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1.
Eur J Clin Pharmacol ; 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33442768

RESUMO

PURPOSE: Due to conflicting scientific evidence for an increased risk of dementia by intake of proton pump inhibitors (PPIs), this study investigates associations between PPI use and brain volumes, estimated brain age, and cognitive function in the general population. METHODS: Two surveys of the population-based Study of Health in Pomerania (SHIP) conducted in Northeast Germany were used. In total, 2653 participants underwent brain magnetic resonance imaging (MRI) and were included in the primary analysis. They were divided into two groups according to their PPI intake and compared with regard to their brain volumes (gray matter, white matter, total brain, and hippocampus) and estimated brain age. Multiple regression was used to adjust for confounding factors. Cognitive function was evaluated by the Verbal Learning and Memory Test (VLMT) and the Nuremberg Age Inventory (NAI) and put in relation to PPI use. RESULTS: No association was found between PPI use and brain volumes or the estimated brain age. The VLMT score was 1.11 lower (95% confidence interval: - 2.06 to - 0.16) in immediate recall, and 0.72 lower (95% CI: - 1.22 to - 0.22) in delayed recall in PPI users than in non-users. PPI use was unrelated to the NAI score. CONCLUSIONS: The present study does not support a relationship between PPI use and brain aging.

2.
Sleep ; 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-33017007

RESUMO

Advanced brain ageing is commonly regarded as a risk factor for neurodegenerative diseases, e.g. Alzheimer's dementia, and it was suggested that sleep disorders such as obstructive sleep apnoea (OSA) are significantly contributing factors to these neurodegenerative processes. To determine the association between OSA and advanced brain ageing, we investigated the specific effect of two indices quantifying OSA, namely the apnoea-hypopnea index (AHI) and the oxygen desaturation index (ODI), on brain age, a score quantifying age-related brain patterns in 169 brain regions, using magnetic resonance imaging and overnight polysomnography data from 690 participants (48.8% women, mean age 52.5±13.4 years) of the Study of Health in Pomerania. We additionally investigated the mediating effect of subclinical inflammation parameters on these associations via a causal mediation analysis. AHI and ODI were both positively associated with brain age (AHI std. effect [95% CI]: 0.07 [0.03; 0.12], p-value: 0.002; ODI std. effect [95% CI]: 0.09 [0.04; 0.13], p-value: <0.0003). The effects remained stable in the presence of various confounders such as diabetes and were partially mediated by the white blood cell count, indicating a subclinical inflammation process. Our results reveal an association between OSA and brain age, indicating subtle but widespread age-related changes in regional brain structures, in one of the largest general population studies to date, warranting further examination of OSA in the prevention of neurodegenerative diseases.

3.
Hum Brain Mapp ; 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32596977

RESUMO

The ENIGMA group on Generalized Anxiety Disorder (ENIGMA-Anxiety/GAD) is part of a broader effort to investigate anxiety disorders using imaging and genetic data across multiple sites worldwide. The group is actively conducting a mega-analysis of a large number of brain structural scans. In this process, the group was confronted with many methodological challenges related to study planning and implementation, between-country transfer of subject-level data, quality control of a considerable amount of imaging data, and choices related to statistical methods and efficient use of resources. This report summarizes the background information and rationale for the various methodological decisions, as well as the approach taken to implement them. The goal is to document the approach and help guide other research groups working with large brain imaging data sets as they develop their own analytic pipelines for mega-analyses.

4.
Mol Genet Genomic Med ; 8(9): e1345, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32558353

RESUMO

BACKGROUND: The mineralocorticoid receptor (MR) in the brain has a key role in the regulation of the central stress response and is associated with memory performance. We investigated whether the genetic polymorphisms rs5522 and rs2070951 of NR3C2 showed main and interactive effects with childhood trauma on memory decline. METHODS: Declarative memory was longitudinally assessed in 1,318 participants from the community-dwelling Study of Health in Pomerania using the Verbal Learning and Memory Test (VLMT). In a subsample of 377 participants aged 60 and older, the Mini-Mental Status Examination (MMSE) was additionally applied. Mean follow-up time for the VLMT and MMSE were 6.4 and 10.7 years, respectively. RESULTS: Homozygous carriers of the G allele of rs2070951 (p < .01) and of the A allele of rs5522 (p < .001) showed higher immediate recall of words as compared to carriers of C allele (rs2070951) or the G allele (rs5522). The CG haplotype was associated with decreased recall (p < .001). Likewise, in the subsample of older patients, the AA genotype of rs5522 was associated with higher MMSE scores (p < .05). CG haplotypes showed significantly reduced MMSE scores in comparison to the reference haplotype (ß = -0.60; p < .01). CONCLUSIONS: Our results indicate that the GG genotype of rs2070951 as well as the AA genotype of rs5522 are associated with diminished memory decline.

5.
Mol Psychiatry ; 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32467648

RESUMO

Emerging evidence suggests that obesity impacts brain physiology at multiple levels. Here we aimed to clarify the relationship between obesity and brain structure using structural MRI (n = 6420) and genetic data (n = 3907) from the ENIGMA Major Depressive Disorder (MDD) working group. Obesity (BMI > 30) was significantly associated with cortical and subcortical abnormalities in both mass-univariate and multivariate pattern recognition analyses independent of MDD diagnosis. The most pronounced effects were found for associations between obesity and lower temporo-frontal cortical thickness (maximum Cohen´s d (left fusiform gyrus) = -0.33). The observed regional distribution and effect size of cortical thickness reductions in obesity revealed considerable similarities with corresponding patterns of lower cortical thickness in previously published studies of neuropsychiatric disorders. A higher polygenic risk score for obesity significantly correlated with lower occipital surface area. In addition, a significant age-by-obesity interaction on cortical thickness emerged driven by lower thickness in older participants. Our findings suggest a neurobiological interaction between obesity and brain structure under physiological and pathological brain conditions.

7.
Neuropsychobiology ; 79(3): 233-244, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32146473

RESUMO

BACKGROUND: Alexithymia is a personality trait characterized by difficulties in identifying and describing emotions and associated with various psychiatric disorders. Neuroimaging studies found evidence for morphological and functional brain alterations in alexithymic subjects. However, the neurobiological mechanisms underlying alexithymia remain incompletely understood. METHODS: We study the association of alexithymia with cortical correlation networks in a large community-dwelling sample of the Study of Health in Pomerania. Our analysis includes data of n = 2,199 individuals (49.4% females, age = 52.1 ± 13.6 years) which were divided into a low and high alexithymic group by a median split of the Toronto Alexithymia Scale. Cortical correlation networks were constructed based on the mean thicknesses of 68 regions, and differences in centralities were investigated. RESULTS: We found a significantly increased centrality of the right paracentral lobule in the high alexithymia network after correction for multiple testing. Several other regions with motoric and sensory functions showed altered centrality on a nominally significant level. CONCLUSIONS: Finding increased centrality of the paracentral lobule, a brain area with sensory as well as motoric features and involvement in bowel and bladder voiding, may contribute to explain the association of alexithymia with functional somatic disorders and chronic pain syndromes.

8.
Hum Brain Mapp ; 2020 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-32198905

RESUMO

Alterations in regional subcortical brain volumes have been investigated as part of the efforts of an international consortium, ENIGMA, to identify reliable neural correlates of major depressive disorder (MDD). Given that subcortical structures are comprised of distinct subfields, we sought to build significantly from prior work by precisely mapping localized MDD-related differences in subcortical regions using shape analysis. In this meta-analysis of subcortical shape from the ENIGMA-MDD working group, we compared 1,781 patients with MDD and 2,953 healthy controls (CTL) on individual measures of shape metrics (thickness and surface area) on the surface of seven bilateral subcortical structures: nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen, and thalamus. Harmonized data processing and statistical analyses were conducted locally at each site, and findings were aggregated by meta-analysis. Relative to CTL, patients with adolescent-onset MDD (≤ 21 years) had lower thickness and surface area of the subiculum, cornu ammonis (CA) 1 of the hippocampus and basolateral amygdala (Cohen's d = -0.164 to -0.180). Relative to first-episode MDD, recurrent MDD patients had lower thickness and surface area in the CA1 of the hippocampus and the basolateral amygdala (Cohen's d = -0.173 to -0.184). Our results suggest that previously reported MDD-associated volumetric differences may be localized to specific subfields of these structures that have been shown to be sensitive to the effects of stress, with important implications for mapping treatments to patients based on specific neural targets and key clinical features.

9.
Cereb Cortex ; 30(4): 2307-2320, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32109272

RESUMO

We analyzed the genomic architecture of neuroanatomical diversity using magnetic resonance imaging and single nucleotide polymorphism (SNP) data from >26 000 individuals from the UK Biobank project and 5 other projects that had previously participated in the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) consortium. Our results confirm the polygenic architecture of neuroanatomical diversity, with SNPs capturing from 40% to 54% of regional brain volume variance. Chromosomal length correlated with the amount of phenotypic variance captured, r ~ 0.64 on average, suggesting that at a global scale causal variants are homogeneously distributed across the genome. At a local scale, SNPs within genes (~51%) captured ~1.5 times more genetic variance than the rest, and SNPs with low minor allele frequency (MAF) captured less variance than the rest: the 40% of SNPs with MAF <5% captured

10.
Mayo Clin Proc ; 95(1): 44-56, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31902428

RESUMO

OBJECTIVE: To analyze the association between cardiorespiratory fitness (CRF) and global and local brain volumes. PARTICIPANTS AND METHODS: We studied 2103 adults (21-84 years old) from 2 independent population-based cohorts (Study of Health in Pomerania, examinations from June 25, 2008, through September 30, 2012). Cardiorespiratory fitness was measured using peak oxygen uptake (VO2peak), oxygen uptake at the anaerobic threshold (VO2@AT), and maximal power output from cardiopulmonary exercise testing on a bicycle ergometer. Magnetic resonance imaging brain data were analyzed by voxel-based morphometry using regression models with adjustment for age, sex, education, smoking, body weight, systolic blood pressure, glycated hemoglobin level, and intracranial volume. RESULTS: Volumetric analyses revealed associations of CRF with gray matter (GM) volume and total brain volume. After multivariable adjustment, a 1-standard deviation increase in VO2peak was related to a 5.31 cm³ (95% CI, 3.27 to 7.35 cm³) higher GM volume. Whole-brain voxel-based morphometry analyses revealed significant positive relations between CRF and local GM volumes. The VO2peak was strongly associated with GM volume of the left middle temporal gyrus (228 voxels), the right hippocampal gyrus (146 voxels), the left orbitofrontal cortex (348 voxels), and the bilateral cingulate cortex (68 and 43 voxels). CONCLUSION: Cardiorespiratory fitness was positively associated with GM volume, total brain volume, and specific GM and white matter clusters in brain areas not primarily involved in movement processing. These results, from a representative population sample, suggest that CRF might contribute to improved brain health and might, therefore, decelerate pathology-specific GM decrease.


Assuntos
Limiar Anaeróbio , Encéfalo , Aptidão Cardiorrespiratória/fisiologia , Substância Cinzenta , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Correlação de Dados , Teste de Esforço/métodos , Teste de Esforço/estatística & dados numéricos , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão
11.
Cereb Cortex ; 30(2): 575-586, 2020 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-31240317

RESUMO

Exposures to life stressors accumulate across the lifespan, with possible impact on brain health. Little is known, however, about the mechanisms mediating age-related changes in brain structure. We use a lifespan sample of participants (n = 21 251; 4-97 years) to investigate the relationship between the thickness of cerebral cortex and the expression of the glucocorticoid- and the mineralocorticoid-receptor genes (NR3C1 and NR3C2, respectively), obtained from the Allen Human Brain Atlas. In all participants, cortical thickness correlated negatively with the expression of both NR3C1 and NR3C2 across 34 cortical regions. The magnitude of this correlation varied across the lifespan. From childhood through early adulthood, the profile similarity (between NR3C1/NR3C2 expression and thickness) increased with age. Conversely, both profile similarities decreased with age in late life. These variations do not reflect age-related changes in NR3C1 and NR3C2 expression, as observed in 5 databases of gene expression in the human cerebral cortex (502 donors). Based on the co-expression of NR3C1 (and NR3C2) with genes specific to neural cell types, we determine the potential involvement of microglia, astrocytes, and CA1 pyramidal cells in mediating the relationship between corticosteroid exposure and cortical thickness. Therefore, corticosteroids may influence brain structure to a variable degree throughout life.

12.
Psychol Med ; 50(6): 1020-1031, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31084657

RESUMO

BACKGROUND: Childhood maltreatment (CM) plays an important role in the development of major depressive disorder (MDD). The aim of this study was to examine whether CM severity and type are associated with MDD-related brain alterations, and how they interact with sex and age. METHODS: Within the ENIGMA-MDD network, severity and subtypes of CM using the Childhood Trauma Questionnaire were assessed and structural magnetic resonance imaging data from patients with MDD and healthy controls were analyzed in a mega-analysis comprising a total of 3872 participants aged between 13 and 89 years. Cortical thickness and surface area were extracted at each site using FreeSurfer. RESULTS: CM severity was associated with reduced cortical thickness in the banks of the superior temporal sulcus and supramarginal gyrus as well as with reduced surface area of the middle temporal lobe. Participants reporting both childhood neglect and abuse had a lower cortical thickness in the inferior parietal lobe, middle temporal lobe, and precuneus compared to participants not exposed to CM. In males only, regardless of diagnosis, CM severity was associated with higher cortical thickness of the rostral anterior cingulate cortex. Finally, a significant interaction between CM and age in predicting thickness was seen across several prefrontal, temporal, and temporo-parietal regions. CONCLUSIONS: Severity and type of CM may impact cortical thickness and surface area. Importantly, CM may influence age-dependent brain maturation, particularly in regions related to the default mode network, perception, and theory of mind.

13.
Child Abuse Negl ; 101: 104311, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31877447

RESUMO

BACKGROUND: Previous studies suggested that childhood maltreatment is associated with altered memory performance in adulthood. Deficits in identifying and describing feelings as captured by the alexithymia construct are strongly linked with childhood trauma and may mediate the associations with memory function. OBJECTIVE: To investigate the associations of childhood trauma with verbal declarative memory performance and the putative mediating role of alexithymia. METHOD: Associations of the different dimensions of childhood trauma with adult declarative memory performance were tested in two large, independent general population samples comprising a total of N = 5574 participants. Moreover, we tested whether associations were mediated by alexithymia. RESULTS: In both samples, childhood emotional neglect, but not abuse emerged as a negative statistical predictor of early (sample 1: ß=-1.79; p < 0.001, sample 2: ß=-0.26; p < 0.001) as well as delayed recall (ß=-0.78; p < 0.001; ß=-0.24; p < 0.05). Likewise, childhood emotional neglect was the strongest predictor for alexithymia (ß = 3.2; p < 0.001; ß = 3.54; p < 0.001). Finally, the association between childhood emotional neglect and early (Total Mediated Effect (TME): 13.2, CI: 0.087-0.302; TME: 20.1; CI: 0.123-0.619) as well as late recall (TME: 13.2, CI: 0.086-0.301; TME: 9; CI: -0.442-0.699) was significantly mediated by alexithymia. CONCLUSIONS: Our findings suggest that childhood emotional neglect is particularly detrimental to memory functioning in adulthood. In comparison, childhood abuse was not associated with reduced declarative memory capacity. Our results contribute to explain the mechanism underlying the relation of childhood trauma and memory deficits: Finding specific associations with emotional neglect and a mediating role of alexithymia highlights the relevance of emotion processing capacities for memory functioning.

14.
Neuropsychopharmacology ; 44(12): 2030-2037, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31284290

RESUMO

Childhood traumatization (CT) is associated with the development of several neuropsychiatric disorders in later life. Experimental data in animals and observational data in humans revealed evidence for biological alterations in response to CT that may contribute to its long-term consequences. This includes epigenetic changes in miRNA levels that contribute to complex alterations of gene expression. We investigated the association between CT and 121 miRNAs in a target sample of N = 150 subjects from the general population and patients from the Department of Psychiatry. We hypothesized that CT exhibits a long-term effect on miRNA plasma levels. We supported our findings using bioinformatics tools and databases. Among the 121 miRNAs 22 were nominally significantly associated with CT and four of them (let-7g-5p, miR-103a-3p, miR-107, and miR-142-3p) also after correction for multiple testing; most of them were previously associated with Alzheimer's disease (AD) or depression. Pathway analyses of target genes identified significant pathways involved in neurodevelopment, inflammation and intracellular transduction signaling. In an independent general population sample (N = 587) three of the four miRNAs were replicated. Extended analyses in the general population sample only (N = 687) showed associations of the four miRNAs with gender, memory, and brain volumes. We gained increasing evidence for a link between CT, depression and AD through miRNA alterations. We hypothesize that depression and AD not only share environmental factors like CT but also biological factors like altered miRNA levels. This miRNA pattern could serve as mediating factor on the biological path from CT to adult neuropsychiatric disorders.


Assuntos
Experiências Adversas da Infância , MicroRNAs/sangue , Adulto , Epigênese Genética , Feminino , Substância Cinzenta/patologia , Hipocampo/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
15.
Alzheimers Dement (Amst) ; 11: 286-290, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30976649

RESUMO

Advances in technology enable increasing amounts of data collection from individuals for biomedical research. Such technologies, for example, in genetics and medical imaging, have also led to important scientific discoveries about health and disease. The combination of multiple types of high-throughput data for complex analyses, however, has been limited by analytical and logistic resources to handle high-dimensional data sets. In our previous EU Joint Programme-Neurodegenerative Disease Research (JPND) Working Group, called HD-READY, we developed methods that allowed successful combination of omics data with neuroimaging. Still, several issues remained to fully leverage high-dimensional multimodality data. For instance, high-dimensional features, such as voxels and vertices, which are common in neuroimaging, remain difficult to harmonize. In this Full-HD Working Group, we focused on such harmonization of high-dimensional neuroimaging phenotypes in combination with other omics data and how to make the resulting ultra-high-dimensional data easily accessible in neurodegeneration research.

17.
Front Psychiatry ; 10: 953, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31992998

RESUMO

Introduction: It has been shown that Alzheimer's disease (AD) is accompanied by marked structural brain changes that can be detected several years before clinical diagnosis via structural magnetic resonance (MR) imaging. In this study, we developed a structural MR-based biomarker for in vivo detection of AD using a supervised machine learning approach. Based on an individual's pattern of brain atrophy a continuous AD score is assigned which measures the similarity with brain atrophy patterns seen in clinical cases of AD. Methods: The underlying statistical model was trained with MR scans of patients and healthy controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI-1 screening). Validation was performed within ADNI-1 and in an independent patient sample from the Open Access Series of Imaging Studies (OASIS-1). In addition, our analyses included data from a large general population sample of the Study of Health in Pomerania (SHIP-Trend). Results: Based on the proposed AD score we were able to differentiate patients from healthy controls in ADNI-1 and OASIS-1 with an accuracy of 89% (AUC = 95%) and 87% (AUC = 93%), respectively. Moreover, we found the AD score to be significantly associated with cognitive functioning as assessed by the Mini-Mental State Examination in the OASIS-1 sample after correcting for diagnosis, age, sex, age·sex, and total intracranial volume (Cohen's f2 = 0.13). Additional analyses showed that the prediction accuracy of AD status based on both the AD score and the MMSE score is significantly higher than when using just one of them. In SHIP-Trend we found the AD score to be weakly but significantly associated with a test of verbal memory consisting of an immediate and a delayed word list recall (again after correcting for age, sex, age·sex, and total intracranial volume, Cohen's f2 = 0.009). This association was mainly driven by the immediate recall performance. Discussion: In summary, our proposed biomarker well differentiated between patients and healthy controls in an independent test sample. It was associated with measures of cognitive functioning both in a patient sample and a general population sample. Our approach might be useful for defining robust MR-based biomarkers for other neurodegenerative diseases, too.

18.
Curr Biol ; 29(1): 120-127.e5, 2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-30554901

RESUMO

One of the features that distinguishes modern humans from our extinct relatives and ancestors is a globular shape of the braincase [1-4]. As the endocranium closely mirrors the outer shape of the brain, these differences might reflect altered neural architecture [4, 5]. However, in the absence of fossil brain tissue, the underlying neuroanatomical changes as well as their genetic bases remain elusive. To better understand the biological foundations of modern human endocranial shape, we turn to our closest extinct relatives: the Neandertals. Interbreeding between modern humans and Neandertals has resulted in introgressed fragments of Neandertal DNA in the genomes of present-day non-Africans [6, 7]. Based on shape analyses of fossil skull endocasts, we derive a measure of endocranial globularity from structural MRI scans of thousands of modern humans and study the effects of introgressed fragments of Neandertal DNA on this phenotype. We find that Neandertal alleles on chromosomes 1 and 18 are associated with reduced endocranial globularity. These alleles influence expression of two nearby genes, UBR4 and PHLPP1, which are involved in neurogenesis and myelination, respectively. Our findings show how integration of fossil skull data with archaic genomics and neuroimaging can suggest developmental mechanisms that may contribute to the unique modern human endocranial shape.


Assuntos
Evolução Biológica , Hibridização Genética , Homem de Neandertal/anatomia & histologia , Crânio/anatomia & histologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Fósseis , Humanos , Masculino , Pessoa de Meia-Idade , Países Baixos , Fenótipo , Adulto Jovem
19.
Stat Methods Med Res ; 28(5): 1427-1438, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-29468943

RESUMO

For the goal of individualized medicine, it is critical to have clinical phenotypes at hand which represent the individual pathophysiology. However, for most of the utilized phenotypes, two individuals with the same phenotype assignment may differ strongly in their underlying biological traits. In this paper, we propose a definition for individualization and a corresponding statistical operationalization, delivering thereby a statistical framework in which the usefulness of a variable in the meaningful differentiation of individuals with the same phenotype can be assessed. Based on this framework, we develop a statistical workflow to derive individualized phenotypes, demonstrating that under specific statistical constraints the prediction error of prediction scores contains information about hidden biological traits not represented in the modeled phenotype of interest, allowing thereby internal differentiation of individuals with the same assigned phenotypic manifestation. We applied our procedure to data of the population-based Study of Health in Pomerania to construct a refined definition of obesity, demonstrating the utility of the definition in prospective survival analyses. Summarizing, we propose a framework for the individualization of phenotypes aiding personalized medicine by shifting the focus in the assessment of prediction models from the model fit to the informational content of the prediction error.


Assuntos
Métodos Epidemiológicos , Modelos Estatísticos , Obesidade/epidemiologia , Medicina de Precisão/estatística & dados numéricos , Alemanha/epidemiologia , Humanos , Fenótipo , Projetos de Pesquisa
20.
Thyroid ; 28(11): 1434-1442, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30259797

RESUMO

BACKGROUND: Previous patient studies suggest that thyroid dysfunction affects volumes of particular regions of the brain. So far, population-based data related to this topic are lacking. The aim of this study was to investigate associations of serum levels of thyrotropin (TSH), free triiodothyronine, and free thyroxine (fT4) with total brain volume, gray matter volume, white matter volume (WMV), and hippocampal volume (HV) in a population-based study. METHODS: Data on 2557 individuals were pooled from two independent population-based surveys of the Study of Health in Pomerania conducted in Northeast Germany. Brain volumes were determined from images derived from 1.5 T magnetic resonance imaging. Low and high TSH were defined using the cutoffs 0.40 and 3.29 mIU/L, respectively. Associations between thyroid hormone levels and segmented brain volumes were analyzed by linear regression models. Further, voxel-based morphometry was conducted to search for associations with thyroid hormone levels in a hypothesis-free way throughout the whole brain. All models were adjusted for confounders. RESULTS: Only 9/70 individuals with high TSH had low free triiodothyronine or fT4 levels. Individuals with high TSH had significantly lower total brain volume (ß = -26.9 [confidence interval (CI) -49.0 to -4.8]; p = 0.017), WMV (ß = -16.1 [CI -29.4 to -2.7]; p = 0.018), and HV (ß = -223 [CI -395 to -50]; p = 0.011) than individuals with TSH within the reference range, while low TSH was not significantly associated with any of the brain volumes. Voxel-based morphometry analyses revealed a significant positive association with serum fT4 levels in the left middle frontal gyrus. CONCLUSIONS: In conclusion, the results of this study indicate that the subclinical hypothyroid state may lead to a reduced brain volume affecting particularly HV in younger subjects and WMV, which might correspond to subtle microstructural changes in white matter fiber tracts or myelination of the axones. Gray matter seems not to be affected by subclinical hypothyroid states.


Assuntos
Hipocampo/diagnóstico por imagem , Doenças da Glândula Tireoide/sangue , Doenças da Glândula Tireoide/diagnóstico por imagem , Tireotropina/sangue , Adulto , Idoso , Feminino , Alemanha , Substância Cinzenta/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão/fisiologia , Testes de Função Tireóidea , Tiroxina/sangue , Tri-Iodotironina/sangue
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