Risk of Congenital Anomalies after the Opening of Landfill Sites

Concern that living near a particular landfill site in Wales caused increased risk of births with congenital malformations led us to examine whether residents living close to 24 landfill sites in Wales experienced increased rates of congenital anomalies after the landfills opened compared with before they opened. We carried out a small-area study in which expected rates of congenital anomalies in births to mothers living within 2 km of the sites, before and after opening of the sites, were estimated from a logistic regression model fitted to all births in residents living at least 4 km away from these sites and hence not likely to be subject to contamination from a landfill, adjusting for hospital catchment area, year of birth, sex, maternal age, and socioeconomic deprivation score. We investigated all births from 1983 through 1997 with at least one recorded congenital anomaly [International Classification of Diseases, Ninth Revision (ICD-9), codes 7400–7599; International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10), codes Q000–Q999]. The ratio of the observed to expected rates of congenital anomalies before landfills opened was 0.87 [95% confidence interval (CI), 0.75–1.00], and this increased to 1.21 (95% CI, 1.04–1.40) after opening, giving a standardized risk ratio of 1.39 (95% CI, 1.12–1.72). Enhanced congenital malformation surveillance data collected from 1998 through 2000 showed a standardized risk ratio of 1.04 (95% CI, 0.88–1.21). Causal inferences are difficult because of possible biases from incomplete case ascertainment, lack of data on individual-level exposures, and other socioeconomic and lifestyle factors that may confound a relationship with area of residence. However, the increase in risk after the sites opened requires continued enhanced surveillance of congenital anomalies, and site-specific chemical exposure studies

Use of time to pregnancy in environmental epidemiology and surveillance

Background Potential sources of environmental pollution, such as incinerators or landfill sites, can adversely affect reproduction and/or development. Time to pregnancy (TTP) is a validated measure of biological fertility that can be studied with relatively small populations. Methods Pregnant local residents living within 3 km of a landfill site (‘exposed’ group, n = 200) or elsewhere in the Rhondda valleys (‘unexposed’ group, n = 400) were interviewed by health visitors or midwives. The response rate was 83%. Results No difference was found in the TTP distributions between the exposed and unexposed groups. Relationships of TTP with covariates were consistent with the literature. Conclusions In a context of public and scientific concern about possible reproductive toxicity, an interview study of TTP was highly acceptable to local women. A large enough sample to generate stable TTP distributions was readily achieved

Cervical screening in 20-24-year olds

BACKGROUND: In 2003 the NHS Cervical Screening Programme in England changed the age at which women are first invited for cervical screening from 20 to 25 years. The aim of this review was to assess the evidence for benefit and harm of undertaking cervical screening in Wales for women aged 20-24 years. METHOD: A literature review looking for evidence of the effectiveness and potential harmful effects of cervical screening was undertaken. Welsh data for the number of cases of high-grade cervical intraepithelial neoplasia (CIN3) were examined and rates of invasive cervical cancer (1981-2003) for young women calculated. The medical notes of women less than 25 years old diagnosed with cervical cancer were reviewed and a cost analysis was performed. RESULTS: The literature review failed to identify any randomized controlled studies of the effectiveness of cervical screening in young women, but demonstrated that organized screening programmes result in a decrease in the incidence of cervical carcinoma. Following the introduction of the Welsh organized call/recall cervical screening programme in 1988, cervical cancer has been reduced by 58% in women aged 20-24 years and 45% in women aged 25-29 years (mean age-specific rate per 100,000 women aged 20-24 years: 4.2 in 1981-88 compared with 2.2 in 1989-2003). If these changes can be attributed to the screening of women aged 20-24, then the costs of at least pound sterling 82,500 are estimated to prevent one cervical cancer in this age group. CONCLUSIONS: The incidence of cervical cancer in young women has halved since the introduction of the Welsh-organized call-recall cervical screening programme. In Wales we recommend that women continue to be invited for cervical screening from 20 years of age. This will provide the information required to compare the incidence and stage at diagnosis of cervical cancer in young women invited for first time cervical screening at different ages across the UK

Community exposures to chemical incidents: development and evaluation of the first environmental public health surveillance system in Europe

OBJECTIVE: To describe the frequency, nature and location of acute chemical incidents in Wales, and the morbidity in employees, emergency responders and the general public who were exposed. DESIGN: Active multi-agency community-based surveillance system. SETTING: Wales, 1993-5. MAIN OUTCOME MEASURES: Frequency, nature and location of incidents, populations potentially exposed and with symptoms. RESULTS: Most of the 402 incidents identified were not associated with sites governed by the Control of Industrial Major Accident Hazard Regulations but with smaller industrial sites and commercial premises. About two in every thousand of the estimated 236 000 members of the public considered to be at risk from exposure reported symptoms, which were mainly nausea, headaches, and irritation of the eye, skin and respiratory tract. The most commonly reported chemicals that members of the public were exposed to were smoke toxins, miscellaneous organics, toxic gases and flammable gases. A health authority was reported to be involved in only 34 (8%) of the incidents and in only 3 of the 29 incidents where more than 100 members of the public were exposed. CONCLUSION: A geographically defined, multi-agency surveillance system can identify high risk locations and types of incidents, together with the chemicals most likely to be involved. Such ongoing surveillance information is essential for appropriate policy making, emergency planning, operational management and training

Screening opportunity bias in case-control studies of cancer screening

In case-control evaluations of cancer screening, subjects who have died from the cancer in question (cases) are compared with those who have not (controls) with respect to screening histories. This method is subject to a rather subtle bias, among others, whereby the cases have greater opportunity to have been screened than the controls. In this paper, we propose a method of correction for this bias. We demonstrate its use on two case-control studies of mammographic screening for breast cancer.cancer screening, case-control study, opportunity bias,

Investigation of an acute chemical incident: exposure to fluorinated hydrocarbons

OBJECTIVES To assess whether attendance at the site after an incident in a sewer was associated with symptoms in emergency personnel and whether the prevalence of symptoms was associated with estimated levels of exposure to any chemical hazard. METHODS Symptoms experienced by people attending an incident involving two dead sewer workers suggested the presence of a chemical hazard, before environmental sampling confirmed any toxic agent. Self reported symptoms, estimated exposures, and biomarkers of exposure for likely agents from all 254 people who attended the incident and a referent occupational group matching the 83 emergency personnel who went to the Accident and Emergency department (A and E) in the first 48 hours were recorded. The prevalence of symptoms and concentrations of creatine phosphokinase in serum of the 83 early patients at A and E were compared with their referent occupational group. In all workers who attended the incident, the trends in symptom prevalences and concentrations of creatine phosphokinase in serum were examined by distance from the site and predefined exposure category. RESULTS Among all workers who attended the incident, symptoms of shortness of breath and sore throat were significantly associated with indirect estimates of exposure but not associated with concentrations of creatine phosphokinase. Freon was detected in two blood samples. The early patients at A and E reported more symptoms than their matched reference group and their median concentrations of creatine phosphokinase were higher. CONCLUSIONS The association between symptoms and concentrations of creatine phosphokinase with attendance at the site indicated the presence of a continuing hazard at the site and led to extra precautions being taken. Comparison values from the referent occupational group prevented unnecessary medical follow up