Lennart Hardell

Cellular and cordless telephones and the risk for brain tumours

Microwave exposure from the use of cellular telephones has been discussed in recent years as a potential risk factor for brain tumours. We included in a case–control study 1617 patients aged 20–80 years of both sexes with brain tumour diagnosed between 1 January 1997 and 30 June 2000. They were alive at the study time and had histopathologically verified brain tumour. One matched control to each case was selected from the Swedish Population Register. The study area was the Uppsala-Örebro, Stockholm, Linköping and Göteborg medical regions of Sweden. Exposure was assessed by a questionnaire that was answered by 1429 (88%) cases and 1470 (91%) controls. In total, use of analogue cellular telephones gave an increased risk with an odds ratio (OR) of 1.3 (95% confidence interval (CI) 1.02–1.6). With a tumour induction period of >10 years the risk increased further: OR 1.8 (95% CI 1.1–2.9). No clear association was found for digital or cordless telephones. With regard to the anatomical area of the tumour and exposure to microwaves, the risk was increased for tumours located in the temporal area on the same side of the brain that was used during phone calls; for analogue cellular telephones the OR was 2.5 (95% CI 1.3–4.9). Use of a telephone on the opposite side of the brain was not associated with an increased risk for brain tumours. With regard to different tumour types, the highest risk was for acoustic neurinoma (OR 3.5, 95% CI 1.8–6.8) among analogue cellular telephone users.

Long-term use of cellular phones and brain tumours - increased risk associated with use for > 10 years

Aim: To evaluate brain tumour risk among long-term users of cellular telephones. Methods: Two cohort studies and 16 case–control studies on this topic were identified. Data were scrutinised for use of mobile phone for ⩾10 years and ipsilateral exposure if presented. Results: The cohort study was of limited value due to methodological shortcomings in the study. Of the 16 case–control studies, 11 gave results for ⩾10 years’ use or latency period. Most of these results were based on low numbers. An association with acoustic neuroma was found in four studies in the group with at least 10 years’ use of a mobile phone. No risk was found in one study, but the tumour size was significantly larger among users. Six studies gave results for malignant brain tumours in that latency group. All gave increased odd ratios (OR), especially for ipsilateral exposure. In a meta-analysis, ipsilateral cell phone use for acoustic neuroma was ORu200a=u200a2.4 (95% CI 1.1 to 5.3) and ORu200a=u200a2.0, (1.2 to 3.4) for glioma using a tumour latency period of ⩾10 years. Conclusions: Results from present studies on use of mobile phones for ⩾10 years give a consistent pattern of increased risk for acoustic neuroma and glioma. The risk is highest for ipsilateral exposure.

A pooled analysis of case-control studies of thyroid cancer II. Menstrual and reproductive factors

Objective: It has been suggested that female hormones, and hence menstrual and reproductive factors, play a role in thyroid cancer etiology. Epidemiological data, however, are limited and inconsistent, partly because of the small number of cases included in each study. To clarify the etiology of thyroid cancer, we conducted a pooled analysis of original data from 14 case-control studies, 4 from the United States, 2 from Asia, and 8 from Europe.Methods: This analysis included a total of 2,247 female cases of thyroid cancer (80% papillary) and 3,699 control women. Pooled odds ratios (OR) were estimated using logistic regression, conditioning on study and (i) matching sets for individually matched studies, or (ii) quinquennia of age for the other studies. Additional terms for age and history of radiation exposure were included in the regression equations.Results: The OR per year of later menarche was 1.04 (95% confidence interval (CI) 1.0–1.1). Compared to pre-menopausal women, the OR was 1.3 for women with natural menopause, and 1.8 for those with artificial menopause, but the studies were heterogeneous and the association may be due, at least in part, to diagnostic or ascertainment bias. Parity, spontaneous or induced abortions and history of infertility were not associated with thyroid cancer risk. The OR was above unity in women reporting later age at first birth (OR=1.1, 95% CI 1.0–1.3 for 5-year delay) and higher in the first years after a birth.Conclusions: The associations of menstrual and reproductive factors with thyroid cancer risk were generally weak, but appeared stronger among women diagnosed with thyroid cancer at younger ages.

Ionizing radiation, cellular telephones and the risk for brain tumours.

A case–control study on brain tumours included 233 patients aged 20–80 years and alive at the study time. They had histopathologically verified brain tumour and lived in the Uppsala-Örebro region (1994–1996) or the Stockholm region (1995–1996). Two matched controls to each case were selected from the Swedish Population Register. Two hundred and nine cases (90%) and 425 controls (91%) answered the questionnaire. Results are presented for the whole study group, as given here, and for malignant and benign tumours separately. For workers in the chemical industry the odds ratio (OR) was 4.10, 95% confidence interval (95% CI) 1.25–13.4 and laboratory workers OR 3.21, 95% CI 1.16–8.85. Radiotherapy of the head and neck region gave OR 3.61, 95% CI 0.65–19.9. Medical diagnostic X-ray of the same area yielded OR 1.64, 95% CI 1.04–2.58. Work as a physician gave OR 6.00, 95% CI 0.62–57.7. All three cases had worked with fluoroscopy. Ipsilateral (same side) use of a cellular telephone increased the risk of tumours in the temporal, temporoparietal and occipital areas, with OR 2.42, 95% CI 0.97–6.05 (i.e. the anatomical areas with highest exposure to microwaves from a mobile phone).

Case-Control Study on Cellular and Cordless Telephones and the Risk for Acoustic Neuroma or Meningioma in Patients Diagnosed 2000-2003

We performed a case-control study on the use of cellular and cordless telephones and the risk for brain tumors. We report the results for benign brain tumors with data from 413 cases (89% response rate), 305 with meningioma, 84 with acoustic neuroma, 24 with other types and 692 controls (84% response rate). For meningioma, analogue phones yielded odds ratio (OR) = 1.7, 95% confidence interval (CI) = 0.97–3.0, increasing to OR = 2.1, 95% CI = 1.1–4.3 with a >10-year latency period. Also digital cellular phones and cordless phones increased the risk to some extent. For acoustic neuroma, analogue phones gave OR = 4.2, 95% CI = 1.8–10 increasing to OR = 8.4, 95% CI = 1.6–45 with a >15-year latency period, but based on low numbers. Digital phones yielded OR = 2.0, 95% CI = 1.05–3.8, whereas for cordless phones OR was not significantly increased. In the multivariate analysis, analogue phones represented a significant risk factor for acoustic neuroma.

Tumour risk associated with use of cellular telephones or cordless desktop telephones

BackgroundThe use of cellular and cordless telephones has increased dramatically during the last decade. There is concern of health problems such as malignant diseases due to microwave exposure during the use of these devices. The brain is the main target organ.MethodsSince the second part of the 1990s we have performed six case-control studies on this topic encompassing use of both cellular and cordless phones as well as other exposures. Three of the studies concerned brain tumours, one salivary gland tumours, one non-Hodgkin lymphoma (NHL) and one testicular cancer. Exposure was assessed by self-administered questionnaires.ResultsRegarding acoustic neuroma analogue cellular phones yielded odds ratio (OR) = 2.9, 95 % confidence interval (CI) = 2.0–4.3, digital cellular phones OR = 1.5, 95 % CI = 1.1–2.1 and cordless phones OR = 1.5, 95 % CI = 1.04–2.0. The corresponding results were for astrocytoma grade III-IV OR = 1.7, 95 % CI = 1.3–2.3; OR = 1.5, 95 % CI = 1.2–1.9 and OR = 1.5, 95 % CI = 1.1–1.9, respectively. The ORs increased with latency period with highest estimates using > 10 years time period from first use of these phone types. Lower ORs were calculated for astrocytoma grade I-II. No association was found with salivary gland tumours, NHL or testicular cancer although an association with NHL of T-cell type could not be ruled out.ConclusionWe found for all studied phone types an increased risk for brain tumours, mainly acoustic neuroma and malignant brain tumours. OR increased with latency period, especially for astrocytoma grade III-IV. No consistent pattern of an increased risk was found for salivary gland tumours, NHL, or testicular cancer.

Pulsed dose rate brachytherapy as the sole adjuvant radiotherapy after breast-conserving surgery of T1-T2 breast cancer : first long time results from a clinical study

BACKGROUND AND PURPOSEnTo evaluate the long time outcome with regard to local tumour control, cosmetic outcome and side effects of a short (5 days) accelerated interstitial brachytherapy treatment delivered to the surroundings of the operated sector.nnnPATIENTS AND METHODSnBetween 1993 and 2003 we treated 50 women with early T1 and T2 breast cancer. Radical sector resection was performed and followed later with an interstitial pulsed dose rate (PDR) brachytherapy of 50Gy in 5 days. The treatment was centred on the tumour with a margin of 30mm. One patient was treated bilaterally. The patients were followed for a median of 86 (32-126) months.nnnRESULTSnIpsilateral breast cancer recurrence was seen in 3 patients (6%). Two of them occurred outside the treated volume. The 5- and 7-year rates of actuarial local control were 96% and 96%, respectively, overall survival 88% and 85%, disease free survival 88% and 88%, respectively. A dosimetrical analysis showed that the partial breast irradiation covered a median of 31% of the total breast volume. Fat necrosis was seen in 12% and local (moderate-strong) fibrosis in 26% of the patients. Independent cosmetic scoring showed good or excellent result in 56% of the patients.nnnCONCLUSIONSnLocal outcome is favourable and very similar to other published studies of accelerated partial breast irradiation. Our long time cosmetic results are lower than other published results.

Use of cellular telephones and brain tumour risk in urban and rural areas

Aims: To investigate the association between the use of cellular or cordless telephones and the risk for brain tumours in different geographical areas, urban and rural. Methods: Patients aged 20–80 years, living in the middle part of Sweden, and diagnosed between 1 January 1997 and 30 June 2000 were included. One control matched for sex and age in five year age groups was selected for each case. Use of different phone types was assessed by a questionnaire. Results: The number of participating cases was 1429; there were 1470 controls. An effect of rural living was most pronounced for digital cellular telephones. Living in rural areas yielded an odds ratio (OR) of 1.4 (95% CI 0.98 to 2.0), increasing to 3.2 (95% CI 1.2 to 8.4) with >5 year latency time for digital phones. The corresponding ORs for living in urban areas were 0.9 (95% CI 0.8 to 1.2) and 0.9 (95% CI 0.6 to 1.4), respectively. This effect was most obvious for malignant brain tumours. Conclusion: In future studies, place of residence should be considered in assessment of exposure to microwaves from cellular telephones, although the results in this study must be interpreted with caution due to low numbers in some of the calculations.

Occupation and occupational exposure to endocrine disrupting chemicals in male breast cancer: a case-control study in Europe

Objectives Male breast cancer is a rare disease of largely unknown aetiology. In addition to genetic and hormone-related risk factors, a large number of environmental chemicals are suspected of playing a role in breast cancer. The identification of occupations or occupational exposures associated with an increased incidence of breast cancer in men may help to identify mammary carcinogens in the environment. Methods Occupational risk factors for male breast cancer were investigated in a multi-centre case–control study conducted in eight European countries which included 104 cases and 1901 controls. Lifetime work history was obtained during in-person interviews. Occupational exposures to endocrine disrupting chemicals (alkylphenolic compounds, phthalates, polychlorinated biphenyls and dioxins) were assessed on a case-by-case basis using expert judgement. Results Male breast cancer incidence was particularly increased in motor vehicle mechanics (OR 2.1, 95% CI 1.0 to 4.4) with a dose–effect relationship with duration of employment. It was also increased in paper makers and painters, forestry and logging workers, health and social workers, and furniture manufacture workers. The OR for exposure to alkylphenolic compounds above the median was 3.8 (95% CI 1.5 to 9.5). This association persisted after adjustment for occupational exposures to other environmental oestrogens. Conclusion These findings suggest that some environmental chemicals are possible mammary carcinogens. Petrol, organic petroleum solvents or polycyclic aromatic hydrocarbons are suspect because of the consistent elevated risk of male breast cancer observed in motor vehicle mechanics. Endocrine disruptors such as alkylphenolic compounds may play a role in breast cancer.

Risk factors for extrahepatic biliary tract carcinoma in men: Medical conditions and lifestyle: Results from a European multicentre case-control study

Objectives To identify risk factors of carcinoma of the extrahepatic biliary tract in men. Methods Newly diagnosed and histologically confirmed patients, 35–70 years old, were interviewed between 1995 and 1997 in Denmark, Sweden, France, Germany and Italy. Population controls were frequency-matched by age and region. Adjusted odds ratios and 95%-confidence intervals were estimated by logistic regression. Results The analysis included 153 patients and 1421 controls. The participation proportion was 71% for patients and 61% for controls. Gallstone disease was corroborated as a risk factor for extrahepatic biliary tract carcinoma in men (odds ratio 2.49; 95% confidence interval 1.32–4.70), particularly for gall bladder tumors (odds ratio 4.68; 95% confidence interval 1.85–11.84). For a body mass index [height (m) divided by squared weight (kg2)] >30 at age 35 years, an excess risk was observed (odds ratio 2.58; 95% confidence interval 1.07–6.23, reference: body mass index 18.5–25) that was even stronger if the body mass index was >30 for the lowest weight in adulthood (odds ratio 4.68; 95% confidence interval 1.13–19.40). Infection of the gall bladder, chronic inflammatory bowel disease, hepatitis or smoking showed no clear association, whereas some increase in risk was suggested for consumption of 40–80u2009g alcohol per day and more. Conclusions Our study corroborates gallstones as a risk indicator in extrahepatic biliary tract carcinoma. Permanent overweight and obesity in adult life was identified as a strong risk factor for extrahepatic biliary tract carcinoma, whereas we did not find any strong lifestyle-associated risk factors. Inconsistent results across studies concerning the association of extrahepatic biliary tract carcinoma with overweight and obesity may be explained by the different approaches to assess this variable.