Prevalence of Autism Spectrum Disorder in 7-9-Year-Old Children in Denmark, Finland, France and Iceland: A Population-Based Registries Approach Within the ASDEU Project.

We estimated autism spectrum disorder (ASD) prevalence in 7-9 year-old children in 2015 using data from three nationwide health registry systems (Denmark, Finland, Iceland) and two French population-based regional registries. Prevalence ranged from 0.48% in South-East France to 3.13% in Iceland (South-West France: 0.73%, Finland: 0.77%, Denmark: 1.26%). Male/female ratios ranged from 3.3 in Finland to 5.4 in South-West France. Between 12% (Denmark) and 39% (South-West France) of cases were diagnosed with intellectual disability. The variations in population-based ASD prevalence across four European countries with universal health care practices likely reflect variation in detection, referral and diagnosis practices and autism awareness across these areas. Using established population-based data systems is an efficient approach to monitor ASD prevalence trends over time.

Mortality of the users of a hospital emergency department.

OBJECTIVE: To ascertain the annual number of users who were discharged home after visits to the emergency department (ED), grouped by age, sex, and number of visits during the calendar year, and to assess whether a higher number of visits to the department predicted a higher mortality. METHODS: This was a retrospective cohort study, with follow up of cause specific mortality through a national registry, in the Reykjavik area of Iceland. In total, 19 259 patients who visited the ED during the period 1995-2001 and who were discharged home at the Landspítali University Hospital, Reykjavik, Iceland, were enrolled. The main outcome measures were the standardised mortality ratio, with expected number based on national mortality rates, and hazard ratio calculations using time dependent multivariate regression analysis. RESULTS: The annual increase in visits to the ED among the patients discharged home was 7-14% per age group during the period 1995-2001, with the highest increase among older men. When emergency department users were compared with the general population, the standardised mortality ratio was 1.81 for men and 1.93 for women. Among those attending the ED two, three, or more times in a calendar year, the mortality rate was higher than among those coming only once in a year. The causes of death that led to the highest mortality among frequent users of the ED were neoplasm, ischaemic heart diseases, and external causes, particularly drug intoxication, suicides, and probable suicides. CONCLUSIONS: The mortality of those who had used the ED and been discharged home was found to be higher than that of the general population. Frequent users of the ED had a higher mortality than those visiting the department no more than once a year. As the ED serves general medicine and surgery patients, not injuries, the high mortality due to drug intoxication, suicide, and probable suicide is interesting. Further studies are needed into the diagnosis at discharge of those frequently using the ED, in an attempt to understand and possibly prevent this marked mortality rate.

Erythrocyte sedimentation rate and cardiovascular disease. Results from a population study of women in Göteborg, Sweden.

In a prospective study of a population sample of women, the erythrocyte sedimentation rate (ESR) was studied in relation to the incidence of myocardial infarction, angina pectoris, stroke and intermittent claudication. ESR could not be proved to be predictive of these manifestations of cardiovascular disease. Similar results were obtained when the population was studied cross-sectionally. The ESR was higher in women with hyperlipidaemia (serum triglyceride greater than or equal to 2.0 mmol/l or serum cholesterol greater than or equal to 9 mmol/l), in women with arterial hypertension (treated or untreated, with systolic blood pressure greater than or equal to 160 mm Hg or diastolic blood pressure greater than 95 mm Hg or both) and in overweight women (women within the upper 10 centiles of weight index) compared to women of the same age in the population sample who did not fulfill the criteria according to the above definitions. ESR was similar in hyperuricaemic women (upper 5 centiles of serum uric acid) and in those who were not hyperuricaemic. No association was found between smoking habits and ESR. Weak correlations were found between ESR and serum triglycerides, serum cholesterol and serum uric acid, respectively. Although some correlations were found, ESR cannot replace other examinations in the search for risk factors for cardiovascular disease.

Mortality from ischemic heart disease in Iceland, 1951-1985.

The objective of this study was to evaluate mortality rates from ischemic heart disease among Icelanders during the period of 1951 to 1985. In some developed countries, the number of deaths from ischemic heart disease declined markedly in this time period, and it is interesting to study whether the same has occurred in Iceland. The study was based on information obtained from the Statistical Bureau of Iceland, which keeps records of deaths based on death certificates as well as other population records. Nonparametric tests were used to correlate death rates and calendar years. Rates per 100,000 were calculated and plotted. The results indicated that the mortality rates from ischemic heart disease among Icelanders have not yet peaked.

Mortality among Icelandic seamen.

BACKGROUND: The aim of this cohort study was to evaluate the mortality of Icelandic seamen with particular reference to cancer deaths. SUBJECTS: In all 27,884 seamen, both fishermen and sailors of the merchant fleet, who had been members of a pension fund between 1958 and 1986 were followed-up. RESULTS: Most standardized mortality ratios (SMR) were greater than 1:1.26 for all causes, 1.13 for all malignant neoplasms, 1.80 for liver cancer, 1.19 for stomach cancer, 1.56 for lung cancer, and 1.21 for kidney cancer. The highest SMR was found for unknown causes, 3.16. There was no 'healthy worker effect'. For most causes of death latency time and mortality were strongly correlated. When analysing the relation between duration of employment and mortality a correlation was found for all-causes and for stomach cancer; however, this was not statistically significant. CONCLUSION: Seamen have an unusual mortality pattern and the excess for unknown causes is a rare finding indicating a peculiar situation for this group. The excess of stomach and lung cancer was high but it was not convincingly related to duration of employment and thus a relationship to occupation cannot be confirmed.

Cancer incidence among Icelandic pesticide users.

BACKGROUND: This study was done to examine the cancer risk among pesticide users in Iceland. METHODS: We have followed a cohort of 2449 licensed pesticide users, students from a horticultural college, members of a pension fund for market gardeners, horticulturists and vegetable farmers up until the end of 1993 in the Icelandic Cancer Registry of cancer incidence. The observed number of cancers was compared with expected values calculated on the basis of cancer incidence for males and females in Iceland. RESULTS: The standardized incidence ratio (SIR) for all cancer sites was 0.80. Among females the increased incidence for cancer of lymphatic and haematopoietic tissue was significant (SIR = 5.56, 95% confidence interval (CI) 1.12-16.23). The incidence of rectal cancer was three times that expected (SIR = 2.94, 95% CI: 1.07-6.40), and this cancer was even more predominant among the licensed pesticides users (SIR = 4.63, 95% CI: 1.49-10.80). All cancers of the rectum were adenocarcinoma, however, one was adenocarcinoma in villous adenoma and one adenocarcinoma in tubulo-villous adenoma. CONCLUSION: The results provide some support for the suggestion that pesticide exposure may lead to cancer of the lymphatic and haematopoietic tissue in females. We suggest that some of the pesticides to which the licensed pesticide users were exposed may lead to rectal cancer.

Mortality among farmers in Iceland.

A retrospective cohort study was performed to determine the cause of death among 5923 farmers in Iceland. Information on deaths occurring between 1977 and 1985 was obtained through the Statistical Bureau of Iceland. The vital status could be ascertained for all subjects in the study. Expected death rates were calculated, based on the national rates for males in the corresponding age groups and calendar years. The number of deaths from all causes, malignant neoplasms, lung cancer, ischaemic heart disease, respiratory diseases and accidents was less than expected in the total cohort and in nearly all subcohorts. There was no statistically significant excess risk, however: SMR for skin cancer was 2.30, SMR for Hodgkin's disease was 1.71, for leukaemia SMR was 1.60, and for brain cancer SMR was 1.23 in the total cohort. The results are in agreement with those of most previous studies of farmers, but because of the short follow-up time, the excess risk found for deaths from skin and haematological malignancies did not reach statistical significance. Further follow-up is planned in the future.

Mortality among female manual workers.

STUDY OBJECTIVE: The aim was to determine whether female manual workers have higher mortality than other women. DESIGN: This was a retrospective cohort study in which mortality was compared with that of the general female population. Main outcome measures were standardised mortality ratio (SMR) and 95% confidence intervals (CI). SETTING: Reykjavík region. PARTICIPANTS: Participants were 18,878 women, the cumulated members of a pension fund for manual workers between 1970 and 1986. MAIN RESULTS: A healthy worker effect was observed in the total cohort. The study was then restricted to those who had contributed to the pension fund any time after reaching 20 years of age, and a 10 year latency period was instituted. When analysing subcohorts by duration of employment the standardised mortality ratios for all causes of death and all cancers increased with longer employment time up to 10 years. However, the ratios were low in the group with over 10 years of employment. Those who began contributing to the fund in 1977 or later had higher mortality than those who began earlier. There was an excess of lung and bladder cancer in the total cohort and in all the subcohorts except in the group with over 10 years' employment. Mortality from accidents and suicides was in excess in all the groups. CONCLUSIONS: Mortality is high among some groups of female manual workers. A deficit was found among those with the longest employment. Differences in mortality have widened in recent years. An excess of suicides shows that women in this group have, for some reason, less will to live than other women.

Breast cancer risk in airline cabin attendants: a nested case-control study in Iceland.

AIMS: To investigate whether length of employment as a cabin attendant was related to breast cancer risk, when adjusted for reproductive factors. METHODS: Age matched case-control study nested in a cohort of cabin attendants. The cases were found from a nationwide cancer registry (followed up to end of year 2000) and the reproductive factors (age at first childbirth and number of children) from a registry of childbirth, in both instances by record linkage with the cabin attendants' identification numbers. The employment time of the cabin attendants at the airline companies and the reproductive factors had been systematically recorded prior to the diagnosis of breast cancer in the cohort. A total of 35 breast cancer cases and 140 age matched controls selected from a cohort of 1532 female cabin attendants were included in the study. RESULTS: The matched odds ratio from conditional logistic regression of breast cancer risk among cases and controls of cabin attendants was 5.24 (95% CI 1.58 to 17.38) for those who had five or more years of employment before 1971 compared with those with less than five years of employment before 1971, adjusted for age at first childbirth and length of employment from 1971 or later. CONCLUSIONS: The association between length of employment and risk of breast cancer, adjusted for reproductive factors, indicates that occupational factors may be an important cause of breast cancer among cabin attendants; the association is compatible with a long induction period.

Risk factors for cutaneous malignant melanoma among aircrews and a random sample of the population.

AIMS: To evaluate whether a difference in the prevalence of risk factors for malignant melanoma in a random sample of the population and among pilots and cabin attendants could explain the increased incidence of malignant melanoma which had been found in previous studies of aircrews. METHODS: A questionnaire was used to collect information on hair colour, eye colour, freckles, number of naevi, family history of skin cancer and naevi, skin type, history of sunburn, sunbed, all sunscreen use, and number of sunny vacations. RESULTS: The 239 pilots were all males and there were 856 female cabin attendants, which were compared with 454 males and 1464 females of the same age drawn randomly from the general population. The difference in constitutional and behavioural risk factors for malignant melanoma between the aircrews and the population sample was not substantial. The aircrews had more often used sunscreen and had taken more sunny vacations than the other men and women. The predictive values for use of sunscreen were 0.88 for pilots and 0.85 for cabin attendants and the predictive values for sunny vacation were 1.36 and 1.34 respectively. CONCLUSION: There was no substantial difference between the aircrew and the random sample of the population with respect to prevalence of risk factors for malignant melanoma. Thus it is unlikely that the increased incidence of malignant melanoma found in previous studies of pilots and cabin attendants can be solely explained by excessive sun exposure.

Cancer incidence among Icelandic nurses.

This study investigated cancer incidence among Icelandic nurses, with a special focus on breast cancer. Cancer incidence in the study group was compared with that of the general female population. Elevated standardized incidence ratios (SIRs) were seen for some cancer sites, including breast cancer. For all cancers, breast cancer, and selected cancer sites, SIR increased with increasing length of time intervals allowed to elapse before the study period began. The nurses with a shorter employment time had a higher incidence of cancer than those with a longer one. Known confounding factors--parity and age at first birth--do not appear to be a convincing explanation of the excess of breast cancer. The possibility cannot be excluded that the nursing occupation constitutes an independent risk factor for breast cancer.

Mortality among professional drivers.

The mortality of truck drivers and taxi drivers was studied in Reykjavík. The national mortality rate was used for comparison, and the follow-up lasted until 1 December 1988. The 868 truck drivers (28,788.0 person-years) had an excess of lung cancer deaths [24 observed, 11.2 expected, standardized mortality ratio (SMR) 2.14], but fewer deaths than expected from respiratory diseases (15 observed versus 30.1 expected). The SMR from lung cancer did not steadily increase as the duration of employment increased, nor did it change with the length of follow-up. The SMR values did not deviate substantially from unity for the taxi drivers. Since the high mortality from lung cancer among the truck drivers did not seem to be due to their smoking habits, it might have been caused by one or more occupational factors, especially in light of this group's exposure to engine exhaust gases.

Mortality among Icelandic nurses.

OBJECTIVE: The goal of the study was to investigate the mortality pattern of female nurses in a retrospective cohort study with special focus on suicide. METHODS: The mortality of nurses was compared with that of the general female population. The main outcome measure was the standardized mortality ratio (SMR). The participants were 2159 female nurses (ie, all registered nurses in Iceland between 1920-1979). RESULTS: A long-lasting healthy worker effect was found in the cohort. A moderate excess of suicide was observed. A deficit was found for stomach cancer, ischemic heart disease, and respiratory disease. When the cohort was divided according to employment time, there was an excess of brain cancer among those with an employment time of less than 20 years, and all the suicides occurred in that group. The deficit of ischemic heart disease and respiratory disease was more pronounced in the group employed more than 20 years. CONCLUSIONS: It was concluded that nurses, primarily those with a long employment time, enjoy the benefits of their initial good health, but the moderate excess of suicide could be associated with stress and frustration, which the nurses relate to their work situation.

Lung cancer incidence among an Icelandic cohort exposed to diatomaceous earth and cristobalite.

OBJECTIVES: The objective of this study was to determine the cancer incidence of a cohort exposed to diatomaceous earth and cristobalite with special focus on lung cancer. METHODS: The cohort was from a diatomaceous plant in northern Iceland and comprised 919 men and 423 women. Diatomite, when heated, is transformed from amorphous to crystalline silica with a high cristobalite content and traces of quartz. With the use of the identification number of all persons, a link was made with the Cancer Registry. The expected number of malignancies was calculated on the basis of person-years of observation for 5-year age categories during the respective calendar period of the study multiplied by the specific incidence of cancer site for men and women in Iceland. RESULTS: There was no increased overall incidence of cancer in the study population; 5 cases of lung cancer were observed versus 4.4 expected, the standardized incidence ratio (SIR) was 1.14 [95% confidence interval (95% CI) 0.37-2.65]. When the men in the cohort were divided according to their length of employment, there was an excess of lung cancer (3 observed versus 1.28 expected, SIR 2.34, 95% CI 0.48-6.85), nonmelanoma skin cancer (2 observed versus 0.19 expected, SIR 10.53, 95% CI 1.27-38.02), and brain cancer (3 observed versus 0.30 expected, SIR 10.00, 95% CI 2.06-29.23) for those who had worked 5 years or longer. A special investigation of smoking habits among the cohort revealed a smoking pattern similar to that of the general population. CONCLUSION: The results concerning lung cancer showed an excess risk for workers exposed to diatomaceous earth and cristobalite; the result was not, however, statistically significant. There was a trend towards a higher incidence of lung cancer with longer exposure to crystalline silica, and, in agreement with the results of a previous study from this industry, the findings indicate a causal relation.

Mortality and cancer incidence among marine engineers and machinists in Iceland.

A retrospective cohort study of mortality and cancer morbidity was carried out among 295 marine engineers and 182 machinists with special regard to cancer of the lung. The cohort was defined as all graduates from engineering and machinists school in Iceland during 1936-1955. During vocational training, as well as in their professional lives, marine engineers and machinists are exposed to asbestos, different kinds of mineral oils, and exhaust gases with marked individual variation as regards mode and magnitude of exposure. For deaths occurring between 1951 and 1982 information was obtained from the Statistical Bureau of Iceland. Significantly increased standardized mortality ratios were determined for cancer of the trachea, bronchus, and lung for the entire cohort. Record linkage with the Cancer Register revealed 36 cancers in the period 1955-1982. No statistically significant excess was found for the overall cancer incidence or for the incidence of cancer at any particular site. A special survey of smoking status showed that cigarette smoking was not as common among the subjects of the cohort as among the general male population in Reykjavik. These results support the suggestion that the increased mortality of lung cancer in the study group had a causal relationship to occupational exposure, particularly to asbestos exposure.

Musculoskeletal symptoms among women currently and formerly working in fish-filleting plants.

The authors surveyed women currently or formerly working in fish-filleting plants to evaluate their musculoskeletal symptoms, using the standardized Nordic Questionnaire on musculoskeletal symptoms. The women's work consisted of cutting and trimming fish fillets, which were transported to and from the work stations by conveyor belts. The prevalence of musculoskeletal symptoms during the preceding 12 months was higher among former than current workers. The Mantel-Haenszel odds ratio for symptoms of the fingers, ankles, and wrists hindering normal work during the preceding 12 months were 7.1 (95% CI 2.8-18.0), 5.3 (95% CI 1.3-21.5(, and 3.4 (95% CI 1. 3-8.8), respectively. The higher prevalence of musculoskeletal symptoms among those who had stopped working at the fish-filleting plants than among those continuing to do so indicates a healthy-worker selection. There may be a causal relationship between musculoskeletal symptoms and ceasing to work at the plants.

Overview of atmospheric ionizing radiation (AIR) research: SST-present.

The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent lowering of ICRP-recommended exposure limits (1990) with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

Long-term follow-up after methyl chloride intoxication.

In this study, the authors investigated mortality and cancer patterns among a group of individuals accidentally exposed to methyl chloride 32 y earlier. This group of 24 persons had survived the immediate intoxication, which had occurred on a trawler during a fishing trip. The authors selected a reference group, which contained five times as many individuals as the study group, from registers of crews, and they controlled for age, occupation, social class, and lifestyle factors. The authors established a record linkage through personal identification numbers with the national death register and cancer register, thus securing 100% follow-up. The Mantel-Haenszel point estimate (M-H) was 2.2, and the 95% confidence interval (CI) was 1.3-3.1 for all causes of death. There was an excess of deaths from cardiovascular diseases (M-H = 2.1, 95% CI = 1.2-3.8). This excess mortality was more prominent among deckhands who had been subject to higher exposure; risk ratios (RRs) were elevated for all causes of death (RR = 2.5, 95% CI = 1.0-5.7), as well as for cardiovascular diseases (RR = 3.9, 95% CI = 1.0-14.4). In addition, the authors noted elevated risks for all cancers (M-H = 1.5, 95% CI = 0.3-5.6) and for lung cancer (M-H = 2.7, 95% CI = 0.1-52.6). The authors concluded that exposure to methyl chloride may have contributed to the risk of cardiovascular disease. Investigators need to conduct further studies on groups exposed to methyl chloride to refute or confirm this result.

Risk of fatal accidents occurring other than at sea among Icelandic seamen.

OBJECTIVE: To study mortality among seamen, particularly from fatal accidents that occurred other than at sea. DESIGN: Cohort study. SETTING: Iceland. SUBJECTS: 27,884 seamen, both fishermen and sailors from the merchant fleet, who had been members of a pension fund from 1958 to 1986. MAIN OUTCOME MEASURES: Cause of death (ICD seventh revision), standardised mortality ratio. RESULTS: Most standardised mortality ratios were greater than 1, being 1.26 for all causes and 1.83 for all external causes. There was no healthy worker effect. The excess of deaths from all external causes included all subcategories of death from accidents, poisonings, and violence and not just accidents at sea (water transport accidents, ICD codes E850-E858). A significant trend was found for length of employment and mortality from all accidents at sea, drowning at sea, accidental poisoning, other accidents, and accidental drowning; correlation coefficients for all causes, all accidents, suicide, and injuries undetermined whether accidentally or purposely inflicted were 0.7-0.8. Compared with seamen who started work during 1968-77, those who started work in 1978 or later had higher mortality from all causes, road traffic accidents, poisoning, other accidents, homicide, and injuries unknown whether accidentally or purposely inflicted, but not from all accidents at sea and accidental drowning. CONCLUSION: Seamen seem to be a special group with a high risk of fatal accidents occurring not only at sea. The association between fatal accidents other than at sea and length of employment as seamen indicates that seamen are modified by their occupation towards hazardous behaviour or a risky lifestyle.