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L Hardell

Publications and source records attributed to L Hardell.

At least 19 recordsLinked to original sources
PubMed2000

Concentrations of organochlorines related to titers to Epstein-Barr virus early antigen IgG as risk factors for hairy cell leukemia.

Hairy cell leukemia (HCL) is a rare chronic B-cell malignancy that, according to modern classifications, is a subgroup of non-Hodgkin lymphomas (NHLs). A rapid increase in incidence of NHL has been reported in many countries. The reasons for this increase are largely unknown, but exposure to organochlorines has been suggested as a risk factor. Epstein-Barr virus is a human herpesvirus that has been associated with certain subgroups of NHL. In this study, we measured lipid adjusted blood concentrations (in nanogram per gram) of 36 congeners of polychlorinated biphenyls (PCBs), p, p'-dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), and four subgroups of chlordanes (trans-nonachlor, cis-nonachlor, MC6, and oxychlordane) in incident cases of HCL and controls from the general population. We obtained results on organochlorines and antibodies for 54 cases and 54 controls. Titers of antibodies to the Epstein-Barr early antigen and Epstein-Barr nuclear antigen, measured as P107, were correlated to concentrations of organochlorines to evaluate the possibility of an interaction between these factors in the pathogenesis of HCL. We found no significant difference in lipid-adjusted blood concentrations of total PCBs, p,p'-DDE, HCB, or the sum of the chlordanes between cases and controls. Titers of antibodies to Epstein-Barr early antigen IgG [Greater and equal to] 40 were correlated to an increased risk for HCL. This risk was further increased in those with a level above the median value of p,p'-DDE, HCB, or the sum of the chlordanes, suggesting an interaction between Epstein-Barr virus and a higher concentration of these chemicals. We also found increased risk for the sum of immunotoxic PCB group.

Antibodies, Viral↗
PubMed1999

Occupational exposures and risk of gastric cancer in a population-based case-control study.

Gastric cancer trends seem to follow improvements in the environment of blue-collar workers, but the etiological role of occupational exposures in gastric carcinogenesis is scantily investigated. The risk of gastric adenocarcinoma in 10 common occupational industries, and particularly the long-term effects of asbestos, organic solvents, impregnating agents, insecticides, and herbicides, were evaluated in a population-based case-control study, including data on most established risk factors. The study base included all individuals of ages 40-79, born in Sweden and living in either of two areas (total population, 1.3 million) with differing gastric cancer incidences, from February 1989 through January 1995. We interviewed 567 cases classified to site (cardia/noncardia) and histological type, and 1,165 population-based controls, frequency-matched for age and sex. Metal workers had a 46% excess gastric cancer risk [adjusted odds ratio (OR), 1.46; 95% confidence interval (CI), 1.10-1.94], increasing to 1.65 (95% CI, 1.17-2.32) for >10 years in the industry. The elevated risk after exposure to herbicides (OR, 1.56; 95% CI, 1.13-2.15) was attributable to phenoxyacetic acids (adjusted OR, 1.70; 95% CI, 1.16-2.48), similarly across tumor subtypes, and not modified by smoking, body mass index, or Helicobacter pylori. The absence of interaction was demonstrated by the pure multiplicative effect found among those exposed to both H. pylori and phenoxyacetic acids (OR, 3.42; 95% CI, 1.41-8.26). Organic solvents, insecticides, impregnating agents, and asbestos were not associated with gastric cancer risk. Employment in the metal industry and exposure to phenoxyacetic acids were both positively and independently associated with gastric cancer risk. The fractions of all gastric cancers attributable to these job-related exposures were small but not negligible (7 and 5%, respectively) in the Swedish population.

Adenocarcinoma↗
PubMed1999

Author reply

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Journal Article↗
PubMed1999

A case-control study of non-Hodgkin lymphoma and exposure to pesticides.

BACKGROUND: The incidence of non-Hodgkin lymphoma (NHL) has increased in most Western countries during the last few decades. Immunodefective conditions are established risk factors. In 1981, the authors reported an increased risk for NHL following exposure to certain pesticides. The current study was designed to further elucidate the importance of phenoxyacetic acids and other pesticides in the etiology of NHL. METHODS: A population-based case-control study in northern and middle Sweden encompassing 442 cases and twice as many controls was performed. Exposure data were ascertained by comprehensive questionnaires, and the questionnaires were supplemented by telephone interviews. In total, 404 cases and 741 controls answered the questionnaire. Univariate and multivariate analyses were performed with the SAS statistical data program. RESULTS: Increased risk for NHL was found for subjects exposed to herbicides (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.0-2.5) and fungicides (OR, 3.7; 95% CI, 1.1-13.0). Among herbicides, the phenoxyacetic acids dominated (OR, 1.5; 95% CI, 0.9-2.4); and, when subclassified, one of these, 4-chloro-2-methyl phenoxyacetic acid (MCPA), turned out to be significantly associated with NHL (OR, 2.7; 95% CI, 1.0-6.9). For several categories of herbicides, it was noted that only exposure during the most recent decades before diagnosis of NHL was associated with an increased risk of NHL. Exposure to impregnating agents and insecticides was, at most, only weakly related to NHL. CONCLUSIONS: Exposure to herbicides in total, including phenoxyacetic acids, during the decades before NHL diagnosis resulted in increased risk for NHL. Thus, the risk following exposure was related to the latency period. Fungicides also increased the risk for NHL when combined, but this group consisted of several different agents, and few subjects were exposed to each type of fungicide.

2-Methyl-4-chlorophenoxyacetic Acid↗
PubMed1999

Sinonasal cancer, occupation, and tobacco smoking in European women and men.

BACKGROUND: In this analysis of European case-control studies on sinonasal cancer, we examined the risk for occupation and smoking, by gender and histological type. METHODS: The pooled data included 104 female and 451 male cases, and 241 female and 1,464 male controls. Lifetime smoking and occupational history were recoded following uniform criteria, and job-exposure matrices were applied for wood and leather dust. RESULTS: Wood dust exposure was associated with an excess risk in men (OR = 2.36, 95% CI 1.75-3.2) but not in women (OR = 1.17, 95% CI 0.31-4.47). Exposure to leather dust was associated with an excess risk in both genders. Both wood and leather dust were associated with adenocarcinomas rather than squamous cell carcinomas. Excess risks for smoking were higher for squamous cell carcinomas and higher in men than in women. CONCLUSIONS: In these European populations, occupation was associated with about 11% of all sinonasal cancers in women and 39% in men. This difference can, in part, be attributed to variation in exposure patterns between genders.

Adenocarcinoma↗
PubMed1999

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 premenopausal 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.

Adenocarcinoma, Papillary↗
PubMed1999

Use of cellular telephones and the risk for brain tumours: A case-control study.

The use of cellular telephones has increased dramatically during the 1990's in the world. In the 1980's the analogue NMT system was used whereas the digital GSM system was introduced in early 1990's and is now the preferred system. Case reports of brain tumours in users initiated this case-control study on brain tumours and use of cellular telephones. Also other exposures were assessed. All cases, both males and females, with histopathologically verified brain tumour living in Uppsala-Orebro region (1994-96) and Stockholm region (1995-96) aged 20-80 at the time of diagnosis and alive at start of the study were included, 233 in total. Two controls to each case were selected from the Swedish Population Register matched for sex, age and study region. Exposure was assessed by questionnaires supplemented over the phone. The analyses were based on answers from 209 (90%) cases and 425 (91%) controls. Use of cellular telephone gave odds ratio (OR) = 0.98 with 95% confidence interval (CI) = 0. 69-1.41. For the digital GSM system OR = 0.97, CI = 0.61-1.56 and for the analogue NMT system OR = 0.94, CI = 0.62-1.44 were calculated. Dose-response analysis and using different tumour induction periods gave similar results. Non-significantly increased risk was found for tumour in the temporal or occipital lobe on the same side as a cellular phone had been used, right side OR = 2.45, CI = 0.78-7.76, left side OR = 2.40, CI = 0.52-10.9 Increased risk was found only for use of the NMT system. For GSM use the observation time is still too short for definite conclusions. An increased risk for brain tumour in the anatomical area close to the use of a cellular telephone should be especially studied in the future.

Adult↗
PubMed1999

Elevated antibody levels to Epstein-Bbarr virus antigens in patients with hairy cell leukemia compared to controls in relation to exposure to pesticides, organic solvents, animals, and exhausts.

Epstein-Barr virus (EBV) is a B-lymphotropic human herpes virus infecting B-cells, which has been associated with lymphoid malignancies, above all non-Hodgkin lymphomas (NHL). Severe immunosuppression is the best recognized risk factor for NHL. Many factors in the environment that have been described as risk factors for NHL cause measurable changes in immune functions. Hairy cell leukemia (HCL) is a rare, indolent non-Hodgkin lymphoma, originating from B-lymphocytes. This was a case-control study including 111 male cases with HCL and 400 controls. In a subgroup of 57 cases and 65 controls analysis of antibodies to EBV early antigen, viral capsid antigen, and EBNA-1, measured as P107, was performed. In this study, we confirm other studies describing elevated levels of antibodies to the EBV early antigen (EA) in patients with HCL compared to controls. We found only minor differences in the levels of antibodies to the viral capsid antigen (VCA) and EBNA-1. measured as P107. We found a positive association of a titer to EA IgG > or =40 (OR 4.1; CI 1.9-9.5). The ORs were further elevated when subjects with high levels of EA IgG and exposed to environmental agents such as organic solvents, certain pesticides, impregnating agents, animals, and exhausts were compared to those subjects with low levels that were not exposed. Antibody reactivity against the EBV EBNA 1-alanine-glycine repeat (P107 IgG) above the median gave an increased OR for HCL, which further increased in subjects exposed to organic solvents, certain pesticides. impregnating agents, animals, and exhausts. However, the numbers of exposed cases and controls were small in some of the calculations.

Air Pollution↗
PubMed1998

[Do flame retardants increase the risk of non-Hodgkin lymphoma? The levels of polybrominated diphenyl ethers are increasing in the environment].

Adipose tissue levels of tetra-BDE (2,2',4,4' tetra-brominated diphenyl ether) were measured in 42 male or female cancer patients [19 with non-Hodgkin's lymphoma (NHL), 23 with malignant melanoma (MM)], and in 27 controls without a diagnosis of cancer. As compared with tetra-BDE concentrations in controls, those in the MM subgroup did not differ, but those in the NHL subgroup were higher. Subgrouping of the cancer patients by occupational categories showed professional car, bus and truck drivers (at possible risk of exposure to PBDEs used as flame retardants in vehicle manufacture) to have higher tetra-BDE levels than controls, but not computer operators (at possible risk of exposure to PBDEs used in VDUs). Due to the small size of the series, however, the results may solely be regarded as hypothesis-generating, and further studies are needed.

Adult↗
PubMed1998

Oral snuff, smoking habits and alcohol consumption in relation to oral cancer in a Swedish case-control study.

The use of oral snuff is a widespread habit in Sweden. We investigated whether the use of Swedish moist snuff leads to an increasing risk of oral cancer. Other risk factors such as smoking tobacco and alcoholic beverages were also investigated. Our study comprised 410 patients with oral cancer, from the period 1980-1989, and 410 matched controls. All subjects received a mailed questionnaire. The response rates were 96% and 91% for cases and controls, respectively. In the study, a total of 20% of all subjects, cases and controls, were active or ex-snuff users. The univariate analysis did not show any increased risk [odds ratio (OR) 0.7, 95% confidence interval (CI) 0.4-1.1] for active snuff users. We found an increased risk (OR 1.8, CI 1.1-2.7) for oral cancer among active smokers. Alcohol consumption showed the strongest risk for oral cancer. Among consumers of beer, an increased risk of 1.9 (CI 0.9-3.9) was found. Corresponding ORs for wine and liquor were 1.3 (CI 0.9-1.8) and 1.6 (CI 1.1-2.3), respectively. A dose-response effect was observed. Although not statistically significant, a multivariate analysis similarly suggested that the most important risk factors were beer and liquor consumption, followed by smoking.

Age Factors↗
PubMed1998

[A new study of patients with cancer in Umeå alternative medicine is no alternative].

A questionnaire study comprising 854 cancer patients in the Umeå health care region and covering the 10-year period, 1987-96, showed only a few cancer patients to use alternative medicine treatment for their disease. As compared with 19.4 per cent of 144 residents selected from the population register who answered the questionnaire in 1987, 16.8 per cent of the cancer patients reported using alternative treatments in 1987, 14.4 per cent in 1990, and 16.4 per cent in 1996. The commonest forms of alternative medicine used were chiropractic and acupuncture, and the majority of treatments were for pain in the muscles or musculoskeletal system.

Acupuncture Therapy↗
PubMed1998

Occupational exposures, animal exposure and smoking as risk factors for hairy cell leukaemia evaluated in a case-control study.

To evaluate occupational exposures as risk factors for hairy cell leukaemia (HCL), a population-based case-control study on 121 male HCL patients and 484 controls matched for age and sex was conducted. Elevated odds ratio (OR) was found for exposure to farm animals in general: OR 2.0, 95% confidence interval (CI) 1.2-3.2. The ORs were elevated for exposure to cattle, horse, hog, poultry and sheep. Exposure to herbicides (OR 2.9, CI 1.4-5.9), insecticides (OR 2.0, CI 1.1-3.5), fungicides (OR 3.8, CI 1.4-9.9) and impregnating agents (OR 2.4, CI 1.3-4.6) also showed increased risk. Certain findings suggested that recall bias may have affected the results for farm animals, herbicides and insecticides. Exposure to organic solvents yielded elevated risk (OR 1.5, CI 0.99-2.3), as did exposure to exhaust fumes (OR 2.1, CI 1.3-3.3). In an additional multivariate model, the ORs remained elevated for all these exposures with the exception of insecticides. We found a reduced risk for smokers with OR 0.6 (CI 0.4-1.1) because of an effect among non-farmers.

Adult↗
PubMed1998

Oral infections and dental factors in relation to oral cancer: a Swedish case--control study.

We investigated the role of oral infections, dentition and dental X-rays for oral cancer in a north Swedish population. This case-control study consisted of 410 cases with oral cancer for the period 1980-89 and 410 matched controls. All subjects received a mailed questionnaire. The response rates were 96% and 91% for cases and controls, respectively. The univariate analysis showed a statistically significant increased risk for oral cancer among individuals reporting problems with recurrent clinical oral infection (odds ratio (OR) 3.8). Separate analyses were made for groups with a clearly stated HSV-1 infection (OR 1.9) and highly suspected HSV-1 infection (OR 3.3) as reported by the subjects. Odds ratios were also calculated for infections in relation to tobacco and alcohol habits. For individuals reporting recurrent infection problems an increased risk was observed in every combination category. Dental factors such as different fillings, dentures and fixed prostheses showed no increased risks. Dental X-ray did not produce an increased OR either. A multivariate analysis suggested that the most important risk factors were oral infections followed by liquor consumption and active smoking.

Alcohol Drinking↗
PubMed1998

Some aspects of the etiology of non-Hodgkin's lymphoma.

In epidemiologic studies, non-Hodgkin's lymphoma (NHL) has been associated with exposure to chemicals such as phenoxyacetic acids; chlorophenols; dioxins; organic solvents including benzene, polychlorinated biphenyls, chlordanes; and immunosuppressive drugs. Experimental evidence and clinical observations indicate that these chemicals may impair the immune system. The risk is increased for NHL in persons with acquired and congenital immune deficiency as well as autoimmune disorders. Also, certain viruses have been suggested to be of etiologic significance for NHL. In some cases of NHL the common mechanism for all these agents and conditions may be immunosuppression, possibly in combination with viruses.

Dioxins↗
PubMed1998

Agent Orange in war medicine: an aftermath myth.

Since the late 1970s several epidemiological studies have appeared linking exposure to phenoxy herbicides or chlorophenols to some malignant tumors. Most of these compounds are contaminated with dioxins and dibenzofurans; for example, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a contaminant of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a component of Agent Orange which was sprayed in Vietnam during the war. The results of some of the epidemiological studies on cancer risks associated with exposure to these compounds have been manipulated and misinterpreted, particularly by the Australian Royal Commission on the Use and Effects of Chemical Agents on Australian Personnel in Vietnam. Furthermore, a book on Australian war history entitled Medicine at War, commissioned by the Federal Government, reiterates several of these misinterpretations, despite available contrary evaluations from Australian and U.S. authorities. These remarkable and confusing circumstances in the scientific process are considered also in the light of the recent classification of TCDD as carcinogenic to humans, Group 1, by a Working Group at the International Agency for Research on Cancer in Lyon, France.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1998

Case-control study on risk factors for testicular cancer.

Occupational exposures were assessed in a case-control study on testicular cancer using self administered questionnaires. Answers were obtained for 148 (91%) cases and 314 (87%) controls. Of the cases 101 had seminoma and 47 had embryonal testicular cancer. Occupational plastics work yielded odds ratio (OR) 2.9 with 95% confidence interval (CI) 1.3-6.5. Increased risk was found for embryonal cancer regarding farming (OR 3.1; CI 1.03-9.1) and contact with farm animals (OR 3.3; CI 1.00-10.9), but not for seminoma. For all testicular cancer exposure to insects repellents, mostly containing N,N-diethyl-m-toluamide (DEET) gave OR 1.7; CI 1.03-2.8, with a dose-response effect. Somewhat increased risks were found for amateur radio operators (OR 2.2; CI 0.7-6.6), work with radar equipment (OR 2.0; CI 0.3-14.2) and engineers in electronics and telecommunication industry (OR 2.3; CI 0.8-6.7) based on few exposed subjects, however. Video display unit work gave OR 1.5; CI 0.98-2.3 and for exposure 480 working days (median number) the risk increased further to OR 1.8; CI 1.1-3.2. Because of low numbers of exposed subjects in some calculations some of these results might be spurious and need to be further studied.

Adult↗
PubMed1998

Concentrations of the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether in human adipose tissue in Swedish persons and the risk for non-Hodgkin's lymphoma.

Concentrations of the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether (2,2',4,4'-TeBDE) in the adipose tissue of 77 individuals from Sweden were determined. The subjects were recruited during the time period 1995-97 and encompassed both men and women ranging from 28 to 85 years in age. Of the subjects included, 19 patients had non-Hodgkin's lymphoma (NHL), 23 patients had malignant melanoma, 8 patients had other cancers or in situ changes, and 27 persons had no cancer diagnosis. The mean concentration of 2,2',4,4'-TeBDE was 5.1 ng/g lipid (range 0.6-27.5) for the 27 persons without malignancies. For NHL patients the mean concentration was 13.0 ng/g lipid (range 1.0-98.2). A nonsignificantly elevated risk with dose response was found for NHL when the cases and controls were compared in the two highest concentration groups (2.05-< 5.43 ng/g lipid and > or = 5.43 ng/g lipid) with the lowest group (< 2.05 ng/g lipid) yielding odds ratio (OR) 1.9 with 95% confidence interval (CI) 0.3-14 and OR 3.8, CI 0.7-26, respectively. The results for the patients with malignant melanoma did not differ from the controls.

Adipose Tissue↗