Reasons for nonuse of antiviral treatment in patients with chronic hepatitis C infection and thrombocytopaenia: a retrospective chart review from five European countries.

Antiviral therapy has been shown to reduce the risk of disease progression, liver damage and death in patients with chronic hepatitis C virus (HCV) infection. While interferon labels recommend that patients with platelet counts below 50 × 10(3) /µL not receive interferon-based therapy, it is unknown to what extent thrombocytopaenia influences treatment decisions in practice. This study profiles the reasons for withholding antiviral treatment in HCV patients with thrombocytopaenia in five European countries. Medical records of 466 patients who had HCV infection and thrombocytopaenia (platelet count <100 × 10(3) /µL) in 2006 were retrospectively reviewed for clinical characteristics. Collected data included use of antiviral therapy and reasons for withholding therapy. In total 184 of 466 patients (39.5%) did not receive interferon-based therapy during the study period, with treatment withheld most frequently due to multiple clinical characteristics including hepatic cirrhosis (16.3%), thrombocytopaenia (16.3%) and age >60 years (10.9%). The reasons for lack of treatment varied among countries, with thrombocytopaenia as a reason being more common in Italy (10.9%) and Spain (20.0%), and less common in France, Germany and the UK (3.2-7.1%). Overall, thrombocytopaenia was reported as the only reason for withholding treatment in 4.9% of untreated patients. This study demonstrates that thrombocytopaenia is one of many factors, indicative of the poor clinical state of the patient, that contributes to withholding antiviral treatment. In 4.9% of untreated patients, thrombocytopaenia can be considered as a modifiable factor to enable more HCV patients to receive guideline-recommended therapy and thus improved clinical outcomes.

Prevalence of thrombocytopenia among patients with chronic hepatitis C: a systematic review.

Thrombocytopenia (TCP) is a haematological condition known to occur in chronically infected hepatitis C (HCV) patients and may interfere with diagnostic procedures, such as liver biopsy, because of risk of bleeding. It may also exclude patients from effective antiviral treatment. We conducted a systematic literature review of articles and conference abstracts, to assess the prevalence of TCP among those with HCV and to describe demographics, liver disease stage and treatment characteristics of these patients. Studies of individuals with confirmed chronic HCV infection were included in the review if the study had a clear definition of thrombocytopenia and a sample size of at least 50 subjects. The final selection included 27 studies (21 articles and six abstracts). The definitions of thrombocytopenia varied between studies and were based either on platelet counts, with threshold levels ranging between ≤ 100 × 10(9) and ≤ 180 × 10(9) /L, or on criteria set in haematological guidelines. The prevalence of TCP ranged from 0.16% to 45.4% and more than half of the studies reported a TCP prevalence of 24% or more. Because of the different TCP definitions, heterogeneity in study design and insufficient data on study characteristics such as age, gender, HCV treatment rates and disease severity an overall summary estimate of TCP prevalence among patients with HCV was not feasible. However, the relatively large prevalence in the majority of the studies suggests that there may be a substantial number of HCV patients at risk of bleeding complications and reduced likelihood of successful HCV antiviral treatment.

Output power levels from mobile phones in different geographical areas; implications for exposure assessment.

BACKGROUND: The power level used by the mobile phone is one of the most important factors determining the intensity of the radiofrequency exposure during a call. Mobile phone calls made in areas where base stations are densely situated (normally urban areas) should theoretically on average use lower output power levels than mobile phone calls made in areas with larger distances between base stations (rural areas). AIMS: To analyse the distribution of power levels from mobile phones in four geographical areas with different population densities. METHODS: The output power for all mobile phone calls managed by the GSM operator Telia Mobile was recorded during one week in four defined areas (rural, small urban, suburban, and city area) in Sweden. The recording included output power for the 900 MHz and the 1800 MHz frequency band. RESULTS: In the rural area, the highest power level was used about 50% of the time, while the lowest power was used only 3% of the time. The corresponding numbers for the city area were approximately 25% and 22%. The output power distribution in all defined urban areas was similar. CONCLUSION: In rural areas where base stations are sparse, the output power level used by mobile phones are on average considerably higher than in more densely populated areas. A quantitative assessment of individual exposure to radiofrequency fields is important for epidemiological studies of possible health effects for many reasons. Degree of urbanisation may be an important parameter to consider in the assessment of radiofrequency exposure from mobile phone use.

Occupational magnetic field exposure among women in Stockholm County, Sweden.

BACKGROUND: Most epidemiological studies on adverse health effects among women in relation to occupational magnetic field exposure have been based on information about men's exposure. AIMS: To create a job-exposure matrix for occupational exposure to extremely low frequency magnetic fields among women. METHODS AND RESULTS: Measurements were performed using personal magnetic field meters (Emdex Lite) carried by the subjects for 24 hours on a normal workday. Subjects were volunteer women working in the occupations identified as common among women in Stockholm County based on the 1980 census. A total of 471 measurements were made in 49 different occupations, with a minimum of 5 and a maximum of 24 measurements in each occupation. The included occupations cover about 85% of the female population gainfully employed in 1980. Parameters representing average and peak magnetic field exposures, temporal change in the exposure, and proportion of time spent above certain exposure levels were calculated both for the workday and for the total 24 hour period grouped by occupational titles. The occupations with higher than average exposure were cashiers, working proprietors in retail trade, air stewardesses, dental nurses, cooks, post-office clerks and kitchen maids. CONCLUSIONS: This new job-exposure matrix substantially increases the knowledge about magnetic field exposure among women and can be used for exposure assessment in future studies.

Occupational and residential magnetic field exposure and breast cancer in females.

The purpose of this study was to evaluate the effect of occupational magnetic field exposure on breast cancer in females and to combine residential and occupational magnetic field exposure to reduce misclassification. The study was conducted as a case-control study within a population living within 300 meters of transmission lines in Sweden. We identified cases of breast cancer in females from the national cancer registry, and we selected one matched control per case at random. Residential exposure was estimated through calculations of the magnetic fields generated by power lines. We obtained information about occupation from censuses, and the occupations were linked to a job-exposure matrix that was based on magnetic field measurements. For occupational exposure to magnetic fields over 0.25 microT closest in time before diagnosis, the estimated relative risk was 1.0 [96% confidence interval (CI) = 0.6-1.7]. Women below age 50 years at diagnosis had a relative risk of 1.5 (95% CI = 0.6-3.5). For women below 50 years of age who had estrogen receptor-positive breast cancer, there was a relative risk of 3.2 (95% CI = 0.5-18.9). The results for residential and occupational exposures combined showed similar results.

Magnetic fields and breast cancer in Swedish adults residing near high-voltage power lines.

We conducted a case-control study to test the hypothesis that residential magnetic field exposures increase the incidence of breast cancer. The study was based on people who had lived within 300 m of 220- or 400-kV power lines in Sweden at any time between 1960 and 1985. We identified 699 cases of breast cancer in women and 9 cases in men. One matched control per female case and eight per male case were selected at random. Estrogen receptor information was available for a subset of female cases. We assessed magnetic field exposure through calculations of the magnetic fields generated by the power lines before diagnosis. For calculated magnetic field levels > or = 0.2 microtesla (microT) closest in times before diagnosis, we estimated the relative risk to be 1.0 [95% confidence interval (CI) = 0.7-1.5] for women and 2.1 (95% CI = 0.3-14.1) for men. Women younger than 50 years of age at diagnosis had a relative risk of 1.8 (95% CI = 0.7-4.3). For women with estrogen receptor-positive breast cancer, the relative risk was estimated at 1.6 (95% CI = 0.6-4.1), using the exposure cutoff point > or = 0.1 microT. Among estrogen receptor-positive women younger than 50 years at diagnosis, the relative risk increased to 7.4 (95% CI = 1.0-178.1).

Occupational and residential magnetic field exposure and leukemia and central nervous system tumors.

Studies of magnetic field exposure and cancer have focused on either residential or occupational exposure. We conducted a case-control study taking into account both exposure sources. We identified leukemia and central nervous system tumor cases and controls from a population living within 300 m of transmission lines in Sweden. We have previously reported results considering residential exposure alone. Here, we evaluate the effect of occupational exposure and of the combined exposures. We estimated residential exposure through calculations of the magnetic fields generated by power lines. We obtained information about occupation from censuses and linked the occupations to a job-exposure matrix based on magnetic field measurements. For occupational exposure of > or = 0.2 microT, we estimated the relative risk for leukemia to be 1.7 [95% confidence interval (CI) = 1.1-2.7]. The increased risk was confined to acute myeloid and chronic lymphocytic leukemia. For residential exposure of > or = 0.2 microT, the relative risk for leukemia was estimated at 1.3 (95% CI = 0.8-2.2), with higher risk estimates for acute and chronic myeloid leukemia. We estimated the relative risk for leukemia among subjects highly exposed both at home and at work to be 3.7 (95% CI = 1.5-9.4). These results provide support for an association between magnetic field exposure and leukemia. Relative risks for nervous system tumors were close to unity.