Estonian Population Research Articles

The incidence of hip fractures in Estonia, 2005–2012

The incidence of hip fractures among individuals aged over 50 in Estonia and trends over time were assessed for 2005-2012. The incidence among women is relatively low, with the declining trend, but the rate among men is among the highest in Eastern and Central Europe. The aim of this study was to assess the incidence and trends of hip fractures among individuals over 50 years in Estonia in 2005-2012 and to increase understanding of the incidence of hip fractures in Eastern Europe. We identified all patients aged 50 years or older with hip fracture (ICD-10 codes S72.0, S72.1 and S72.2) in 2005-2012 using medical claims data from the Estonian Health Insurance Fund. Crude and age-specific incidence rates were calculated for men and women using the population of Estonia in 2005-2012. To adjust for age differences in the population, standardized incidence rates (SIR) were estimated. The SIR per 100,000 for the entire observation period was 209.2 (95% CI 204.2 to 214.2) in women and 215.6 (95%CI 208.2 to 223.1) in men, resulting in a female to male rate ratio of 0.97 (95% CI 0.84 to 1.11). Over the period of 2005-2012 the estimated SIR/100,000 ranged from 211.5 (95% CI 196.8-226.3) in 2005 to 183.7 (95% CI 170.8-196.7) in 2012 in women, and from 238.5 (95% CI 215.4-261.7) in 2005 to 187.9 (95% CI 169.0-206.8) in 2012, in men. For women, the decrease in SIR for the study period approached statistical significance (p = 0.058), and for the period of 2009-2012, we observed an accelerated 16% decrease (p = 0.008). The incidence of hip fractures among Estonian women is relatively low, whereas the rate among men is among the highest in Eastern and Central Europe. In line with many countries, we found a recent decline in incidence among women.

Educational differences in cigarette smoking among adult population in Estonia, 1990-2010: does the trend fit the model of tobacco epidemic?

BackgroundIn developed countries, smoking spreads through society like an epidemic in which adults from higher socioeconomic groups are the first to adopt and earlier to quit smoking, and in which exists a lag in adoption of smoking between men and women.The objective of this study was to describe trends in daily and occasional smoking, to investigate association between smoking status and education, and to examine if the associations in 1990–2010 in Estonia fit the pattern predicted by the model of tobacco epidemic.MethodsThe study was based on a 20–64-year-old subsample (n = 18740) of nationally representative postal cross-sectional surveys conducted every second year in Estonia during 1990–2010. Cigarette smoking and education were examined. χ2 test for trend was used to determine daily and occasional smoking trends over study years. Multinomial logistic regression model was used to test educational differences in daily and occasional smoking for every study year. Adjusted relative risk ratios (RRRs) with 95% confidence intervals were calculated.ResultsIn 1990–2010, daily smoking varied largely between genders showing decreasing trend among men, but not among women. In 2010, one third of men and one fifth of women were daily smokers. Daily smoking was not clearly associated with education among men in 1990–1994 and among women in 1990–2000. Men revealed inverse relationship between daily smoking and education since 1996, but women since 2002. In 2010, compared to men and women with higher education, relative risk ratio of daily smoking was 2.92 (95% CI = 2.01–4.25) among men and 2.29 (95% CI = 1.65–3.17) among women with secondary education, but 4.98 (95% CI 3.12–7.94) among men and 6.62 (95% CI = 4.07–10.76) among women with basic education.In 1990–2010, occasional smoking was stable and similar (varying between 7–10%) among men and women, no association with education was found.ConclusionsDaily smoking patterns in Estonia fit the model of tobacco epidemic in developed countries. Educational differences in daily smoking highlight the importance of addressing smoking behaviour in the general population by educational subgroups in Estonia.

Anthelmintic resistance of intestinal nematodes to ivermectin and pyrantel in Estonian horses

There is evidence of resistance in horses to anthelmintic treatment using ivermectin and pyrantel. However, little information is available about the parasites, treatment practices or anthelmintic resistance in the horse population in Estonia. In the present study, we examined 41 trotting and riding horses aged <3 years from four stables in Estonia. Faecal samples were collected, and horses were selected for treatment if the nematode egg count per gram faeces exceeded 200. Horses (n=32) that shed strongyle-type eggs were treated with pyrantel, whereas Parascaris equorum-positive animals received ivermectin. Up to 78% of horses required anthelmintic treatment and the efficiency of the anthelmintics was evaluated using a faecal egg count reduction test. Resistance of P. equorum was observed in 50% of horses treated with ivermectin and of strongyles in 27% of horses treated with pyrantel. Ivermectin treatment resulted in a mean reduction of 100% for strongyle eggs and an 89% reduction in P. equorum, and pyrantel-treated horses exhibited an 88% reduction in strongyle eggs. These results are considered to be the first indication of resistance to pyrantel, but further studies of ivermectin resistance are required. According to questionnaires completed by the owners of horses, resistance might be explained by a lack of evidence-based strategies, a strong preference for using ivermectin and possibly a subjective evaluation of the body weight of horses.

Proliferative kidney disease (PKD) agent Tetracapsuloides bryosalmonae in brown trout populations in Estonia.

Proliferative kidney disease (PKD) caused by the myxozoan parasite Tetracapsuloides bryosalmonae is a serious parasitic disease threatening both farmed and wild salmonid populations, but very little is currently known about the distribution of the parasite in the Baltic Sea region. In this study we (1) report the development of a novel multiplex PCR method for fast and reliable screening of T. bryosalmonae; (2) use this multiplex PCR method to show that the PKD agent T. bryosalmonae is widespread in natural brown trout Salmo trutta L. populations in Estonia; (3) evaluate monthly and yearly variation of T. bryosalmonae prevalence in juvenile trout; (4) assess T. bryosalmonae prevalence in different age-classes of fish (0+ vs. 1+ and older) and report the presence of the PKD agent in the kidneys of returning sea trout spawners; and (5) suggest the freshwater bryozoan Plumatella fungosa as a putative invertebrate host of T. bryosalmonae in Estonia. Our results demonstrate a highly heterogeneous distribution of T. bryosalmonae at the micro-geographic scale, indicating that PKD could have an important negative effect on recruitment in Estonian brown trout populations.

Full-length genome sequences of Estonian HIV-1 CRF06 and Eastern-European subtype A1 recombinant forms

“Eastern-European type” of HIV-1 epidemic started among Estonian intravenous drug users (IDU) population in 2000. Unlike in other former Soviet Union countries the Estonian HIV-1 epidemic was not caused by subtype A1 viruses but recombinant form CRF06_cpx and its next generation recombinants with subtype A1. A high variety of different recombinant forms has also been described in other IDU driven HIV-1 epidemics in other countries. Aim: to sequence and describe the subtypic structure of near-full genome Estonian HIV-1 inter-subtype recombinant forms in Estonian IDU population. The study included plasma samples from 10 HIV positive subjects collected in 2000-2010. Samples were selected based on discordant subtypes or recombinant sequences in different genomic regions in recent Estonian studies. Patients’ viral genomic RNA was reverse transcribed, amplified, cloned and Sanger sequenced in four overlapping genomic regions. Phylogenetic trees were constructed using the Maximum-Likelihood method and recombination pattern was assessed using Simplot software (similarity and bootscanning blots). Drug resistance mutations and tropism were determined by Stanford HIV Drug Resistance Database and geno2pheno analysis tool using a false positive rate of 10%. According to bootscanning analysis the majority of strains (80%) indicated unique recombination structure between Estonian CRF06_cpx and Russian subtypes A1 sequences, whereas prevailing proportions of regions belong to the CRF06_cpx clade. Phylogenetic tree analysis confirmed these results indicating monophyletic clustering with Estonian CRF06_cpx or Russian subtype A1 sequences in corresponding regions. Of 10 sequences in one NNRTI DRM K103N and V179E was found and in 9 INI accessory mutations L74I was found. Of seven gag region sequences in three cases protease inhibitor associated substitution L449F, and in one case V128I, P452S and maturation inhibitor substitutions V370M were present. Of 9 env sequences one strain was R4 tropic, the others were R5 tropic. Analyzed sequences revealed high recombinational diversity of Estonian inter-subtype HIV-1 recombinant strains, which is also characteristic to other IDU HIV-1 epidemics. Nearly full-length genome sequences generated by this study provide reference material for high-throughput sequencing and for tracking the molecular epidemics in different risk groups and in Estonia and neighboring countries.

Adapting the Sniffin' Sticks olfactory test to diagnose Parkinson's disease in Estonia.

The aim of the study was to develop a culturally adapted translation of the 12-item smell identification test from Sniffin' Sticks (SS-12) for the Estonian population in order to help diagnose Parkinson's disease (PD). A standard translation of the SS-12 was created and 150 healthy Estonians were questioned about the smells used as response options in the test. Unfamiliar smells were replaced by culturally familiar options. The adapted SS-12 was applied to 70 controls in all age groups, and thereafter to 50 PD patients and 50 age- and sex-matched controls. 14 response options from 48 used in the SS-12 were replaced with familiar smells in an adapted version, in which the mean rate of correct response was 87% (range 73-99) compared to 83% with the literal translation (range 50-98). In PD patients, the average adapted SS-12 score (5.4/12) was significantly lower than in controls (average score 8.9/12), p < 0.0001. A multiple linear regression using the score in the SS-12 as the outcome measure showed that diagnosis and age independently influenced the result of the SS-12. A logistic regression using the SS-12 and age as covariates showed that the SS-12 (but not age) correctly classified 79.0% of subjects into the PD and control category, using a cut-off of <7 gave a sensitivity of 76% and specificity of 86% for the diagnosis of PD. The developed SS-12 cultural adaption is appropriate for testing olfaction in Estonia for the purpose of PD diagnosis.

Population changes and phenotypic diversity of Phytophthora infestans isolates from Estonia and Finland.

In Estonia and Finland, 386 and 671 isolates, respectively, of Phytophthora infestans were collected during the growing seasons of 2001-2007. Collection was from groups of potato cultivars of different origin from field plots at two research institutions in eastern and northern Estonia and from variety trials at two locations and commercial potato fields in Finland. Mating type, pathotype based on virulence on a differential set of 11 R genes of Solanum demissum and response to the fungicide metalaxyl were determined in both countries by comparable methods. The diversity of the P. infestans populations in both countries over the monitoring period was high. In Finland, the proportion of A1/A2 mating types was almost equal throughout the monitoring period, while in Estonia the A1 population, dominating in 2001-2004, shifted towards an equal proportion of both mating types in 2005-2007. The diversity of the P. infestans population, as measured by virulence pathotypes and the number of avirulence factors per isolate, developed in opposite directions in Estonia and Finland from 2001-2004 to 2005-2007: the diversity decreased in Estonia and increased in Finland. Metalaxyl sensitivity in the Estonian P. infestans population increased while in Finland it decreased during the same period. Results clearly show differences between Estonian and Finnish populations of P. infestans in several aspects, which may derive from cropping practices. The high A2 mating type percentage during 2005-2007 in both countries points to soil contamination with oospores.

Cohort Profile: Estonian Biobank of the Estonian Genome Center, University of Tartu

The Estonian Biobank cohort is a volunteer-based sample of the Estonian resident adult population (aged ≥18 years). The current number of participants-close to 52000--represents a large proportion, 5%, of the Estonian adult population, making it ideally suited to population-based studies. General practitioners (GPs) and medical personnel in the special recruitment offices have recruited participants throughout the country. At baseline, the GPs performed a standardized health examination of the participants, who also donated blood samples for DNA, white blood cells and plasma tests and filled out a 16-module questionnaire on health-related topics such as lifestyle, diet and clinical diagnoses described in WHO ICD-10. A significant part of the cohort has whole genome sequencing (100), genome-wide single nucleotide polymorphism (SNP) array data (20 000) and/or NMR metabolome data (11 000) available (http://www.geenivaramu.ee/for-scientists/data-release/). The data are continuously updated through periodical linking to national electronic databases and registries. A part of the cohort has been re-contacted for follow-up purposes and resampling, and targeted invitations are possible for specific purposes, for example people with a specific diagnosis. The Estonian Genome Center of the University of Tartu is actively collaborating with many universities, research institutes and consortia and encourages fellow scientists worldwide to co-initiate new academic or industrial joint projects with us.

On Certain Aspects of the Need and Possibility for the Administrative-Territorial Reform in Estonia

The paper treats important problems of regional and local government policy, such as the possibility of and need for the administrative-territorial reform, including merging of municipalities and definition of mutual relationships between the state and local governments and their functions. The need for sustainable and strong municipalities has been emphasised also on the level of the European Union already several years ago. Possible mergers of Estonian county centres with their surrounding rural municipalities, also the possibility for having several centres of attraction in a county are discussed. Statistics on demographic changes in the Estonian population, concentration of the population above all to larger cities, and decrease in rural population are presented. Also statistics, for instance, on changes in the number of pupils in counties are presented. A few suggestions are made for the further development of the regional and local government policy, including based on the considerably more radical activities in Finland in this field.

Smoking by socioeconomic status among adult population in Estonia, 1990–2010

Background Smoking is the largest single cause of preventable serious ill health and premature death. Effective tobacco policy to prevent and reduce smoking requires knowledge of smoking prevalence, trends and socioeconomic differences in smoking in the country concerned. Methods This study was based on the study of Health Behavior among Estonian Adult Population conducted in 1990–2010. The target group were 20–64 year-old adults (N = 18740). Gender, age, nationality, marital status, education and employment status were used as socioeconomic factors. …

Spatial Genetic Analyses Reveal Cryptic Population Structure and Migration Patterns in a Continuously Harvested Grey Wolf (Canis lupus) Population in North-Eastern Europe

Spatial genetics is a relatively new field in wildlife and conservation biology that is becoming an essential tool for unravelling the complexities of animal population processes, and for designing effective strategies for conservation and management. Conceptual and methodological developments in this field are therefore critical. Here we present two novel methodological approaches that further the analytical possibilities of STRUCTURE and DResD. Using these approaches we analyse structure and migrations in a grey wolf ( Canis lupus ) population in north-eastern Europe. We genotyped 16 microsatellite loci in 166 individuals sampled from the wolf population in Estonia and Latvia that has been under strong and continuous hunting pressure for decades. Our analysis demonstrated that this relatively small wolf population is represented by four genetic groups. We also used a novel methodological approach that uses linear interpolation to statistically test the spatial separation of genetic groups. The new method, which is capable of using program STRUCTURE output, can be applied widely in population genetics to reveal both core areas and areas of low significance for genetic groups. We also used a recently developed spatially explicit individual-based method DResD, and applied it for the first time to microsatellite data, revealing a migration corridor and barriers, and several contact zones.

OP0266-PARE Osteoporosis Prevention Project in Estonia: Bone Density Measurements, Patient Counseling, Information Days, Lectures and Materials

BackgroundOsteoporosis is an increasing problem among aging population in Estonia and elsewhere in the world. By assessing the case rate, mortality and financial costs concerning osteoporosis it turns out that...

Preferences in media use and perception of inter-generational differences among age groups in Estonia: A cultural approach to media generations

This article adopts a cultural approach in order to provide an empirical grounding to the multidimensional concept of media generations. Data from the representative survey ‘Me. The World. The Media’, conducted in autumn 2011 among members of the Estonian population aged 15–74 (N=1510), are used to map similarities and distinctions among four age groups with regard to the use of media technologies and channels, format and topic preferences, spatial orientations of media use, and attitudes towards the Internet. The findings demonstrate significant and multifaceted differences between the age cohorts, suggesting that in addition to the ascent of new media technologies, broader social and cultural changes need to be considered in interpreting generational groups’ relations with the media. The study partially confirms the hypothesis that media experiences shared with members of another media generation are related to a weaker perception of inter-generational gaps.

Can selenium levels act as a marker of colorectal cancer risk?

BackgroundSelenium has attracted attention because of its antioxidant properties. Antioxidants protects cells from damage. Certain breakdown products of selenium are believed to prevent tumor growth by enhancing the immune cell activity and suppressing the development of tumor blood vessels. In this observational study, selenium level was measured in a series of patients from Poland and Estonia to determine a correlation between levels of this microelement and colorectal cancer risk.MethodsA total of 169 colorectal cancer patients and 169 healthy controls were enrolled in the study after obtaining their informed consent. Selenium level in the blood serum was measured using Graphite Furnace Atomic Absorption Spectrometry (GFAAS). The statistical analysis was performed by Fisher’s exact test.ResultsThe threshold point of selenium level was 55 μg/l and 65 μg/l for Poland and Estonia respectively, for an increase in cancer risk. The lower levels of selenium were associated with greater risk of colorectal cancer.ConclusionsThe result reveals a significant strong association between low selenium level and the colorectal cancer risk in both Estonian and Polish populations.

Fusarium avenaceum causes burn spot disease syndrome in noble crayfish (Astacus astacus)

Burn spot disease has been causing epidemics both in the Estonian mainland and in Saaremaa Island in the threatened noble crayfish (Astacus astacus) stocks. To study the cause of the disease, we isolated several Fusarium spp. from Estonian noble crayfish (A. astacus) populations suffering from burn spot disease syndrome. We first identified fungi directly from melanised cuticle by their ITS sequences. Then we isolated Fusarium spp. from melanised spots of crayfish showing burn spot disease symptoms, such as melanisation and shell erosion, from two different crayfish populations and watercourses in Estonia. The isolates were then identified based on ITS and EF1α-gene sequences. Isolates of Fusarium spp. taken from two separate Estonian noble crayfish populations were used in infection studies. Koch postulates confirmed that the studied agent was causing burn spot disease symptoms including shell erosion in the noble crayfish, which were significantly more severe after molts. After the infection period, an identical Fusarium spp. was re-isolated from carapace lesions and was thus shown to be the disease agent causing burn spot disease syndrome and shell erosion in noble crayfish. Based on GenBank database searches, the isolates causing burn spot disease symptoms were identified as Fusarium avenaceum in mainland Estonia and F. solani in Saaremaa crayfish.

Two Single-Nucleotide Polymorphisms in ADAM12 Gene Are Associated with Early and Late Radiographic Knee Osteoarthritis in Estonian Population

Objectives. To investigate associations of selected single-nucleotide polymorphisms (SNPs) in ADAM12 gene with radiographic knee osteoarthritis (rKOA) in Estonian population. Methods. The rs3740199, rs1871054, rs1278279, and rs1044122 SNPs in ADAM12 gene were genotyped in 438 subjects (303 women) from population-based cohort, aged 32 to 57 (mean 45.4). The rKOA features were evaluated in the tibiofemoral joint (TFJ) and patellofemoral joint. Results. The early rKOA was found in 51.4% of investigated subjects (72% women) and 12.3% of participants (63% women) had advanced stage of diseases. The A allele of synonymous SNP rs1044122 was associated with early rKOA in TFJ, predominantly with the presence of osteophytes in females (OR 1.57; 95% CI 1.08–2.29, P = 0.018). The C allele of intron polymorphism rs1871054 carried risk for advanced rKOA, mostly to osteophyte formation in TFJ in males (OR 3.03; 95% CI 1.11–7.53, P = 0.018). Also the CCAA haplotype of ADAM12 was associated with osteophytosis, again mostly in TFJ in males (P = 0.014). For rs3740199 and rs1278279, no statistically significant associations were observed. Conclusion. ADAM12 gene variants are related to rKOA risk during the early and late stages of diseases. The genetic risk seems to be predominantly associated with the appearance of osteophytes—a marker of bone remodelling and neochondrogenesis.

Chernobyl cleanup workers from Estonia: follow-up for cancer incidence and mortality

This study examined cancer incidence (1986–2008) and mortality (1986–2011) among the Estonian Chernobyl cleanup workers in comparison with the Estonian male population. The cohort of 4810 men was followed through nationwide population, mortality and cancer registries. Cancer and death risks were measured by standardised incidence ratio (SIR) and standardised mortality ratio (SMR), respectively. Poisson regression was used to analyse the effects of year of arrival, duration of stay and time since return on cancer and death risks. The SIR for all cancers was 1.06 with 95% confidence interval 0.93–1.20 (232 cases). Elevated risks were found for cancers of the pharynx, the oesophagus and the joint category of alcohol-related sites. No clear evidence of an increased risk of thyroid cancer, leukaemia or radiation-related cancer sites combined was apparent. The SMR for all causes of death was 1.02 with 95% confidence interval 0.96–1.08 (1018 deaths). Excess mortality was observed for mouth and pharynx cancer, alcohol-related cancer sites together and suicide. Duration of stay rather than year of arrival was associated with increased mortality. Twenty-six years of follow-up of this cohort indicates no definite health effects attributable to radiation, but the elevated suicide risk has persisted.

Genetic variability, population size and reproduction potential in Ligularia sibirica (L.) populations in Estonia

Ligularia sibirica (L.) Cass. (Asteraceae) is a EU Habitats Directive Annex II plant species that has suffered a lot from human-caused major changes in quality and availability of habitats in Estonia. The aim of this study was to find out if the observed decline in population size is reflected in the amount of genetic variation and fertility in remnant populations of this species. AFLP technique was used for that purpose. Genetic diversity within populations was assessed as the percentage of polymorphic loci in a given population and average gene diversity over loci. The degree of genetic differentiation among populations and genetic differentiation between pairs of populations was estimated. The amount of viable seeds per flower stem was compared among populations and between years (2007 and 2008). Average genetic diversity over loci and proportion of polymorphic loci in L. sibirica populations were significantly correlated with population size, suggesting the action of genetic drift and/or inbreeding. No correlation was found between genetic and geographic distances. Natural barriers like forests may have been efficiently preventing seed migration even between geographically closer populations. Results of this study suggest that genetic erosion could be partially responsible for the lower fitness in smaller populations of this species.

Risk factors for sickness absence among Estonian employees

During the last decade, sickness absence rates in Estonia have reached the level of Nordic countries. This places Estonia in a group of countries with the highest absence rate in the European Union. Unlike Nordic countries, factors associated with sickness absence have not been studied in Estonia. To investigate which work-related, individual and health factors, other than current illness, influence sickness absence among Estonian paid employees. The study population consisted of 2941 employees who completed an Estonian Health Interview Survey conducted in 2006. Multiple logistic regression analysis was performed to explore associations between individual, health and work-related factors and recent sickness absence. Sickness absence was significantly associated with poor self-rated general health (OR = 1.82; 95% CI = 1.34-2.48), presence of chronic disease (OR = 1.66; 95% CI = 1.21-2.27), lower education (OR = 1.59; 95% CI = 1.20-2.12) and job dissatisfaction (OR = 1.74, 95% CI = 1.23-2.26) in the final multivariate model after adjustment for age and gender conclusions: Most sickness absence risk factors revealed by previous studies were only moderately associated with sickness absence in the Estonian working population. In contrast to Nordic countries, there was no gender difference or age gradient. Among workplace risk factors, job dissatisfaction was most strongly associated with sickness absence.

Normal Weight Estonian Prepubertal Boys Show a More Cardiovascular-Risk-Associated Adipose Tissue Distribution than Austrian Counterparts

Objective. Risk phenotypes for cardiovascular disease (CVD) differ markedly between countries, like the reported high difference in CVD mortality in Austria and Estonia. Hitherto, the goal of this study was to find out risk profiles in body fat distribution yet present in childhood, paving the way for later clinical end points. Methods. he subcutaneous adipose tissue (SAT) distribution patterns in 553 Austrian (A) and Estonian (E) clinically healthy normal weight boys aged 11.1 (±0.8) years were analysed. We applied the patented optical device Lipometer which determines the individual subcutaneous adipose tissue topography (SAT-Top). Results. Total body fat did not differ significantly between E and A boys. A discriminant analysis using all Lipometer data, BMI, and the total body fat (TBF) yielded 84.6% of the boys correctly classified in Estonians and Austrians by 9 body sites. A factor analysis identified the SAT distribution of E as critically similar to male adult patients with coronary heart disease (CHD). Conclusions. We show in normal weight Estonian boys a highly significant decreased fat accumulation on the lower body site compared to age matched Austrian males. This SAT-Top phenotype may play an important role for the increased cardiovascular risk seen in the Estonian population.