Cancer incidence among Chernobyl cleanup workers from Estonia: A 34-year follow-up.

From 1986 to 1991, 4831 men from Estonia were sent to clean up radioactively contaminated areas near Chernobyl (Chornobyl). Their cancer incidence during 1986 to 2019 was compared to that of the male population of Estonia. The cohort of cleanup workers was linked to national population and cancer registers based on unique personal identification numbers. Nineteen (0.4%) workers could not be traced. A total of 4812 men contributing 120 770 person-years of follow-up were eligible for the analyses. Standardized incidence ratios (SIR) and adjusted relative risks (ARR, expressed as ratios of SIRs) with 95% confidence intervals (CI) were calculated. A total of 687 incident cancer cases were registered in the cohort (SIR 1.11, 95% CI 1.03-1.19). Presumptive radiation-related cancers combined were in excess, but not when smoking- and alcohol-related cancers were excluded (SIR 0.92, 95% CI 0.71-1.18). For smoking-related cancers, the SIR was 1.24 (95% CI 1.13-1.36) and for alcohol-related cancer the SIR was 1.53 (95% CI 1.31-1.75). Less educated workers had a higher risk of all cancers (ARR = 1.21, 95% CI 1.02-1.44) and smoking-related cancers (ARR = 1.42, 95% CI 1.14-1.76). An elevated risk of alcohol-related cancers was evident 15 to 24 years (vs <15 years) after return from the Chernobyl area. This updated register-based follow-up of Chernobyl cleanup workers from Estonia revealed an excess of radiation-related cancer sites combined, but the excess was not apparent after excluding cancers associated with smoking and alcohol.

Suicide and other causes of death among Chernobyl cleanup workers from Estonia, 1986 - 2020: an update.

Mortality was studied in a cohort of 4831 men from Estonia who participated in the environmental cleanup of the radioactively contaminated areas around Chernobyl in 1986-1991. Their mortality in 1986-2020 was compared with the mortality in the Estonian male population. A total of 1503 deaths were registered among the 4812 traced men. The all-cause standardized mortality ratio (SMR) was 1.04 (95% CI 0.99-1.09). All-cancer mortality was elevated (SMR 1.16, 95% CI 1.03-1.28). Radiation-related cancers were in excess (SMR 1.20, 95% CI 1.03-1.36); however, the excesses could be attributed to tobacco and alcohol consumption. For smoking-related cancers, the SMR was 1.20 (95% CI 1.06-1.35) and for alcohol-related cancers the SMR was 1.56 (95% CI 1.26-1.86). Adjusted relative risks (ARR) of all-cause mortality were increased among workers who stayed in the Chernobyl area ≥ 92 days (ARR 1.20, 95% CI 1.08-1.34), were of non-Estonian ethnicity (ARR 1.33, 95% CI 1.19-1.47) or had lower (basic or less) education (ARR 1.63, 95% CI 1.45-1.83). Suicide mortality was increased (SMR 1.31, 95% CI 1.05-1.56), most notably among men with lower education (ARR 2.24, 95% CI 1.42-3.53). Our findings provide additional evidence that unhealthy behaviors such as alcohol and smoking play an important role in shaping cancer mortality patterns among Estonian Chernobyl cleanup workers. The excess number of suicides suggests long-term psychiatric and substance use problems tied to Chernobyl-related stressors, i.e., the psychosocial impact was greater than any direct carcinogenic effect of low-dose radiation.

Trends in teenage delivery and abortion rates in Estonia over more than two decades: a nationwide register-based study.

BACKGROUND: In the last 30 years, Estonia has undergone major socio-economic changes, including profound educational and healthcare reforms. The study aimed to analyse trends in teenage delivery and induced abortion rates among younger and older teens, including Estonians and non-Estonians, and to study trends in repeat teenage pregnancies in more detail. METHODS: The register-based study included data on 29 818 deliveries (1992-2019) and 25 865 (1996-2019) induced abortions among 15-19-year-old girls. Delivery and abortion rates per 1000 girls were calculated by age group, ethnicity and reproductive history. Poisson regression models were applied to estimate average annual percentage changes in delivery and abortion rates over the whole period and in two sub-periods with change points in the trend in 2007. RESULTS: The delivery rate decreased by 5.3% per year, from 49.9 in 1992 to 8.4 in 2019; the abortion rate decreased by 6.0% per year, from 42.4 in 1996 to 8.6 in 2019. A faster decline in delivery rates took place among Estonians than non-Estonians, but the opposite trend occurred in abortion rates. Delivery rates for first and repeat pregnancies decreased nearly at the same pace, while abortion rates for repeat pregnancies decreased faster than those for first pregnancies. CONCLUSIONS: A decreasing trend in teenage births is evident in parallel with society becoming wealthier. A remarkable decline in teenage abortions occurs when young people's rights to safe abortion, contraception, mandatory sexuality education and youth-friendly services are ensured. There always remains a small group of adolescents who repeatedly become pregnant.

The fall and rise of cancer registration in Estonia: The dangers of overzealous application of data protection.

BACKGROUND: The population-based Estonian Cancer Registry (ECR) has maintained a database of cancer cases since 1968. Between 2001 and 2007 the ECR was prohibited from linking cancer records to death certificates. In January 2008, the prohibition was lifted, and two years later the ECR was able to begin tracing back unmatched deaths. This paper estimates the effect of the linkage ban on reported cancer incidence and survival. METHODS: Incident cancers in 2001-2007 were extracted from the ECR database in May 2018 to allow for late registrations. Two datasets were created: one with all incident cases and another without death-certificate-initiated (DCI) cases. Using both datasets, age-standardised incidence rates (ASIR) and their ratios; age-standardised five-year relative survival ratios (ARSR) and excess mortality rate ratios were calculated. RESULTS: In 2001-2007, 46,535 incident cancers were registered in the ECR. Of them, 2299 (4.9 %) were DCI cases. The inclusion of DCI cases increased the ASIR for overall cancer by 6 % in men and 3 % in women. An increase ≥10 % in ASIR for lung, liver and pancreatic cancer was observed. The effect of accrued DCI cases to the ARSR was minor. Excess mortality in the dataset without DCI cases was 4 % underestimated in men and 3 % in women. CONCLUSION: Biases in cancer incidence and survival measures generated by the temporary record linkage ban were largely correctable by using trace-back procedures when this became possible. Nevertheless, this type of ban and the arguments put forward to justify it, harm disease registration and register-based research.

Sex disparities in premature adult mortality in Estonia 1995-2016: a national register-based study.

OBJECTIVES: To quantify sex disparities in cause-specific premature adult mortality in Estonia, to determine the causes of death with the largest differences, to provide insight into related behaviours and to offer some guidance to public health policy-makers based on the results of the study. DESIGN: A national register-based study. SETTING: Estonia. DATA: Individual records of deaths at ages 20-69 years in 1995-2016 from the Estonian causes of death register; data on tobacco smoking and alcohol consumption in the adult population in 1996-2016 from the biennial postal survey of health behaviour. MAIN OUTCOME MEASURES: Overall and cause-specific age-standardised mortality rates, average annual percentage changes in mortality, and cause-specific men-to-women mortality rate ratios were calculated. In addition, the age-standardised prevalence proportions of tobacco smoking and alcohol consumption and men-to-women prevalence rate ratios were determined. RESULTS: Overall premature adult mortality decreased considerably during 1995-2016, but no reduction was observed with respect to the large relative sex disparities. In circulatory disease mortality, the disparities widened significantly over time. Extremely high mortality rate ratios were observed for cancer of the upper aerodigestive tract and for lung cancer. There was a stable, more than fivefold male excess mortality from external causes. A fourfold male disadvantage was evident for alcohol poisoning, mental disorders due to alcohol and alcohol-related degeneration of the nervous system as a group. The prevalence of tobacco smoking and harmful alcohol consumption among men exceeded that among women by factors of two and six, respectively. CONCLUSIONS: Even though premature adult mortality has markedly decreased over time, there has been no success in diminishing the large sex differences in the mortality patterns, mostly associated with smoking and excessive alcohol consumption, both more prevalent among men. Estonia needs a comprehensive and consistent alcohol policy while maintaining and further developing antitobacco measures.

Singleton pregnancies after in vitro fertilization in Estonia: a register-based study of complications and adverse outcomes in relation to the maternal socio-demographic background.

BACKGROUND: An increased risk of adverse conditions related to in vitro fertilization (IVF) pregnancies has been repeatedly reported. Our study aimed to summarize outcome differences between pregnancies after IVF and after spontaneous conception (SC) in Estonia. METHODS: Data on all liveborn singletons to primiparas women aged 25-40 years during the period 2005-2014 were obtained from the Estonian Medical Birth Registry. There were 1778 and 33,555 newborns in the IVF and SC cohort, respectively. The relative risk of pregnancy-related complications and adverse pregnancy outcomes in the IVF cohort in comparison with the SC cohort was quantified by prevalence proportion ratios (RR) with 95% confidence intervals (CI) using modified Poisson regression models adjusted for maternal age, education, ethnicity, marital status and study period. RESULTS: The cohort of IVF singletons experienced a higher risk of preterm birth (RR 1.51; 95% CI 1.28-1.78), iatrogenic preterm birth (RR 1.62; 95% CI 1.32-1.98), very preterm birth (RR 1.49; 95% CI 1.00-2.23), low birthweight (RR 1.47; 95% CI 1.20-1.80), congenital anomalies (RR 1.51; 95% CI 1.08-2.11), and admission to a neonatal intensive care unit (RR 1.13; 95% CI 1.01-1.26). Somewhat elevated risk of spontaneous preterm birth did not reach statistical significance (RR 1.32; 95% CI 0.97-1.80). IVF mothers were at increased risk of placenta previa (RR 7.15; 95% CI 4.04-12.66), placental abruption (RR 2.12; 1.43-3.14) and cesarean section (RR 1.28; 95% CI 1.20-1.37). The risk of pre-eclampsia was borderline (RR 1.25; 95% CI 0.98-1.59). Adjustment for maternal age attenuated the associations between IVF and adverse outcomes. Maternal education, ethnicity and marital status had no effect on the magnitude of the risk estimates. CONCLUSIONS: The increased risk of pregnancy-related complications and adverse pregnancy outcomes was observed in the Estonian cohort of IVF singletons in comparison with the cohort of SC singletons. The relative risk estimates grew with maternal age but were not influenced by the maternal education, ethnicity and marital status. To monitor the efficacy and safety of the used assisted reproductive technology, a specialized country-wide register should be created in Estonia.

Factors associated with serum 25-hydroxyvitamin D concentrations in older people in Europe: the EUREYE study.

BACKGROUND/OBJECTIVES: We aimed to describe serum 25-hydroxyvitamin D (25OHD) concentrations in older Europeans and to investigate associations between 25OHD and lifestyle factors, including dietary intake and supplement use. SUBJECTS/METHODS: Men and women aged ≥ 65 years were recruited from seven centres across north to south Europe. Serum 25OHD2 and 25OHD3 concentrations were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 4495 samples and total 25OHD (25OHD2 + 25OHD3) was adjusted for season of blood collection. RESULTS: The mean (25th, 75th quartile) of seasonally adjusted 25OHD was 46 (34, 65) nmol/L, with the highest concentration of 25OHD in Bergen [61 (49, 79) nmol/L], and the lowest in Paris [36 (24, 57) nmol/L)]. Vitamin D deficiency (25-50 nmol/L) and vitamin D insufficiency (50-75 nmol/L) were found in 41 and 33% of the population, respectively. In multivariable analysis controlled for confounders, seasonally adjusted 25OHD concentrations were significantly (p < 0.05) lower in smokers and participants with self-reported diabetes and higher with increasing dietary vitamin D, and supplement use with fish liver oil, omega-3, and vitamin D. Additionally, in further analysis excluding Bergen, 25OHD was associated with higher intakes of oily fish and increasing UVB exposure. We observed low concentrations of 25OHD in older people in Europe. CONCLUSIONS: Our findings of the higher 25OHD concentrations in supplement users (omega-3 fish oil, fish liver oil, vitamin D) add to current recommendations to reduce vitamin D deficiency. We were unable to fully assess the role of dietary vitamin D as we lacked information on vitamin D-fortified foods.

Quality of IVF status registration in the Estonian Medical Birth Registry: a national record linkage study.

BACKGROUND: Information regarding in vitro fertilization (IVF) as a pregnancy risk factor (yes/ no) is stored in each birth record of the Estonian Medical Birth Registry (EMBR). This study aimed to assess the validity of registration of newborns' IVF status in the EMBR. METHODS: To identify the newborns conceived by IVF, the birth records in the EMBR were compared to individual records on the embryo transfer procedures in the Estonian Health Insurance Fund (EHIF) database as a reference. Maternal age was restricted to 40 years, the age limit for IVF treatment covered by the EHIF. The embryo transfer procedures, that dated up to eight weeks before pregnancy, were additionally checked in the infertility treatment clinics. The validity of IVF status was measured by sensitivity, specificity, positive and negative predictive values (PPV and NPV). Relative risk (RR) of unrecorded IVF status among IVF mothers by socio-demographic characteristics and birth plurality was estimated using modified Poisson regression models. RESULTS: There were 3198 newborns identified as conceived by IVF in the EMBR in 2005-2014. Eight of them were incorrectly entered as born after IVF. The record linkage with the EHIF database revealed 1014 newborns with unrecorded IVF status in the EMBR. A total of 4204 newborns were verified as conceived by IVF, 24.1% of them were not categorized as born after IVF. The sensitivity of the IVF status registration was poor (75.9%), specificity (100.0%), PPV (99.8%) and NPV (99.3%) were high. The misclassifications were significantly more common among mothers of younger age or non-Estonians or with singleton birth. CONCLUSION: Information based on mother's self-report or her antenatal chart does not accurately identify the newborn's IVF status. The lack of a specialized country-wide assisted reproductive technology register in Estonia requires routine record linkage of the EMBR, EHIF and the infertility treatment clinics' databases to obtain adequate information regarding IVF status in the EMBR. Electronic record linkages between databases would help considerably to improve the validity of data to be used in medical decision making, in research and for statistical purposes.

Novel quantitative pigmentation phenotyping enhances genetic association, epistasis, and prediction of human eye colour.

Success of genetic association and the prediction of phenotypic traits from DNA are known to depend on the accuracy of phenotype characterization, amongst other parameters. To overcome limitations in the characterization of human iris pigmentation, we introduce a fully automated approach that specifies the areal proportions proposed to represent differing pigmentation types, such as pheomelanin, eumelanin, and non-pigmented areas within the iris. We demonstrate the utility of this approach using high-resolution digital eye imagery and genotype data from 12 selected SNPs from over 3000 European samples of seven populations that are part of the EUREYE study. In comparison to previous quantification approaches, (1) we achieved an overall improvement in eye colour phenotyping, which provides a better separation of manually defined eye colour categories. (2) Single nucleotide polymorphisms (SNPs) known to be involved in human eye colour variation showed stronger associations with our approach. (3) We found new and confirmed previously noted SNP-SNP interactions. (4) We increased SNP-based prediction accuracy of quantitative eye colour. Our findings exemplify that precise quantification using the perceived biological basis of pigmentation leads to enhanced genetic association and prediction of eye colour. We expect our approach to deliver new pigmentation genes when applied to genome-wide association testing.

Associations between Serum Vitamin D and Genetic Variants in Vitamin D Pathways and Age-Related Macular Degeneration in the European Eye Study.

PURPOSE: To study associations between early and late age-related macular degeneration (AMD) and neovascular AMD (nvAMD) with serum 25-hydroxy vitamin D (25(OH)D) and genetic variants in vitamin D pathway genes. DESIGN: Population-based, cross-sectional study in a random sample aged 65 years or older from 7 European countries. PARTICIPANTS: Of 4753 participants, 4496 (2028 men and 2468 women), with a mean age of 73 years, provided a blood sample; 2137 had no signs of AMD, 2209 had early AMD, and 150 had late AMD, of whom 104 had nvAMD. METHODS: Participants were interviewed to determine smoking and alcohol use, sunlight exposure, and diet; underwent fundus photography. Fundus images were graded using the International Classification System for Age-Related Maculopathy. The 25(OH)D was measured by liquid chromatography-tandem mass spectrometry and categorized as deficient (<30 nmol/l), insufficient (30-50 nmol/l), or adequate (≥50 nmol/l). Genotyping was performed on a subsample of 1284 AMD cases and controls for 93 single nucleotide polymorphisms (SNPs) from 7 genes. Associations were investigated by linear or logistic regression adjusted for potential confounders. MAIN OUTCOME MEASURES: Adjusted odds ratio (OR) for 3 outcomes (early AMD, late AMD, nvAMD). RESULTS: No linear association was found with 25(OH)D and early or late AMD or nvAMD. There was no association between insufficient or deficient status with early or late AMD. Deficient status was associated with nvAMD (adjusted OR, 1.27; 95% confidence interval, 1.1-1.45; P < 0.0001). Significant (P < 0.05) associations with 25(OH)D were found for SNPs in genes GC, VDR, CYP2R1, and CYP27B1. Two SNPs (VDR) were associated with early AMD, 4 SNPs (RXRA) and 1 SNP (VDR) were associated with nvAMD, and 1 SNP (RXRA), 2 SNPs (VDR), and 1 SNP (CYP2R1) were associated with late AMD. After Bonferroni correction, no SNPs were associated with early AMD, late AMD, or nvAMD. CONCLUSIONS: Deficiency in 25(OH)D was associated with nvAMD, but the adjusted OR was small, and we cannot exclude residual confounding. The hypothesis of a causal association of vitamin D with AMD is not supported by clear evidence for an association of vitamin D SNPs with early AMD, late AMD, or nvAMD.

Association Between Myopia, Ultraviolet B Radiation Exposure, Serum Vitamin D Concentrations, and Genetic Polymorphisms in Vitamin D Metabolic Pathways in a Multicountry European Study.

IMPORTANCE: Myopia is becoming increasingly common globally and is associated with potentially sight-threatening complications. Spending time outdoors is protective, but the mechanism underlying this association is poorly understood. OBJECTIVE: To examine the association of myopia with ultraviolet B radiation (UVB; directly associated with time outdoors and sunlight exposure), serum vitamin D concentrations, and vitamin D pathway genetic variants, adjusting for years in education. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional, population-based random sample of participants 65 years and older was chosen from 6 study centers from the European Eye Study between November 6, 2000, to November 15, 2002. Of 4187 participants, 4166 attended an eye examination including refraction, gave a blood sample, and were interviewed by trained fieldworkers using a structured questionnaire. Myopia was defined as a mean spherical equivalent of -0.75 diopters or less. Exclusion criteria included aphakia, pseudophakia, late age-related macular degeneration, and vision impairment due to cataract, resulting in 371 participants with myopia and 2797 without. EXPOSURES: Exposure to UVB estimated by combining meteorological and questionnaire data at different ages, single-nucleotide polymorphisms in vitamin D metabolic pathway genes, serum vitamin D3 concentrations, and years of education. MAIN OUTCOMES AND MEASURES: Odds ratios (ORs) of UVB, serum vitamin D3 concentrations, vitamin D single-nucleotide polymorphisms, and myopia estimated from logistic regression. RESULT: Of the included 3168 participants, the mean (SD) age was 72.4 (5) years, and 1456 (46.0%) were male. An SD increase in UVB exposure at age 14 to 19 years (OR, 0.81; 95% CI, 0.71-0.92) and 20 to 39 years (OR, 0.7; 95% CI, 0.62-0.93) was associated with a reduced adjusted OR of myopia; those in the highest tertile of years of education had twice the OR of myopia (OR, 2.08; 95% CI, 1.41-3.06). No independent associations between myopia and serum vitamin D3 concentrations nor variants in genes associated with vitamin D metabolism were found. An unexpected finding was that the highest quintile of plasma lutein concentrations was associated with a reduced OR of myopia (OR, 0.57; 95% CI, 0.46-0.72). CONCLUSIONS AND RELEVANCE: Increased UVB exposure was associated with reduced myopia, particularly in adolescence and young adulthood. The association was not altered by adjusting for education. We found no convincing evidence for a direct role of vitamin D in myopia risk. The relationship between high plasma lutein concentrations and a lower risk of myopia requires replication.

Mediterranean Diet Score and Its Association with Age-Related Macular Degeneration: The European Eye Study.

PURPOSE: To examine associations between adherence to a Mediterranean diet and prevalence of age-related macular degeneration (AMD) in countries ranging from Southern to Northern Europe. DESIGN: Cross-sectional, population-based epidemiologic study. PARTICIPANTS: Of 5060 randomly sampled people aged 65 years or older from 7 study centers across Europe (Norway, Estonia, United Kingdom, France, Italy, Greece, and Spain), full dietary data were available in 4753. The mean age of participants was 73.2 years (standard deviation, 5.6), and 55% were women. METHODS: Participants underwent an eye examination and digital retinal color photography. The images were graded at a single center. Dietary intake during the previous 12 months was assessed by using a semiquantitative food-frequency questionnaire (FFQ). A previously published Mediterranean Diet Score (MDS) was used to classify participants according to their responses on the FFQ. Multivariable logistic regression was used to investigate the association of the MDS score and AMD, taking account of potential confounders and the multicenter study design. MAIN OUTCOME MEASURES: Images were graded according to the International Classification System for age-related maculopathy and stratified using the Rotterdam staging system into 5 exclusive stages (AMD 0-4) and a separate category of large drusen (≥125 µm). Age-related macular degeneration 4 included neovascular AMD (nvAMD) and geographic atrophy (GA). RESULTS: Increasing MDS was associated with reduced odds of nvAMD in unadjusted and confounder-adjusted analysis. Compared with the lowest MDS adherence (≤4 score), those in the highest category MDS adherence (>6 score) showed lower odds of nvAMD (odds ratio, 0.53; 0.27-1.04; P trend = 0.01). The association with MDS did not differ by Y204H risk allele (P = 0.89). For all early AMD (grade 1-3), there was no relationship with MDS (P trend = 0.9). There was a weak trend (P = 0.1) between MDS and large drusen; those in the highest category of MDS had 20% reduced odds compared with those in the lowest (P = 0.05). CONCLUSIONS: This study adds to the limited evidence of the protective effect of adherence to a Mediterranean dietary pattern in those with late AMD, although it does not support previous reports of a relationship with genetic susceptibility. Interventions to encourage the adoption of the Mediterranean diet should be developed, and methods by which such behavior change can be achieved and maintained investigated.

Recent changes in breast cancer incidence and mortality in Estonia: Transition to the west.

Background The aim of this study was to examine breast cancer (BC) incidence and mortality trends in Estonia during recent decades and to compare the pattern of these trends with other selected European countries and regions. We attempt to explain the findings in relation to changes in Estonian society and healthcare system. Methods BC incidence (1985-2012) and mortality (1985-2013) data for Estonia were obtained from the Estonian Cancer Registry and Statistics Estonia. Data for selected European countries were obtained from the EUREG database. Joinpoint regression was used to analyze age-standardized rates in Estonia by age. For international comparison of incidence and mortality rates, we used scatterplot with 95% confidence ellipses and the mortality to incidence ratio. Results The overall BC incidence continues to increase in Estonia, while mortality has been in decline since 2000. Both incidence and mortality trends varied considerably across age groups. Among women aged 60 years and older, BC incidence increased at a rate of nearly 3% per year. Significant decrease in mortality was seen only among women aged 50-59 years. Comparison of scatterplots between countries and regions revealed two clusters in Europe separated along the incidence axis. The correlation between incidence and mortality in Estonia changed its direction in the mid-1990s. Conclusion In recent years, the dynamics of BC burden in Estonia has transitioned towards the high incidence-low mortality type model, which is characteristic to Western, Northern and Southern Europe. Although overall BC incidence is much lower in Estonia than in more affluent European countries, mortality from BC is still relatively high, particularly among elderly women.

Contraceptive use among young women in Estonia: Association with contraceptive services.

OBJECTIVES: Our study aimed to explore the association between the use of effective contraceptive methods and access to different contraceptive services, as well as to describe accessibility-related obstacles when using contraceptive services and satisfaction with those services. METHODS: From a population-based cross-sectional study carried out in 2004 (response rate 53.8%), the data of 16- to 24-year-old women requiring contraception (N = 868) were analysed. Factors associated with the use of effective contraceptive methods and, specifically, hormonal methods, were explored using multiple logistic regression analysis. RESULTS: Effective contraception was used by 75.1% of the respondents. The use of effective contraceptive methods was associated with school-based sexuality education (adjusted prevalence odds ratio 2.69; 95% confidence interval 1.32 - 5.50), visiting a youth-friendly clinic (YFC) (1.82; 1.03-3.23) or a private gynaecologist (2.08; 1.11-3.92). The use of hormonal methods was additionally associated with being a native Estonian speaker and visiting a family doctor. More than half of the respondents reported some obstacle in accessing contraceptive services. The highest satisfaction ratings were given to YFCs. CONCLUSIONS: Steps to promote the use of services that are youth-friendly and associated with better uptake of effective contraceptive methods are needed among all 16- to 24-year-old women.

Chernobyl cleanup workers from Estonia: cohort description and related epidemiological research.

The Estonian study of Chernobyl cleanup workers was one of the first investigations to evaluate the possible health consequences of working in the Chernobyl area (the 30 km exclusion zone and/or adjacent territories) after the 1986 reactor accident. The cohort consists of 4831 men who were dispatched in 1986-1991 for tasks involving decontamination, construction of buildings, transport, radiation measurement, guard duty or other activities. By 31 December 2012, the follow-up of the cohort yielded 102 158 person-years of observation. Exposure and health data were collected by postal questionnaires, biodosimetry evaluations, thyroid screenings, and record-linkages with cancer, causes of death and health insurance reimbursement registers and databases. These data cover socio-demographic factors, employment history, aspects of health behaviour, medical history, work and living conditions in the Chernobyl area, biomarkers of exposure, cancer and non-cancer disease occurrence and causes of death. Cancer incidence data were obtained for 1986-2008, mortality data for 1986-2011 and non-cancer morbidity data for 2004-2012. Although the cohort is relatively small, it has been extensively examined and benefited from comprehensive nationwide population and health registers. The major finding was an increased risk of suicide. Thyroid examinations did not reveal an association with thyroid nodular disease and radiation dose, but did indicate the importance of accounting for screening when making comparisons with unscreened populations. No risk of leukaemia was observed and risks higher than 2.5-fold could be excluded with 95% confidence. Biodosimetry included GPA analyses and chromosomal translocation analyses and indicated that the Estonian cleanup workers experienced a relatively low mean exposure of the order of 0.1 Gy. One value of the Estonian study is in the methodologic processes brought to bear in addressing possible health effects from the Chernobyl accident. Twenty-five years of research are summarised and opportunities for the future listed.

Non-cancer morbidity among Estonian Chernobyl cleanup workers: a register-based cohort study.

OBJECTIVE: To examine non-cancer morbidity in the Estonian Chernobyl cleanup workers cohort compared with the population sample with special attention to radiation-related diseases and mental health disorders. DESIGN: Register-based cohort study. SETTING: Estonia. PARTICIPANTS: An exposed cohort of 3680 men (cleanup workers) and an unexposed cohort of 7631 men (population sample) were followed from 2004 to 2012 through the Population Registry and Health Insurance Fund database. METHODS: Morbidity in the exposed cohort compared with the unexposed controls was estimated in terms of rate ratio (RR) with 95% CIs using Poisson regression models. RESULTS: Elevated morbidity in the exposed cohort was found for diseases of the nervous system, digestive system, musculoskeletal system, ischaemic heart disease and for external causes. The most salient excess risk was observed for thyroid diseases (RR=1.69; 95% CI 1.38 to 2.07), intentional self-harm (RR=1.47; 95% CI 1.04 to 2.09) and selected alcohol-related diagnoses (RR=1.25; 95% CI 1.12 to 1.39). No increase in morbidity for stress reactions, depression, headaches or sleep disorders was detected. CONCLUSIONS: No obvious excess morbidity consistent with biological effects of radiation was seen in the exposed cohort, with the possible exception of benign thyroid diseases. Increased alcohol-induced morbidity may reflect alcohol abuse, and could underlie some of the higher morbidity rates. Mental disorders in the exposed cohort were probably under-reported. The future challenge will be to study mental and physical comorbidities in the Chernobyl cleanup workers cohort.

Population health and status of epidemiology: WHO European Region I.

BACKGROUND: This article of the International Epidemiological Association commissioned paper series stocktakes the population health and status of epidemiology in 21 of the 53 countries of the WHO European Region. By United Nations geographical classification, these countries belong to Eastern Europe, Western Asia and South-Central Asia. METHODS: Published data were used to describe population health indicators and risk factors. Epidemiological training and research was assessed based on author knowledge, information searches and E-mail survey of experts. Bibliometric analyses determined epidemiological publication outputs. RESULTS: Between-country differences in life expectancy, amount and profile of disease burden and prevalence of risk factors are marked. Epidemiological training is affected by ongoing structural reforms of educational systems. Training is advanced in Israel and several Eastern European countries. Epidemiological research is mainly university-based in most countries, but predominantly conducted by governmental research institutes in several countries of the former Soviet Union. Funding is generally external and limited, partially due to competition from and prioritization of biomedical research. Multiple relevant professional societies exist, especially in Poland, the Czech Republic and Hungary. Few of the region's 39 epidemiological academic journals have international currency. The number of epidemiological publications per population is highest for Israel and lowest for South-Central Asian countries. CONCLUSIONS: Epidemiological capacity will continue to be heterogeneous across the region and depend more on countries' individual historical, social, political and economic conditions and contexts than their epidemiologists' successive efforts. National and international research funding, and within- and between-country collaborations should be enhanced, especially for South-Central Asian countries.

Site-specific cancer risk in the Baltic cohort of Chernobyl cleanup workers, 1986-2007.

OBJECTIVE: To assess site-specific cancer risk in the Baltic cohort of Chernobyl cleanup workers, 1986-2007. METHODS: The Baltic cohort includes 17,040 men from Estonia, Latvia and Lithuania who participated in the environmental cleanup after the accident at the Chernobyl Nuclear Power Station in 1986-1991 and who were followed up for cancer incidence until the end of 2007. Cancer cases diagnosed in the cohort and in the male population of each country were identified from the respective national cancer registers. The proportional incidence ratio (PIR) with 95% confidence interval (CI) was used to estimate the site-specific cancer risk in the cohort. For comparison and as it was possible, the site-specific standardised incidence ratio (SIR) was calculated for the Estonian sub-cohort, which was not feasible for the other countries. RESULTS: Overall, 756 cancer cases were reported during 1986-2007. A higher proportion of thyroid cancers in relation to the male population was found (PIR=2.76; 95%CI 1.63-4.36), especially among those who started their mission shortly after the accident, in April-May 1986 (PIR=6.38; 95%CI 2.34-13.89). Also, an excess of oesophageal cancers was noted (PIR=1.52; 95% CI 1.06-2.11). No increased PIRs for leukaemia or radiation-related cancer sites combined were observed. PIRs and SIRs for the Estonian sub-cohort demonstrated the same site-specific cancer risk pattern. CONCLUSION: Consistent evidence of an increase in radiation-related cancers in the Baltic cohort was not observed with the possible exception of thyroid cancer, where conclusions are hampered by known medical examination including thyroid screening among cleanup workers.

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.