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T Haldorsen

Publications and source records attributed to T Haldorsen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cancer incidence among workers in six Norwegian aluminum plants.

OBJECTIVES: This study investigated associations between exposure to polycyclic aromatic hydrocarbons (PAH) and the incidence of lung, bladder, kidney, and pancreatic cancer among Norwegian aluminum plant workers. METHODS: Cancer incidence was investigated from 1953 to 1996 among 11,103 men employed for more than 3 years in the industry, giving 272,554 person-years during follow-up. A job exposure matrix was constructed to estimate exposure to particulate PAH and fluorides. The observed cases of cancer were compared with expected figures calculated from national rates. Dose-response relations were investigated by internal comparisons using Poisson regression and stratified analyses for standardized incidence ratio. Potential confounding by smoking was investigated in subanalyses restricted to 3 of the plants. RESULTS: The study showed an overall excess for bladder cancer, standardized incidence ratio 1.3 (95% confidence interval 1.1-1.5), which increased with increasing cumulative exposure to PAH and reached a relative risk of about 2 for the upper exposure category in the analysis with 30 years of lag time. There was no association between cumulative PAH exposure and lung cancer, but there were indications of an elevated risk of kidney cancer among the most heavily PAH-exposed persons in the analyses with a lag time of 30 years. For pancreatic cancer we found a higher incidence among the PAH-exposed persons than among the unexposed ones, but no clear dose-response association was found. CONCLUSIONS: The study showed an association between bladder cancer and exposure to PAH, but gave no support to an association between PAH exposure and lung cancer in the primary aluminum industry.

Aluminum↗
PubMed2000

Nonmalignant mortality among workers in six Norwegian aluminum plants.

OBJECTIVES: This study investigated the associations between exposure to fluorides and polycyclic aromatic hydrocarbons (PAH) and mortality from nonmalignant diseases among workers in the Norwegian primary aluminum industry. METHODS: Mortality among 10,857 men, employed for more than 3 years in 1 of 6 aluminum plants, was investigated from 1962 to 1996, giving 239,246 person-years during follow-up. Ajob-exposure matrix covering all 6 plants was used to estimate the individual exposure to total fluorides and particulate PAH. The observed cause-specific deaths were compared with expected figures calculated from national rates. Dose-response relations were investigated by internal comparisons using Poisson regression and by stratified analyses for standardized mortality ratio. Potential confounding by smoking was investigated in subanalyses restricted to 3 of the plants for which information on smoking habits was accessible. RESULTS: Mortality from circulatory disease was slightly lower than expected [SMR 0.95, 95% confidence interval (95%CI) 0.9-1.0], while there was an increased mortality from asthma, emphysema, and chronic bronchitis combined, SMR 1.2 (95% CI 1.0-1.5). Mortality from these diseases was associated with cumulative exposure to fluorides. The rate ratio in the internal analysis rose steadily to 2.5 (95% CI 1.5-4.3) for the upper exposure category. No association was observed between cumulative fluoride exposure or PAH exposure and circulatory mortality. CONCLUSIONS: The study showed an association between exposure to potroom emissions measured by fluorides and mortality from asthma, emphysema, and chronic bronchitis combined.

Aluminum↗
PubMed1999

Exposure to PAH and fluoride in aluminum reduction plants in Norway: historical estimation of exposure using process parameters and industrial hygiene measurements.

BACKGROUND: In this study, we describe the methodology used for historical estimation of exposure to fluoride and to PAH in vertical stud Søderberg (VSS) potrooms at two Norwegian aluminum smelters. The assessment was performed in order to develop exposure data for epidemiological studies of cause-specific mortality and cancer incidence. METHODS: The estimation was performed in several steps. In the first step, we estimated the area concentrations of fluoride and PAH in periods with no measurements. Relationships between measured area concentrations and process parameters were investigated by statistical modeling. Process parameters and the models were then used to estimate area concentrations in periods lacking area measurement data. In the second step, the relationships between the area measurements and job specific exposure (personal measurements) were investigated by use of a measurement model. In the last step, the obtained relationships were used to estimate job specific exposure in different periods. RESULTS: The range for the annual exposure estimates in the VSS-potrooms was 0.05-1.7 mg/m3 for fluoride and 3-3,437 micrograms/m3 for PAH. CONCLUSIONS: Despite limitations of available measurements in the early production period, we have concluded that the exposure estimates from this study provide a reasonable tool for the estimation of dose-response relations in subsequent epidemiological analyses.

Air Pollutants, Occupational↗
PubMed1999

Cohort analysis of cigarette smoking and lung cancer incidence among Norwegian women.

BACKGROUND: Cancer registries have for decades surveyed the development of cancer diseases. Data on incident cases includes demographic variables. Knowledge of the temporal distribution of risk factors on the same variables makes it possible to model the relationship between disease and risk factor. The results of such analyses might be difficult to interpret since they are based on aggregated data. But the availability of these data sources should encourage further exploration of its possibilities and limitations. METHODS: The temporal pattern of smoking habits in 5-year birth cohorts from 1890-1949 was established, with data on the proportions of current smokers, former smokers and non-smokers and estimated average daily consumption of tobacco and average duration of smoking. The lung cancer incidence among the cohorts in 1953-1992 was analysed by a model which included an additive excess risk for smokers that depended on daily dose and duration of smoking. RESULTS: The lung cancer incidence in later decades was adequately described by the model, which showed a simple relationship with smoking behaviour in the cohorts. For both current smokers and former smokers, the excess risk was about proportional to the daily amount smoked and the 4.5 power of duration of smoking. The age-specific rates for non-smokers were close to a fifth-power curve of age. CONCLUSIONS: Even if lung cancer incidence is not determined separately for groups with known smoking habits, plausible estimates of the effect of smoking can be derived if appropriate information is available on temporal smoking habits in the population.

Adult↗
PubMed1999

Do morphology and stage explain the inferior lung cancer survival in Denmark?

Danish lung cancer patients diagnosed during 1983-1987 experienced 5-yr relative survival rates 2-7% inferior to patients in the other Nordic countries, despite the similarity of cancer registration and healthcare systems in the Nordic countries. Is the inferior relative survival in Denmark due to differences in morphology or stage of lung cancers? The present study compared in detail the survival of 92,719 patients diagnosed with lung cancer during 1978-1992 in Denmark, Finland, and Norway. In particular, differences in morphology and extent of disease were studied. A poor survival rate for small cell anaplastic lung carcinoma compared with all other morphologies was confirmed. However, this could not explain the relative survival differences observed between countries. Extent of disease was the most important predictor of survival. Part of the observed survival differences could be explained by a less favourable stage distribution in Denmark, combined with a slightly lower relative survival rate for those with metastatic disease. Differences in treatment are unlikely to explain the findings, although delays in diagnosing and treating patients in Denmark compared with neighbouring countries could partially explain the lower patient survival in Denmark. In conclusion, the main factor in the lower survival rate in Denmark is unfavourable stage distribution.

Aged↗
PubMed1999

Occupational exposure and cancer incidence among workers from an aluminum smelter in western Norway.

OBJECTIVES: This study investigated the associations between specific cancers and occupational exposure to polycyclic aromatic hydrocarbons (PAH), asbestos, electromagnetic fields, and heat in a cohort of workers from a Norwegian aluminum smelter. METHODS: Cancer incidence between 1953 and 1993 was observed for 2647 male short-term workers and 2 cohorts of men with at least 4 years' employment (2888 production workers and 373 maintenance workers). Standardized incidence ratios (SIR) were calculated from the national male cancer incidence, and associations with cumulative exposure were investigated by stratified analysis. Cumulative exposure in 15-year time windows was used as an alternative dose indicator. RESULTS: Investigation of the a priori hypotheses in the production cohort revealed a positive association between bladder cancer and PAH exposure 30 years or more before observation. The results also suggested an association between PAH and pancreatic cancer, although not statistically significant. No association was seen between exposure to PAH and cancers of the lungs or between magnetic field exposure and lymphatic and hematopoietic cancer. In the maintenance cohort there was a positive association between employment as an electrician and lymphatic and hematopoietic cancer and a statistically nonsignificant association between PAH and lung cancer. The short-term workers showed a statistically significant excess of lung cancer. CONCLUSIONS: The results support previous findings of an association between exposure to PAH and bladder cancer.

Dose-Response Relationship, Drug↗
PubMed1999

Pulmonary and auditory function among experienced construction divers: a cross-sectional study.

We studied pulmonary and auditory function in a cross-sectional study of 26 experienced construction divers compared with 26 workshop workers matched for age, height, and smoking habits. The divers used air as breathing gas and performed open-sea bounce dives to a maximum of 50 m in sea water. The mean number of dives over a mean diving period of 20 yr (SD = 11) was 4746 (SD = 4743) (Range: 450-17000). Assessment of lung function included dynamic lung volume and flow and diffusion capacity (transfer factor) for carbon monoxide (TlCO). The auditory examination was performed measuring air conduction thresholds in a cabin. The results show a significantly higher mean forced vital capacity (FVC) of 6.01 L (SD = 0.88) in the divers compared with 5.67 L (SD = 0.84) (p = 0.045) in the controls, and an alveolar volume (VA) of 7.74 L (SD = 0.99) in the divers compared with 7.35 L (SD = 0.74) (p = 0.035) in the controls. There was a nonsignificant reduction in forced mid-expiratory flow rate (FEF25-75%) and a significant reduction in forced expiratory flow rate at 50% of FVC (FEF50%) among the divers of 4.69 L (SD = 1.41) compared with 5.76 L (SD = 2.03) among the controls of (p = 0.03). There were no differences in FEV1 and TlCO between the two groups. The divers showed reduced auditory function in their left ear compared with their right ear in the 3 kHz (p = 0.006) and 8 kHz (p = 0.022) area. No statistical difference was found in hearing thresholds of the divers compared with those of the controls. Our results indicate that exposure to diving may be associated with changes in pulmonary function and that the left ear may be more vulnerable than the right ear to hearing impairment in construction divers.

Adult↗
PubMed1999

Sex differences in adolescent suicides in Norway, 1990-1992.

All suicides in persons under 20 years in Norway in the time period 1990-1992 (99 males, 30 females) were included in a postmortem case-control study with seven controls for each suicide, focusing on gender differences. Few sex differences between the suicide completers were evident, in spite of the difference in suicide rates (M/F rate ratio = 3.0). Females more often attempted suicide (p = .05), more often wrote farewell notes (p = .03), and used less violent suicide methods (ns). The adjusted risk for suicide related to affective disorders (Female OR = 22,1; Male OR = 24.0, both p = .000) and disruptive disorders (female OR = 14,7, ns; male OR = 5.0, p = .002) differed little, as did the effect of frequent use of alcohol or substances (female OR = 0.4, ns; male OR = 0.4, ns).

Adolescent↗
PubMed1998

Prognosis of patients with lung cancer diagnosed in Norway, 1954-93.

Lung cancer is the most common cancer in the world today, and the prognosis for lung cancer patients is poor. In the Nordic countries, the five-year relative survival was only seven percent in patients diagnosed in 1983-87. In the present study, the survival of 36,010 lung cancer patients diagnosed in Norway in 1954-93 was examined, based on data from the population-based Cancer Registry of Norway. The variation in survival by gender, age, stage, period of diagnosis, and histologic group was explored. Relative survival rates were calculated and relative risks of dying were obtained from multivariate Cox proportional hazards regression analysis. Only a slight improvement in the prognosis of lung cancer patients was observed during the 40-year study period. More than half the patients died during the first six months after diagnosis. Patients with small cell carcinoma had the lowest frequency of localized tumors and also had the poorest prognosis, even after adjustment for stage. Patients with squamous cell carcinoma had the highest frequency of localized tumors. The patients with a localized tumor also have a poor prognosis, with a crude median survival time of nine months in males and 11 months in females in 1984-93.

Adolescent↗
PubMed1998

Relative survival of cancer patients--a comparison between Denmark and the other Nordic countries.

The results of a Nordic collaborative project revealed that Danish cancer patients had a poorer prognosis than patients in the other Nordic countries for some major cancer sites. The present study was undertaken to further explore the differences in survival between Denmark and the other Nordic countries. All cancer cases diagnosed in the Nordic countries during 1958 to 1991/92 were included in the analysis. Relative survival and excess mortality were calculated for intervals in the first five years after diagnosis. Since the 1950s, the prognosis of cancer patients has improved in all the countries, but more moderately in Denmark. For cancers of the stomach, colon, rectum, breast (female), and prostate, the Danish patients had a markedly lower relative survival than the patients in the other countries. They also had the lowest proportion of localized tumours. It appears that Danish cancer patients are diagnosed at a later stage of disease than patients in the other Nordic countries.

Adolescent↗
PubMed1998

Suicide among children and younger and older adolescents in Norway: a comparative study.

OBJECTIVE: To compare characteristics and risk factors of suicide in early adolescence (younger than age 15 years) and in late adolescence. The authors examined whether differences in risk factors or resilience might explain the different suicide rates in the two age groups. METHOD: Information about all registered suicides of young people in Norway from 1990 through 1992 was gathered from several professional informants. Children younger than 15 years old who committed suicide (n = 14) were compared with late-adolescent suicides (15 through 19 years) (n = 115) and with controls (n = 889). RESULTS: Younger compared with older adolescent suicides more often hanged themselves (93% versus 35%). Suicidal ideation (7% versus 39%) and precipitating events were described less frequently (29% versus 49%). Older adolescents more often had psychiatric disorders (77% versus 43%). Compared with controls, the risk factors for suicide were affective disorders (young adolescents: odds ratio [OR] = 23.8, 95% confidence interval [CI] = 2.3 to 1,183; older adolescents: OR = 19.6, CI = 10.6 to 38.8); disruptive disorders (young adolescents: OR = 3.4, CI = 0.0 to 340; older adolescents: OR = 6.1, CI = 3.0 to 12.7); and not living with two biological parents (young adolescents: OR = 3.1, CI = 0.6 to 14.7; older adolescents: OR = 2.5, CI = 1.6 to 3.8). CONCLUSION: Children and young adolescents completing suicide were less exposed to known risk factors than older adolescents. The increased suicide risk was similar for both groups when they were compared with community controls. The low suicide incidence in childhood may be related to fewer risk factors, rather than to resilience to risk factors.

Adolescent↗
PubMed1997

Use of multiple primary cancers to indicate associations between smoking and cancer incidence: an analysis of 500,000 cancer cases diagnosed in Norway during 1953-93.

The occurrence of multiple primary cancers is relatively rare, but may provide indications of common or opposite risk factors for different types of cancer. In the present study, the occurrence of multiple primary cancers was used to indicate possible associations between smoking and the incidence of cancers other than those generally accepted as smoking-associated. All cancer cases in persons above the age of 30, registered at the population-based Cancer Registry of Norway (1953-1993), were used in the analysis. For each type of cancer, the observed occurrence of smoking-associated cancers in the patients was compared with the expected occurrence if the patients had the same risk as the general population. Similar comparisons were made for the occurrence of other cancers in patients with a smoking-associated cancer. The results were presented as standardized incidence ratio (SIR), the ratio of the observed and the expected numbers of cases. The results indicated that uterine cervical cancer may share some important risk factor(s) with the cancers generally accepted as smoking-associated. This is in accordance with the literature, where an association between smoking and uterine cervical cancer has been found consistently. In addition, the results for liver cancer and leukemia indicated that these types of cancer also share some risk factor(s) with the smoking-associated cancers.

Adult↗
PubMed1997

Electromagnetic fields and cancer in children residing near Norwegian high-voltage power lines.

The aim of the nested case-control study reported here was to test the hypothesis that exposure to electromagnetic fields of the type generated by high-voltage power lines increases the incidence of cancer in children aged 0-14 years. The study population comprised children who during at least one of the years 1960, 1970, 1980, 1985, 1987, or 1989 had lived in a census ward crossed by a high-voltage power line. The cases were diagnosed from 1965 to 1989 and were matched to controls by year of birth, sex, and municipality. Exposure to electric and magnetic fields was calculated by means of computer programs in which power line characteristics and distance were taken into account. No association was found between exposure to time-weighted average exposure to magnetic fields and cancer at all sites, brain tumors, lymphoma, or leukemia. Cancer at other sites showed elevated odds ratios in the two highest exposure categories in some, but not all, measures of exposure. This study provides little support for an association between children's exposure to magnetic fields and cancer and no support for an association between leukemia and such exposure, but no firm conclusions can be drawn owing to the small numbers involved.

Adolescent↗
PubMed1997

Exposure of children to residential magnetic fields in Norway: is proximity to power lines an adequate predictor of exposure?

The aim of this work was to study the exposure to magnetic fields of children living at different distances from a power line and to evaluate how well theoretical calculations compared with actual exposure. Personal exposure instruments were carried for 24 h by 65 schoolchildren living 28-325 m from a 300 kV transmission line; the current load was 200-700 A. About half of the children attended a school far from the power line, whereas the other half attended a school located about 25 m from the line. Exposure to magnetic fields was analyzed for three categories of location: at home, at school, and at all other places. Time spent in bed was analyzed separately. The results indicated that children who lived close to a power line had a higher magnetic field exposure than other children. The power line was the most important source of exposure when the magnetic field due to the line was greater than about 0.2 microT. Exposure at school influenced the 24 h time-weighted average results considerably in those cases where the distance between home and power line was very different from the distance between school and power line. The calculated magnetic field, based on line configuration, current load, and distance between home and power line, corresponded reasonably well with the measured field. However, the correlation depends on whether home only or 24 h exposure is used in the analysis and on which school the children attended. The calculated magnetic field seems to be a reasonably good predictor of actual exposure and could be used in epidemiological studies, at least in Norway, where the electrical system normally results in less ground current than in most other countries.

Child↗
PubMed1997

Youth suicide in Norway, 1990-1992: a comparison between children and adolescents completing suicide and age- and gender-matched controls.

In Norway 1990-1992, the suicide rate was 18.6 per 100,000 individuals per year for boys 15-19 years old and 6.3 for girls, and for 10-14 year olds the rate was 2.7 for boys and 0.5 for girls. Comparison of all completed suicides (N = 129) with gender- and age-matched control subjects identified depression (OR = 19.9; CI = 11.2, 35.5), disruptive disorders (OR = 6.0; CI = 3.1, 11.4), and previous suicidal behavior (OR = 3.4, CI = 2.0, 5.6) as main risk factors. Of the suicide completers, 74% had mental disorders. Suicidal intent was previously expressed by 48%, but few (24%) had received treatment, despite well-developed health services. A history of disruptive disorders (17%) and substance abuse (10%) were less frequently found than in previous studies, but binge drinking may contribute to the adolescent suicide rate.

Adolescent↗
PubMed1996

Incidence of breast cancer in Norwegian female radio and telegraph operators.

Exposure to electromagnetic fields may cause breast cancer in women if it increases susceptibility to sex-hormone-related cancer by diminishing the pineal gland's production of melatonin. We have studied breast cancer incidence in female radio and telegraph operators with potential exposure to light at night, radio frequency (405 kHz-25 MHz), and, to some extent, extremely low frequency fields (50 Hz). We linked the Norwegian Telecom cohort of female radio and telegraph operators working at sea to the Cancer Registry of Norway to study incident cases of breast cancer. The cohort consisted of 2,619 women who were certified to work as radio and telegraph operators between 1920 and 1980. Cancer incidence was analyzed on the basis of the standardized incidence ratio (SIR), with the Norwegian female population as the comparison group. The incidence of all cancers was close to unity (SIR = 1.2). An excess risk was seen for breast cancer (SIR = 1.5). Analysis of a nested case-control study within the cohort showed an association between breast cancer in women aged 50+ years and shift work. In a model with adjustment for age, calendar year, and year of first birth, the rate ratio for breast cancer associated with being a radio and telegraph operator--in comparison with all Norwegian women born 1935 or later--analyzed with Poisson regression, was 1.5 after adjustment for fertility factors. These results support a possible association between work as a radio and telegraph operator and breast cancer. Future epidemiologic studies on breast cancer in women aged 50 and over, should address possible disturbances of chronobiological parameters by environmental factors.

Adult↗
PubMed1996

Smoking habits and risk of cancers other than lung cancer: 28 years' follow-up of 26,000 Norwegian men and women.

The impact of tobacco smoking on lung cancer risk has been investigated thoroughly since the 1950s, but other types of cancer also have been associated with smoking. In the present study, the aim was to explore the variation in risk connected with cigarette, cigar, and pipe smoking of suspected smoking-associated cancers other than lung cancer. Data were obtained from a survey of a random sample of the Norwegian population. A self-administered mailed questionnaire, which included questions about smoking habits, was completed by 26,000 men and women in 1965 (response rate: 76 percent). The cohort was followed from 1966 through 1993, including registration of all incident cancer cases. A dose-response relationship of cigarette smoking to the risk of urinary bladder cancer and cancers of the upper digestive and respiratory tract was observed. For the latter forms of cancer, a dose-response relationship of pipe smoking also was observed. In cancer of the pancreas, a stronger association between cigarette smoking and cancer risk was observed when the analysis was confined to histologically confirmed cases only. Current cigarette smokers at baseline had a significantly higher risk of cervical cancer than those who never smoked cigarettes. In cancers of the stomach, colon, rectum, breast, corpus uteri, ovary, and prostate, and in leukemia, no association between smoking and cancer risk was observed.

Adult↗