:From 2004 to 2008, 612 consecutive C. trachomatis positive anal swab and urine samples were collected for genotyping and quantification from MSM attending 2 sexual health centers (Melbourne and Sydney).RESULTS:The most common serovars detected were D (35.2%), G (32.7%), and J (17.7%), although these distributions changed significantly by year and city. C. trachomatis infections (2.8%) involved more than 1 serovar and only 1 lymphogranuloma venereum isolate was detected. The majority of serovar strains showed an identical omp1 genotype, with only 7.5% showing genotypic variability. Serovar G infections were not associated with overseas sexual activity; whilst individuals with serovar J were less likely to have had a prior C. trachomatis infection, and with serovar E were those who had prior C. trachomatis infection. Symptoms were present in 68% of urethral infections and 28% anal infections, and were associated with gonorrheal coinfection (13.8%), prior C. trachomatis infection (20.6%) and increasing age. A higher C. trachomatis load was identified in anal samples versus urine (1.48 × 10(4) genome copies/anal swab; 3.72 × 10(3) copies/mL urine) and no association was made to concentration including the presence of symptoms and prior C. trachomatis infection.CONCLUSIONS:This is the largest study of C. trachomatis serovars in MSM: it is the first to report C. trachomatis rectal loads, and provides an overview on C. trachomatis serovars and genotypic variants that circulate in Australian MSM communities.

Women reporting childhood sexual abuse (CSA) that involved actual or attempted penetration may not identify this as their first sexual intercourse. Data were drawn from a population-based, prospective cohort study spanning adolescence to adulthood. CSA prior to age 16 and age of first sexual intercourse with a male were assessed retrospectively. More than half of women reporting CSA in the form of actual or penetrative abuse reported an age of first sexual intercourse at or beyond 16 years. Direct questioning about CSA is needed to accurately ascertain sexual history.

Knowledge regarding the natural history of human papillomavirus (HPV) infection and its clinical sequelae in adolescents has increased significantly over the last decade; as a result, there have been world‐wide recommendations for less aggressive Pap screening and management of cervical dysplasias in young women. It is important that adolescent health providers understand these issues, as knowledge of HPV and its sequelae in the Australian community is limited, despite the introduction of a national immunisation programme. Parents and young women have expressed a desire for further information to make informed choices. This paper reviews the natural history of HPV infection in adolescents and the evidence behind new conservative guidelines for cervical screening, plus prophylactic vaccination in young women.

The purpose of this study was to investigate risk for neuroticism due to the joint action of low maternal care and compromised mesocorticolimbic 'reward' system function linked to a variable number tandem repeat (VNTR) in the dopamine 4 receptor gene (DRD4). Data were drawn from the Victorian Adolescent Health Cohort Study, a longitudinal study of the health and well-being of 2,000 young Australians followed from adolescence to young adulthood across 8 waves from 14- to 28-years. Genetic risk was defined by carriage of at least one copy of the 7-repeat allele or derivative alleles 5, 6, and 8 (labeled 7R+). Neuroticism was assessed in adolescence and young adulthood. We observed an approximately fourfold increase in the odds of reporting neurotic symptoms in carriers of the 7R+ disposition who reported low maternal care compared with non-carriers who reported high maternal care. The percentage of risk attributable to mechanisms in which both factors played a role was 35%. Findings are discussed in terms of implications for prevention.

To investigate the combined effect of an exon III variable number tandem repeat in the dopamine receptor gene (DRD4) and insecure attachment style on risk for tobacco, cannabis and alcohol use problems in young adulthood. It was hypothesized that (1) individuals with 5, 6, 7 or 8 repeats (labelled 7R+) would be at increased risk for problematic drug use, and (2) risk for drug use would be further increased in individuals with 7R+ repeats who also have a history of insecure parent-child attachment relations. Data were drawn from the Victorian Adolescent Health Cohort Study, an eight-wave longitudinal study of adolescent and young adult development. DRD4 genotypes were available for 839 participants. Risk attributable to the combined effects of 7R+ genotype and insecure attachments was evaluated within a sufficient causes framework under the assumptions of additive interaction using a two-by-four table format with a common reference group. 7R+ alleles were associated with higher tobacco, cannabis and alcohol use (binging). Insecure attachments were associated with higher tobacco and cannabis use but lower alcohol use. For tobacco, there was evidence of interaction for anxious but not avoidant attachments. For cannabis, there was evidence of interaction for both anxious and avoidant attachments, although the interaction for anxious attachments was more substantial. There is no evidence of interaction for binge drinking. Results are consistent with a generic reward deficit hypothesis of drug addiction for which the 7R+ disposition may play a role. Interaction between 7R+ alleles and attachment insecurity may intensify risk for problematic tobacco and cannabis use.

BackgroundRegular adolescent cannabis use predicts a range of later drug use and psychosocial problems. Little is known about whether occasional cannabis use carries similar risks.AimsTo examine associations between occasional cannabis use during adolescence and psychosocial and drug use outcomes in young adulthood; and modification of these associations according to the trajectory of cannabis use between adolescence and age 20 years, and other potential risk factors.MethodA 10-year eight-wave cohort study of a representative sample of 1943 secondary school students followed from 14.9 years to 24 years.ResultsOccasional adolescent cannabis users who continued occasional use into early adulthood had higher risks of later alcohol and tobacco dependence and illicit drug use, as well as being less likely to complete a post-secondary qualification than non-users. Those using cannabis at least weekly either during adolescence or at age 20 were at highest risk of drug use problems in young adulthood. Adjustment for smoking in adolescence reduced the association with later educational achievement, but associations with drug use problems remained.ConclusionsOccasional adolescent cannabis use predicts later drug use and educational problems. Partial mediation by tobacco use raises a possibility that differential peer affiliation may play a role.

Objectives: Childhood sexual abuse (CSA) is associated with both short- and long-term adverse mental and physical health consequences, yet there remains considerable controversy about the prevalence of CSA in the general population. There is also little prospective data on unwanted sexual contact (USC) collected during adolescence.Methods: Data from a 10-year cohort study of a nationally representative sample of students aged 14-15 years in Victoria, Australia from 1992 to 2003 was used. CSA prior to age 16 was assessed retrospectively at age 24 years using a 6-item validated questionnaire. USC was assessed prospectively via questionnaire at 3 time points during adolescence. Multiple imputation was used to handle missing data.Results: One thousand nine hundred forty-three of 2032 eligible adolescents participated in at least one wave of the study. One thousand seven hundred forty-five (812 males and 933 females) provided sufficient information to allow for multiple imputation and inclusion in the main analysis. The prevalence of any CSA was substantially higher among girls [17%, 95% confidence interval (Cl): 14-20%] than boys (7%, 95% Cl: 3-10%), as was the prevalence of USC reported during adolescence (14%, 95% CI 11-16%, versus 6%, 95% Cl: 4-8% respectively).Conclusions: These findings highlight the high prevalence of childhood sexual abuse and unwanted sexual contact among girls as well as boys.Practice implications: In order to accurately inform early recognition, intervention and education programs for individuals with a history of CSA the frequency of sexual abuse must first be precisely quantified. Developing more standardized approaches will be important in order to improve our understanding of the extent of this problem. (C) 2010 Elsevier Ltd. All rights reserved.