Childhood central nervous system tumors and leukemia: Incidence and familial risk. A comparative population-based study in Utah and Norway.

BACKGROUND: In this study, we aimed to evaluate incidence rates and family risk of the most common childhood cancers, tumors in the central nervous system (CNS), and leukemia among individuals from Norway and individuals with Scandinavian ancestry living in Utah. METHODS: We used the Utah Population Database and the Norwegian National Population Register linked to Cancer registries to identify cancers in children born between 1966 and 2015 and their first-degree relatives. We calculated incidence rates and hazards ratios. RESULTS: The overall incidence of CNS tumors increased with consecutive birth cohorts similarly in Utah and Norway (both P < 0.001). Incidence rates of leukemia were more stable and similar in both Utah and in Norway with 4.6/100 000 person-years among children (<15 years) born in the last cohort. A family history of CNS tumors was significantly associated with risk of childhood CNS tumors in Utah HR = 3.05 (95% CI 1.80-5.16) and Norway HR = 2.87 (95% CI 2.20-3.74). In Norway, children with a first-degree relative diagnosed with leukemia had high risk of leukemia (HR = 2.39, 95% CI 1.61-3.55). CONCLUSION: Despite geographical distance and assumed large lifestyle differences, two genetically linked pediatric populations show similar incidences of CNS tumors and leukemia in the period 1966-2015. CNS tumors and leukemia aggregated in families in both countries.

Family history of cancer and risk of paediatric and young adult's testicular cancer: A Norwegian cohort study.

BACKGROUND: The aim of this study was to examine the association of a family history of cancer with the risk of testicular cancer in young adults. METHODS: This is a prospective cohort study including 1,974,287 males born 1951-2015, of whom 2686 were diagnosed with TC before the age of 30. RESULTS: A history of TC in male relatives was significantly associated with a diagnosis of TC among children and young adults, including brothers (6.3-fold), sons (4.7-fold), fathers (4.4-fold), paternal uncles (2.0-fold) and maternal uncles (1.9-fold). Individuals with a father diagnosed with a carcinoma or sarcoma showed an elevated risk (1.1-fold and 1.8-fold, respectively). A family history of mesothelioma was positively associated with a risk of TC [(father (2.8-fold), mother (4.6-fold) and maternal uncles and aunt (4.4-fold)]. Elevated risks were also observed when siblings were diagnosed with malignant melanoma (1.4-fold). The risk of TC was also increased when fathers (11.1-fold), paternal (4.9-fold) and maternal uncles and aunts (4.6-fold) were diagnosed with malignant neuroepithelial-tumours. CONCLUSION: We found an increased risk of TC among children and young adults with a family history of TC, carcinoma, mesothelioma, sarcoma, malignant melanoma and malignant neuroepithelial tumours. Hereditary cancer syndromes might underlie some of the associations reported in this study.

Family history of cancer and the risk of childhood solid tumours: a Norwegian nationwide register-based cohort study.

This corrects the article DOI: 10.1038/bjc.2017.85.

Poverty and the risk of leukemia and cancer in the central nervous system in children: A cohort study in a high-income country.

AIMS: The association between childhood cancer and socioeconomic status is inconclusive. Family income has seldom been included in large population-based studies, and the specific contributions of it remain unknown. METHODS: A total of 712,674 children born between 1967 and 2009 in the Oslo region were included. Of these, 864 were diagnosed with leukemia or cancer in the central nervous system before the age of 15 years. The association between poverty and childhood leukemia or brain cancer was analyzed using logistic regression and Cox proportional hazards models. Family income was stratified according to poverty lines. Parents' educational level and several perinatal variables were also examined. RESULTS: Family poverty during the first 2 years of life was associated with lymphoid leukemia before the age of 15 years: odds ratio 1.72, 95% confidence interval 1.11-2.64. In the same age group we found a significant dose response, with a 21% increased risk of lymphoid leukemia with increasing poverty. The risk for intracranial and intraspinal embryonal tumors in the whole study period was lower for children in the middle family income category. For astrocytomas there was a more than 70% increased risk in the medium income category when analyzing the two first years of life. The observed increase was reduced when all years each child contributed to the study were included. The risk of cancer in the central nervous system overall was 20% higher in the medium income category compared to the high-income category. CONCLUSIONS: Being born into a household of low family income the first 2 years of life was found to be a risk factor for development of lymphoid leukemia. For astrocytomas we observed an increased risk among children born into the medium income category throughout the first two years of life.

Use of mobile phones in Norway and risk of intracranial tumours.

To test the hypothesis that exposure to radio-frequency electromagnetic fields from mobile phones increases the incidence of gliomas, meningiomas and acoustic neuromas in adults. The incident cases were of patients aged 19-69 years who were diagnosed during 2001-2002 in Southern Norway. Population controls were selected and frequency-matched for age, sex, and residential area. Detailed information about mobile phone use was collected from 289 glioma (response rate 77%), 207 meningioma patients (71%), and 45 acoustic neuroma patients (68%) and from 358 (69%) controls. For regular mobile phone use, defined as use on average at least once a week or more for at least 6 months, the odds ratio was 0.6 (95% confidence interval 0.4-0.9) for gliomas, 0.8 (95% confidence interval 0.5-1.1) for meningiomas and 0.5 (95% confidence interval 0.2-1.0) for acoustic neuromas. Similar results were found with mobile phone use for 6 years or more for gliomas and acoustic neuromas. An exception was meningiomas, where the odds ratio was 1.2 (95% confidence interval 0.6-2.2). Furthermore, no increasing trend was observed for gliomas or acoustic neuromas by increasing duration of regular use, the time since first regular use or cumulative use of mobile phones. The results from the present study indicate that use of mobile phones is not associated with an increased risk of gliomas, meningiomas or acoustic neuromas.

The risk of cancer in the offspring and parental length of life.

BACKGROUND: We investigated if cancer onset in offspring is related to having short-lived parents for different cancer types and to see if there was a difference in smoking- and non-smoking related cancers. METHODS: Our study included 524,391 individuals born in Norway 1940-1950. All children were followed up for cancer from the age of 20 until they were between 59 and 69 years. Parental longevity was examined by grouping parental age of death into parents dying before 75 years of age and parents dying at 75 years of age or older. RESULTS: An increased risk of 1.14 (95%CI=1.10-1.19) among male offspring and 1.08 (95%CI=1.04-1.12) among female offspring was observed for total cancer when both parents died before the age of 75 compared to offspring with two long-lived parents. The highest increase was found for cancer in the lungs and trachea for both male (HR=1.67, 95%CI=1.50-1.86) and female offspring (HR=1.53, 95%CI=1.33-1.76). For other smoking-related cancers, the risk was lower. No increased risk was observed for non-smoking-related cancers. CONCLUSION: Offspring of long-lived parents have lower risk of developing cancer compared with offspring of short-lived parents. Intergenerational transmission of risk factors from parents to offspring may play an important role, especially for tobacco-related cancers. However, genetic factors cannot be ruled out, since consistent evidence has implicated genetic factors in smoking behaviour.

Paternal occupational exposure to radiofrequency electromagnetic fields and risk of adverse pregnancy outcome.

BACKGROUND: During the last decades, public concern that radiofrequency radiation (RFR) may be related to adverse reproductive outcomes has been emerging. Our objective was to assess associations between paternal occupational exposure to RFR and adverse pregnancy outcomes including birth defects using population-based data from Norway. METHODS: Data on reproductive outcomes derived from the Medical Birth Registry of Norway were linked with data on paternal occupation derived from the general population censuses. An expert panel categorized occupations according to exposure. Using logistic regression, we analyzed 24 categories of birth defects as well as other adverse outcomes. RESULTS: In the offspring of fathers most likely to have been exposed, increased risk was observed for preterm birth (odds ratio (OR): 1.08, 95% confidence interval (CI): 1.03, 1.15). In this group we also observed a decreased risk of cleft lip (OR: 0.63, 95% CI: 0.41, 0.97). In the medium exposed group, we observed increased risk for a category of "other defects" (OR: 2.40, 95% CI: 1.22, 4.70), and a decreased risk for a category of "other syndromes" (OR: 0.75, 95% CI: 0.56, 0.99) and upper gastrointestinal defects (OR: 0.61, 95% CI: 0.40, 0.93). CONCLUSION: The study is partly reassuring for occupationally exposed fathers.

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.

Comparison of three different ways of measuring distances between residences and high voltage power lines.

The aim of this study was to evaluate whether distance data based on calculations by use of digitalized geographical information systems (GIS) and distance data based on measurements on 1:5000 maps agree sufficiently with on site distance measurements to be used as input to magnetic field calculations in epidemiological studies. The analysis were performed by use of weighted kappa (kappa(w)) statistical method described by Bland and Altman for comparison of measures of agreement. Map measurements showed better agreement with on site measurements than GIS calculations did. However, we consider both methods appropriate for use in larger epidemiological studies if the results are interpreted with caution. GIS calculations have the advantage of being both time and cost saving.

Residence near power lines and the risk of birth defects.

BACKGROUND: There has been some concern that exposure to electromagnetic fields may cause birth defects. We studied risks of birth defects by residential exposure to 50-Hz magnetic fields from power lines. METHODS: We estimated the distance between residence and power lines for 161,844 Norwegian residences, and their corresponding magnetic fields in the period 1980 to 1997. Risks of 24 categories of birth defects were compared across exposure levels, adjusting for social and demographic variables. RESULTS: Among those living near power lines, the greatest reductions in risk were for cardiac defects (odds ratio = 0.5; 95% confidence interval = 0.3-0.9) and respiratory defects (0.4; 0.2-0.9). The largest increase in risk was for esophageal defects (2.5; 1.0-5.9). Other associations were weaker and had wide confidence intervals. CONCLUSIONS: There was little evidence that residence near power lines affected the risk of birth defects. The observed decreased risks of cardiac and respiratory defects and the increased risk of esophageal defects should be interpreted with caution given the number of endpoints, the imprecision in the calculations of the distance from the residence to the power line, and the limited information on pregnant women's change of residence.