Unique Personal Identification Number Research Articles

Weight status at age 18 influences marriage prospects. A population-based study of Swedish men

BackgroundIn a longitudinal population-based study of the relationship between body mass index (BMI) in early adulthood and marital status at 40 years of age, obese men were half as likely to be married compared with men of normal weight. Significant associations between obesity and marital status among men in a longitudinal setting are novel findings.MethodsThe study cohort comprised Swedish men born from 1951 to 1961. Height and weight at age 18 was gathered from the Military Service Conscription Register and information on marital status at 40 years of age was obtained from population registers by record-linkage using the unique personal identification number. The odds ratio (OR) for being married was calculated by polytomous logistic regression analysis adjusting for birth year, intellectual performance, education, country of birth, residential area, socioeconomic position in childhood and adulthood, parental education and muscle strength.ResultsOur study included 486 599 Swedish men. Young men who were obese (BMI≥30.0) at 18 years of age had an OR of 0.49 (95% CI: 0.46–0.52) for being married at 40 years of age compared to normal weight men (BMI: 18.5–24.9). Underweight men (BMI≤18.5) had an OR of 0.84 (0.82–0.86) and overweight men (BMI: 25.0–29.9) had an OR of 0.83 (0.80–0.85) for being married at 40 years of age.ConclusionUnderweight, overweight and obese men were less likely to be married than their normal weight counterparts. Obese men had the lowest likelihood of being married. Stigmatization and discrimination may partly explain these findings, but further research is needed before firm conclusions can be drawn.

Extra- and intramedullary implants for the treatment of pertrochanteric fractures – Results from a Finnish National Database Study of 14,915 patients

We analysed registry-based data on 14,915 patients treated for pertrochanteric fracture obtained from the Finnish Health Care Register during the years 1999–2009. Data on the comorbidities, residential status and deaths of the cohort were extracted from several Finnish registries using patients’ unique personal identification numbers. The use of intramedullary implants increased substantially during the study period. One-year mortality was slightly higher in the patients treated with intramedullary implant (26.6% vs. 24.9%; P=0.011). In the first year after the fracture, there were more new operations on hip and thigh in patients treated with an intramedullary implant (11.1% vs. 8.9%; P<0.0001). Similarly, there were more new subtrochanteric and diaphyseal fractures of the femur in patients treated with intramedullary implants (3.2% vs. 1.05%; P<0.0001). Our findings suggest that more expensive intramedullary implants do not lead to better clinical outcomes than extramedullary implants for the treatment of pertrochanteric fractures.

Incidence of progressive multifocal leukoencephalopathy in patients with rheumatoid arthritis: a national population-based study

BackgroundCases of progressive multifocal leukoencephalopathy (PML), a rare but serious disease, have been reported in patients with rheumatoid arthritis (RA) in association with biological therapy, but little is known about...

Mortality in cancer patients with a history of cutaneous squamous cell carcinoma - a nationwide population-based cohort study

BackgroundCutaneous squamous cell carcinoma (SCC) is associated with underlying immunosuppression, so it may be a prognostic marker in patients with subsequent cancer. We therefore conducted a nationwide population-based Danish cohort study to evaluate whether a history of cutaneuos SCC has prognostic impact in patients with one of the following index cancers: non-Hodgkin's lymphoma (NHL), or cancer of the lung, colon, rectum, breast, or prostate.MethodsWe used Danish medical databases, which cover the entire Danish population of 5.6 million inhabitants and linked them using the unique personal identification number assigned to all Danish residents. From 1982 through 2003, we identified 745 index cancer patients with and 79,143 without previous cutaneous SCC. Using Cox proportional hazards regression, we calculated adjusted mortality rate ratios (MRRs) with 95% confidence intervals (CIs).ResultsOverall, previous SCC was associated with an increased mortality of cancer (MRR 1.13, 95% CI: 1.04-1.23). When examining index cancers separately, increased MRRs were found for cancer of the lung (MRR 1.23, 95% CI: 1.05-1.43), colon (MRR 1.13, 95% CI: 0.92-1.40), rectum (MRR 1.29, 95% CI: 1.00-1.67), breast (MRR 1.09, 95% CI: 0.82-1.43), and NHL (MRR 1.09, 95% CI: 0.81-1.47), but not for prostate cancer (MRR 0.99, 95% CI: 0.83-1.18).ConclusionsOur results suggest that previous cutaneous SCC is associated with poor prognosis of some cancers. This finding stresses the importance of adherence to the existing recommendations of screening, diagnosis, and treatment of cancer in patients with a history of SCC.

A NESTED CASE-CONTROL STUDY OF INTRAUTERINE EXPOSURE TO PERSISTENT ORGANOCHLORINE POLLUTANTS IN RELATION TO RISK OF HYPOSPADIA

Background and aims: In western countries the prevalence of hypospadias varies from two to eight cases per 1,000 live births. Knowledge about risk factors for hypospadias is still scarce. However, environmental exposures to so called endocrine disrupting chemicals (EDCs) have been suggested as a risk factor. An important group of EDCs is persistent organochlorine pollutants (POPs). Due to the unique personal identification number present in the biobank databases and the national health registries in Sweden we have the possibility to investigate the association between POPs and hypospadias in relatively large studies. Methods: The Malmö Microbiology Biobank (MMB) contains about 200 000 deep-frozen serum samples, stored after population-based serological screening for virus infections and rubella immunity during pregnancy week 14. Linkages between the Medical Birth Register, the Malformation Register and the In-patient Register resulted in 390 boys with hypospadia. For 237 (61 %) of them, sufficient amount of serum samples were found in the biobank. For each case a control boy was randomly selected from the MMB. 2,2’,4,4’,5,5’-hexachlorobiphenyl (PCB-153), the major DDT metabolite 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p´-DDE) and hexachlorbenzene (HCB) were used as biomarkers of POP exposure. Results: A 65 percent statistically significantly increased risk in the highest maternal exposure quartile of HCB as compared to the three lowest HCB exposure categories was observed. The pattern was, although not statistically significant, similar for maternal exposure for p,p´-DDE. Conclusion: The present study indicates that in utero exposure to HCB and perhaps exposure to p,p´-DDE is a risk factor for hypospadia. The fact that HCB and p,p´-DDE may affect the androgen-signalling pathway should reinforce the concept that ECDs, though present at low doses, may affect human health negatively.

Fatal occupational injuries are underreported in Norway

ObjectivesThe Norwegian Labour Inspection Authority records fatal occupational injuries in all sectors (except offshore, aviation, shipping and fishing). For 2000–03 the Labour Inspection Authority recorded 171 fatal occupational injuries where...

P2-241 Evaluation of the national cervical screening programme in Chile

IntroductionThe Chilean Cervical Screening Programme (CCSP) was implemented nationally in 1994, but its performance and effectiveness in reducing mortality from cervical cancer (CC) have not been assessed at an individual...

The Danish Civil Registration System

The Danish Civil Registration System (CRS) was established in 1968, and all persons alive and living in Denmark were registered for administrative use. CRS includes individual information on the unique personal identification number, name, gender, date of birth, place of birth, citizenship, identity of parents and continuously updated information on vital status, place of residence and spouses. Since 1968, CRS has recorded current and historical information on all persons living in Denmark. Among persons born in Denmark in 1960 or later it contains complete information on maternal identity. For women born in Denmark in April 1935 or later it contains complete information on all their children. CRS contains complete information on immigrations and emigrations from 1969 onwards, permanent residence in a Danish municipality from 1971 onwards, and full address in Denmark from 1977 onwards. CRS in connection with other registers and biobanks will continue to provide the basis for significant knowledge relevant to the aetiological understanding and possible prevention of human diseases.

The Copenhagen School Health Records Register

The Copenhagen School Health Records Register is an electronic register of health examination information on 372,636 children who attended school in Copenhagen, Denmark from 1936 to 2005. The register contains serial measurements of height and weight as well as birth weight from 1942 onwards. Through unique personal identification numbers, linkages are possible to national registers and population studies. Measurements were recorded in the health records with precision. Virtually every schoolchild is included in the register. The unique qualities of the size, population-based nature and linkage possibilities of the cohort make it an invaluable resource for research.

Danish population-based registers for public health and health-related welfare research: Introduction to the supplement

Denmark and other Nordic countries have exceptional opportunities to perform register-based research, because of the unique personal identification number available to all persons with permanent residence [1]. This number makes it possible to link information at the individual level from several registers for investigation of various research questions. The unique personal identification number was introduced in Denmark in 1968, which enables follow-up of individuals for decades. This supplement of the Scandinavian Journal of Public Health presents public health and health-related registers and health-related welfare research based on Danish nationwide registers. The topics range from presentations of important registers, to introduction to the Danish legal foundations for register-based research, to short reviews of selected applications of registers for public health research. Linkage of the Danish registers is based on three base registers including identification numbers for persons, businesses, and real estates (Figure 1). All three base registers have linking keys to related registers and also to the other base registers. The linking keys are: the personal identification number (CPR-number) [1], the business identification number (SE/CVR-number) [2], and the building and housing identification number (BBR-number) [3]. The Civil Registration System contains the CPRnumber and includes references to parents and spouses, making it possible to establish the family unit. The Business Register contains the SE/CVRnumber of all businesses. The Building and Housing Register (BBR) contains the BBR-number, which identifies all unique housing unities. By the base registers it is possible to link persons, businesses and housing units. The aim of the supplement is to present a wide range of Danish registers and register-based research. We invited Danish key researchers performing register-based research to contribute to this supplement. Thus, this publication also highlights that registerbased research in Denmark is widely distributed at various research institutions and that registers are fundamental data sources in health and healthrelated welfare research. Twenty two institutes and departments at four Danish universities and 21 Danish administrative and research institutions contributed to the papers in this supplement. The supplement has three sections. The first section gives an overview of Danish registers, briefly introduces how to get access to data at Statistics Denmark and the legal foundation for register-based research. The section also presents an online database, which gives further information and an overview of the content of various Danish registers. This database also includes a search engine to help researchers to get more details on register contents. The second section includes presentations of important Danish registers on health and social factors. All papers have the same format, including four sections – in the Introduction section the background and rationale for establishing the register, the current purpose and historical pioneers are presented. In the Content section information on central variables in the register is provided and changes in variables and content, in reporting to the

Introduction to Danish (nationwide) registers on health and social issues: Structure, access, legislation, and archiving

Danish registers contain information on many important health and social issues. Because all Danish citizens have a unique personal identification number, linkage at the individual level between these nationwide registers and other data sources is possible and feasible. In this paper we briefly introduce selected Danish registers and the data structure and requirements forgetting access to data at Statistics Denmark, which is the main provider of register data. We introduce the Danish Data Archive and briefly present the Act on Processing of Personal Data, which is the legal foundation for analyses of register-based data in Denmark.

Register-based studies of mental disorders

Denmark has been pioneering international psychiatric register research for decades. In this article we review central publications, by Danish and international authors, based on data from the Danish Psychiatric Central Research Register and other related registers. Our aim was to describe the history, development and achievements of psychiatric research, based on the Danish national registers. The studies considered in this review can be categorized as follows: i) health service research, mainly studies on prevalence and incidence, ii) studies on the outcome of mental disorders, iii) studies on the aetiology of mental disorders. Studies based on Danish registers have provided significant contributions to international psychiatric research. The major advantage of the registers is that they cover the entire population, which makes the conduction of nationwide population-based studies possible. Furthermore, all information in the registers is connected to each citizen's unique personal identification number, which enables linkage between various registers and biobanks. Such linkage studies have provided important knowledge on the aetiology of mental disorders. Despite inherent limitations about internal and external validity, the Danish national registers have been extremely valuable to international psychiatric research and will continue to play an important role in years to come.

Database on Danish population-based registers for public health and welfare research

Population-based studies with information from registers can take place in Denmark due to linkage between registers at the individual level by means of a unique personal identification number (CPR-number), which all persons with residence in Denmark have. Registers with information on health can be linked to other population registers containing information on, for example, transfer payments, education, housing, income, and socioeconomic position. This article introduces a database and search engine, which is available for public health and welfare researchers as an aid to seek information on the content of important Danish registers.

The Supplementary Pension Fund Register

Information on individual long-term work history is often required in occupational studies of diseases. The Supplementary Pension Fund Register has kept individual information on all employments, including start and end, on a company level backdating to 1964 for all wage earners in Denmark. Based on the computerised information, which also includes the unique personal identification number, it is possible to link information on employment history to information on individuals in nationwide registers of diseases. Membership is compulsory and controlled by the Danish authorities, therefore information is considered to be accurate and complete. This register is unique and of high value in occupational epidemiology.

Register-based studies of cardiovascular disease

The use of the unique personal identification number in the Nordic database systems enables the researchers to link the registers at the individual level. The registers can be used for both defining specific patient populations and to identify later events during follow-up. This review gives three examples within cardiovascular epidemiology to illustrate the use of the national administrative registers available to all researchers upon request. The hospitalisation rate of acute myocardial infarction (AMI) was expected to be increased and case-fatality rate to decrease when the diagnostic criteria were changed in 2000. Linkage of national registers found a relative increase in hospitalisation rate of 14% while the case-fatality rate was unaffected. The pharmacological treatment of AMI patients was evaluated by linkage of administrative data. The use of evidence-based treatment increased significantly over time and adherence to treatment was high. Finally, use of specific nonsteroidal antiinflammatory drugs by healthy subjects was associated with a dose-dependent increase in cardiovascular risk. The nationwide registers have proven very useful in monitoring the hospitalisation rate and treatment of cardiovascular disease. The risk of unmeasured factors affecting the results calls for cautious interpretation of the results.

Occupation and cancer risk by use of Danish registers

Based on evidence from animal experiments and case reports, certain occupational exposures may contribute to yet undetected cancer risk in humans. Since traditional epidemiological studies are time consuming, the use of existing information from registers may facilitate the research process. Due to the existence of a unique personal identification number (CPR-number), a national cancer register operating since 1943, a nationwide pension fund scheme with compulsory membership for all employees covering long-term individual employment history, and sometimes with addition of information from external sources, e.g. interviews or job exposure matrices, it is possible to conduct large nationwide studies of occupational exposures and cancer risk in Denmark. In this review we give three examples of cancer studies of widespread occupational exposures: formaldehyde, night shift work, and bitumen. Results from register-based studies have contributed to the now-existing evidence on occupational exposures and risk of cancer.

Ecology of medical care in a publicly funded health care system: A registry study in Sweden

Objective. To explore the influence of sociodemographic factors on access to appointments with physicians in primary, secondary, and tertiary health care in a publicly funded health care system. Design. A population-based registry study. Setting. Different health care settings in Västernorrland county, Sweden. Subjects. All residents in the county at the end of 2006. Main outcome measures. The number of people per 1000 residents who had at least one appointment with a physician in an average month in different health care settings. Results. A total of 87 people had appointments with a physician in primary health care, 44 in outpatient clinics at a regional hospital, 20 in an emergency department, 14 in home care, and two in a university hospital outpatient clinic. Twelve were hospitalized at a regional hospital and <1 at the university hospital. Being young or elderly, female, divorced, widowed, and having a contractor as usual source of care were all independently associated with higher odds of receiving primary care. Conclusions. The physician's office in primary care is the setting that has the potential to affect the largest number of people. The extent of the use of health care was independently influenced by all sociodemographic characteristics studied, which highlights the importance of individual factors in future resource allocation. Regarding availability the ecology model provides superior information as compared with the absolute number of physicians' appointments. The prerequisites in Sweden of high-quality registries and unique personal identification numbers encourage future research on the ecology model to optimize accessibility of health care.

Nationwide register‐based surveillance system on drugs and pregnancy in Finland 1996–2006

The aim of this population-based nationwide drugs and pregnancy surveillance system was to get basic information on the use of prescribed drugs during pregnancy and to achieve more detailed information on drug exposure-outcome associations with data obtained from the Finnish national health registers. The data are based on information on all pregnancies ending in births (n = 632,629) or termination of pregnancy (TOP) (n = 117,255) in Finland between 1996 and 2006. The data containing information on maternal background factors, chronic diseases and drug purchases during pregnancy, born children, induced abortions, perinatal health and major congenital malformations were obtained from the Finnish national health registers. Information from the different registers was merged through record linkages based on unique personal identification numbers. Statistical analyses were conducted between the exposed and unexposed for individual drugs or Anatomical Therapeutic Chemical (ATC) classification drug groups in multivariate logistic regression including potential confounding factors. Nearly half of parturients and almost every third woman with TOP purchased drugs at least once 1 month prior to pregnancy and/or during pregnancy. The most frequent chronic diseases during pregnancy were asthma, hypothyroidism, epilepsy, rheumatoid arthritis and diabetes. Previously known causal connections between maternal chronic diseases and/or medication and perinatal health risks were already seen in the ATC-group-level analysis. Comprehensive and detailed information for pharmacoepidemiological research on the effects of drug use during pregnancy in a cohort setting is possible with long-term and cumulative data collection.

Effectiveness of an Adjuvanted Monovalent Vaccine Against the 2009 Pandemic Strain of Influenza A(H1N1)v in Stockholm County, Sweden

Vaccination against the pandemic influenza A(H1N1)v was performed in many countries during 2009, but population-based data on vaccine effectiveness are lacking. We conducted a prospective cohort study involving all inhabitants in Stockholm County (n = 2,019,183) who were offered a monovalent AS03-adjuvanted influenza A(H1N1)v vaccine (Pandemrix, GSK), between 12 October and 31 December 2009. Overall vaccine coverage was 52%. A Web-based register with data on all vaccinated was linked by unique personal identification number to mandatory reports of influenza A(H1N1)v diagnoses. Vaccine failure was defined as a diagnosis or admission to hospital because of influenza >14 days after vaccination. Risk factors associated with vaccine failure were investigated by conditional stepwise logistic regression in a nested case-control study. The weekly incidence rate ratio for being diagnosed with influenza among vaccinated versus nonvaccinated persons was calculated. Vaccine failure was seen in 25 patients, 11 children and 14 adults, of 2594 patients diagnosed with influenza A(H1N1)v. Compared with age-matched controls, patients with vaccine failure were more often immunocompromised (Hazard Ratio, 4.89; 95% confidence interval [CI], 2.19-10.89). During the 4 weeks with maximum influenza activity, the relative risk per week for an influenza A(H1N1)v diagnosis in the vaccinated population was .06 (95% CI .008-.41), .13 (95% CI .06-.27), .05 (95% CI .02-.12), and .07 (95% CI .03-.15), respectively, corresponding to a weekly vaccine effectiveness of 87-95%. The monovalent AS03-adjuvanted influenza vaccine was highly effective in prevention of the pandemic influenza in Stockholm County. A single dose seemed to be sufficient in most, both children and adults, except in immunocompromised hosts.

Abstract 1893: Cancer risk in families with childhood adrenocortical tumors, choroid plexus tumors and rhabdomyosarcoma

Abstract Background: Childhood adrenocortical tumors (ACT), choroid plexus tumors (CPT) and rhabdomyosarcoma (RMS) belong to the core tumors in Li-Fraumeni syndrome. We aimed to study the cancer risk for relatives to children with these diagnoses and if tumor spectra is associated with Li-Fraumeni syndrome (LFS). Material and Methods: Children (≤18 years) diagnosed with either ACT (n=3) or CPT (n=7) and children (≤ 5 years) diagnosed with RMS (n=29) between 1958-2008 were identified by the population based Cancer Registry of South Sweden. First to third degree relatives were identified by the Swedish Population Registration. Information about vital status and tumor diagnoses, diagnosed between 1958-2008, were collected by linking the unique personal identification number to the Total Populace Register and the Swedish Cancer Registry respectively. Person year at risk were stratified by age, sex and calendar year and multiplied by year-, age-, and sex specific rates of cancer types of interest from Swedish National data to yield expected rates of each type of cancer. Standardized morbidity ratios (SMR), was computed with 95 % confidence interval (CI). A total number of 1376 relatives (44 699 person years) were included in the analyses. Mutational screening for TP53 mutation was performed for probands still alive; ACT n=3, CPT n=5 and RMS n=18. Results: The risk and tumor spectra among relatives differed between the three histological subtypes. A significant increased risk was seen for relatives to patients with CPT and RMS (SMR=1.84, 95 % CI: 1.34-2.47, p&amp;lt; 0.001; SMR=1.52, 95 % CI: 1.29-1.77, p&amp;lt;0.001, respectively) while a non-significant increased risk was found for relatives to children with ACT (SMR=1.62, 95 % CI: 0.77-2.97, p=0.10). Overall, women seemed to be more affected then men. A significant increased risk for early (&amp;lt;50 years) breast cancer was found for relatives to children with CPT (SMR=3.97, 95 % CI: 0.82-11.61, p=0.04). A significant increased risk for kidney-, pancreas- and lung tumors was found among female relatives to CPT-patients. Among relatives to children with RMS a significantly increased risk for melanoma was found among women both early (&amp;lt;50 years) and before 80 years of age (SMR=6.58, 95% CI: 1.79-16.85, p=0.004 and SMR=2.68, 95 % CI: 0.87-6.25, p=0.04, respectively). Also a significantly increased risk for ovarian-, prostate- and squamous cell cancer of the skin was found among relatives to RMS patients. A non-significant increased risk for sarcoma was also seen for RMS relatives. Mutational TP53 screening revealed a germline mutation only in two out of 26 probands; in a child with ACT and RMS, respectively. Conclusion: Different patterns of tumors were seen for the histological subtypes of the proband. The observed tumor spectra is not a typical one for LFS which is in line with the TP53 screening results. This suggests that so far unrecognized family associations may account for the main findings. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1893. doi:10.1158/1538-7445.AM2011-1893