Evaluating the human effects of combinations of neurotoxicants is extremely difficult. Parallel studies correlating exposure parameters and "surrogate" indicators of neural cell function may represent a promising strategy. Molecular markers such as cholinergic muscarinic receptors (MRs) and monoamine oxidase activity (MAO-B) are expressed not only in brain but also in peripheral blood cells. Measurements of MRs and MAO-B in these easily accessible matrices can provide valuable information on early sub-clinical effects of drugs and chemicals in the CNS. In this paper, examples of application of lymphocyte-MRs and platelet-MAO-B as surrogate markers of CNS function in humans are described. They include (i) neuroepidemiological studies examining 7-year-old members of a birth-cohort at the Faroe-Islands prenatally exposed to elevated concentrations of methylmercury (MeHg) and polychlorinated biphenyls; (ii) clinical investigations in a series of unmedicated children with Attention-Deficit/Hyperactivity Disorder (ADHD). The neurochemical markers were examined in association with exposure indicators and neuropsychological tests (Faroe Islands Study) or with specific disease symptoms (ADHD children). Studies of this type have produced valuable information on subclinical responses to low/moderate perinatal exposures to MeHg and/or PCBs, and in addition further supported the applicability of these biomarkers in children with subtle neuropsychiatric disorders. Additional studies investigated the ability of MeHg and/or PCBs to modify the expression of genes codifying for the MR subtypes in rat offspring cerebellum at distinct developmental stages. The results demonstrated persistent gender- and age-related differences in MR density and their associated gene expression pathways. Studies on pathways and metabolic networks involved in developmental toxicity may contribute to elucidate the mode of action of environmental pollutant mixtures and also considerably impact on the risk assessment process.
American Indian Alaska Native people of the United States face challenges in attaining physical, mental, spiritual, and environmental health. This article presents a concept analysis of Diné Hózhó, a complex and misunderstood wellness concept the Diné (Navajo) strive to attain. Findings from a literature review are presented to explore anthropological definitions and uses of the concept Hózhó. The method of concept analysis of Walker and Avant is utilized, model cases are presented. Recommendations for application in nursing practice are presented.
Fetal loss and maternal serum levels of 2,2',4,4',5,5'-hexachlorbiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) exposure: a cohort study in Greenland and two European populations.
BACKGROUND: In the present study, the aim is to examine the risk of fetal loss related to environmental 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) or 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) exposure. METHODS: We related LC/MS/MS measurements of CB-153 and p,p'-DDE in serum samples to interview-data on previous fetal loss in populations of pregnant women from Poland, Ukraine and Greenland. RESULTS: In total, 1710 women were interviewed, and 678 of these had at least one previous pregnancy. The risk of ever experiencing a fetal loss increased at higher levels of CB-153 and p,p'-DDE exposure, with an adjusted odds ratio (OR) of 2.4; confidence interval (CI) (1.1-5.5) for CB-153>200 ng/g lipid compared to 0-25 ng CB-153/g lipid and OR of 2.5 CI (0.9-6.6) for p,p'-DDE>1500 ng/g lipid compared to 0-250 ng DDE/g lipid. However, no clear dose response associations were observed. The results further suggest that high level of organochlorine serum concentrations may be related to repeated loss. CONCLUSIONS: The risk of fetal loss may increase at higher levels of CB-153 and p,p'-DDE exposure, although lack of dose response and inconsistencies between countries did not allow for firm conclusions.
Human subjects obtain their vitamin D from the diet, especially from marine food, and from endogenous synthesis following cutaneous sun exposure. The risk of an insufficient vitamin D synthesis is increased in northern populations, but it may be counteracted by a high intake of marine food in fishing populations, e.g. at the Faroe Islands. We examined the vitamin D status and its statistical determinants in a cross-sectional study of 713 elderly Faroese aged 70-74 years, about two-thirds of all the eligible residents in this age group. Clinical examination included measurement of body weight and height, and marine food intake was estimated using a questionnaire. We measured serum 25-hydroxyvitamin D3 (S-25(OH)D3) by LC-MS/MS in 669 of the 713 subjects in whom sufficient serum was available. Of the population, 19 % had S-25(OH)D3 concentrations 80 nmol/l. In a logistic regression analysis, BMI 80 nmol/l. The high prevalence of low vitamin D levels among the elderly Faroese population reflects the low skin synthesis during most months of the year, which is caused by the limited sun exposure and insufficient benefits from marine diet. Thus, even in a population with a high intake of marine food, the northern latitude causes a low vitamin D status. Efforts to improve vitamin D status in this population are warranted.
Sweden has only just begun remediation of its many contaminated sites, a process that will cost an estimated SEK 60,000 million (USD 9100 million). Although the risk assessment method, carried out by the Swedish EPA, is driven by health effects, it does not consider actual exposure. Instead, the sites are assessed based on divergence from guideline values. This paper uses an environmental medicine approach that takes exposure into account to analyse how cancer risks on and near arsenic-contaminated sites are implicitly valued in the remediation process. The results show that the level of ambition is high. At 23 contaminated sites, the cost per life saved varies from SEK 287 million to SEK 1,835,000 million, despite conservative calculations that in fact probably underestimate the costs. It is concluded that if environmental health risks are to be reduced, there are probably other areas where economic resources can be used more cost-effectively.
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden, Centre for Health Equity Studies (CHESS), Stockholm University/Karolinska Institutet, Stockholm, Sweden, Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA and Unit of Clinical Epidemiology, Department of Medicine, Karolinska University Hospital, Stockholm, Sweden.
BACKGROUND: Smoking during pregnancy has been shown to increase the risks of several adverse birth outcomes. Associations with overweight and/or obesity in the offspring have also been suggested. We aim to investigate whether familial factors confound the association between maternal smoking during pregnancy and overweight in early adulthood in young Swedish males born 1983-88. METHODS: In a population-based Swedish cohort comprising 124 203 singleton males born to Nordic mothers between 1983 and 1988, we examined the association between maternal smoking during pregnancy and the risk of overweight in the offspring at age approximately 18 years. We also investigated the association within siblings, controlling for common genes and shared environment. RESULTS: In the cohort analyses, the risk of overweight was increased in sons of smoking mothers compared with sons of non-smokers: adjusted odds ratios 1.41, 95% confidence interval (CI) 1.34-1.49, and 1.56, 95% CI 1.46-1.66, for one to nine cigarettes per day, and >10 cigarettes per day, respectively. Stratifying for maternal smoking habits across two subsequent male pregnancies, there was an increased risk of overweight for the second son only if the mother was smoking in both male pregnancies. The effect of smoking during pregnancy on the offspring's body mass index was not present when the association was evaluated within full and half sibling pairs. CONCLUSION: The association between maternal smoking during pregnancy and offspring's risk of overweight appears to be confounded by familial factors.
Small-scale enterprises face difficulties in fulfilling the regulations for organising Systematic Work Environment Management. This study compared three groups of small-scale manufacturing enterprises with and without support for implementing the provision. Two implementation methods, supervised and network method, were used. The third group worked according to their own ideas. Twenty-three enterprises participated. The effects of the implementation were evaluated after one year by semi-structured dialogue with the manager and safety representative. Each enterprise was classified on compliance with ten demands concerning the provision. The work environment was estimated by the WEST-method. Impact of the implementation on daily work was also studied. At the follow-up, the enterprises in the supervised method reported slightly more improvements in the fulfilment of the demands in the provision than the enterprises in the network method and the enterprises working on their own did. The effect of the project reached the employees faster in the enterprises with the supervised method. In general, the work environment improved to some extent in all enterprises. Extensive support to small-scale enterprises in terms of advise and networking aimed to fulfil the regulations of Systematic Work Environment Management had limited effect - especially considering the cost of applying these methods.
The aim of the present study was to assess and understand the long-term trajectory of psychological problems among young Middle Eastern refugees in Denmark. Participants were 131 young refugees from the Middle East (76 girls, 55 boys; mean age = 15.3 years) from 67 families. They were assessed first on arrival in Denmark in 1992-1993 and again 8-9 years later. The high prevalence of psychological problems at arrival was considerably reduced by the time of follow-up, but it was still somewhat higher than what has been found in most community studies using the same assessment tools. Groups of children differed in showing low levels of symptoms at arrival that were stable (spared) or increased (reacting) and high levels at arrival that persisted (traumatized) or decreased (adapted). The number of types of traumatic experiences before arrival distinguished the spared and the traumatized young refugees and the number of types of stressful events after arrival the adapted and the traumatized, also after corrections for age, sex, specific traumatic events, parents' education and health, and the social situation of the young refugees. The study emphasizes the importance of environmental factors for healthy long-term adaptation after traumatic experiences related to war and other organized violence.
The objective of the study is to investigate the prevalence, distribution and predictors of mental health problems in 5-7-year-old Danish children in the general population. This study is a 5-7-year follow-up study of a birth cohort of 6,090 children, the Copenhagen Child Cohort 2000. The extended version of the Strengths and Difficulties Questionnaire (SDQ) was answered by parents and pre-school teachers. Data from Danish national registers included perinatal data, socioeconomic data and data on child mental illness diagnosed at hospital in preschool age. Register data from the first year of life was obtained from 99.7% of the children in the cohort. Of 5,898 eligible children, 3,501 participated in the SDQ assessment (59%). The overall estimated 6-month prevalence of mental health problems was 4.8% (95% CI 4.1-5.6). Conduct problems were found in 3.0% (95% CI 2.4-3.6), problems of hyperactivity/inattention in 0.7% (95% CI 0.4-1.0) and emotional problems in 1.5% (95% CI 1.1-1.9). Boys showed a higher risk of having mental health problems as compared to girls: risk ratio 2.0 (95% CI 1.5-2.8). Several markers of socioeconomic disadvantages were associated with mental health problems at 5-7 years of age. In conclusion, the 6-month prevalence of SDQ-measured mental health problems was relatively low in Danish children when compared with findings from several European countries, but was in line with findings from other studies in Nordic countries. The lower prevalence might reflect differences in psychosocial risk load and environmental stress given the social and cultural context.
Quality assurance of exposure biomarkers usually focuses on laboratory performance only. Using data from a prospective birth cohort study in the Faroe Islands, we have assessed the total imprecision of exposure biomarkers. As biomarkers of prenatal methylmercury exposure, mercury concentrations were determined in cord blood, cord tissue, and maternal hair. We determined their mutual correlations and their associations with the child's neurobehavioral effect variables at age 7 years. The exposure biomarkers correlated well with one another, but the cord blood mercury concentration showed the best associations with neurobehavioral deficits. Because at least three exposure parameters were available, factor analysis and structural equation modeling could be applied to determine the total imprecision of each biomarker. For the cord-blood parameter, the total imprecision was 25-30%, and almost twice as much for maternal hair. The total imprecision of these biomarkers much exceeded the normal laboratory variability of less than 5%. Such imprecision can cause underestimation of dose-related toxicity, and data analysis should therefore include sensitivity analyses that take this factor into account. Ignoring preanalytical imprecision may cause serious bias.
Fundamental to the nursing profession is understanding what issues are important to quality of life (QoL) for older adults. The aim of this study was to explore issues of importance to older adults and to compare findings with Lawton's theoretical QoL conceptualization. Five focus groups were conducted with healthy and hospitalized adults and health professionals. Many valued aspects of human existence were found to affect QoL, and results lend empirical support to many of the themes appearing under Lawton's four sectors. Results indicate the need for multidimensional assessments of QoL among older adults related to health, psychological, personal competency, social, environmental, and spiritual indicators. Issues related to time use, happiness, cognitive functioning, self-concept, coping with change, social functioning, self-determination, altruistic activity, living conditions, security, and technological aids should also be considered in future assessments of QoL. Research is needed to explore the relevancy of these issues in future assessments of QoL among older adults.
Several studies have reported diverging trends in the prevalence of asthma and wheeze. The aim of this study was to investigate the clinical expression of childhood asthma in 1996 and 2006 by studying asthma morbidity, treatment, and environmental exposures in school children with physician-diagnosed asthma and wheeze, respectively. All children enrolled in first or second grade (7-8 yr-old) in three municipalities in northern Sweden were invited to a questionnaire study in 1996 and 2006, respectively. In 1996, 3430 (97%) participated; and in 2006, 2585 (96%) participated. The same parental completed questionnaire, including the ISAAC questions, was used in both surveys. Physician-diagnosed asthma was reported at 5.7% in 1996 and 7.4% in 2006. A significantly greater proportion of children with asthma were using inhaled corticosteroids (ICS) in 2006, 67% vs. 55% in 1996. This increase was parallel to a major decrease in severe asthma symptoms such as disturbed sleep because of wheeze (49% vs. 38%) and troublesome asthma (21% vs. 11%). The prevalence of current wheeze among the asthmatics decreased significantly; however, this was seen only among children not using ICS. Parental smoking decreased significantly as did the proportion living in damp buildings. In conclusion, although asthma remains a major public health issue in school age children, children with asthma had less respiratory symptoms and a better asthma control in 2006 compared to 1996. This parallels with an increase in treatment with ICS, more beneficial environmental conditions, and an increased diagnostic intensity resulting in a larger proportion of children with mild symptoms being diagnosed as having asthma.
OBJECTIVE: This study aimed to investigate empirically how and in what way individuals with symptoms of functional somatic syndromes should be classified. We also aimed to look into genetic and environmental influences on the classification. METHOD: A total of 28,531 twins aged 41-64 underwent screening interviews via a computer-assisted data collection system from 1998 to 2002. Nine functional somatic symptoms (abnormal tiredness, general muscular pain, recurrent abdominal discomfort, back pain, gastroesophageal reflux, recurrent headache, recurrent urinary problem, dizziness, breathlessness at rest) were assessed using structured questions in a blinded manner. Latent class analysis was applied to the data. Structural equation modeling was further performed in order to estimate the relative importance of genetic and environmental influences on class probability. RESULTS: Latent class analysis resulted in a five-class solution. Individuals in the first class did not show any health problems. Those assigned to the second, third, and fourth classes tended to have abnormal tiredness, gastrointestinal problems, and pain-related symptoms, respectively. Individuals in the fifth class had multiple symptoms to a greater extent than the other classes. All the five classes showed modest genetic influences (7-29% of the total variation) with gender differences except Class 3; however, the majority of influences on the class membership derived from unique environmental effects. CONCLUSION: The findings suggested the necessity of redefining the existing classification criteria for functional somatic syndromes in terms of single (uncomplicated) or multiple (complicated) syndromes. Environmental influences are important for the etiology of functional somatic syndromes.
The aim of this review is to provide a thorough overview of the health effects from the complexed biomagnified mixture of long-range transported industrial organochlorines (OCs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs) and mercury (Hg) on polar bear (Ursus maritimus) health. Multiple scientific studies of polar bears indicate negative relationships between exposure to these contaminants and health parameters; however, these are all of a correlative nature and do not represent true cause-and-effects. Therefore, information from controlled studies of farmed Norwegian Arctic foxes (Vulpes lagopus) and housed East and West Greenland sledge dogs (Canis familiaris) were included as supportive weight of evidence in the clarification of contaminant exposure and health effects in polar bears. The review showed that hormone and vitamin concentrations, liver, kidney and thyroid gland morphology as well as reproductive and immune systems of polar bears are likely to be influenced by contaminant exposure. Furthermore, exclusively based on polar bear contaminant studies, bone density reduction and neurochemical disruption and DNA hypomethylation of the brain stem seemed to occur. The range of tissue concentration, at which these alterations were observed in polar bears, were ca. 1-70,000 ng/g lw for OCs (blood plasma concentrations of some PCB metabolites even higher), ca. 1-1000 ng/g lw for PBDEs and for PFCs and Hg 114-3052 ng/g ww and 0.1-50 microg/g ww, respectively. Similar concentrations were found in farmed foxes and housed sledge dogs while the lack of dose response designs did not allow an estimation of threshold levels for oral exposure and accumulated tissue concentrations. Nor was it possible to pinpoint a specific group of contaminants being more important than others nor analyze their interactions. For East Greenland polar bears the corresponding daily SigmaOC and SigmaPBDE oral exposure was estimated to be 35 and 0.34 microg/kg body weight, respectively. Furthermore, PFC concentrations, at which population effect levels could occur, are likely to be reached around year 2012 for the East Greenland polar bear subpopulation if current increasing temporal trends continue. Such proposed reproductive population effects were supported by physiological based pharmacokinetic (PBPK) modelling of critical body residues (CBR) with risk quotients >or=1 for SigmaPCB, dieldrin, SigmaPFC and SigmaOHC (organohalogen contaminant). The estimated daily TEQ for East Greenland polar bears and East Greenland sledge dogs were 32-281-folds above WHO SigmaTEQ guidelines for humans. Compared to human tolerable daily intake (TDI), these were exceeded for PCBs, dieldrin, chlordanes and SigmaHCH in East Greenland polar bears. Comparisons like these should be done with caution, but together with the CBR modelling and T-score estimations, these were the only available tools for polar bear risk evaluation. In conclusion, polar bears seem to be susceptible to contaminant induced stress that may have an overall sub-clinical impact on their health and population status via impacts on their immune and reproductive systems.
BACKGROUND: Danish breast cancer patients diagnosed in 1978-1994 experienced a trend over time towards a more favourable distribution of lymph node status at time of diagnosis, which was not due to mammography screening. We investigated how this trend could be explained by patient characteristics at diagnosis: age (biological processes), calendar period (e.g. environmental changes), birth cohort (living conditions over a life time), post-menopausal status (a predictor of less favourable nodal status), and tumour diameter (a marker of detection time). MATERIAL AND METHODS: The data set consisted of 22 955 patients aged 30-69 years at time of diagnosis with known lymph node status, known tumour diameter, known menopausal status, and clinically detected tumours, available from the Danish Breast Cancer Cooperative Group (DBCG). Age, period, cohort, menopausal status, and tumour diameter were used as predictors in generalised linear models with either node-positive status (at least one of the excised lymph nodes being tumour-positive) or severely node-positive status (at least half of the excised lymph nodes being tumour-positive) as outcomes. Lymph node status was assessed both empirically and estimated using an EM algorithm in order to reduce misclassification. RESULTS AND DISCUSSION: We found that the improved lymph node status distribution was most likely a period effect due to a combination of earlier detection of clinical tumours, explaining most of the trend in node-positive breast cancer and half of the trend in severely node-positive breast cancer, and some unknown factor affecting lymph node status but not necessarily other tumour characteristics.
Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. The study cohorts included 575 Danish (age range 18-67 years) and 2009 Finnish (age range 22-27 years) adult twin pairs. Self-reported frequency of eating bread was obtained by food frequency questionnaires. Univariate models based on linear structural equations for twin data were used to estimate the relative magnitude of the additive genetic, shared environmental and individual environmental effects on bread eating frequency and choice of bread. The analysis of bread intake frequency demonstrated moderate heritability ranging from 37-40% in the Finnish cohort and 23-26% in the Danish cohort. The genetic influence on intake of white bread was moderate (24-31%), while the genetic influence on intake of rye bread was higher in men (41-45%) than in women (24-33%). Environmental influences shared by the twins were not significant. Consumption of bread as well as choice of bread is influenced by genetic predisposition. Environmental factors shared by the co-twins (e.g., childhood environment) seem to have no significant effects on bread consumption and preference in adulthood.
This paper reports findings from a survey of 239 psychiatric nursing staff. This study aimed to investigate how often psychiatric nursing staff participates in clinical supervision and any possible associations among individual and workplace factors in relation to participation. The survey findings are followed by a prospective longitudinal registration of participants in clinical supervision. The registration revealed that participation varies considerably and large numbers of the staff may not participate in clinical supervision at all. Characteristics of the workplace, including organisational location, work shift, and work-environmental factors, are related to participation and, consequently, may affect the outcome of clinical supervision.
Bulky DNA adducts are considered a potential biomarker of cancer risk. In this study, the association between various lifestyle, environmental, and genetic factors and the levels of bulky DNA adducts in peripheral leukocytes was examined in a study group nested within a population-based prospective Danish cohort. At enrollment, blood samples were collected and information on lifestyle, including dietary and smoking habits, obtained. Previously, bulky DNA adducts were measured in 245 individuals who developed lung cancer and 255 control members of the cohort. Of these 500 individuals, data on 375 individuals were included in this study, excluding 125 cases, which developed lung cancer within the first 3 yr after blood sampling. Bulky DNA adduct levels were measured by 32P-postlabeling technique and polymorphisms in carcinogen metabolism and DNA repair genes were determined. Potential predictors of bulky DNA adduct levels were analyzed by univariate and multivariate regression analyses. Women tended to have higher adduct levels than men. Living in central Copenhagen and surface darkness of fried meat and fish were associated with quantitative higher adduct levels. No significant associations were found between dietary factors or smoking and DNA adduct levels. Further, the results showed no prominent associations between any of 12 genetic polymorphisms and adduct levels. Overall, our study showed only few associations between dietary, environmental, and genetic factors and levels of bulky DNA adducts measured in peripheral leukocytes in a general Danish population.
The aim of this study was to examine the plasma, liver, and kidney status of vitamin A (retinol) and vitamin E (alpha-tocopherol) in two groups of Greenland sled dogs (Canis familiaris), with a total number of 16 bitches and 8 pups. The dogs were fed either minke whale (Balaenoptera acuterostrata) blubber (exposed dogs) or uncontaminated (control group) porcine fat for up to 12 to 21 mo of age. The daily intake of 50-200 g whale blubber (mean: 112 g) constituted between 10.4 and 11.7 microg/kg body weight summation operatororganohalogen contaminants (OHC) (or between 4.6 and 6.1 microg/kg body weight summation operatorpolychlorinated biphenyls [PCB]). Retinol was approximately 18% and alpha-tocopherol 22% higher in the diet of the exposed dogs compared to controls. In adipose tissue, mean of SigmaOHC was 92 ng/g lipid weight (lw) and 5005 ng/g lw for all control (n = 12) and exposed dogs (n = 10), respectively. Hepatic retinol correlated negatively with Sigma-dichlorodiphenyldichloroethane (SigmaDDT) and and Sigma-polybrominated diphenyl ethers (SigmaPBDE) for all exposed animals. A negative correlation between kidney alpha-tocopherol and SigmaPCB concentrations was observed, whereas two positive significant correlations were observed between kidney retinol and Sigma-chlordane-related compounds (SigmaCHL) and dieldrin concentrations. Hepatic alpha-tocopherol concentrations were significantly lower in exposed compared to controls, most likely due to a combination by OHC exposure and high dietary intake of unsaturated fatty acids. These results suggest that dietary exposure from OHC may, even at low concentrations, possibly affect retinol and alpha-tocopherol status in Arctic top predators.