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Tor Haldorsen

Publications and source records attributed to Tor Haldorsen.

At least 19 recordsLinked to original sources
PubMed2006

[Incidence of breast cancer before and after implementation of mammography screening].

BACKGROUND: A nationwide governmentally founded breast cancer screening program for women aged 50 - 69 years was gradually implemented in all Norwegian counties between November 1995 and February 2004 (the Norwegian Breast Cancer Screening Program, NBCSP). Such an implementation is expected to give an initial increased incidence followed by a decrease. We here present general and stage-specific incidences of breast cancer by age groups, in the first 9 counties that implemented the NBCSP. MATERIAL AND METHOD: The incidence of invasive breast cancer is shown for the counties Akershus, Hordaland, Oslo and Rogaland (AHOR), and Agder (east and west), Telemark, Troms and Finnmark (AgTmTF) for the period 1990-2003. AHOR started the NBCSP in 1995/1996, and AgTmTF started in 1999/2000. The incidence is based on recordings in the main database at the Cancer Registry, and is shown in rates per 100,000 women years. RESULTS: The incidence of breast cancer in women aged 50-69 years increased from 200 to 350 per 100,000 women years at start-up of the NBCSP and subsequently decreased to approximately 250. Before starting the program, the incidence was higher in women aged 70-74 years than in those aged 50 - 69. This changed in the subsequent period. During 1990-2003, the incidence of breast cancer was stable in women aged 20-49 and in those older than 74 years. At start-up of the NBCSP, a higher proportion of breast cancers in Stadium I were diagnosed as compared to the period before, especially among women aged 50-69 years. INTERPRETATION: Introduction of the NBCSP has changed the incidence of breast cancer in women aged 50-69 and in those aged 70-74 years.

Adult↗
PubMed2006

Influence of interval between primary surgery and chemotherapy on short-term survival of patients with advanced ovarian, tubal or peritoneal cancer.

OBJECTIVE: To investigate the impact on short-term survival of time between surgery and start of first chemotherapy cycle in patients with advanced ovarian cancer. METHODS: This prospective, population-based study comprised 371 patients with epithelial ovarian, tubal or peritoneal cancer diagnosed in 2002-2003. All patients underwent primary surgery, followed at different intervals by chemotherapy. The data were derived from notifications to the Norwegian Cancer Registry and included medical, surgical and histopathological records. Kaplan-Meier plots were used to show differences in survival, and Cox regression analysis was used to show the effect of prognostic factors on survival, expressed as hazard ratios (HRs). RESULTS: No difference in survival between patient groups was seen when time between surgery and start of chemotherapy was divided into quartiles. The group of patients with no residual disease and an interval between surgery and start of chemotherapy equal to or more than 6 weeks had non-significantly worse survival (unadjusted HR = 1.86; adjusted HR = 1.35) than those with an interval of less than 6 weeks. Patients with residual disease after surgery and chemotherapy at an interval of less than 6 weeks had worse short-term survival than patients without residual disease and the same interval before chemotherapy: unadjusted HR = 3.66 (95% CI, 2.09-6.40) and adjusted HR = 2.36 (95% CI, 1.22-4.57). CONCLUSIONS: The interval between surgery and start of chemotherapy had no major impact on short-term survival after ovarian cancer. Patients might be included in chemotherapy trials when interval between surgery and start of chemotherapy is more than 6 weeks. Any further investigation of a possible effect of interval between surgery and start of chemotherapy should be performed as a randomized trial.

Aged↗
PubMed2006

Alcohol use before and during pregnancy: a population-based study.

BACKGROUND: Few population-based studies have estimated alcohol consumption and binge drinking before and during pregnancy. METHODS: The study is a longitudinal questionnaire study. In Norway, virtually 100% attend an ultrasound screening at 17-18 weeks of pregnancy. In Oslo, a representative sample attending this between June 2000 and May 2001 were invited to join the study, accepted by 92%. Non-Norwegian-speaking and/or immigrants from non-Western countries were not invited; 1,749 (93%) completed the first questionnaire. MEASURES: T-ACE (screening for pregnancy risk drinking), frequency of alcohol use, Standard Units (SU) per occasion, SU/week, and binge drinking (>or=5 SU per occasion). Binary logistic regression analyses, Student's t-test and Pearson's chi square were used. RESULTS: Alcohol use was reported by 89% pre-pregnancy and by 23% after pregnancy week 12. Binge drinking was reported by 59% pre-pregnancy and by 25% during weeks 0-6. Change of drinking pattern occurred at pregnancy recognition for 85%, although 78% had planned the pregnancy, fetal welfare being the main reason. Participants reporting alcohol use during pregnancy were older, smokers, with more SU/week pre-pregnancy, had some elevated anxiety score, higher income, and a partner with higher education. However, mental health, high income, or education were not predictive of usually drinking 1 SU per occasion or more, and not of binge drinking. The latter was predicted mainly by smoking during pregnancy and being T-ACE positive. CONCLUSIONS: The study shows a drinking pattern before pregnancy recognition that, according to other studies, in 25% or more may cause suboptimal fetal development.

Adolescent↗
PubMed2006

Alcohol consumption, smoking and breastfeeding in the first six months after delivery.

AIM: To study alcohol use and smoking after delivery, and to relate this to breastfeeding. METHODS: A longitudinal questionnaire study, representative of pregnant women in Oslo. Ninety-two per cent agreed to join the study. Non-Norwegian speaking and/or immigrants from non-western countries were not invited. Questionnaires were answered at 17 (T1) and 30 (T2) wk of pregnancy, and 6 mo after term (T3). They were completed by 93% (1749 women) at T1, 82% at T2, and 92% at T3. RESULTS: Six months after delivery, 80% reported alcohol use. The mean alcohol consumption per week was less than half compared to the last 6 mo before pregnancy. The women with the highest pre-pregnancy use reduced the most. Binge drinking (> or = 5 drinks) was also reported by half as many women (29%). However, 6% reported 12 or more drinks per occasion at least once. No demographic or mental health variables predicted binge drinking after pregnancy. Smoking 6 mo after pregnancy was reported by 18%, a reduction of 50% from before pregnancy. Women breastfeeding for at least 6 mo had higher education, less frequently reported binge drinking after delivery and less frequently suffered postnatal depression. CONCLUSION: In this population-based sample were 86% breastfed for at least 6 mo, the level of binge drinking is concerning.

Adult↗
PubMed2006

Alcohol consumption before and during pregnancy comparing concurrent and retrospective reports.

BACKGROUND: Reported alcohol consumption during pregnancy has proven to be higher when reported retrospectively during or after the pregnancy, compared with concurrent reports. In a longitudinal, population-based questionnaire study, we investigated whether these findings could be replicated. METHODS: A longitudinal, population-based questionnaire study. Among a representative half of pregnant women in Oslo, 92% accepted to join the study. Non-Norwegian speaking and/or immigrants from nonwestern countries were not invited. Questionnaires were answered at 17 (T1) and 30 weeks of pregnancy (T2) and 6 months after term (T3). The response rate was at T1 93% (N = 1,749), at T2 82%, and at T3 94% [representing 86% (T1), 70% (T2), and 64% of those invited to join the study]. RESULTS: Significantly more alcohol consumption after pregnancy recognition was reported retrospectively at both T2 and T3 [T2 0.15 and T3 0.18 standard units per week (SU/wk)] than concurrently at T1 or T2 (T1 0.10 and T2 0.14 SU/wk). When comparing the 2 retrospective reports at T2 and T3, there was a significant increase over time. Predictive factors for higher retrospective reports were higher age, more SU per week before pregnancy, reported alcohol use after pregnancy recognition (at T1), and depression after the pregnancy. A predictive factor for lower retrospective reporting was anxiety during, but not after, the pregnancy. Contrary to previous suggestions, anxiety concerning abnormality in the 6-month-old child was not a predictive factor. CONCLUSION: Concurrently reported alcohol consumption during pregnancy is probably under-reported. Thus, concurrent reports appear to underestimate fetal exposure.

Adult↗
PubMed2005

Empirical evaluation of prediction intervals for cancer incidence.

BACKGROUND: Prediction intervals can be calculated for predicting cancer incidence on the basis of a statistical model. These intervals include the uncertainty of the parameter estimates and variations in future rates but do not include the uncertainty of assumptions, such as continuation of current trends. In this study we evaluated whether prediction intervals are useful in practice. METHODS: Rates for the period 1993-97 were predicted from cancer incidence rates in the five Nordic countries for the period 1958-87. In a Poisson regression model, 95% prediction intervals were constructed for 200 combinations of 20 cancer types for males and females in the five countries. The coverage level was calculated as the proportion of the prediction intervals that covered the observed number of cases in 1993-97. RESULTS: Overall, 52% (104/200) of the prediction intervals covered the observed numbers. When the prediction intervals were divided into quartiles according to the number of cases in the last observed period, the coverage level was inversely proportional to the frequency (84%, 52%, 46% and 26%). The coverage level varied widely among the five countries, but the difference declined after adjustment for the number of cases in each country. CONCLUSION: The coverage level of prediction intervals strongly depended on the number of cases on which the predictions were based. As the sample size increased, uncertainty about the adequacy of the model dominated, and the coverage level fell far below 95%. Prediction intervals for cancer incidence must therefore be interpreted with caution.

Adolescent↗
PubMed2005

Residential and occupational exposure to 50-Hz magnetic fields and brain tumours in Norway: a population-based study.

Our case-control study was conducted to investigate whether residential and occupational exposure to magnetic fields increased the risk for brain tumours in adults. Data from an occupational exposure matrix was also evaluated. The study population in this nested case-control study was made up of subjects aged 16 years and older who had resided in a broad corridor around a high-voltage power line in 1980 or during one of the years from 1986-1996. The cases were incident cases diagnosed during 1980-96. Two controls were matched to each case by year of birth, sex, municipality and first year entering the cohort. The time-weighted average exposure to residential magnetic fields generated by the power lines was calculated for the exposure follow-up from 1 January 1967 to diagnosis. In addition, job titles and branches of industry were classified as categories of hours per week in a magnetic field above background level (0.1 microT). Exposures were cumulated over occupationally active years for the exposure follow-up from 1 January 1955 to diagnosis. When residential magnetic fields are evaluated, the 2 upper residential, time-weighted, average magnetic field categories showed elevated odds ratios (ORs) for all brain tumours (OR = 1.6; 95% confidence interval [95%CI] 0.9-2.7 and OR = 1.3; 95% CI 0.7-2.3). Occupational exposure showed no association to exposure for any site. We found an elevated risk for residential exposure to magnetic fields and brain tumours, although the risk was not significant, and no clear exposure-response pattern was found. The findings for the occupational exposure groups showed an inverse association.

Adolescent↗
PubMed2005

Suicide rates according to education with a particular focus on physicians in Norway 1960-2000.

BACKGROUND: Suicide rates are higher in certain educational groups. The highest rates are generally found in the medical and allied professions, but the empirical evidence for high suicide rates may be questionable. This study compares the rate of suicide among trained physicians, dentists, nurses, police officers and theologians with the rate among other university graduates and the general population according to sex, age and time period. METHOD: Census data from 1960, 1970, 1980 and 1990 relating to education were linked to suicide as cause of death data from Statistics Norway, and followed up for the period 1960-2000, comprising 46 and 49 million person-years among men and women respectively. RESULTS: Physicians still have a higher rate compared with other graduates and the general population, both among males [43.0, 95% confidence interval (CI) 35.3-52.5] and females (26.1, 95% CI 15.1-44.9). Suicide rates increased steeply by age among physicians and other graduates, whereas for non-graduates the rate was highest in the 40-60 years age group. The suicide rate among female nurses was also elevated, whereas police officers seemed to have an intermediate suicide risk. The rate among theologians was low (7.0, 95% CI 2.9-16.9). The suicide rates in the 1990s were significantly lower than in the 1980s. CONCLUSIONS: The high suicide rates among physicians and elderly graduates are of concern. The reasons why graduates are more vulnerable than others when getting older and the low rate among theologians warrant further study.

Adult↗
PubMed2005

Consistency of reported alcohol use by pregnant women: anonymous versus confidential questionnaires with item nonresponse differences.

BACKGROUND: Self-report is the best method to attain information about moderate alcohol consumption. However, reported alcohol consumption before and during pregnancy is sensitive to response bias. METHODS: We compared identical questionnaires completed either confidentially or anonymously by pregnant women. A representative half of the pregnant women in Oslo attending ultrasound screening between June 2000 and May 2001 were invited to join a confidential questionnaire study. Another group of pregnant women, selected in the identical manner, were asked to answer the same questionnaire anonymously during the summer of 2001. The questionnaire was completed by 1749 confidentially and 191 anonymously (response rate 93.4% vs 84.4%). For the current study, only women with Scandinavian ethnicity were included: 1707 and 178, respectively. Measures were T-ACE (screening measure for pregnancy risk drinking), reported frequency of alcohol use, Standard Units (SU) per occasion (po), SU per week, and binge drinking (>or=5 SU po), before and during pregnancy. RESULTS: There were no significant differences in reported alcohol consumption between the confidential and the anonymous group for the sample as a whole. Any alcohol consumption was reported by 22.6% and 23.3% during pregnancy week 7-12 and 13+ (confidential group) versus 22.5% and 25.8% (anonymous group). Differences between the groups tended to be larger for SU per week (p=0.07 both before pregnancy and after week 12 of pregnancy) than for the indirect alcohol (T-ACE) and the binge drinking questions. In the confidential group, the women with lower education had close to twice as high item nonresponse on the direct alcohol questions during pregnancy compared with those with higher education. This difference was smaller in the anonymous group. The rate of smoking was not reported differently in the anonymous group. CONCLUSIONS: Among pregnant women, there was no significant difference in self-reported alcohol consumption obtained by confidential or anonymous questionnaires.

Adult↗
PubMed2005

Can lung cancer risk among nickel refinery workers be explained by occupational exposures other than nickel?

BACKGROUND: Exposures in nickel refineries represent complex chemical mixtures, but only the effect of nickel has been evaluated quantitatively in epidemiologic studies of nickel workers. METHODS: For a Norwegian refinery, time- and department-specific exposure estimates were developed for arsenic, sulfuric acid mists, and cobalt in air on the basis of personal measurements and chemical data on raw materials and process intermediates. Exposure to asbestos, as well as employment in high-risk occupations outside the refinery, were assessed. We conducted a case-control study nested in a cohort of refinery workers, with 213 cases (diagnosed 1952-1995) and 525 age-matched controls. We analyzed lung cancer risk, adjusted for smoking, by cumulative exposure and duration of work. RESULTS: There was a substantial association between cumulative exposure to water-soluble nickel and lung cancer risk. Weaker effects were suggested for exposure to arsenic at the refinery and for occupational exposures outside the refinery for 15 years or more. No detectable excess risk was found for refinery exposure to asbestos or sulfuric acid mists, and no dose-related increase in risk was seen from cobalt. CONCLUSIONS: Exposure to water-soluble nickel remained the most likely explanation for the excess lung cancer risk in the cohort. Other occupational exposures did not confound the strong dose-related effect of nickel to any appreciable degree.

Air Pollution, Indoor↗
PubMed2005

Suicidal and nonsuicidal adolescents: different factors contribute to self-esteem.

Some risk and protective factors differ in their importance to suicidal and nonsuicidal people. In this research we explore the cross-sectional differences between risk factors among suicidal adolescents and nonsuicidal adolescents by focusing on self-esteem. Sixty-five suicidal and 390 nonsuicidal adolescents were compared on Harter's Self-Perceived Profile for Adolescents, self-concept stability, seeking support, loneliness, and depression. Self-concept stability, loneliness, and peer support correlated differently with self-esteem. In multivariate regression analyses, variance in self-esteem was explained by depression and loneliness, and among nonsuicidal adolescents also by self-concept stability, support, and competencies. Loneliness and self-concept stability related differently to self-esteem in suicidal and nonsuicidal adolescents. When the aim is to enhance self-esteem, this difference may delineate suicidal subgroups that need special interventions.

Adolescent↗
PubMed2005

Hearing thresholds among young professional divers: a 6-year longitudinal study.

INTRODUCTION: Diving is associated with pressure effects and noise exposure that can impair hearing. We were interested in finding out whether changes in hearing thresholds were related to cumulative exposure in young professional divers. METHODS: In a prospective follow-up design, we studied a cohort of 47 men from the beginning of their education as professional divers at a mean age of 25.6 yr (range 18-38 yr). They had audiograms taken at baseline, after 1 and 3 yr, and finally after 6 yr, during which they performed 40-1458 (median 184) sea dives, most of them to a depth of 10 m or less. The hearing tests measured pure tone air conduction thresholds at 0.25-8.0 kHz in a sound-treated booth. Annual change of hearing thresholds were calculated by fitting linear regression lines to individual data. For purposes of analysis, the divers were divided into two groups, low-exposure (199 or fewer dives, n = 26) and high-exposure (200 or more dives, n = 21). RESULTS: Hearing was better in the divers than in the general population at baseline and follow-up. At 6 yr, significant reductions were found in the divers' hearing at 4 kHz and 8 kHz. Significant increases in thresholds were found at 0.5, 2, 3, and 6 kHz for the right ear and 3, 4, and 6 kHz for the left ear. The annual change at 4 kHz was 0.95 dB in the left ear and 0.18 dB in the right ear (p = 0.01). There was no significant difference in hearing changes between the high- and low-exposure groups. DISCUSSION: The results suggest that a mild hearing impairment can occur in young professional divers due to occupational and other noise exposure.

Adolescent↗
PubMed2004

Suicide risk in cancer patients from 1960 to 1999.

PURPOSE: Suicide risk is reportedly higher for cancer patients than for the general population, but estimates vary and analyses of trends are few. The aim of the present study was to determine whether cancer patients had a higher suicide risk between 1960 and 1999. PATIENTS AND METHODS: A cohort comprising patients from the Cancer Registry of Norway 1960 to 1997 was linked to suicide diagnosis in the Register of Deaths at Statistics Norway and observed during 1960 to 1999. The cohort consisted of all cancer patients registered in the Cancer Registry of Norway 1960 to 1997 (N = 490,245 patients with 520,823 cancer diagnoses). Suicide was defined according to death certificates based on the International Classification of Diseases (versions 7, 8, 9, and 10). RESULTS: During the period, 589 cancer patients (407 males and 182 females) committed suicide. The relative risk was elevated for males and females, with standardized mortality ratios (SMRs) of 1.55 (95% CI, 1.41 to 1.71) and 1.35 (95% CI, 1.17 to 1.56), respectively. Risk was highest in the first months after diagnosis. For both sexes, there was a significant decrease in the relative suicide risk over decades. The risk was markedly increased among male patients with cancer of respiratory organs (SMR, 4.08; 95% CI, 2.96 to 5.47). Otherwise, the SMRs varied from 0.76 to 3.67 across cancer types. CONCLUSION: Cancer may be a risk factor for suicide, particularly shortly after diagnosis. However, the relative risk gradually decreased during the period 1960 to 1999.

Adolescent↗
PubMed2004

Smoking-adjusted incidence of lung cancer by occupation among Norwegian men.

OBJECTIVE: To use aggregated data on smoking habits and lung cancer incidence in occupations assumed to carry no lung cancer risk to control for confounding in other occupational groups. METHODS: Lung cancer incidence was observed from 1971 to 1991 for 53 occupational groups and a group of economically inactive men in a national cohort study. Data on occupation and smoking habits were collected from national surveys during 1965-1980. The relationship between smoking habits and lung cancer incidence was estimated on aggregated level using data from 12 occupational groups that were initially assumed not to be exposed to occupational lung carcinogens. The estimated relationship was used to control confounding from smoking in the other groups. The results were presented as smoking-adjusted incidence ratios. RESULTS: A significant excess risk was found for 26 groups. It was estimated that about 20% of all lung cancer among men could be related to occupation after adjusting for the effect of smoking. CONCLUSIONS: Our method provided a clearer picture of the occupational risk and could be useful in other situations where individual information on smoking habits is lacking.

Adult↗
PubMed2003

Mortality from cancer and other causes among male airline cockpit crew in Europe.

Airline pilots and flight engineers are exposed to ionizing radiation of cosmic origin and other occupational and life-style factors that may influence their health status and mortality. In a cohort study in 9 European countries we studied the mortality of this occupational group. Cockpit crew cohorts were identified and followed-up in Denmark, Finland, Germany, Great Britain, Greece, Iceland, Italy, Norway and Sweden, including a total of 28,000 persons. Observed and expected deaths for the period 1960-97 were compared based on national mortality rates. The influence of period and duration of employment was analyzed in stratified and Poisson regression analyses. The study comprised 547,564 person-years at risk, and 2,244 deaths were recorded in male cockpit crew (standardized mortality ratio [SMR] = 0.64, 95% confidence interval [CI] = 0.61-0.67). Overall cancer mortality was decreased (SMR = 0.68; 95% CI = 0.63-0.74). We found an increased mortality from malignant melanoma (SMR = 1.78, 95% CI = 1.15-2.67) and a reduced mortality from lung cancer (SMR = 0.53, 95% CI = 0.44-0.62). No consistent association between employment period or duration and cancer mortality was observed. A low cardiovascular mortality and an increased mortality caused by aviation accidents were noted. Our study shows that cockpit crew have a low overall mortality. The results are consistent with previous reports of an increased risk of malignant melanoma in airline pilots. Occupational risk factors apart from aircraft accidents seem to be of limited influence with regard to the mortality of cockpit crew in Europe.

Accidents, Aviation↗
PubMed2003

Prediction of cancer incidence in the Nordic countries: empirical comparison of different approaches.

Prediction of the future number of cancer cases is of great interest to society. The classical approach is to use the age-period-cohort model for making cancer incidence predictions. We made an empirical comparison of different versions of this model, using data from cancer registries in the Nordic countries for the period 1958-1997. We have applied 15 different methods to 20 sites for each sex in Denmark, Finland, Norway and Sweden. Median absolute value of the relative difference between observed and predicted numbers of cases for these 160 combinations of site, sex and country was calculated. The medians varied between 10.4 per cent and 15.3 per cent in predictions 10 years ahead, and between 15.1 per cent and 32.0 per cent for 20 year predictions. We have four main conclusions: (i) projecting current trends worked better than assuming that future rates are equal to present rates; (ii) the method based on the multiplicative APC model often overestimated the number of cancer cases due to its exponential growth over time, but using a power function to level off this growth improved the predictions; (iii) projecting only half of the trend after the first 10 years also gave better long-term predictions; (iv) methods that emphasize trends in the last decade seem to perform better than those that include earlier time trends.

Cohort Studies↗
PubMed2003

Mortality from cancer and other causes among airline cabin attendants in Europe: a collaborative cohort study in eight countries.

There is concern about the health effects of exposure to cosmic radiation during air travel. To study the potential health effects of this and occupational exposures, the authors investigated mortality patterns among more than 44,000 airline cabin crew members in Europe. A cohort study was performed in eight European countries, yielding approximately 655,000 person-years of follow-up. Observed numbers of deaths were compared with expected numbers based on national mortality rates. Among female cabin crew, overall mortality (standardized mortality ratio (SMR) = 0.80, 95% confidence interval (CI): 0.73, 0.88) and all-cancer mortality (SMR = 0.78, 95% CI: 0.66, 0.95) were slightly reduced, while breast cancer mortality was slightly but nonsignificantly increased (SMR = 1.11, 95% CI: 0.82, 1.48). In contrast, overall mortality (SMR = 1.09, 95% CI: 1.00, 1.18) and mortality from skin cancer (for malignant melanoma, SMR = 1.93, 95% CI: 0.70, 4.44) among male cabin crew were somewhat increased. The authors noted excess mortality from aircraft accidents and from acquired immunodeficiency syndrome in males. Among airline cabin crew in Europe, there was no increase in mortality that could be attributed to cosmic radiation or other occupational exposures to any substantial extent. The risk of skin cancer among male crew members requires further attention.

Adult↗