Kaare Christensen

University of Southern Denmark, Odense, South Denmark, Denmark

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Publications (500)2451.87 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A low birth weight has been extensively related to poor adult health outcomes. Birth weight can be seen as a proxy for environmental conditions during prenatal development. Identical twin pairs discordant for birth weight provide an extraordinary model for investigating the association between birth weight and adult life health while controlling for not only genetics but also postnatal rearing environment. We performed an epigenome-wide profiling on blood samples from 150 pairs of adult monozygotic twins discordant for birth weight to look for molecular evidence of epigenetic signatures in association with birth weight discordance. Our association analysis revealed no CpG site with genome-wide statistical significance (FDR < 0.05) for either qualitative (larger or smaller) or quantitative discordance in birth weight. Even with selected samples of extremely birth weight discordant twin pairs, no significant site was found except for 3 CpGs that displayed age-dependent intra-pair differential methylation with FDRs 0.014 (cg26856578, p = 3.42e-08), 0.0256 (cg15122603, p = 1.25e-07) and 0.0258 (cg16636641, p = 2.05e-07). Among the three sites, intra-pair differential methylation increased with age for cg26856578 but decreased with age for cg15122603 and cg16636641. There was no genome-wide statistical significance for sex-dependent effects on intra-pair differential methylation in either the whole samples or the extremely discordant twins. Genome-wide DNA methylation profiling did not reveal epigenetic signatures of birth weight discordance although some sites displayed age-dependent intra-pair differential methylation in the extremely discordant twin pairs.
    BMC genomics. 12/2014; 15(1):1062.
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    ABSTRACT: FOXO3A variation has repeatedly been reported to associate with human longevity, yet only few studies have investigated whether FOXO3A variation also associates with aging-related traits. Here, we investigate the association of 15 FOXO3A tagging single nucleotide polymorphisms (SNPs) in 1088 oldest-old Danes (age 92-93) with 4 phenotypes known to predict their survival: cognitive function, hand grip strength, activity of daily living (ADL), and self-rated health. Based on previous studies in humans and foxo animal models, we also explore self-reported diabetes, cancer, cardiovascular disease, osteoporosis, and bone (femur/spine/hip/wrist) fracture. Gene-based testing revealed significant associations of FOXO3A variation with ADL (P = 0.044) and bone fracture (P = 0.006). The single-SNP statistics behind the gene-based analysis indicated increased ADL (decreased disability) and reduced bone fracture risk for carriers of the minor alleles of 8 and 10 SNPs, respectively. These positive directions of effects are in agreement with the positive effects on longevity previously reported for these SNPs. However, when correcting for the test of 9 phenotypes by Bonferroni correction, bone fracture showed borderline significance (P = 0.054), while ADL did not (P = 0.396). Although the single-SNP associations did not formally replicate in another study population of oldest-old Danes (n = 1279, age 94-100), the estimates were of similar direction of effect as observed in the Discovery sample. A pooled analysis of both study populations displayed similar or decreased sized P-values for most associations, hereby supporting the initial findings. Nevertheless, confirmation in additional study populations is needed. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.
    Aging cell 12/2014; · 7.55 Impact Factor
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    ABSTRACT: To describe temporal trends in the incidence rate of surgically treated middle ear cholesteatoma in Danish children from 1977 to 2010. Data on surgically treated middle ear cholesteatoma was drawn from the Danish National Patient Register. A change in incidence rate over time was examined using Poisson regression analysis, while the cumulative incidence proportion was estimated using life-tables. A total of 5850 cases of surgically treated middle ear cholesteatoma distributed among 3874 children aged 0-15 years were identified. From 1977 to 2002 the age-standardized incidence rates for first-time surgically treated middle ear cholesteatoma increased from 8 to 15 per 100,000 person-years with an estimated annual increase of 1.8% (95% confidence interval (CI) 1.3-2.2%). From 2002 to 2010 the rates decreased from 15 to 10 per 100,000 person-years with an annual decrease of 5.4% (95% CI 3.2-7.5%). Age-specific incidence rates were at maximum around the age of 9 years during the whole period. The estimated cumulative incidence proportion at age 16 years based on the 2010 age-specific incidence rates was 0.16% (95% CI 0.09-0.32%) compared with 0.20% (95% CI 0.11-0.37%) based on the 2000 age-specific incidence rates. From 2002 to 2010 there was a decrease in the incidence rate of first-time surgically treated middle ear cholesteatoma. The decrease was preceded by a significant increase in the incidence rate of middle ear ventilation tube insertion. However, further studies are needed to find possible explanations for the decrease. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    International journal of pediatric otorhinolaryngology. 11/2014;
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    ABSTRACT: To estimate the risk of surgically treated middle ear cholesteatoma in individuals with a nonsyndromic orofacial cleft and in their siblings compared with the general population.
    The Laryngoscope 11/2014; · 1.98 Impact Factor
  • Lene Christiansen, Kaare Christensen
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    ABSTRACT: Lifespan, longevity and healthy aging are complex phenotypes, and unravelling of the genetic background has been challeng-ing. Excess of advantageous gene variants seems to be of more importance for longevity than absence of known disease-sus-ceptibility genes. Animal studies have pointed to candidate path--ways related to ageing, but only a few genes have repeatedly been associated to human lifespan. Research into the genetic contribution to a long and healthy life is currently focusing on epigenetic phenomena and the importance of rare variants in families enriched for longevity.
    Ugeskrift for laeger 11/2014; 176(46).
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    ABSTRACT: There are genetic influences on memory ability as we age, but no specific genes have been identified.
    JAMA Neurology 10/2014; · 7.58 Impact Factor
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    ABSTRACT: Background Few human cohort studies on anesthesia-related neurotoxicity and the developing brain have focused on and compared specific surgeries and conditions. These studies cannot disentangle the effects of anesthesia from those of the surgery and underlying conditions. This study aimed at assessing the impact of specific neurosurgical conditions and procedures in infancy on mortality and academic achievements in adolescence.MethodsA nationwide unselected register-based follow-up study of the Danish birth cohorts 1986–1990 compared academic performances of all children having undergone neurosurgeries as infants with a randomly selected, age-matched 5% sample of the same cohorts. The two groups were compared regarding mortality prior to June 1st, 2006, average test scores at ninth grade, and finally the proportion of children not attaining test scores.ResultsThe exposure group comprised 228 and the control group 14 698 individuals. Hydrocephalus (n = 130), craniotomy (n = 43), and myelomeningocele/encephalocele children (n = 55) had a higher mortality (18.5.0%, 18.6%, and 7.3%, respectively) vs controls (1.3%; P < 0.00001, P < 0.00001, and P = 0.0052, respectively). Average test scores were significantly lower than controls in hydrocephalus and craniotomy (P = 0.0043 and P = 0.0077) but not myelomeningocele/encephalocele children (P = 0.2785); the proportion of available test scores were significantly lower in all three groups (40.8%, 60.0%, and 67.3%, respectively) vs 86.8% in controls (P < 0.00001, P = 0.000077, and P = 0.000064).Conclusion Neurosurgery in infancy was associated with high mortality and significantly impaired academic achievements in adolescence. When studying anesthesia-related neurotoxicity and the developing brain, focus on specific surgeries/conditions is important. Pooling of major/minor conditions and major/minor surgeries should be avoided.
    Pediatric Anesthesia 09/2014; · 2.44 Impact Factor
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    ABSTRACT: Objective To examine mortality and hospitalisations among infant twins and singletons after the perinatal period in Guinea-Bissau.Methods The study was conducted from September 2009 to November 2012 by the Bandim Health Project (BHP). Newborn twins and unmatched singleton controls were included at the National Hospital Simão Mendes in the capital Bissau. Children were examined clinically at enrolment. Maternal, pregnancy and obstetric information was collected and HIV testing offered at birth. Follow-up occurred at home at 2, 6 and 12 months and through linkage with the paediatric admission register at the National Hospital.ResultsAbout 495 twins and 333 singletons were alive on day 7 after birth. In total, 36 twins and 12 singletons died during follow-up, the post-perinatal infant mortality rate being 91/1000 person-years for twins and 42/1000 for singletons (HR = 2.11, 95% CI: 1.09–4.07). In a multivariable analysis among twins only, birth weight <2000 g [3.32, (1.36–8.07)], death of the cotwin perinatally [2.54, (1.16–5.57)] and severe maternal illness during pregnancy [2.35, (1.00–5.51)] were significant risk factors for twin death. In the subgroup with available HIV status, maternal HIV infection was strongly associated with twin mortality [3.16, (1.24–8.05)]. Death occurred at home for 60% of twins and 67% of singletons. During follow-up, 90 first-time hospital admissions were registered, with similar rates observed for twins (139/1000) and singletons (143/1000) [0.97, (0.61–1.52)].Conclusion The post-perinatal infant mortality rate of twins was double that of singletons. No excess in twin hospitalisations was observed, possibly implying obstacles to hospital admission for twins in case of severe illness.
    Tropical Medicine & International Health 09/2014; · 2.94 Impact Factor
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    ABSTRACT: Animal studies (including non-human primates) have shown that most general anaesthetics cause enhanced neuroapoptosis with subsequent long-term neurocognitive deficits later in life. Some human cohort studies have indicated an association between anaesthesia/surgery and adverse neurocognitive outcome whereas other studies have not. Overall, the data do not justify any change in paediatric anaesthetic clinical practice. Naturally, the risks and benefits of a procedure should always be carefully considered before exposing a child to general anaesthesia.
    Ugeskrift for laeger 08/2014; 176(34).
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    ABSTRACT: Objectives: Little is known about whether the feeling of happiness follows the age-related decline in physical and mental functioning. The objective of this study was to analyze differences with age in physical and mental functions and in the feeling of happiness among Danes aged 45 years and older. Method: Three Danish population-based surveys including 11,307 participants aged 45+ years, of whom 2411 were in the age group of 90+, were conducted in the period 1995-2001. The participation rate in the three surveys was between 63% and 82% and the same design and the same instrument were used. Self-reported mobility, a cognitive composite score, and a depression symptomatology score including a question about happiness were assessed. T-score metric was used to compare across domains and age groups. Results: Overall, successively older age groups performed worse than the youngest age group (45-49 years), and the estimated linear decline was greater after age 70 than before age 70. For example, when comparing the oldest age group (90+ years) with the youngest, the T-score differences were found to be the largest for the mobility score (men: 40.2, women: 41.4), followed by the cognitive function (men: 22.0, women: 24.9), and the total depression symptomatology score (men: 15.5, women: 17.4). Conversely, the T-score difference in happiness was small (men: 5.6, women: 6.0). Conclusion: Despite markedly poorer physical and mental functions with increasing age, in this Danish sample age did not seem to affect happiness to a similarly notable extent, although, in this study, cohort and age effects cannot be disentangled.
    Aging and Mental Health 08/2014; · 1.68 Impact Factor
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    ABSTRACT: Background: In eutherian mammals and in humans, the female fetus may be masculinized while sharing the intra-uterine environment with a male fetus. Telomere length (TL), as expressed in leukocytes, is heritable and is longer in women than in men. The main determinant of leukocyte TL (LTL) is LTL at birth. However, LTL is modified by age dependent attrition. Methods: We studied LTL dynamics (LTL and its attrition) in adult same-sex(monozygotic, n=268; dizygotic, n=308) twins and opposite-sex (n=144) twins. LTL was measured by Southern blots of the terminal restriction fragments. Results: We observed that in same-sex (both monozygotic and dizygotic) twins, as reported in singletons, LTL was longer in females than in males [estimate ± standard error (SE):163 ± 63 bp, P<0.01]. However, in opposite-sex twins, female LTL was indistinguishable from that of males (-31 ± 52 bp, P=0.6), whereas male LTL was not affected. Findings were similar when the comparison was restricted to opposite-sex and same-sex dizygotic twins (females relative to males: same-sex: 188 ± 90 bp, P<0.05; other-sex: -32 ± 64 bp, P=0.6). Conclusions: These findings are compatible with masculinization of the female fetus in opposite-sex twins. They suggest that the sex difference in LTL, seen in the general population, is largely determined in utero, perhaps by the intrauterine hormonal environment. Further studies in newborn twins are warranted to test this thesis.
    International Journal of Epidemiology 07/2014; · 6.98 Impact Factor
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    ABSTRACT: To study the incidence rates of middle ear ventilation tube insertion in children aged 0 to 15 years in Denmark from 1997 to 2010.
    International journal of pediatric otorhinolaryngology. 07/2014;
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    ABSTRACT: Oral clefts are among the most common birth defects affecting thousands of newborns each year, but little is known about their potential long-term consequences. In this paper, we explore the impact of oral clefts on health care utilization over most of the lifespan. To account for time-invariant unobservable parental characteristics, we compare affected individuals with their own unaffected siblings. The analysis is based on unique data comprising the entire cohort of individuals born with oral clefts in Denmark tracked until adulthood in administrative register data. We find that children with oral clefts use more health services than their unaffected siblings. Additional results show that the effects are driven primarily by congenital malformation-related hospitalizations and intake of anti-infectives. Although the absolute differences in most health care utilization diminish over time, affected individuals have slightly higher utilization of some health care services in adulthood (particularly for diseases of the nervous and respiratory system). These results have important implications for affected individuals, their families, and their health professionals.
    The European journal of health economics : HEPAC : health economics in prevention and care. 06/2014;
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    ABSTRACT: The role of the mitochondria in disease, general health and aging has drawn much attention over the years. Several attempts have been made to describe how the numbers of mitochondria correlate with age, although with inconclusive results. In this study, the relative quantity of mitochondrial DNA compared to nuclear DNA, i.e. the mitochondrial DNA copy number, was measured by PCR technology and used as a proxy for the content of mitochondria copies. In 1,067 Danish twins and singletons (18-93 years of age), with the majority being elderly individuals, the estimated mean mitochondrial DNA copy number in peripheral blood cells was similar for those 18-48 years of age [mean relative mtDNA content: 61.0; 95 % CI (52.1; 69.9)], but declined by -0.54 mtDNA 95 % CI (-0.63; -0.45) every year for those older than approximately 50 years of age. However, the longitudinal, yearly decline within an individual was more than twice as steep as observed in the cross-sectional analysis [decline of mtDNA content: -1.27; 95 % CI (-1.71; -0.82)]. Subjects with low mitochondrial DNA copy number had poorer outcomes in terms of cognitive performance, physical strength, self-rated health, and higher all-cause mortality than subjects with high mitochondrial DNA copy number, also when age was controlled for. The copy number mortality association can contribute to the smaller decline in a cross-sectional sample of the population compared to the individual, longitudinal decline. This study suggests that high mitochondrial DNA copy number in blood is associated with better health and survival among elderly.
    Human genetics. 06/2014;
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    ABSTRACT: The Danish Conscription Database (DCD) was established to enable studies of the influence of early physical and mental exposures on adverse health and social outcomes from a life-course perspective. In Denmark, all young men are requested to appear before the conscription board when they turn 18 years, to be assessed for military service. The DCD was established by digitizing information from conscription board register cards on the height, weight, educational level, intelligence test score and examination details of Danish conscripts. The DCD contains information on 728 160 men born from 1939 through 1959 and examined by the conscription board from 1957 through 1984. The unique Danish personal identification number of each individual conscript has been traced, and this allows linkage of the DCD to all Danish health and socioeconomic registers. More than 130 000 deaths have been identified in a recent linkage to the Danish Register of Cause of Death. We encourage collaboration, and interested researchers should contact: danishconscriptiondatabase.glostrup-hospital@regionh.dk.
    International Journal of Epidemiology 06/2014; · 6.98 Impact Factor
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    ABSTRACT: Background: Prostate cancer is thought to be the most heritable cancer, although little is known about how this genetic contribution varies across age. Methods: To address this question, we undertook the world's largest prospective study in the Nordic Twin Study of Cancer cohort, including 18,680 monozygotic and 30,054 dizygotic same sex male twin pairs. We incorporated time-to-event analyses to estimate the risk concordance and heritability while accounting for censoring and competing risks of death, essential sources of biases that have not been accounted for in previous twin studies modeling cancer risk and liability. Results: The cumulative risk of prostate cancer was similar to that of the background population. The cumulative risk for twins whose co-twin was diagnosed with prostate cancer was greater for MZ than for DZ twins across all ages. Among concordantly affected pairs, the time between diagnoses was significantly shorter for MZ than DZ pairs (median 3.8 versus 6.5 years, respectively). Genetic differences contributed substantially to variation in both the risk and the liability (heritability=58% (95% CI 52%-63%) of developing prostate cancer. The relative contribution of genetic factors was constant across age through late life with substantial genetic heterogeneity even when diagnosis and screening procedures vary. Conclusions: Results from the population based twin cohort, indicate a greater genetic contribution to the risk of developing prostate cancer when addressing sources of bias. The role of genetic factors is consistently high across age Impact: Findings impact the search for genetic and epigenetic markers and frame prevention efforts.
    Cancer Epidemiology Biomarkers &amp Prevention 05/2014; · 4.56 Impact Factor
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    ABSTRACT: Gene variants found to associate with human longevity in one population rarely replicate in other populations. The lack of consistent findings may partly be explained by genetic heterogeneity among long-lived individuals due to cohort differences in survival probability. In most high-income countries the probability of reaching e.g. 100years increases by 50-100% per decade, i.e. there is far less selection in more recent cohorts. Here we investigate the cohort specificity of variants in the APOE and FOXO3A genes by comparing the frequencies of the APOE ε4 allele and the minor alleles of two variants in FOXO3A at age 95+ and 100+ in 2,712 individuals from the genetically homogeneous Danish birth cohorts 1895-96, 1905, 1910-11, and 1915. Generally, we find a decrease in the allele frequencies of the investigated APOE and FOXO3A variants in individuals from more recent birth cohorts. Assuming a recessive model, this negative trend is significant in 95+ year old individuals homozygous for the APOE ε4 allele (P=0.026) or for the FOXO3A rs7762395 minor allele (P=0.048). For the APOE ε4 allele, the significance is further strengthened when restricting to women (P=0.006). Supportive, but non-significant, trends are found for two of the three tested variants in individuals older than 100years. Altogether, this indicates that cohort differences in selection pressure on survival to the highest ages are reflected in the prevalence of longevity gene variants. Although the effect seems to be moderate, our findings could have an impact on genetic studies of human longevity.
    Experimental gerontology 05/2014; · 3.34 Impact Factor
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    ABSTRACT: To isolate the effect of education from the influence of potential underlying factors, we investigated the association of education with the risk of cardiovascular disease (CVD) and ischemic heart disease (IHD) using twin data to adjust for familial factors shared within twins, including genetic make-up and childhood environment. The study was based on data from the Danish Twin Registry linked to administrative and heath registers in Statistics Denmark. A total of 11,968 monozygotic and 20,464 dizygotic same sexed twins were followed from 1980 to 2009, including more than 8000 events of CVD. Unpaired and intra-pair analyses were compared. In the unpaired analyses, an inverse educational gradient in CVD- and IHD risk was observed. This association was not replicated in the intra-pair analyses that control for shared familial factors exploiting that twins share their intrauterine- and childhood environment and are matched partly or fully on genetic setup. The attenuation of association of education with CVD and IHD in the intra-pair analyses suggests that shared familial factors account for a substantial part of the observed association of education with CVD and IHD in Denmark.
    Social Science [?] Medicine 04/2014; · 2.73 Impact Factor
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  • Matt McGue, Axel Skytthe, Kaare Christensen
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    ABSTRACT: With the greying of the industrialized world has come increased interest in identifying the modifiable lifestyle factors that promote healthy and successful ageing. Whereas many of the behavioural correlates of late-life morbidity and mortality have been identified, relatively little is known about the origins of individual differences in these factors. A sample of 12 714 twins, including both members of 3806 pairs of known zygosity, ascertained through the Danish Twin Registry and aged 40 to 80 years, completed a self-report assessment of six lifestyle factors associated with ageing: smoking, drinking, diet and physical, social and intellectual activities. Standard biometric methods were used to analyse the twin data and determine the extent to which individual differences in each of the lifestyle factors are heritable. For each of the six lifestyle factors, the estimate of heritability ranged from 32% (95% CI: 19-42%) for the diet scale to 69% (62-72%) for the smoking measure. Biometric estimates of the contribution of the twins' common rearing environment were uniformly small (≤6%). There was little evidence that standardized biometric estimates varied by gender or age. Individuals likely construct lifestyles in part to complement and reinforce underlying genetically influenced dispositions and talents. The heritable nature of lifestyle factors implies that the behavioural and genetic contributors to ageing processes are not necessarily conceptually distinct but rather reflect the complexity of gene-environment interplay in ageing.
    International Journal of Epidemiology 04/2014; · 6.98 Impact Factor

Publication Stats

12k Citations
2,451.87 Total Impact Points


  • 1999–2014
    • University of Southern Denmark
      • Institute of Public Health
      Odense, South Denmark, Denmark
  • 1990–2014
    • Odense University Hospital
      • • Department of Endocrinology - M
      • • Department of Cardiology - B
      • • Department of Neurology - N
      Odense, South Denmark, Denmark
  • 2012–2013
    • Statens Serum Institut
      • • Department of Clinical Biochemistry and Immunology
      • • Department of Microbiology and Infection Control
      København, Capital Region, Denmark
    • Columbia University
      • Taub Institute for Research on Alzheimer's Disease and the Aging Brain
      New York City, New York, United States
  • 2011–2013
    • Leiden University Medical Centre
      • Department of Gerontology and Geriatrics
      Leyden, South Holland, Netherlands
    • Roosevelt University
      • Department of Psychology
      Chicago, IL, United States
    • University of Tampere
      • School of Health Sciences
      Tampere, Western Finland, Finland
    • Universität Mannheim
      • Department of Economics
      Mannheim, Baden-Wuerttemberg, Germany
  • 2010–2012
    • University of Copenhagen
      • • Department of Public Health
      • • Department of International Health, Immunology and Microbiology
      Copenhagen, Capital Region, Denmark
    • University of Minnesota Duluth
      • Department of Psychology
      Duluth, MN, United States
    • IT University of Copenhagen
      København, Capital Region, Denmark
    • Helsinki University Central Hospital
      • Department of Neurosurgery
      Helsinki, Province of Southern Finland, Finland
  • 2003–2012
    • University of Iowa
      • • Department of Pediatrics
      • • Department of Biology
      Iowa City, Iowa, United States
    • Baylor College of Dentistry
      • Department of Biomedical Sciences
      Houston, Texas, United States
  • 2002–2012
    • King's College London
      • Department of Twin Research and Genetic Epidemiology
      Londinium, England, United Kingdom
  • 2001–2012
    • Università della Calabria
      • Department of Cell Biology
      Rende, Calabria, Italy
    • Hospital of the University of Pennsylvania
      • Department of Biostatistics and Epidemiology
      Philadelphia, Pennsylvania, United States
    • Army Center for Epidemiology and Public Health
      Marsiglia, Provence-Alpes-Côte d'Azur, France
  • 1997–2012
    • University of Minnesota Twin Cities
      • Department of Psychology
      Minneapolis, MN, United States
  • 2010–2011
    • Johns Hopkins University
      • Department of Medicine
      Baltimore, MD, United States
    • Norwegian Institute of Public Health
      • Division of Epidemiology
      Oslo, Oslo, Norway
  • 2009–2011
    • Duke University
      • Department of Sociology
      Durham, North Carolina, United States
    • Glostrup Hospital
      • Research Centre for Prevention and Health
      Glostrup, Capital Region, Denmark
    • Unilever
      Londinium, England, United Kingdom
    • Copenhagen University Hospital
      København, Capital Region, Denmark
    • The University of Edinburgh
      • Centre for Cognitive Ageing and Cognitive Epidemiology
      Edinburgh, SCT, United Kingdom
    • VU University Amsterdam
      • Department of General Economics
      Amsterdam, North Holland, Netherlands
    • Murdoch Childrens Research Institute
      Melbourne, Victoria, Australia
    • Second University of Naples
      Caserta, Campania, Italy
  • 2002–2011
    • University of Pennsylvania
      • • Smell and Taste Center
      • • Department of Sociology
      Philadelphia, PA, United States
  • 1998–2009
    • Max Planck Institute for Demographic Research
      Rostock, Mecklenburg-Vorpommern, Germany
  • 2008
    • Rutgers New Jersey Medical School
      Newark, New Jersey, United States
    • University of Oklahoma
      • Department of Psychology
      Oklahoma City, OK, United States
  • 2007
    • The University of Warwick
      • Department of Economics
      Warwick, ENG, United Kingdom
    • The Forsyth Institute
      • Department of Cytokine Biology
      Cambridge, Massachusetts, United States
    • National Institute of Public Health, Denmark
      København, Capital Region, Denmark
    • University of Bologna
      Bolonia, Emilia-Romagna, Italy
  • 2003–2007
    • Nordic Institute of Chiropractic and Clinical Biomechanics
      Odense, South Denmark, Denmark
  • 1997–2007
    • Aarhus University
      • • Department of Public Health
      • • Institute of Human Genetics
      • • Department of Epidemiology and Social Medicine
      Aars, Region North Jutland, Denmark
  • 2006
    • University of Helsinki
      • Department of Dental Public Health
      Helsinki, Province of Southern Finland, Finland
  • 2003–2006
    • London School of Hygiene and Tropical Medicine
      Londinium, England, United Kingdom
  • 1997–2006
    • Aarhus University Hospital
      • • Department of Occupational Medicine
      • • Department of Clinical Epidemiology
      Aarhus, Central Jutland, Denmark
  • 2005
    • Martin Luther University of Halle-Wittenberg
      • Institute of Medical Epidemiology, Biostatistics, and Computer Science
      Halle, Saxony-Anhalt, Germany
    • Aalborg University
      Ålborg, North Denmark, Denmark
  • 2004
    • Christian-Albrechts-Universität zu Kiel
      • Unit of Neurobiology
      Kiel, Schleswig-Holstein, Germany
    • National Institutes of Health
      • Branch of Epidemiology (EPI)
      Bethesda, MD, United States
  • 1992
    • Institut for Sygdomsforebyggelse
      København, Capital Region, Denmark