Biomedical subjects

T Haldorsen

Publications and source records attributed to T Haldorsen.

At least 19 recordsLinked to original sources

PubMed2006

Suicide among Indigenous Sami in Arctic Norway, 1970-1998.

Suicide mortality was examined between 1970 and 1998 in a cohort of 19,801 persons categorized as indigenous Sami in Arctic Norway. Standardized mortality ratios (SMR) were calculated using the suicide rates of the rural population of Arctic Norway as reference. There was a significant moderate increased risk for suicide among indigenous Sami (SMR = 1.27, 95% Confidence interval (CI): 1.02-1.56). In the study period, 89 suicides occurred in the cohort (70 men and 19 women) with increased suicide mortality both for indigenous Sami males (SMR = 1.27; 95% CI: 0.99-1.61) and females (SMR = 1.27; 95% CI: 0.77-1.99). Significant increased suicide mortality was found for young Sami aged 15-24 for both males (SMR = 1.82; 95% CI: 1.13-2.78) and females (SMR = 3.17; 95% CI: 1.17-6.91). Significant increased suicide mortality was found for indigenous Sami males residing in Sami core area (SMR = 1.54; 95% CI: 1.04-2.20) and for indigenous Sami males not belonging to semi-nomadic reindeer herding (SMR = 1.30; 95% CI: 1.00-1.65). Clusters of suicides in Sami core area may explain the increased suicide mortality found in subgroups among indigenous Sami.

Adolescent↗

PubMed2006

Respiratory symptoms and 30 year mortality from obstructive lung disease and pneumonia.

BACKGROUND: As little is known about the long term relationship between respiratory symptoms and mortality from non-malignant respiratory diseases, a study was undertaken to investigate the predictive value of respiratory symptoms and symptom load for mortality from obstructive lung disease (OLD) and pneumonia in the long term in a Norwegian population. METHODS: In 1972, 19 998 persons aged 15-70 years living in Oslo were randomly selected for a respiratory survey. The response rate was 89%. All were followed for 30 years. The association between cough, asthma-like symptoms, two levels of dyspnoea on exercise, a symptom score, and mortality from OLD and pneumonia were investigated separately for men and women by multivariable analyses, with adjustment for age, occupational exposure to air pollution, and smoking habits. RESULTS: OLD accounted for 43% and pneumonia for 50% of all deaths from respiratory causes. In men the hazard ratio for mortality from OLD varied from 4.0 (95% confidence interval (CI) 2.4 to 6.5) for cough to 9.6 (95% CI 5.1 to 18.3) for severe dyspnoea, and in women from 5.1 (95% CI 2.3 to 11.3) for moderate dyspnoea to 13.0 (95% CI 6.0 to 28.3) for severe dyspnoea. The symptom score was strongly predictive of death from OLD in a dose-response manner. CONCLUSIONS: There is a significant, positive, strong association between respiratory symptoms and 30 year mortality from OLD. The association between respiratory symptoms and mortality from pneumonia is weaker and not significant.

Adolescent↗

PubMed2005

Cancer in the Sami population of North Norway, 1970-1997.

The Sami population in North Norway constitutes an ethnic minority with a lifestyle that diverges from that of the rest of the population. A cohort of 19 801 people of Sami origin was followed for cancer incidence over the period 1970-1997 by the Norwegian Cancer Registry. Among the Sami 1340 cases of cancer were observed versus 1658.2 expected, based on a regional reference population. For both sexes a significantly decreased incidence of colon cancer was observed. The standardized incidence ratio (SIR) for men was 0.50 (95% confidence interval (CI) 0.34-0.71) and for women 0.62 (95% CI 0.43-0.85). Low SIRs were observed for lung cancer: 0.63 (95% CI 0.51-0.77) and 0.60 (95% CI 0.37-0.91), for men and women, respectively. Men of Sami ancestry had a decreased risk of prostate cancer: SIR 0.57 (95% CI 0.45-0.71). Among women 127 cases of breast cancer were observed versus 149.6 expected. A relatively high physical activity and a diet rich in fish may in part explain the low cancer incidence. Some Sami were exposed to radioactivity as a result of their diet based on reindeer products. Adverse effects on their cancer incidence were not observed.

Adult↗

PubMed2005

The influence of mammographic screening on national trends in breast cancer incidence.

Introducing an organized mammographic screening programme affects the breast cancer incidence rate in a population. The diagnosis is advanced in time, and initially, an increase will occur in the number of cases, followed by a drop in the rate when women leave the programme. The aim of this study was to quantify the potential effects that mammographic screening programmes have on breast cancer incidence. In addition, we wanted to investigate how the incidence of breast cancer varies between different birth cohorts, age groups and time periods in the five Nordic countries Finland, Denmark, Iceland, Norway and Sweden, adjusting for the effects of the screening programmes. Time trends were analysed over the period 1978-1997, using age-period-cohort models. In Sweden, the rates more than doubled (relative risk (RR)=2.20, 95% confidence interval (CI) 1.8-2.6) in women offered screening for the first time compared with women not offered screening. The risk remained elevated (RR=1.34, 95% CI 1.2-1.6) for women who were continued to be offered screening, compared with women who were not offered screening. Finally, the rates dropped (RR=0.68, 95% CI 0.6-0.8) when the women left the programme. This indicates that screening advances the time of diagnosis, which is a prerequisite to subsequent reduction in mortality. Analysis of secular trends, corrected for the influence of screening, showed that the rates in Finland increased by 13% per 5-year period, with a more modest increase in the other countries. There were strong cohort effects in all Nordic countries, and the risk seemed to be flattening for the youngest cohorts in most of the countries.

Adult↗

PubMed2003

Cosmic radiation and cancer mortality among airline pilots: results from a European cohort study (ESCAPE).

Cosmic radiation is an occupational risk factor for commercial aircrews. In this large European cohort study (ESCAPE) its association with cancer mortality was investigated on the basis of individual effective dose estimates for 19,184 male pilots. Mean annual doses were in the range of 2-5 mSv and cumulative lifetime doses did not exceed 80 mSv. All-cause and all-cancer mortality was low for all exposure categories. A significant negative risk trend for all-cause mortality was seen with increasing dose. Neither external and internal comparisons nor nested case-control analyses showed any substantially increased risks for cancer mortality due to ionizing radiation. However, the number of deaths for specific types of cancer was low and the confidence intervals of the risk estimates were rather wide. Difficulties in interpreting mortality risk estimates for time-dependent exposures are discussed.

Adult↗

PubMed2003

Residential and occupational exposure to 50 Hz magnetic fields and hematological cancers in Norway.

OBJECTIVE: The aim of this nested case-control study was to test the hypothesis that exposure to electromagnetic fields from high-voltage power lines increases the incidence of hematological cancers in adults. Data from an occupational exposure matrix was also used. METHODS: The study population comprised subjects aged 16 and above who had lived in a residence situated in a broad corridor around a high-voltage power line in 1980, or one of the years from 1986 to 1996. The cases were incident cases diagnosed 1980-1996. Two controls were matched to each case by year of birth, sex, municipality and first year entering the cohort. Time-weighted average exposure to residential magnetic fields generated by the power lines was calculated for the exposure follow-up from January 1, 1967 until diagnosis using cut-off points at 0.05 and 0.20 microT. In addition, job titles and industrial branch was classified as categories of hours per week in a magnetic field above background (0.1 microT). Subjects exposures were cumulated over occupationally active years for the exposure follow-up January 1, 1955 until diagnosis. RESULTS: When residential magnetic fields are evaluated, the two upper residential time weighted average magnetic field categories showed non-significant elevated odds ratios (ORs) for all leukemia combined (OR: 1.3, 95% confidence interval (CI) 0.7-2.5 and OR: 1.5, 95% CI: 0.8-3.0). The increased risk was confined to chronic lymphocytic leukemia, acute lymphocytic and acute myeloid leukemia. Lymphoma showed a non-significant lower OR in the upper exposure category. Multiple myeloma showed non-significant elevated ORs. Occupational exposure showed no significant association to exposure for any site. CONCLUSIONS: Some elevated ORs were observed in the present study, but the results are based on small numbers and no firm conclusions can be drawn.

Adult↗

PubMed2003

Residential and occupational exposure to 50 Hz magnetic fields and malignant melanoma: a population based study.

AIMS: To test the hypothesis that exposure to electromagnetic fields from high voltage power lines increases the incidence of cutaneous malignant melanoma in adults aged 16 and above. METHODS: Nested case-control study. The study population comprised subjects aged 16 and above who had lived in a residence situated in a broad corridor around a high voltage power line in 1980, or one of the years from 1986 to 1996. The cases were incident cases that were diagnosed in 1980-96 and reported to the Cancer Registry of Norway. Two controls were matched to each case by year of birth, sex, municipality, and first year entering the cohort. Time weighted average exposure to residential magnetic fields generated by the power lines was calculated for the exposure follow up from 1 January 1967 until diagnosis by means of a computer program, in which distance from residency to the line, line configuration, and current load were taken into account. Exposure was analysed using cut off points at 0.05 and 0.2 microtesla ( microT). Exposure to magnetic fields at work was classified by an expert panel who assessed magnetic field exposure by combining branch and occupation into one of three levels: <4 hours, 4-24 hours, and >24 hours per week above background (0.1 micro T). The categories were cumulated over the occupationally active years for the exposure follow up from 1 January 1955 until diagnosis, and cut off points at 18 and 31 category-years were evaluated. RESULTS: Analysis of the two upper residential magnetic field categories showed an odds ratio of 2.01 (95% CI 1.09 to 3.69) and 2.68 (95% CI 1.43 to 5.04) for women, and an odds ratio of 1.70 (95% CI 0.96 to 3.01) and 1.37 (95% CI 0.77 to 2.44) for men, respectively. Occupational exposure showed no significant association with cutaneous malignant melanoma, and analysis of both residential and occupational exposure simultaneously, showed no additional effect. CONCLUSION: The present study provides some support for an association between exposure to calculated residential magnetic fields and cutaneous malignant melanoma, but because of the lack of a biological hypothesis and the known strong association between solar radiation and melanoma, no firm conclusions can be drawn and further studies would be of interest.

Adolescent↗

PubMed2002

Non-malignant mortality among Norwegian silicon carbide smelter workers.

OBJECTIVES: To investigate associations between exposures in the silicon carbide (SiC) industry and mortality from non-malignant diseases. METHODS: Mortality among 2562 men, working in one of three silicon carbide smelters was investigated, giving 52,618 person-years of follow up from 1962 to 1996. Dose-response relations were investigated by internal comparisons using Poisson regression and by stratified standardised mortality ratio (SMR) analyses. RESULTS: Mortality from all causes was significantly raised compared with the Norwegian mortalities among men, SMR=1.12, (95% confidence interval (95% CI) 1.05 to 1.20). An excess mortality from asthma, emphysema, and chronic bronchitis combined was found, SMR=2.21 (95% CI 1.61 to 2.95), increasing from 1.05 in the unexposed category to 2.64 (95% CI 1.44 to 4.43) in the upper category of exposure to total dust. The Poisson regression analysis confirmed the results from the stratified SMR analyses, and suggested that smoking did not act as a confounder. No association was found for circulatory mortality. CONCLUSIONS: There was an increased mortality from asthma, emphysema, and chronic bronchitis combined among SiC workers exposed to dust.

Aged↗

PubMed2002

Lung function over six years among professional divers.

AIMS: To analyse longitudinal changes in pulmonary function in professional divers and their relation with cumulative diving exposure. METHODS: The study included 87 men at the start of their education as professional divers. At follow up one, three, and six years later, 83, 81, and 77 divers were reexamined. The median number of compressed air dives in the 77 divers over the follow up period was 196 (range 37-2000). A group of non-smoking policemen (n = 64) were subjected to follow up examinations in parallel with the divers. Assessment of lung function included dynamic lung volumes, maximal expiratory flow rates, and transfer factor for carbon monoxide (Tl(CO)). The individual rates of change of the lung function variables were calculated by fitting linear regression lines to the data, expressed as percent change per year. RESULTS: The annual reductions in forced vital capacity (FVC) and forced expired volume in one second (FEV(1)) were 0.91 (SD 1.22) and 0.84 (SD 1.28) per cent per year in divers, which were significantly higher than the reductions in the policemen of 0.24 (SD 1.04) and 0.16 (SD 1.07) per cent per year (p < 0.001). The annual reduction in the maximal expiratory flow rates at 25% and 75% of FVC expired (FEF(25%) and FEF(75%)) were related to the log(10) transformed cumulative number of dives in a multiple regression analysis (p < 0.05). The annual reductions in Tl(CO) were 1.33 (SD 1.85) and 0.43 (SD 1.53) per cent per year in divers and policemen (p < 0.05). CONCLUSIONS: FVC, FEV(1), maximal expiratory flow rates, and Tl(CO) were significantly reduced in divers over the follow up period when compared with policemen. The contrasts within and between groups suggest that diving has contributed to the reduction in lung function.

Accidents, Occupational↗

PubMed2001

Cancer incidence among workers in the Norwegian silicon carbide industry.

The presence of silicon carbide (SiC) fibers in the SiC smelter work environment has suggested a possible cancer hazard. The authors studied cancer incidence among 2,620 men employed for more than 6 months in three Norwegian SiC smelters. Follow-up from 1953 to 1996 revealed an overall excess risk of lung cancer (standardized incidence ratio = 1.9, 95% confidence interval (CI): 1.5, 2.3) and an elevated risk of stomach cancer (standardized incidence ratio = 1.5, 95% CI: 1.1, 2.0). Both standardized incidence ratio and Poisson regression analyses showed that lung cancer risk increased according to cumulative exposure to total dust, SiC fibers, SiC particles, and crystalline silica. The standardized incidence ratio for the upper SiC fiber exposure category was 3.5 (95% CI: 2.1, 5.6) when exposure was lagged by 20 years, while the Poisson regression analysis showed a rate ratio of 4.4 (95% CI: 2.1, 9.0). Smoking did not seem to be an important confounder. The excess risk of lung cancer may be explained by exposure to SiC fibers, but a strong correlation between the different exposures made it difficult to distinguish between them.

Adult↗

PubMed2001

Cancer incidence among Norwegian airline cabin attendants.

BACKGROUND: Cabin crews are exposed to cosmic radiation at work and this may increase their incidence of radiation-induced cancers. Former studies indicate an increased risk of breast cancer. METHODS: A retrospective cohort study was performed. The cohort was established from the files of the Civil Aviation Administration and included people with a valid licence as a cabin attendant between 1950 and 1994. The cohort was linked to the Cancer Registry of Norway. Observed number of cases was compared with expected, based on national rates. Breast cancer incidence was analysed, adjusting for individual fertility variables. RESULTS: A group of 3693 cabin attendants were followed over 72 804 person-years. Among the women, 38 cases of breast cancer were observed (standardized incidence ratio (SIR) = 1.1, 95% CI : 0.8-1.5). Among men excess risks were found for cancers in the upper respiratory and gastric tract (SIR = 6.0, 95% CI : 2.7-11.4) and cancer of the liver (two cases, SIR = 10.8, 95% CI : 1.3-39.2). For both sexes elevated risks were found for malignant melanoma and non-melanoma skin cancer; for men these were SIR = 2.9 (95% CI : 1.1-6.4) and SIR = 9.9 (95% CI : 4.5-18.8) respectively, while for women these were SIR = 1.7 (95% CI : 1.0-2.7) and SIR = 2.9 (95% CI : 1.0-6.9) respectively. For no cancer site was a significant decreased risk found. CONCLUSIONS: An increased risk of radiation-induced cancers was not observed. The excess risks of some other cancers are more probably explained by factors related to lifestyle.

Adult↗

PubMed2000

Cancer incidence and cause specific mortality among workers in two Norwegian aluminum reduction plants.

BACKGROUND: Concern about the health hazards in the aluminum industry has initiated this study where we have investigated associations between exposure to polycyclic aromatic hydrocarbons (PAH) and fluorides, and cancer incidence and cause specific mortality among workers in two Norwegian aluminum plants in operation since 1954 and 1957, respectively. METHODS: The study was designed as a historical cohort study and comprised 5627 identified men employed for more than six months. Cancer incidence was investigated from start of employment to 1995, and cause specific mortality was investigated from 1962 to 1995. The observed cases of cancers and observed deaths were compared with expected numbers calculated from national rates. Internal comparisons were made using Poisson regression with age and smoking included in the models. Historical exposure to PAH and fluoride had been estimated previously by use of statistical modeling on industrial hygiene measurements and process parameters. A job exposure matrix was used to investigate possible associations between cumulative exposures, and cancer incidence and cause specific mortality. Smoking habits were identified for 92% of the cohort members. RESULTS: The study showed a significant excess risk for urinary bladder cancer among workers exposed to PAH, but no clear dose-response relationship. When using a 30-year lag period, a significant excess of bladder cancer in the highest exposure category (> 2000 microg/m(3);year PAH) was shown (SIR 4.08). The data also suggested an association between exposure to PAH and pancreatic cancer, but no association with lung cancer was seen. The mortality analysis indicated an association between exposure to pot-room emissions (fluorides) and mortality from chronic bronchitis, emphysema and asthma, but no associations with cardiovascular diseases. CONCLUSIONS: The study findings are compatible with an excess risk for bladder cancer for aluminum plant workers exposed to PAH. The increased risk for cancer of the pancreas indicated, should be further evaluated in larger exposed populations.

Aged↗

PubMed2000

Adolescents hospitalised with deliberate self-harm: the significance of an intention to die.

All suicide attempters admitted to medical wards in the greater Oslo area, (n = 91) aged 13-19 years, were dichotomised on the basis of one item in the Motives for Parasuicide Questionnaire (MPQ) and one item in the Suicide Intent Scale (SIS): if the intent was to die (n = 57), or not (n = 34). The two groups were compared regarding the attempt, mental health problems, and psychosocial risk factors. The attempt of adolescents with an intent to die were more serious, rated with SIS (15.7 vs. 5.7, p < 0.001), with Risk Rescue Rating (p = 0.003) or rated medically (p < 0.05). They were clinically more often depressed (61% vs. 32%, p < 0.01), felt more hopeless (Hopelessness Scale) (10.8 vs. 8.2, p < 0.05), were less disruptive (11% vs. 32%, p < 0.05) and less often abused substances (0 vs. 12%, p < 0.05). Both groups were equally burdened with other factors. Differentiation on the basis of suicidal intent delineated two groups, both with considerable psychosocial problems. Those with suicide intent had more internalising problems including depression, while those with other intents showed more externalising behaviour. The need for help in the group with no intent to die may be underestimated.

Adolescent↗

PubMed2000

Auditory function among young occupational divers: a 3-year follow-up study.

Auditory function was measured in a 3-year follow-up study of 54 young occupational divers divided into high-exposure (n = 23) and low-exposure (n = 31) groups. The divers performed open-sea dives with a median number of 132 dives (range 44-766) during follow-up. At the start of follow-up, hearing in the high-exposure group was reduced compared with that in the low-exposure group. During the follow-up period, the total group experienced a significantly reduced hearing ability at 4 kHz in the left ear. No difference in change between the last and the first measurement for both ears combined was found when the two groups were compared. A regression analysis of measurements at the end of follow-up shows an association between the loss of hearing in the left ear at 6 and 8 kHz and the total number of years of diving. This indicates that diving may contribute to hearing impairment.

Adolescent↗

PubMed2000

Young suicide attempters: a comparison between a clinical and an epidemiological sample.

OBJECTIVE: To compare risk factors for self-harm in 2 groups: hospitalized adolescents who had attempted suicide and adolescents reporting suicide attempts in a community survey. METHOD: All suicide attempters aged 13 to 19 years admitted to medical wards (n = 91) in a region of Norway were assessed and interviewed. Risk factors were identified by comparisons with a general population sample participating in a questionnaire study in the same community (n = 1,736). In this population sample, a separate analysis of risk factors for reporting deliberate self-harm (n = 141) was performed, applying bivariate and multivariate logistic regression models. RESULTS: Adjusted risk factors for suicide attempts in hospitalized adolescents were depression (odds ratio [OR] = 4.7), disruptive disorders (OR = 9.4), low self-worth (OR = 1.3), infrequent support from parents (OR = 3.3) or peers (OR = 3.3), parents' excessive drinking (OR = 4.3), and low socioeconomic status (OR = 2.4). For adolescents who self-reported self-harm, depression (OR = 3.1) and loneliness (OR = 1.13) were significant adjusted risk factors (p < .001). Low self-worth, low socioeconomic status, and little support from parents or peers characterized hospitalized suicidal adolescents compared with those who were not hospitalized. CONCLUSIONS: The risk factors were more powerful for hospitalized than for nonhospitalized adolescents. Prevention efforts should target the same factors for both groups, at a population level for nonhospitalized adolescents and at an individual level for hospitalized adolescents, with a focus on depression, low self-esteem, and family communication.

Adolescent↗

PubMed2000

Lung function over the first 3 years of a professional diving career.

OBJECTIVES: To characterise diving exposure and pulmonary function in professional divers at the start of their formal education and during the first 3 years of their professional career. METHODS: The study included 87 men at the start of their education as professional divers. At follow up 1 and 3 years after the school 83 and 81 divers respectively were re-examined. Assessment of lung function included dynamic lung volumes and flows and transfer factor for carbon monoxide (Tl(CO)). RESULTS: 69 Divers had preschool SCUBA diving experience and had a median number of 70 dives (range 2-3000) to a median maximal depth of 40 (range 10-73) metres. During the 15 week introductory diving course, they had 44 dives (range 38-50) in the depth range 10-50 metres. The median number of dives over the follow up period was 95 (range 0-722) to a maximal median depth of 38 (range 0-98) metres. At the start of the diving course there were no differences in forced vital capacity (FVC), forced expired volume in 1 second (FEV(1)), and in Tl(CO) between the 69 pre-exposed divers and the 18 never exposed divers. The FVC was significantly larger than predicted in both groups. At follow up at 3 years there was a significant reduction in mean (SD) FEV(1) of 1.8% (6.5), in forced mid-expiratory flow rate (FEF(25-75%)) of 6.5% (11.7) and in forced expiratory flow at 75% of FVC expired (FEF(75%)) of 10.4% (16. 8). There was no change in FVC. The Tl(CO) was significantly decreased by 4.6% (8.8). No significant effects were found of cumulative diving exposure, including the number of dives, on the relative changes of any of the lung function variables. CONCLUSIONS: The results indicate that divers initially belong to a selected group with large FVC. Exposure to diving may contribute to changes in pulmonary function, mostly affecting small airways conductance.

Adult↗

PubMed2000

Lung and bladder cancer among workers in a Norwegian aluminium reduction plant.

OBJECTIVE: To investigate the relation between exposure to polycyclic aromatic hydrocarbons (PAHs) and the incidence of lung and bladder cancer among aluminium production workers. METHODS: The cohort comprised 1790 men employed for more than 5 years at a Norwegian aluminium plant contributing 36 587 person-years to the study. Historical exposure to PAHs was estimated by the use of industrial hygiene measurements and by a panel of three people familiar with the industry. Cancer incidence was investigated from 1953 to 1995. The observed cases of cancer among men were compared with expected numbers calculated from national rates for men, and dose-response relations were investigated by internal comparison by Poisson regression with age, period, smoking, and cumulative exposure included in the models. The effect of lagging exposure by 10, 20, and 30 years was also investigated. RESULT: The present study showed no increased risk of urinary bladder cancer or lung cancer with increasing cumulative exposure to PAHs. No significant changes in risk were found for different lag times. CONCLUSIONS: Due to the small size of this study, a minor increase in risk could not be excluded.

Adult↗

PubMed2000

Cancer incidence among Norwegian airline pilots.

OBJECTIVES: In this retrospective cohort study, the cancer incidence of commercial pilots was studied to determine whether exposure at work has any influence on the incidence of cancer. METHODS: The cohort was established from the files of the Civil Aviation Administration and included people who had valid licenses as commercial pilots between 1946 and 1994. Basic data about their flight careers were recorded, and exposure to cosmic radiation was estimated. The cohort was linked to the Cancer Register of Norway. The observed number of cases was compared with that expected based on national rates. RESULTS: A group of 3701 male pilots was followed over 70 560 person-years. There were 200 cases of cancer versus 188.8 expected, with a standardized incidence ratio (SIR) of 1.06 and a 95% confidence interval (95% CI) of 0.92-1.22. No significant decreased risk was found for any cancer site. Excess risks were found for malignant melanoma (22 cases SIR 1.8, 95% CI 1.1-2.7) and nonmelanoma skin cancer (14 cases, SIR 2.4, 95% CI 1.3-4.0). For malignant melanoma, there was a significant trend for the SIR by cumulative dose. CONCLUSIONS: For most cancer sites, the incidence among pilots did not deviate from that of the general population and could not be related to block hours of flight time or dose. It seems more likely that the excess risks of malignant melanoma and skin cancer are explained by factors related to life-style rather than by conditions at work.

Adult↗