Kaare Christensen

University of Southern Denmark, Odense, South Denmark, Denmark

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Publications (486)2367.68 Total impact

  • [Show abstract] [Hide abstract]
    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;
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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
  • Anesthesiology 04/2014; · 5.16 Impact Factor
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    ABSTRACT: The genetic contribution to the variation in human lifespan is approximately 25%. Despite the large number of identified disease-susceptibility loci, it is not known which loci influence population mortality.We performed a genome-wide association meta-analysis of 7729 long-lived individuals of European descent (≥ 85 years) and 16121 younger controls (< 65 years) followed by replication in an additional set of 13060 long-lived individuals and 61156 controls. In addition, we performed a subset analysis in cases≥90 years.We observed genome-wide significant association with longevity, as reflected by survival to ages beyond 90 years, at a novel locus, rs2149954, on chromosome 5q33.3 (OR=1.10, P =1.74 x 10(-8)). We also confirmed association of rs4420638 on chromosome 19q13.32 (OR=0.72, P=3.40 x 10(-36)), representing the TOMM40/APOE/APOC1 locus. In a prospective meta-analysis (n=34103) the minor allele of rs2149954 (T) on chromosome 5q33.3 associates with increased survival (HR=0.95, P=0.003). This allele has previously been reported to associate with low blood pressure in middle age. Interestingly, the minor allele (T) associates with decreased cardiovascular mortality risk, independent of blood pressure.We report on the first GWAS-identified longevity locus on chromosome 5q33.3 influencing survival in the general European population. The minor allele of this locus associates with low blood pressure in middle age, although the contribution of this allele to survival may be less dependent on blood pressure. Hence, the pleiotropic mechanisms by which this intragenic variation contributes to lifespan regulation have to be elucidated.
    Human Molecular Genetics 03/2014; · 7.69 Impact Factor
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    ABSTRACT: In high income countries females outlive men, although they generally report worse health, the so-called male-female health-survival paradox. Russia has one of the world's largest sex difference in life expectancy with a male disadvantage of more than 10 years. We compare components of the paradox between Denmark and Moscow by examining sex differences in mortality and several health measures. The Human Mortality Database and the Russian Fertility and Mortality Database were used to examine sex differences in all-cause death rates in Denmark, Russia, and Moscow in 2007-2008. Self-reported health data were obtained from the Study of Middle-Aged Danish Twins (n = 4,314), the Longitudinal Study of Aging Danish Twins (n = 4,731), and the study of Stress, Aging, and Health in Russia (n = 1,800). In both Moscow and Denmark there was a consistent female advantage at ages 55-89 years in survival and a male advantage in self-rated health, physical functioning, and depression symptomatology. Only on cognitive tests males performed similarly to or worse than women. Nevertheless, Muscovite males had more than twice higher mortality at ages 55-69 years compared to Muscovite women, almost double the ratio in Denmark. The present study showed that despite similar directions of sex differences in health and mortality in Moscow and Denmark, the male-female health-survival paradox is very pronounced in Moscow suggesting a stronger sex-specific disconnect between health indicators and mortality among middle-aged and young-old Muscovites.
    European Journal of Epidemiology 03/2014; · 5.12 Impact Factor
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    ABSTRACT: It is widely believed that females have longer telomeres than males, although results from studies have been contradictory. We carried out a systematic review and meta-analyses to test the hypothesis that in humans, females have longer telomeres than males and that this association becomes stronger with increasing age. Searches were conducted in EMBASE and MEDLINE (by November 2009) and additional datasets were obtained from study investigators. Eligible observational studies measured telomeres for both females and males of any age, had a minimum sample size of 100 and included participants not part of a diseased group. We calculated summary estimates using random-effects meta-analyses. Heterogeneity between studies was investigated using sub-group analysis and meta-regression. Meta-analyses from 36 cohorts (36,230 participants) showed that on average females had longer telomeres than males (standardised difference in telomere length between females and males 0.090, 95% CI 0.015, 0.166; age-adjusted). There was little evidence that these associations varied by age group (p=1.00) or cell type (p=0.29). However, the size of this difference did vary by measurement methods, with only Southern blot but neither real-time PCR nor Flow-FISH showing a significant difference. This difference was not associated with random measurement error. Telomere length is longer in females than males, although this difference was not universally found in studies that did not use Southern blot methods. Further research on explanations for the methodological differences is required.
    Experimental gerontology 03/2014; 51:15-27. · 3.34 Impact Factor
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    ABSTRACT: Almost 40 years ago, evidence from large studies of adult twins and their relatives suggested that between 30 and 60 % of the variance in social and political attitudes could be explained by genetic influences. However, these findings have not been widely accepted or incorporated into the dominant paradigms that explain the etiology of political ideology. This has been attributed in part to measurement and sample limitations, as well the relative absence of molecular genetic studies. Here we present results from original analyses of a combined sample of over 12,000 twins pairs, ascertained from nine different studies conducted in five democracies, sampled over the course of four decades. We provide evidence that genetic factors play a role in the formation of political ideology, regardless of how ideology is measured, the era, or the population sampled. The only exception is a question that explicitly uses the phrase "Left-Right". We then present results from one of the first genome-wide association studies on political ideology using data from three samples: a 1990 Australian sample involving 6,894 individuals from 3,516 families; a 2008 Australian sample of 1,160 related individuals from 635 families and a 2010 Swedish sample involving 3,334 individuals from 2,607 families. No polymorphisms reached genome-wide significance in the meta-analysis. The combined evidence suggests that political ideology constitutes a fundamental aspect of one's genetically informed psychological disposition, but as Fisher proposed long ago, genetic influences on complex traits will be composed of thousands of markers of very small effects and it will require extremely large samples to have enough power in order to identify specific polymorphisms related to complex social traits.
    Behavior Genetics 02/2014; · 2.61 Impact Factor
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    ABSTRACT: DNA-damage response and repair are crucial to maintain genetic stability, and are consequently considered central to aging and longevity. Here, we investigate whether this pathway overall associates to longevity, and whether specific sub-processes are more strongly associated with longevity than others. Data were applied on 592 SNPs from 77 genes involved in nine sub-processes: DNA-damage response, base excision repair (BER), nucleotide excision repair, mismatch repair, non-homologous end-joining, homologous recombinational repair (HRR), RecQ helicase activities (RECQ), telomere functioning and mitochondrial DNA processes. The study population was 1089 long-lived and 736 middle-aged Danes. A self-contained set-based test of all SNPs displayed association with longevity (P-value=9.9 × 10(-5)), supporting that the overall pathway could affect longevity. Investigation of the nine sub-processes using the competitive gene-set analysis by Wang et al indicated that BER, HRR and RECQ associated stronger with longevity than the respective remaining genes of the pathway (P-values=0.004-0.048). For HRR and RECQ, only one gene contributed to the significance, whereas for BER several genes contributed. These associations did, however, generally not pass correction for multiple testing. Still, these findings indicate that, of the entire pathway, variation in BER might influence longevity the most. These modest sized P-values were not replicated in a German sample. This might, though, be due to differences in genotyping procedures and investigated SNPs, potentially inducing differences in the coverage of gene regions. Specifically, five genes were not covered at all in the German data. Therefore, investigations in additional study populations are needed before final conclusion can be drawn.European Journal of Human Genetics advance online publication, 12 February 2014; doi:10.1038/ejhg.2013.299.
    European journal of human genetics: EJHG 02/2014; · 3.56 Impact Factor
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    ABSTRACT: We evaluated which equations best predicted the lung function of a cohort of nonagenarians based on which best accounted for subsequent survival.In 1998, we measured lung function, grip strength and dementia score (Mini Mental State Examination (MMSE)) in a population-based sample of 2262 Danes born in 1905. Mortality was registered to 2011 when only five (0.2%) subjects were alive. In half the cohort, we recorded forced expiratory volume in 1 s (FEV1).Complete data were available in 592 subjects with results expressed as standardised residuals (SR) using various prediction equations. Cox proportional hazard regression found lower FEV1SR was a predictor of mortality having controlled for MMSE, grip strength and sex. The US National Health and Nutrition Examination Survey (NHANES) III (1999) equations gave a better spread of median survival by FEV1SR quartile: 3.94, 3.65, 3.51 and 2.61 years with a hazard ratio for death of 1, 1.16, 1.32 and 1.60 respectively, compared with equations derived with the inclusion of elderly subjects.We conclude that extrapolating from NHANES III equations to predict lung function in nonagenarians gave better survival predictions from spirometry than when employing equations derived using very elderly subjects with possible selection bias. These findings can help inform how future lung function equations for the elderly are derived.
    European Respiratory Journal 01/2014; · 6.36 Impact Factor
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    ABSTRACT: Preservation of functional ability is a well-recognised marker of longevity. At a molecular level, a major determinant of the physiological decline occurring with aging is the imbalance between production and accumulation of oxidative damage to macromolecules, together with a decreased efficiency of stress response to avoid or repair such damage. In this paper we investigated the association of 38 genes (311 SNPs) belonging to the pro-antioxidant pathways with physical and cognitive performances, by analysing single SNP and gene-based associations with Hand Grip strength (HG), Activities of Daily Living (ADL), Walking Speed (WS), Mini Mental State Examination (MMSE) and Composite Cognitive Score (CCS) in a Cohort of 1089 Danish nonagenarians. Moreover, for each gene analysed in the pro-antioxidant pathway, we tested the influence on longitudinal survival. In the whole sample, nominal associations were found for TXNRD1 variability with ADL and WS, NDUFS1 and UCP3 with HG and WS, GCLC and UCP2 with WS (p<0.05). Stronger associations although not holding the multiple comparison correction, were observed between MMSE and NDUFV1, MT1A and GSTP1 variability (p<0.009). Moreover, we found that association between genetic variability in the pro-antioxidant pathway and functional status at old age is influenced by sex. In particular, most significant associations were observed in nonagenarian females, between HG scores and GLRX and UCP3 variability, between ADL levels and TXNRD1, MMSE and MT1A genetic variability. In males, a borderline statistically significant association with ADL level was found for UQCRFS1 gene. Nominally significant associations in relation to survival were found in the female sample only with SOD2, NDUFS1, UCP3 and TXNRD1 variability, the latter two confirming previous observations reported in the same cohort. Overall, our work supports the evidence that genes belonging to the pro-anti-oxidant pathway are able to modulate physical and cognitive performance after the ninth decade of life, finally influencing extreme survival.
    Experimental gerontology 01/2014; · 3.34 Impact Factor
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    ABSTRACT: Background: Thyroid hormones are necessary for fetal brain development, while hypothyroidism in adults has been associated with mood symptoms and reduced quality of life. Nevertheless, our knowledge regarding the association and temporal relation between hypothyroidism and mental disorders is ambiguous. Our objective was to investigate, at a nationwide level, whether a diagnosis of hypothyroidism is associated with psychiatric morbidity. Methods: Observational cohort study. Based on record-linkage between different Danish health registers, 2822 hypothyroid singletons each matched with 4 non-hypothyroid controls were identified and followed over a mean period of 6 years (range 1-13). Additionally, we included 385 same sex twin pairs discordant for hypothyroidism. Diagnoses of psychiatric disorders as well as treatment with antidepressants, antipsychotics and anxiolytics were recorded. Logistic and cox regression models were used to assess the risk of psychiatric morbidity before and after the diagnosis of hypothyroidism, respectively. Results: Prior to the diagnosis of hypothyroidism, such individuals had an increased prevalence of diagnoses with psychiatric disorders (Odds ratio, OR, 1.51; 95% confidence interval (CI): 1.12-2.04) and increased prevalence of treatment with antipsychotics (OR 1.49; 95% CI: 1.29-1.73), antidepressants (OR 1.50; 95% CI: 1.35-1.67), and anxiolytics (OR 1.28; 95% CI: 1.16-1.41). After the diagnosis of hypothyroidism, patients had a higher risk of being diagnosed with a psychiatric disorder (Hazard ratio, HR, 2.40; 95% CI: 1.81-3.18), and an increased risk of being treated with antidepressants (HR 1.30; 95% CI: 1.15-1.47) and anxiolytics (HR 1.27; 95% CI: 1.10-1.47), but not antipsychotics (HR 1.13; 95% CI: 0.91-1.41). Based on the twin data, we could not demonstrate genetic confounding. Conclusions: Subjects with hypothyroidism have an increased risk of being diagnosed with a psychiatric disorder as well as being treated with antidepressants, antipsychotics and anxiolytics both before and after the diagnosis of hypothyroidism.
    Thyroid: official journal of the American Thyroid Association 01/2014; · 2.60 Impact Factor

Publication Stats

11k Citations
2,367.68 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
    • University of Tampere
      • School of Health Sciences
      Tampere, Western Finland, Finland
    • Roosevelt University
      • Department of Psychology
      Chicago, IL, United States
    • 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
    • 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
  • 1996–2007
    • 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