Population In Northern Norway Research Articles

Construct Validity of the Orientation to Life Questionnaire in a General Adult Population in Norway and Its Association with Self‐Reported General and Oral Health

ABSTRACTObjectiveIndividuals' Sense of Coherence (SOC) is measured with the Orientation to Life Questionnaire (OLQ‐13). SOC reflects a person's orientation to life and ability to manage stress, which can impact health. The aim of the study was to test the reliability and construct validity of the OLQ‐13, with self‐reported general and oral health as criterion measures, in a Norwegian general adult population.MethodsData were collected using the OLQ‐13 in addition to items measuring sociodemographic information, self‐reported general health and self‐reported oral health. This study was based on data from a population‐based cross‐sectional oral health study in Troms County, conducted from October 2013 to November 2014 (n = 1875, mean age 47.4 years, 50.5% women). Internal consistency was examined with Cronbach's alpha (α). Confirmatory factor analysis (CFA) was used to test the construct validity (one‐ and three‐factor structure of the OLQ‐13). The associations between SOC and self‐reported general and oral health were tested using one‐way ANOVA.ResultsThe internal consistency of the OLQ‐13 was good (α = 0.84). The CFA showed that while the OLQ‐13 demonstrated an unacceptable fit, a shortened 11‐item version with a three‐factor structure revealed an acceptable fit and good internal consistency (α = 0.86). The highest mean SOC scores were found among individuals reporting good or very good general and oral health.ConclusionA three‐factor structure with an 11‐item version of the OLQ to assess SOC showed better validity than OLQ‐13 in a general population in Northern Norway. Self‐reported general and oral health can be considered appropriate criterion measures when validating SOC. To achieve a valid measurement scale for assessing SOC, a revision of the OLQ‐13 appears necessary, and further studies are needed.

Sense of coherence in a general adult population in Northern Norway and its associations with oral health

BackgroundSense of coherence (SOC) is a global orientation to life that may affect a person’s way of acting and living within his or her life context, which can have an impact on general and oral health. The aims of this study were (i) to describe the distribution of SOC in a general adult population; (ii) to explore whether sociodemographic characteristics, oral health-related behaviours, self-reported oral health, and clinical oral status were associated with SOC; and (iii) to explore whether SOC was associated with self-reported oral health, controlling for sociodemographic characteristics, oral health-related behaviours, and oral clinical status.MethodsThis study was based on data from the cross-sectional population-based study Oral Health in Northern Norway (N = 1819 individuals, 923 women, mean age 47.1 ± 15.2 years). Data were collected between October 2013 and November 2014 in Troms County. Participants answered a questionnaire that included items on SOC, sociodemographic characteristics, oral health-related behaviours, and self-reported oral health. Clinical oral status (number of teeth, dental caries, and periodontal status) was determined through oral and radiographic examination. Linear regression analysis was used to examine factors associated with SOC. Logistic regression analysis was used to examine SOC and its association with self-reported oral health adjusted for sociodemographic characteristics, behaviours, and clinical oral status.ResultsThe mean SOC score was 68.5 (standard deviation 10.5). The younger age groups (20–29 and 30–39 years) had mean SOC scores of 64.0 (95% CI: 62.7,65.3) and 67.2 (95% CI: 66.0,68.5), respectively, and the older age groups (40–79 years) had mean SOC scores between 69.8 and 70.1 (95% CI: 68.2,71.3). A higher mean SOC score was associated with older age, higher education level, higher income (all p < 0.001), being married/cohabiting (p = 0.005), and toothbrushing ≥ 2 times/day (p = 0.008). Approximately 49% of participants reported good oral health. SOC was positively associated with self-reported good oral health in the adjusted model (odds ratio:1.03 [95% CI: 1.02,1.05] p < 0.001).ConclusionsSOC was associated with sociodemographic characteristics and toothbrushing habits. There was no significant association between SOC and clinical oral status; however, SOC was positively associated with self-reported good oral health. This indicates that a person’s SOC might have an impact on how an individual perceives their oral health, independent of sociodemographic characteristics and the presence of oral diseases.

Home-range, movements and use of powerline poles of Eagle-Owls (Bubo bubo) at an island population in northern Norway

A dense island population of Eagle-Owls (Bubo bubo) close to the Arctic circle had suffered considerable mortality due to powerlines (electrocution and collision) throughout many decades. A study using GPS transmitter technology was carried out between 2009 and 2014. We studied home-range sizes, dispersal distances, mortality, and proposed mitigation techniques to prevent accidents. We found as expected that juvenile Eagle-Owls had larger home-ranges and moved farther than adults, but both age-groups moved much less than shown elsewhere in Europe. The probable reason for this was thought to be that this population was isolated by the surrounding sea, which might act as a barrier. The GPS data indicated that the poles of the grid were used as perching posts more than expected from a random distribution. This was explained by the lack of high trees and other elevated landscape features on these low islands. As a mitigation effort, we contributed to designing a perching-device for fitting on the poles that would prevent electrocution of the owls. This is now used by several grid-owners in coastal areas with high electrocution risk and is followed up by the National action plan for Eagle-Owl in Norway.

Diving and feeding of adult Atlantic salmon when migrating through the coastal zone in Norway

Atlantic salmon post-spawners from a population in northern Norway were tagged with data storage tags (N = 773), and the depth use and diving behaviour of recaptured individuals within the coastal zone were examined, both on their outward migration to sea (N = 44) and their return to the natal river after overwintering at sea (N = 34). In addition, the stomach contents of 909 returning adults caught in the fjord were examined to determine the extent to which, how recently and on what species they had fed. The tagged individuals migrated through surface waters and performed aperiodic dives, regardless of whether they were leaving the fjord as post-spawners (kelts) or returning after a winter or more at sea. However, diving behaviour differed between the fjord and outer coast. During both outward and return migration, dives when fish were likely in the fjord were shallower than on the outer coast. Deep dives of longer duration were more frequent on the outer coast than in the fjord. The stomach content analysis of salmon captured in the fjord did not show strong evidence of recent feeding: 58% of the salmon had empty stomachs, and most stomach contents were highly digested fish (mainly herring, but some capelin and unidentifiable species). We conclude that the inferred diving behaviour in the coastal zone, both on outward migration to sea and on return to the natal river, did not provide sufficient evidence of foraging within the water column, and hypothesize that diving in search for navigation cues is a more likely explanation.

Temporomandibular disorders in an adult population in northern Norway: A cross-sectional study.

ObjectivesThe aim of the study was to assess the prevalence of symptoms indicative of temporomandibular disorders (TMD) in an adult population in Troms County in Northern Norway, as well as the associations between TMD and socio‐demographic factors, dental status, self‐reported general, and oral health as well as oral health related quality of life (OHQoL).MethodsData were collected from a structured questionnaire and a clinical examination of a random sample of almost 2000 adults, 20–79‐year‐old, in Troms County in Northern Norway.ResultsWomen had a higher prevalence of all self‐reported and clinical signs of pain and dysfunction in the temporomandibular complex compared to men. For both genders, sounds from the temporomandibular joint (TMJ) upon clinical examination was the most common symptom, followed by pain to palpation of jaw muscles. Headache was the most common of the self‐reported symptoms and sounds from the TMJ the second most common. Young women had a higher prevalence of self‐reported headache and jaw‐ and face pain compared to middle‐aged and elderly women. TMD‐related symptoms of pain were significantly associated with poor self‐reported general health and correlated with OHQoL as assessed by the oral health impact profile 14 questionnaire.ConclusionBeing women and having moderate to poor self‐reported general health were associated with clinical signs and self‐reported symptoms of pain in the jaw, face and head region. Self‐reported symptoms of TMD correlated more strongly with OHQoL than clinical signs.

Demographic consequences of harvesting: a case study from a small and isolated moose population

Harvesting can have a substantial impact on population dynamics and individual performance in wild populations. While the direct consequences of harvest on individual survival and population growth rate are often apparent, harvesting can also have indirect and more subtle demographic consequences. Disentangling these consequences, however, requires in-depth knowledge of individual life histories of both females and males in the population. Here, we summarise demographic research on a population where such data exist: the Vega moose population in northern Norway. In this population, vital rates vary considerably among both females and males, and harvesting increases this variation by generating positive covariation between reproductive performance and survival. The skewed age and sex structure, which is typical of many harvested populations, also has demographic consequences: it reduces the ratio of effective to total population size and influences variation in vital rates in males and females. The moose harvest at Vega is structured by age- and sex-specific quotas, but it is not intentionally selective regarding size or other phenotypic characteristics. Still, harvest selection for earlier birth rates and larger calves was apparent, likely due to habitat-performance relationships and habitat-specific harvest mortality. Together, the bulk of research on this population shows that harvesting impacts population demography through many different pathways, with some being more subtle than others. These complex pathways influence the demographic variance and affect stochastic processes such as population growth, genetic drift, and rates of evolutionary change, and they must therefore be acknowledged in management plans to achieve sustainable harvesting.

Periodontal health in an indigenous S\xe1mi population in Northern Norway: a cross-sectional study

BackgroundThe aim of the study was to describe prevalence, severity and distribution of periodontal disease as well as associated risk factors in an indigenous Sámi population in Northern Norway, and to investigate differences between the indigenous Sámi and the non-Sámi population.MethodsThis cross-sectional study included data from the Dental Health in the North study (N = 2078; 18–75 years). Data on Ethnicity, household income, education, smoking habits, dental attendance, and tooth brushing habits were collected by a questionnaire. Periodontal conditions were assessed by clinical examination. A modified version of the new AAP/EFP classification system of periodontal disease was used to estimate the severity of periodontitis. Three stages were used: ‘Non-severe periodontitis’, ‘Stage II’, and stage ‘III/IV’.ResultsOf the total study population 66.5% reported Sámi affiliation. The total prevalence of periodontitis was 49.7%, with 20.1% in Stage III/IV, but no differences between Sámi and non-Sámi. When controlled for sex, age, education, smoking and dental attendance the Sámi had higher probability of having more severe stages of periodontitis; Odds RatioStage II (OR) = 1.3; 95% CI: 1.1–1.7; and ORStage III/IV (OR) = 1.6; 95% CI: 1.1–2.2) compared to non-Sámi. A higher proportion of Sámi had one or more PD ≥ 6 mm than the non-Sámi (p < 0.05).ConclusionsThe prevalence of periodontitis was high in communities in the core area of Sámi settlement in Northern Norway, regardless of ethnicity. People with Sámi ethnicity had deep periodontal pockets and an increased odds of having severe stages of periodontitis. Future studies should address possible explaining factors behind the potential higher risk of having more severe periodontitis among indigenous people in Sámi settlements.

Relationships between metabolic markers and obesity measures in two populations that differ in stature-The SAMINOR Study.

SummaryBackgroundThe relationships between metabolic markers and obesity measures may differ by ethnicity, sex, and height. Questions have been posed whether these relationships differ by ethnicity in the population in Northern Norway, but this has not been explored yet.ObjectivesInvestigate the relationships between metabolic markers and obesity measures in Sami and non‐Sami and explore the impact of stature.MethodsIn total, 13 921 men and women aged 30 and 36 to 79 years (22.0% Sami) from a population‐based cross‐sectional survey in Norway, the SAMINOR 1 Survey (2003‐2004, 57.2% attendance), were included. Relationships between triglycerides, high‐density lipoprotein cholesterol, glucose, systolic/diastolic blood pressure (BP), metabolic syndrome and diabetes mellitus as outcomes, and body mass index (BMI), waist circumference (WC), and waist‐to‐height ratio (WHtR), respectively, were modelled using fractional polynomial regression. Appropriate interaction analyses and adjustments were made.ResultsThe non‐Sami were approximately 6 cm taller than the Sami. No interactions were found between ethnicity and obesity. At the same levels of WC, BMI, or WHtR, levels of lipids and BP differed marginally between Sami and non‐Sami, but these were eliminated by height adjustment, with one exception: At any given WC, BMI, or WHtR, Sami had approximately 1.4 mmHg (95% CI, −2.1 to −0.7) lower systolic BP than non‐Sami (P values < .001).ConclusionsHeight explained the marginal ethnic differences in metabolic markers at the same level of obesity, except for systolic BP, which was lower in Sami than in non‐Sami at any given BMI, WC, or WHtR.

Persistent pain associated with socioeconomic and personal factors in a Sami and Non-Sami population in Norway: an analysis of SAMINOR 2 survey data

ABSTRACT In international studies, higher prevalence of persistent pain has been reported in indigenous populations compared to majority populations. The present study aimed to determine the prevalence of persistent pain within a Sami and a non-Sami population in northern Norway, with adjustment for the confounding factors of age, sex, marital status, education, income, mental health, smoking status and ethnic background. Using SAMINOR 2 survey data including Sami and non-Sami populations, we analysed 5,546 responses, from individuals aged 40–79 years, to questions concerning persistent pain (≥ 3 months). In total, 2,426 (43.7%) participants reported persistent pain with differences between Sami women and non-Sami women (44.1% versus 51.1%, respectively), but none between Sami men and non-Sami men (38.7% versus 38.2%, respectively). Elderly Sami women were less likely to report persistent pain than were elderly non-Sami women. In men, no ethnic differences in pain were observed according to age-group. Marital status, education levels, household income, psychological distress, and smoking status did not influence the association between ethnicity and pain. Pain severity and location did not differ between Sami and non-Sami participants. In this study, we found only minor ethnic differences in persistent pain. Similar living conditions and cultural features may explain these findings.

Dietary patterns of adults and their associations with Sami ethnicity, sociodemographic factors, and lifestyle factors in a rural multiethnic population of northern Norway - the SAMINOR 2 clinical survey

BackgroundFew population-based studies have assessed dietary behaviors in the rural multiethnic population of Northern Norway. The present study determined dietary patterns and investigated their association with Sami ethnicity, sociodemographic factors, and lifestyle factors in a multiethnic population in rural Northern Norway.MethodsThis cross-sectional study included 4504 participants of the SAMINOR 2 Clinical Survey (2012–2014) aged 40–69 years. All participants completed a lifestyle and food frequency questionnaire. Dietary patterns were determined using principal component analysis. Associations between food patterns and ethnicity, sociodemographic factors, and lifestyle factors were examined by multiple linear regression.ResultsSix dietary patterns were identified that accounted for 28% of the variability in food intake in the study sample: ‘processed meat/westernized’, ‘fish/traditional’, ‘fruit/vegetables’, ‘reindeer/traditional’, ‘bread and sandwich spreads’, and ‘sweets and bakery goods’. The ‘reindeer/traditional’ pattern was most common among the inland Sami population. The ‘fish/traditional’ pattern was most common among costal multiethnic Sami and least common among inland Sami and among women independent of ethnicity. The ‘fish/traditional’ pattern was also positively associated with older age, high education level, small household size, and smoking. Adherence to the ‘processed meat/westernized’ pattern was lower among inland Sami than inland/coastal non-Sami; no ethnic differences in adherence to this pattern were found between costal multiethnic Sami and inland/coastal non-Sami. Unhealthy lifestyle factors, like low physical activity level and smoking, and younger age were mainly associated with the ‘processed meat/westernized’ pattern, whereas socioeconomic factors like low education, low gross annual household income, and large household size were related to the ‘sweets and bakery goods’ pattern. Male gender, low education level, and smoking were associated with the ‘bread and sandwich spreads’ pattern. The ‘fruit/vegetables’ pattern was characterized by healthy dietary choices and a health-conscious lifestyle, and was more common in women with a high education level and income.ConclusionsAdherence to the six identified dietary patterns was characterized by different sociodemographic and lifestyle factors. Ethnicity, in combination with geographical region of residence, was associated with dietary behaviors. This study provides knowledge that will be useful in future studies on dietary patterns related to chronic diseases in the rural population of Northern Norway.

The frequency of enamel and dentin caries lesions among elderly Norwegians

Aim: To describe the distribution of enamel-, dentin-, root- and secondary caries within an elderly population in Northern-Norway.Material and methods: A study population (n = 1 173) was divided into age groups: 65–69 (seniors), 70–74 (young elderly), 75–79 (elderly) and 80–94 (old elderly). Seven examiners registered presence, location and severity of caries lesions on x-rays and intra-oral photos. Severity of approximal, occlusal, secondary and root caries was graded (D1–2: into enamel; D3–5: into dentin, root caries), and decayed missing filled surfaces/teeth (DMFS/DMFT) were calculated. T-test, ANOVA and a Bonferroni correction were used.Results: The seniors had more primary caries (DS1–5) compared to the oldest age groups, while the old elderly had significantly more secondary caries than the other groups (p < .05). Of those ≥65 years 13.8% were affected with root caries, 21% among the oldest. About 48% of the old elderly had one or more surfaces with untreated caries lesions into dentin, while for the other groups the number was 35% (p < 0.05).Conclusion: Individuals seem to maintain good oral health up to at least 80 years of age. Those older than 80 years have more root caries needing more intensified caries-controlling measures and a higher prevalence of untreated dentin lesions often in need of operative treatment.

Correction to: Seroprevalence of hepatitis E virus (HEV) in a general adult population in Northern Norway: the Tromsø study

Unfortunately, the supplement tables are missing in the original article. The missing files have been included here.

Seroprevalence of hepatitis E virus (HEV) in a general adult population in Northern Norway: the Tromsø study.

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis in many parts of the world but only a few cases have been diagnosed in Norway. To investigate the HEV exposure rate in a presumed low-risk area, we have conducted a population-based study of anti-HEV IgG seroprevalence in Northern Norway. A total of 1800 serum samples from 900 women and 900 men, age 40-79years, were randomly selected from the 21,083 participants in the 7th Tromsø Study, representing the 32,591 inhabitants of the Tromsø municipality that were ≥ 40years. All samples were analyzed by ELISA-1 (recomWell HEV IgG). Samples testing positive or borderline, as well as a 1.5-fold excess of negative samples, were retested by ELISA-2 (DiaPro HEV IgG). If still borderline or a result discordant from ELISA-1, the sample was retested by ELISA-3 (Wantai HEV IgG) and strip-immunoassay (recomLine HEV IgG). Anti-HEV IgG was detected in 205 individuals (11.4%), yielding an estimated seroprevalence of 10.4% in the age-matched population of Tromsø. Using logistic regression analysis followed by multivariable backward elimination analysis, increasing age (OR 1.036per year; p < 0.001) and higher education (OR 2.167; p < 0.001) were found as potential risk factors, whereas travel abroad or eating of red meat were not. Our results indicate that HEV-infection is common in Northern Norway and suggest that HEV testing should be included in the evaluation of elevated liver enzymes.

Food in rural northern Norway in relation to Sami ethnicity: the SAMINOR 2 Clinical Survey.

To estimate current food intake in the population of northern Norway and to investigate the impact of self-perceived Sami ethnicity and region of residence on food intake. The data are part of the second cross-sectional survey of the Population-based Study on Health and Living Conditions in Regions with Sami and Norwegian Populations (the SAMINOR 2 Clinical Survey, 2012-2014). Food intake was assessed by an FFQ. Ethnic and regional differences in food intake were studied by sex-specific, multivariable-adjusted quantile regression models. Ten municipalities (rural northern Norway). Males (n 2054) and females (n 2450) aged 40-69 years (2743 non-Sami, 622 multi-ethnic Sami, 1139 Sami). The diet of Sami participants contained more reindeer meat, moose meat, food made with animal blood and freshwater fish; and contained less lean fish and vegetables. In the inland region, the consumption of reindeer meat was greatest in Sami participants, followed by multi-ethnic Sami participants and non-Sami participants, who had the lowest consumption (median 25, 12 and 8 g/d, respectively). Compared with the inland region, fish roe/liver intake was higher in the coastal region and lean fish intake was twice as high (41 and 32 g/d in males and females, respectively). When compared with non-Sami participants, those with solely self-perceived Sami ethnicity reported a significantly different intake of several foods, especially reindeer meat in the inland region. Multi-ethnic Sami tended to have similar diets to non-Sami. Residence in the coastal region predicted higher fish and roe/liver intake.

5.10-P5Metabolic syndrome in a multi-ethnic, rural population in northern Norway

5.10-P5Metabolic syndrome in a multi-ethnic, rural population in northern Norway

Do Norwegian Sami and non-indigenous individuals understand questions about mental health similarly? A SAMINOR 2 study

ABSTRACTThe Western culturally developed Hopkins Symptom Checklist (HSCL-10) is a self-report measure of mental distress widely used for both clinical and epidemiological purposes – also in the multiethnic epidemiological SAMINOR studies in Northern Norway, but without any proper cross-cultural validation. Our objective was to test invariance of the HSCL-10 measurements among Sami and the non-indigenous majority population in Northern Norway (participants in the SAMINOR 2 study) and whether the previously used HSCL-10 cut-off level (1.85) fits the Sami subgroups in the study. Participants belonged to Sami core, Sami affiliation, Sami background or majority Norwegian groups. The confirmatory factor analysis framework adapted for testing of measurement invariance showed no significant measurement invariance between the groups indicating that the HSCL-10 response scale predominantly was used in the same way and that significantly different meanings were not ascribed to the same set of questions. The cut-off criteria of 1.85 as indicative of psychological distress based on Norwegian data equal a score of 1.89, 1.94 and 1.91 in the Sami core, Sami affiliation and Sami background groups, respectively. Thus, the same cut-off criterion 1.85 may be safely used in all groups. However, one should still be looking for culture-specific expressions of mental stress.

Arctic charr exploit restricted urbanized coastal areas during marine migration: Could they be in harm’s way?

Human and industrial activities in Arctic areas are increasing, as are global water temperatures. Combined, these factors can result in altered conditions for species living in these, until recently, pristine areas. Of the anadromous salmonids, Arctic charr may be particularly vulnerable to these changes, as this species is adapted to cold waters and exploits restricted areas at sea. In order to test to what extent Arctic charr utilized coastal areas with anthropogenic interference versus more pristine waters, the marine area use of a population in northern Norway was documented over three consecutive years by use of acoustic telemetry. Their depth utilization, temperature preference and survival was also recorded. The tagged fish spent a minimum of half of their marine residency time within 5 km of the river outlet proximate to urbanized coastal areas. The fish also resided within a narrow temperature and depth range and spent a very limited period at sea. The marine habitat available to Arctic charr should be carefully considered in coastal development and management plans, as human activities and coastal water temperatures increase in the Arctic regions. The current study illustrates the importance of species and population-specific knowledge during development of management strategies for anadromous salmonids.

Coastal Sami revitalization and rights claims in Finnmark (North Norway) - two aspects of one issue? Preliminary observations from the field

The focus of this paper is on the rights claim processes and the revitalization process of the indigenous coastal Sami population in northern Norway. By examining the available research literature and reflecting upon preliminary observations gathered in anthropological fieldwork, I examine how the fight for resource protection and special resource rights are interlinked with Sami identity management. To do so, I analyze the different levels of the claiming of rights in their specific setting throughout time, with a special focus on the period from 1990 onwards. I will show how the actors, the argumentations, and strategies have changed over the course of time leading to the current &amp;lsquo;indigenization&amp;rsquo; of the rights claim process.

Population dynamics of Salmincola salmoneus on Atlantic salmon in a northern Norwegian river

Atlantic salmon Salmo salar are often heavily infected by the gill maggot Salmincola salmoneus, but little information exists on the population dynamics of this parasite. Through a combination of in vivo field examination and laboratory analysis of gills from the Alta River S. salar population in northern Norway, we describe the population dynamics of the parasite and suggest a model for the host-parasite interactions. S. salar did not become infected with S. salmoneus until they returned to the river as first-time spawners. The infection increased rapidly until autumn, and just after spawning 96% of the spent fish (kelts) were infected with a mean intensity of 53 parasites per fish. In May, the prevalence of S. salmoneus on the descending kelts had increased to 100%, but the intensity exhibited little change. A small proportion of the adult S. salar population returned as immature to the river during autumn and had lower parasite intensities than the kelts the following spring. When the fish that had spawned previously (repeat spawners) returned from their second (or more) sea migration, they had an average infection rate of 36 S. salmoneus individuals per fish. The kelts seemed to be the main habitat for the parasite during winter and spring, and they stay long enough in the river to pass the infection to maiden S. salar that enter the river early in summer. These fish then became a source of infection for the maiden fish entering the river later. However, in years that have a possible mismatch between the opposite migration of kelts and maiden S. salar, the immature fall-running and returning repeat spawners will be crucial for maintaining the parasite population. We hypothesize that heavily infected S. salar may suffer reduced growth and survival at sea, potentially reducing the abundance of repeat spawners.

Iron status and prevalence of hereditary haemochromatosis in a multiethnic population in northern Norway

Objectives. The main aims of this research were to evaluate the iron status in ethnically and geographic diverse populations in northern Norway and in addition investigate the prevalence of hereditary haemochromatosis and iron overload in the same populations.Study design. Three different population surveys formed the basis, used in the subprojects. All three surveys were cross-sectional population based studies of health and living conditions. The SAMINOR study was performed in areas with mixed Sámi and Norwegian population. It was carried out in 2003 -2004. Inhabitants aged 30 years and from 36 to 79 years were invited to participate. The eligible population consisted of 27987 individuals, of whom 16640 participated, corresponding to a response rate of 61.3%. The Sør-Varanger study was carried out in 1994. All adults between 18 and 69 years of age were invited to participate (n=6822). In total 3671 individuals participated corresponding to a participation rate of 60 %. In the year of 2000, blood samples were thawed and analysed from a total of 3344 participants (61.4%), between the ages 25 - 69 years at participation. Participants younger than 25 year were not included in the present iron study. The Tromsø V study in 2001 was a population-based, prospective study of birth cohorts. The subset consisted of those who attended a more extended examination of the 1994 – 95 survey, Tromsø IV, (all men born 1925 – 39, all women born 1925 – 44 and 5 – 10% random selection of the other age groups). In addition, all inhabitants born 1971, 1961, 1956 and 1941 were also invited in 2001.In the fifth Tromsø study 8130 subjects (78% of those invited) were investigated.In total approximately 28 000 individuals from northern Norway, were analysed for iron status.