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Background: This study aimed to investigate the associations between hysterectomy for benign indications and risk of breast, colorectal, kidney, and thyroid cancer, and to explore whether these associations are modified by removal of ovaries at the time of surgery or by age at surgery. Methods: We conducted a retrospective cohort study of the female population of Western Australia (n = 839,332) linking data from electoral, hospital, births, deaths, and cancer records. We used Cox regression to estimate HRs and 95% confidence intervals (CI) for the associations between hysterectomy and diagnosis of breast, colorectal, kidney, and thyroid cancers. Results: Compared with no surgery, hysterectomy without oophorectomy (hysterectomy) and hysterectomy with bilateral salpingo-oophorectomy (hysterectomy-BSO) were associated with higher risk of kidney cancer (HR, 1.32; 95% CI, 1.11–1.56 and HR, 1.29; 95% CI, 0.96–1.73, respectively). Hysterectomy, but not hysterectomy-BSO, was related to higher risk of thyroid cancer (HR, 1.38; 95% CI, 1.19–1.60). In contrast, hysterectomy (HR, 0.94; 95% CI, 0.90–0.98) and hysterectomy-BSO (HR, 0.92; 95% CI, 0.85–1.00) were associated with lower risk of breast cancer. We found no association between hysterectomy status and colorectal cancer. Conclusions: The associations between hysterectomy and cancer varied by cancer type with increased risks for thyroid and kidney cancer, decreased risk for breast cancer, and no association for colorectal cancer. Impact: As breast, colorectal, and gynecologic cancers comprise a sizeable proportion of all cancers in women, our results suggest that hysterectomy is unlikely to increase overall cancer risk; however, further research to understand the higher risk of thyroid and kidney cancer is warranted.

Background Epithelial ovarian cancer (EOC) is the eighth most common cancer in women, has a five-year survival of ∼45%, and very few established modifiable risk factors. Some evidence suggests that bisphosphonates could have chemopreventive benefits, but few epidemiological studies have investigated the association between bisphosphonate use and incidence of EOC. Methods We conducted a nested case-control study using linked administrative data. We identified 9,367 women over 50 years diagnosed with EOC (cases) from 2004 to 2013, and for each case identified five controls from the Australian Medicare Enrolment database matched by age, state, area of residence, and area-level socioeconomic disadvantage. We assessed the associations between bisphosphonate use using dispensed prescription data (ever use, duration and dose) and EOC (overall, by histotype), adjusting for comorbidities and MHT use. We conducted sensitivity analyses in women with complete ascertainment of dispensing claims and for residents of one Australian state that had linked with data linked to hospital procedures, including oophorectomy. Results Our analyses show an inverse association between bisphosphonate use and risk of EOC overall (OR = 0.81, 95%CI:0.75-0.88), and for endometrioid (OR = 0.51, 95%CI:0.33-0.79) and serous (OR = 0.84, 95%CI:0.75-0.93) histotypes. There was some evidence that higher dose and duration were associated with a greater reduction in risk. Results from sensitivity analyses were not appreciably different. Conclusions Bisphosphonate use was associated with lower risk of EOC, suggesting bisphosphonates may reduce risk of ovarian cancer development. Key messages Bisphosphonates may protect against development of serous and endometrioid ovarian cancers.

Background Ovarian carcinoma is not a single disease, but rather a collection of subtypes with differing molecular properties and risk profiles. The most common of these, and the subject of this work, is high-grade serous ovarian carcinoma (HGSC). Methods In this population-based study we identified a cohort of 441,382 women resident in Western Australia who had ever been admitted to hospital in the State. Of these, 454 were diagnosed with HGSC. We used Cox regression to derive hazard ratios (HRs) comparing the risk of disease in women who had each of a range of medical diagnoses and surgical procedures with women who did not. Results We found an increased risk of HGSC associated with a diagnosis of pelvic inflammatory disease (PID) (HR 1.47, 95% CI 1.04–2.07) but not with a diagnosis of infertility or endometriosis with HRs of 1.12 (95% CI 0.73–1.71) and 0.82 (95% CI 0.55–1.22) respectively. A personal history of breast cancer was associated with a three-fold increase in the rate of HGSC. Increased parity was associated with a reduced risk of HGSC in women without a personal history of breast cancer (HR 0.57; 95% CI 0.44-0.73), but not in women with a personal history of breast cancer (HR 1.48; 95% CI 0.74–2.95). Conclusions Our finding of an increased risk of HGSC associated with PID lends support to the hypothesis that inflammatory processes may be involved in the etiology of HGSC.

Ovarian neoplasia comprises a heterogenous group of tumors with distinct clinicopathologic and molecular features and therefore assessment of potential risk factors should be tumor subtype specific. As part of ongoing epidemiological investigations of ovarian neoplasia in Western Australia, we performed an initial review of original pathology reports followed, in selected cases, by reassessment of histology material to optimize accurate diagnosis. Additional immunohistochemistry, often using antibodies unavailable at the time of initial assessment, was also performed as required. From an initial cohort of 1660 cases identified through the Western Australia Cancer Registry, benign, nonepithelial, nonovarian, miscellaneous, and indeterminate cases were excluded. Also excluded were 33 cases that were reclassified as ovarian metastases rather than primary ovarian tumors. Following exclusions there remained 1321 borderline and malignant epithelial neoplasms. The diagnosis was considered accurate in 1186 cases (89.8%) based upon information in the initial pathology reports and clinical follow-up data but uncertain in 135 cases (10.2%). Histologic review was possible in 92 of the latter tumors leading to an amended diagnosis in 63 cases (68.5%). The most common types of diagnostic amendment were the reclassification of high-grade carcinomas of undifferentiated, endometrioid, or transitional appearance as high-grade serous carcinoma, and the reclassification of most carcinomas of mixed epithelial type as "pure'' carcinomas. This review illustrated specific pitfalls in the diagnosis of ovarian epithelial neoplasia and helped to maintain the accuracy of the Western Australia Cancer Registry. Accurate diagnosis will optimize further epidemiological studies assessing risk factors in specific subtypes of ovarian neoplasia.

Objective Risk factors for ovarian borderline tumors and low-grade serous carcinoma (LGSC) are poorly understood. The aim of this study was to examine the association between infertility, pelvic inflammatory disease (PID), endometriosis, ectopic pregnancy, hysterectomy, tubal ligation and parity and the risk of serous borderline tumor (SBT), mucinous borderline tumor (MBT) and LGSC. Methods This was a population-based cohort study using linked administrative and hospital data. Participants were 441,382 women born between 1945 and 1975 who had been admitted to hospital in Western Australia between 1 January 1980 and 30 June 2014. We used Cox regression to estimate hazard ratios (HRs). Results We observed an increased rate of SBT associated with infertility, PID and ectopic pregnancy (HRs and 95% CIs were, respectively, 1.98 (1.20–3.26); 1.95 (1.22–3.10) and 2.44 (1.20–4.96)). We did not detect an association between any of the factors under study and the rate of MBT. A diagnosis of PID was associated with an increased rate of LGSC (HR 2.90, 95% CI 1.21–6.94). Conclusions The association with PID supports the hypothesis that inflammatory processes within the upper gynaecological tract and/or peritoneum may predispose to the development of SBT and LGSC.

Background Recent studies have called into question the long-held belief that hysterectomy without oophorectomy protects against ovarian cancer. This population-based longitudinal record-linkage study aimed to explore this relationship, overall and by age at hysterectomy, time period, surgery type, and indication for hysterectomy. Methods We followed the female adult Western Australian population (837 942 women) across a 27-year period using linked electoral, hospital, births, deaths, and cancer records. Surgery dates were determined from hospital records, and ovarian cancer diagnoses (n = 1640) were ascertained from cancer registry records. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between hysterectomy and ovarian cancer incidence. Results Hysterectomy without oophorectomy (n = 78 594) was not associated with risk of invasive ovarian cancer overall (HR = 0.98, 95% CI = 0.85 to 1.11) or with the most common serous subtype (HR = 1.05, 95% CI = 0.89 to 1.23). Estimates did not vary statistically significantly by age at procedure, time period, or surgical approach. However, among women with endometriosis (5.8%) or with fibroids (5.7%), hysterectomy was associated with substantially decreased ovarian cancer risk overall (HR = 0.17, 95% CI = 0.12 to 0.24, and HR = 0.27, 95% CI = 0.20 to 0.36, respectively) and across all subtypes. Conclusions Our results suggest that for most women, having a hysterectomy with ovarian conservation is not likely to substantially alter their risk of developing ovarian cancer. However, our results, if confirmed, suggest that ovarian cancer risk reduction could be considered as a possible benefit of hysterectomy when making decisions about surgical management of endometriosis or fibroids.

Background Hysterectomy is one of the most commonly performed gynecological surgeries, with an estimated 30% of women in Australia undergoing the procedure by age 70. In the USA, about 45% of women have a hysterectomy in their lifetime. Some studies have suggested this procedure increases the risk of premature mortality. With many women making the decision to have a hysterectomy for a benign indication each year, additional research is needed to clarify whether there are long-term health consequences of hysterectomy. Objective Our aim was to examine the association between hysterectomy for benign indications, with or without removal of the ovaries, and cause-specific and all-cause mortality. Study Design Our cohort of 666,588 women comprised the female population of Western Australia with linked hospital and health records from 1970 to 2015. We used Cox regression models to assess the association between hysterectomy and all-cause, cardiovascular disease, cancer and other mortality by oophorectomy type (categorized as none, unilateral and bilateral), with no hysterectomy or oophorectomy as the reference group. We repeated these analyses using hysterectomy without oophorectomy as the reference group. We also investigated whether associations varied by age at the time of surgery, although small sample size precluded this analysis in women who had a hysterectomy with unilateral salpingo-oophorectomy. In our main analysis, women who had hysterectomy and/or oophorectomy undertaken as part of treatment for cancer were retained in the analysis and considered unexposed to that surgery. As a sensitivity analysis, we censored procedures undertaken for cancer. Results Compared to no surgery, having a hysterectomy without oophorectomy before age 35 was associated with an increase in all-cause mortality (HR=1.29, 95% CI:1.19-1.40); for surgery after age 35, there was an inverse association (35-44 years: HR=0.93, 95%CI:0.89,0.97). Similarly, hysterectomy with bilateral salpingo-oophorectomy was associated with increased all-cause mortality when undertaken before age 45 (35-44 years: HR=1.15, 95%CI:1.04-1.27), but decreased mortality rates when surgery was undertaken after age 45. In our sensitivity analysis, censoring gynecological surgeries for cancer resulted in many cancer-related deaths being excluded for women who did not have surgery for benign indications, and thus increased the hazard ratios for the associations between both hysterectomy without oophorectomy and hysterectomy with bilateral salpingo-oophorectomy and risk of all-cause and cancer-specific mortality. The sensitivity analysis therefore potentially biased the results in favor of no surgery. Conclusion Among women having surgery for benign indications, hysterectomy without oophorectomy performed prior to 35 years and hysterectomy with bilateral salpingo-oophorectomy performed prior to 45 years were associated with an increase in all-cause mortality. These procedures are not associated with poorer long-term survival when performed at older ages.

Objectives To determine the magnitude and characteristics of the increase in ED demand in Western Australia (WA) from 2007 to 2013. Methods We conducted a population-based longitudinal study examining trends in ED demand, stratified by area of residence, age group, sex, Australasian Triage Scale category and discharge disposition. The outcome measures were annual number and rate of ED presentations. We calculated average annual growth, and age-specific and age-standardised rates. We assessed the statistical significance of trends, overall and within each category, using the Mann–Kendall trend test and analysis of variance ANOVA. We also calculated the proportions of growth in ED demand that were attributable to changes in population and utilisation rate. Results From 2007 to 2013, ED presentations increased by an average 4.6% annually from 739 742 to 945 244. The rate increased 1.4% from 354.1 to 382.6 per 1000 WA population (P = 0.02 for the trend). The main increase occurred in metropolitan WA, age 45+ years, triage category 2 and 3 and admitted cohorts. Approximately three-quarters of this increase was due to population change (growth and ageing) and one-quarter due to increase in utilisation. Conclusion Our study reveals a 4.6% annual increase in ED demand in WA in 2007–2013, mostly because of an increase in people with urgent and complex care needs, and not a shift (demand transfer) from primary care. This indicates that a system-wide integrated approach is required for demand management.

Background Female sterilisation is usually performed on an elective basis at perceived family completion, however, around 1–3% of women who have undergone sterilisation elect to undergo sterilisation reversal (SR) at a later stage. The trends in SR rates in Western Australia (WA), proportions of SR procedures between hospital types (public and private), and the effects of Federal Government policies on these trends are unknown. Methods Using records from statutory state-wide data collections of hospital separations and births, we conducted a retrospective descriptive study of all women aged 15–49 years who underwent a SR procedure during the period 1st January 1990 to 31st December 2008 (n = 1868 procedures). Results From 1991 to 2007 the annual incidence rate of SR procedures per 10,000 women declined from 47.0 to 3.6. Logistic regression modelling showed that from 1997 to 2001 the odds of women undergoing SR in a private hospital as opposed to all other hospitals were 1.39 times higher (95% CI 1.07–1.81) and 7.51 times higher (95% CI 5.46–10.31) from 2002 to 2008. There were significant decreases in SR rates overall and among different age groups after the Federal Government interventions. Conclusion Rates of SR procedures in WA have declined from 1990 to 2008, particularly following policy changes such as the introduction of private health insurance (PHI) policies. This suggests decisions to undergo SR may be influenced by Federal Government interventions.

Background. There is uncertainty around whether the risks of pelvic inflammatory disease (PID) differ following Chlamydia trachomatis (chlamydia) and Neisseria gonorrhoeae (gonorrhea) infection. We quantified the risk of PID associated with chlamydia and gonorrhea infection and subsequent repeat infections in a whole-population cohort. Methods. A cohort of 315 123 Western Australian women, born during 1974-1995, was probabilistically linked to chlamydia and gonorrhea testing records and to hospitalizations and emergency department presentations for PID from 2002 to 2013. Timeupdated survival analysis was used to investigate the association between chlamydia and gonorrhea testing, and positivity, and risk of PID. Results. Over 3 199 135 person-years, 120 748 women had pathology test records for both chlamydia and gonorrhea, 10 745 chlamydia only, and 653 gonorrhea only. Among those tested, 16 778 (12.8%) had ≥1 positive chlamydia test, 3195 (2.6%) ≥1 positive gonorrhea test, and 1874 (1.6%) were positive for both. There were 4819 PID presentations (2222 hospitalizations, 2597 emergency presentations). Adjusting for age, Aboriginality, year of follow-up, health area, and socioeconomic status, compared to women negative for chlamydia and gonorrhea, the relative risk (adjusted incidence rate ratio) of PID was 4.29 (95% confidence interval [CI], 3.66-5.03) in women who were both chlamydia and gonorrhea positive; 4.54 (95% CI, 3.87-5.33) in those only gonorrhea positive; and 1.77 (95% CI, 1.61-1.94) in those only chlamydia positive. Conclusions. Gonorrhea infection conferred a substantially higher risk than chlamydia of hospitalization or emergency department presentation for PID. The emergence of gonorrhea antimicrobial resistance may have a serious impact on rates of PID and its associated reproductive health sequelae.

Objectives To compare the risk of borderline ovarian tumours in women having in vitro fertilization (IVF) with women diagnosed with infertility but not having IVF. Methods This was a whole-population cohort study of women aged 20–44years seeking hospital infertility treatment or investigation in Western Australia in 1982–2002. Using Cox regression, we examined the effects of IVF treatment and potential confounders on the rate of borderline ovarian tumours. Potential confounders included parity, age, calendar year, socio-economic status, infertility diagnoses including pelvic inflammatory disorders and endometriosis and surgical procedures including hysterectomy and tubal ligation. Results Women undergoing IVF had an increased rate of borderline ovarian tumours with a hazard ratio (HR) of 2.46 (95% confidence interval [CI] 1.20–5.04). Unlike invasive epithelial ovarian cancer, neither birth (HR 0.89; 95% CI 0.43–1.88) nor hysterectomy (1.02; 0.24–4.37) nor sterilization (1.48; 0.63–3.48) appeared protective and the rate was not increased in women with a diagnosis of endometriosis (HR 0.31; 95% CI 0.04–2.29). Conclusions Women undergoing IVF treatment are at increased risk of being diagnosed with borderline ovarian tumours. Risk factors for borderline ovarian tumours appear different from those for invasive ovarian cancer.

Objective To examine the incidence rate of breast cancer in a cohort of women undergoing treatment for infertility, comparing the rate in women who had in vitro fertilization (IVF) with those who did not. Design Population-based cohort study using linked hospital and registry data. Setting Hospital. Patient(s) All women aged 20–44 years seeking hospital investigation and treatment for infertility in Western Australia during the period 1983–2002 (n = 21,025). Intervention(s) None. Main Outcome Measure(s) Hazard ratios (HRs) for breast cancer. Result(s) There was no overall increase in the rate of breast cancer in women who had IVF (HR 1.10, 95% confidence interval [CI] 0.88–1.36), but there was an increased rate in women who commenced IVF at a young age. Women who commenced hospital infertility treatment at 24 years and required IVF had an unadjusted HR of breast cancer of 1.59 (95% CI 1.05–2.42) compared with women of the same age who had infertility treatment but no IVF. When adjusted for late age at first delivery, which is associated with an increased rate of breast cancer, and delivery of twins and higher-order multiples, which is associated with a decreased rate of breast cancer, the HR remained elevated at 1.56 (95% CI 1.01–2.40). Hazard ratios were not elevated in women who commenced treatment at age 40 and required IVF (adjusted HR 0.87, 95% CI 0.62–1.22). Conclusion(s) Commencing IVF treatment at a young age is associated with an increased rate of breast cancer.

Objective To measure IVF effectiveness, which is defined as the cumulative incidence of live delivery over real time in women after commencing IVF treatment. Design Population-based retrospective cohort study. Setting IVF clinics in Western Australia (WA). Patient(s) All women ages 20–44 years inclusive at start of treatment, commencing IVF in 1982–1992 and 1993–2002 at clinics in WA (n = 8,275). Intervention(s) Data on IVF cycles were extracted from hospital records and a statutory reproductive technology register and linked to records of births. Main Outcome Measure(s) Cumulative incidence of an IVF-attributed live delivery and cumulative incidence of an IVF-attributed or IVF treatment-independent live delivery. Result(s) IVF effectiveness in the 1993–2002 cohort was 47% overall. It was highest in women ages 20–29 years at the start of treatment, measuring 58%; and 79% with the inclusion of IVF treatment-independent deliveries, and declined to 22% and 33%, respectively, in women ages 40–44 years. Couples underwent, on average, only three cycles, even though the cumulative probability of a live delivery increased with each successive cycle for at least the first five cycles. Conclusion(s) IVF effectiveness could be improved if women, particularly those over 35, underwent more cycles.

To compare rates of visits to a general practitioner between users and non-users of mental health services (MHS).Population-based retrospective cohort study of 204 727 users and 294 076 matched non-users of MHS in Western Australia from 1 January 1990 to 30 June 2006, based on linked records of the use of MHS, hospital admissions, Medicare claims for GP and specialist services, electoral roll registration and deaths.Adjusted rate ratios (ARRs) for the number of visits to GPs by users of MHS relative to non-users, and for different categories of mental disorders.Relative to non-users of MHS, the ARR of visits to GPs by users of MHS was 1.622 (95% CI, 1.613-1.631) overall, and was elevated in each separate category of mental illness. ARRs were highest for alcohol/drug disorders, schizophrenia and affective psychoses (2.404, 1.834 and 1.798, respectively). The results were not changed by location (metropolitan, rural or remote addresses). However, the 4% of MHS users with no fixed address had a very low ARR of visits to GPs (0.058; 95% CI, 0.057-0.060).Users of MHS visit GPs substantially more often than non-users, with the exception of those with no fixed address who seldom see a GP at all.

Purpose – The purpose of this paper is to examine the influence of offence type, prior imprisonment and various socio-demographic characteristics on mortality at 28 and 365 days following prison release. Design/methodology/approach – Using whole-population linked, routinely collected administrative state-based imprisonment and mortality data, the authors conducted a retrospective study of 12,677 offenders released from Western Australian prisons in the period 1994-2003. Cox proportional hazards regression was used to examine the association between mortality at 28 and 365 days post-release and offence type, prior imprisonment, and a range of socio-demographic characteristics (age, gender, social disadvantage and Indigenous status). Findings – Overall, 135 (1.1 per cent) died during the 365 days follow-up period, of these, 17.8 per cent (n=24) died within the first 28 days (four weeks) of their index release. Ex-prisoners who had committed drug-related offences had significantly higher risk of 28-day post-release mortality (HR=28.4; 95 per cent CI: 1.3-615.3, p=0.033), than those who had committed violent (non-sexual) offences. A significant association was also found between the number of previous incarcerations and post-release mortality at 28 days post-release, with three prior prison terms carrying the highest mortality risk (HR=73.8; 95 per cent CI: 1.8-3,092.5, p=0.024). No association between mortality and either offence type or prior imprisonment was seen at 365 days post-release. Originality/value – Post-release mortality at 28 days was significantly associated with offence type (with drug-related offences carrying the greatest risk) and with prior imprisonment, but associations did not persist to 365 days after release. Targeting of short-term transitional programmes to reduce preventable deaths after return to the community could be tailored to these high-risk ex-prisoners.

Objective: To compare the risk of death in a cohort of Western Australian released prisoners with the risk experienced by the general population of Western Australia. Methods: A cohort study of prisoners in Western Australia whose last date of release ranged from 1 January 1994 to 1 January 1999. Overall mortality and cause of death were determined by data linkage to the Registrar General's record of deaths. Results: Aboriginal prisoners had a significantly lower survival rate after release than non-Aboriginal prisoners (p

Objective To examine the association between in vitro fertilization (IVF) and later admission to hospital with a mental health diagnosis in women who remained childless after infertility treatment. Methods This was a population-based cohort study using linked administrative hospital and registry data. The study population included all women commencing hospital treatment for infertility in Western Australia between the years 1982 and 2002 aged 20–44 years at treatment commencement who did not have a recorded birth by the end of follow-up (15 August 2010) and did not have a hospital mental health admission prior to the first infertility admission (n=6,567). Of these, 2,623 women had IVF and 3,944 did not. We used multivariate Cox regression modeling of mental health admissions and compared women undergoing IVF treatment with women having infertility treatment but not IVF. Results Over an average of 17 years of follow-up, 411 women in the cohort were admitted to hospital with a mental health diagnosis; 93 who had IVF and 318 who did not. The unadjusted hazard ratio (HR) for a hospital mental health admission comparing women who had IVF with those receiving other infertility treatment was 0.50 (95% confidence interval [CI] 0.40–0.63). After adjustment for age, calendar year and socio-economic status the HR was 0.56 (95% CI 0.44–0.71). Conclusions IVF treatment is associated with a reduced risk of hospital mental health admissions in women after unsuccessful infertility treatment. This may be explained by the healthy cohort effect.

usc Objective: To determine the cumulative incidence of live delivery in women who underwent reversal of tubal sterilization. Design: Population-based retrospective cohort study. Setting: Hospitals in Western Australia. Patient(s): All women aged 20-44 years, with a history of hospital admission for tubal sterilization, who subsequently underwent reversal of sterilization during the period 1985 to 2009 in Western Australia (n - 1,898). Intervention(s): Data regarding reversal of sterilization and prior tubal sterilization were extracted from routinely collected administrative hospital separation records, until commencement of IVF treatment. Main Outcome Measure(s): First live-delivery rates. Result(s): There were 969 first live deliveries observed during the study period. The overall cumulative live-delivery rate was 20% (95% confidence interval [CI] 18-23) within the first year after reversal, 40% (95% CI 38-42) at 2 years, 51% (95% CI 48-53) at 5 years, and 52% (95% CI 50-55) at 10 years. The 5-year cumulative live-delivery rate was significantly lower in women who were aged 40-44 years (26%) compared with younger women (aged 20-29, 30-34, and 35-39 years) (50%, 56%, and 51%, respectively). Conclusion(s): Women undergoing reversal of sterilization before they reach age 40 years have at least a 50% chance of delivering a live baby within the next 5 years. Up to that age, there is no significant difference in live deliveries. The live-delivery rate halves after the age of 40 years. Refereed/Peer-reviewed

Objectives The presence and severity of pelvic inflammatory disease (PID) symptoms are thought to vary by microbiological etiology but there is limited empirical evidence. We sought to estimate and compare the rates of hospitalisation for PID temporally related to diagnoses of gonorrhoea and chlamydia. Methods All women, aged 15–45 years in the Australian state of New South Wales (NSW), with a diagnosis of chlamydia or gonorrhoea between 01/07/2000 and 31/12/2008 were followed by record linkage for up to one year after their chlamydia or gonorrhoea diagnosis for hospitalisations for PID. Standardised incidence ratios compared the incidence of PID hospitalisations to the age-equivalent NSW population. Results A total of 38,193 women had a chlamydia diagnosis, of which 483 were hospitalised for PID; incidence rate (IR) 13.9 per 1000 person-years of follow-up (PYFU) (95%CI 12.6–15.1). In contrast, 1015 had a gonorrhoea diagnosis, of which 45 were hospitalised for PID (IR 50.8 per 1000 PYFU, 95%CI 36.0–65.6). The annual incidence of PID hospitalisation temporally related to a chlamydia or gonorrhoea diagnosis was 27.0 (95%CI 24.4–29.8) and 96.6 (95%CI 64.7–138.8) times greater, respectively, than the age-equivalent NSW female population. Younger age, socio-economic disadvantage, having a diagnosis prior to 2005 and having a prior birth were also associated with being hospitalised for PID. Conclusions Chlamydia and gonorrhoea are both associated with large increases in the risk of PID hospitalisation. Our data suggest the risk of PID hospitalisation is much higher for gonorrhoea than chlamydia; however, further research is needed to confirm this finding.

A link between reproductive hormones and melanoma has long been suspected, and has been examined for numerous hormonal exposures, but the association between in-vitro fertilization (IVF) and melanoma has not been studied in depth. We used whole-population linked hospital and registry data to carry out a cohort study of women aged 20–44 years seeking hospital investigation and treatment for infertility in Western Australia from 1982 to 2002 with follow-up to 2010. The cohort comprised a total of 21 604 women followed for an average of 17.2 years. Of these, 7524 had IVF treatment, 14 870 gave birth and 149 women were diagnosed with an incident invasive melanoma. Using Cox regression analysis, we estimated hazard ratios (HRs) for melanoma associated with IVF and parity. Women who had IVF and gave birth had an increased rate of invasive melanoma compared with women who had IVF and remained nulliparous (HR 3.61; 95% confidence interval 1.79–7.26). There was little or no increase in the rate of invasive melanoma associated with giving birth in women who had non-IVF infertility treatment (HR 1.39; 95% confidence interval 0.88–2.20). These results suggest an association between reproductive factors and melanoma in the subgroup of women undergoing IVF treatment.

Objectives To examine the risk of invasive epithelial ovarian cancer in a cohort of women seeking treatment for infertility. Methods Using whole-population linked hospital and registry data, we conducted a cohort study of 21,646 women commencing hospital investigation and treatment for infertility in Western Australia in the years 1982–2002. We examined the effects of IVF treatment, endometriosis and parity on risk of ovarian cancer and explored potential confounding by tubal ligation, hysterectomy and unilateral oophorectomy/salpingo-oophorectomy (USO). Results Parous women undergoing IVF had no observable increase in the rate of ovarian cancer (hazard ratio [HR] 1.01; 95% confidence interval [CI] 0.35–2.90); the HR in women who had IVF and remained nulliparous was 1.76 (95% CI 0.74–4.16). Women diagnosed with endometriosis who remained nulliparous had a three-fold increase in the rate of ovarian cancer (HR 3.11; 95% CI 1.13–8.57); the HR in parous women was 1.52 (95% CI 0.34–6.75). In separate analyses, women who had a USO without hysterectomy had a four-fold increase in the rate of ovarian cancer (HR 4.23; 95% CI 1.30–13.77). Hysterectomy with or without USO appeared protective. Conclusions There is no evidence of an increased risk of ovarian cancer following IVF in women who give birth. There is some uncertainty regarding the effect of IVF in women who remain nulliparous. Parous women diagnosed with endometriosis may have a slightly increased risk of ovarian cancer; nulliparous women have a marked increase in risk.