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1.
Nat Commun ; 10(1): 2358, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31127096

RESUMO

The original HTML version of this Article was updated shortly after publication to add links to the Peer Review file.In addition, affiliations 16 and 17 incorrectly read 'School of Medicine Sydney, University of Notre Dame Australia, Sydney, WA, 6160, Australia' and 'St Vincent's Clinical School, University of New South Wales Medicine, University of New South Wales, Sydney, NSW, 2052, Australia.' This has now been corrected in both the PDF and HTML versions of the Article.

2.
Nat Commun ; 10(1): 2054, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053729

RESUMO

Bone area is one measure of bone size that is easily derived from dual-energy X-ray absorptiometry (DXA) scans. In a GWA study of DXA bone area of the hip and lumbar spine (N ≥ 28,954), we find thirteen independent association signals at twelve loci that replicate in samples of European and East Asian descent (N = 13,608 - 21,277). Eight DXA area loci associate with osteoarthritis, including rs143384 in GDF5 and a missense variant in COL11A1 (rs3753841). The strongest DXA area association is with rs11614913[T] in the microRNA MIR196A2 gene that associates with lumbar spine area (P = 2.3 × 10-42, ß = -0.090) and confers risk of hip fracture (P = 1.0 × 10-8, OR = 1.11). We demonstrate that the risk allele is less efficient in repressing miR-196a-5p target genes. We also show that the DXA area measure contributes to the risk of hip fracture independent of bone density.


Assuntos
Densidade Óssea/genética , Fraturas do Quadril/genética , MicroRNAs/genética , Osteoartrite/genética , Absorciometria de Fóton , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Estatura/genética , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/fisiologia , Estudos de Casos e Controles , Colágeno Tipo XI/genética , Feminino , Seguimentos , Loci Gênicos , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Fator 5 de Diferenciação de Crescimento/genética , Fraturas do Quadril/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/epidemiologia , Fatores de Risco
3.
Diabetes Res Clin Pract ; 151: 224-230, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31004670

RESUMO

AIMS: Type1 diabetes is generally regarded as an abruptly presenting disease in children without family history. The incidence and prevalence of insulin requiring diabetes in adults is unclear. The aim of this study was to clarify this issue by examining the epidemiology of type 1 diabetes diagnosed in adulthood in a countrýs whole population. METHODS: Complete clinical and prescription data were used to identify cases of insulin requiring diabetes in the Icelandic population 18 years and older during the decade preceding February 2013. Health care databases and the insulin reimbursement system allowed for near 100% ascertainment of cases. RESULTS: Mean age at diagnosis was 32.1 years. The WHO age-adjusted incidence rate was 4.29/100.000 individuals and the point prevalence 0.10%. One fourth of cases were diagnosed after the age of forty. The male-to-female incidence rate ratio was 1.59. Almost 30% of cases presented with diabetic ketoacidosis and 40% had a positive family history. CONCLUSION: Type 1 like diabetes commonly presents in adults and family history is not rare. One can expect one case of type 1 diabetes in adults for every two children diagnosed. These results emphasize the need to acknowledge the possibility of absolute insulin deficiency in any newly presenting adult with diabetes.


Assuntos
Diabetes Mellitus Tipo 1/epidemiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Islândia , Incidência , Masculino , Pessoa de Meia-Idade , Prevalência , Adulto Jovem
4.
Nat Commun ; 10(1): 1777, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992453

RESUMO

Nerve conduction (NC) studies generate measures of peripheral nerve function that can reveal underlying pathology due to axonal loss, demyelination or both. We perform a genome-wide association study of sural NC amplitude and velocity in 7045 Icelanders and find a low-frequency splice-donor variant in PRPH (c.996+1G>A; MAF = 1.32%) associating with decreased NC amplitude but not velocity. PRPH encodes peripherin, an intermediate filament (IF) protein involved in cytoskeletal development and maintenance of neurons. Through RNA and protein studies, we show that the variant leads to loss-of-function (LoF), as when over-expressed in a cell line devoid of other IFs, it does not allow formation of the normal filamentous structure of peripherin, yielding instead punctate protein inclusions. Recall of carriers for neurological assessment confirms that from an early age, homozygotes have significantly lower sural NC amplitude than non-carriers and are at risk of a mild, early-onset, sensory-negative, axonal polyneuropathy.


Assuntos
Condução Nervosa/genética , Periferinas/genética , Polineuropatias/genética , Sítios de Splice de RNA/genética , Nervo Sural/fisiopatologia , Adulto , Idade de Início , Idoso , Axônios/patologia , Estudos de Casos e Controles , Linhagem Celular , Feminino , Seguimentos , Estudo de Associação Genômica Ampla , Homozigoto , Humanos , Islândia/epidemiologia , Mutação com Perda de Função , Masculino , Pessoa de Meia-Idade , Polineuropatias/epidemiologia , Polineuropatias/fisiopatologia , Prevalência , Processamento de RNA/fisiologia
6.
NPJ Genom Med ; 2: 24, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29263835

RESUMO

A meta-analysis of publicly available summary statistics on multiple sclerosis combined with three Nordic multiple sclerosis cohorts (21,079 cases, 371,198 controls) revealed seven sequence variants associating with multiple sclerosis, not reported previously. Using polygenic risk scores based on public summary statistics of variants outside the major histocompatibility complex region we quantified genetic overlap between common autoimmune diseases in Icelanders and identified disease clusters characterized by autoantibody presence/absence. As multiple sclerosis-polygenic risk scores captures the risk of primary biliary cirrhosis and vice versa (P = 1.6 × 10-7, 4.3 × 10-9) we used primary biliary cirrhosis as a proxy-phenotype for multiple sclerosis, the idea being that variants conferring risk of primary biliary cirrhosis have a prior probability of conferring risk of multiple sclerosis. We tested 255 variants forming the primary biliary cirrhosis-polygenic risk score and found seven multiple sclerosis-associating variants not correlated with any previously established multiple sclerosis variants. Most of the variants discovered are close to or within immune-related genes. One is a low-frequency missense variant in TYK2, another is a missense variant in MTHFR that reduces the function of the encoded enzyme affecting methionine metabolism, reported to be dysregulated in multiple sclerosis brain.

7.
Nat Genet ; 49(9): 1398-1402, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28783164

RESUMO

Sequence variants that affect mean fasting glucose levels do not necessarily affect risk for type 2 diabetes (T2D). We assessed the effects of 36 reported glucose-associated sequence variants on between- and within-subject variance in fasting glucose levels in 69,142 Icelanders. The variant in TCF7L2 that increases fasting glucose levels increases between-subject variance (5.7% per allele, P = 4.2 × 10-10), whereas variants in GCK and G6PC2 that increase fasting glucose levels decrease between-subject variance (7.5% per allele, P = 4.9 × 10-11 and 7.3% per allele, P = 7.5 × 10-18, respectively). Variants that increase mean and between-subject variance in fasting glucose levels tend to increase T2D risk, whereas those that increase the mean but reduce variance do not (r2 = 0.61). The variants that increase between-subject variance increase fasting glucose heritability estimates. Intuitively, our results show that increasing the mean and variance of glucose levels is more likely to cause pathologically high glucose levels than increase in the mean offset by a decrease in variance.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença/genética , Variação Genética , Alelos , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/sangue , Jejum , Feminino , Frequência do Gene , Glucoquinase/genética , Glucose-6-Fosfatase/genética , Hemoglobina A Glicada/metabolismo , Humanos , Islândia , Masculino , Penetrância , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética
8.
Diabetes ; 66(11): 2888-2902, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28566273

RESUMO

To characterize type 2 diabetes (T2D)-associated variation across the allele frequency spectrum, we conducted a meta-analysis of genome-wide association data from 26,676 T2D case and 132,532 control subjects of European ancestry after imputation using the 1000 Genomes multiethnic reference panel. Promising association signals were followed up in additional data sets (of 14,545 or 7,397 T2D case and 38,994 or 71,604 control subjects). We identified 13 novel T2D-associated loci (P < 5 × 10-8), including variants near the GLP2R, GIP, and HLA-DQA1 genes. Our analysis brought the total number of independent T2D associations to 128 distinct signals at 113 loci. Despite substantially increased sample size and more complete coverage of low-frequency variation, all novel associations were driven by common single nucleotide variants. Credible sets of potentially causal variants were generally larger than those based on imputation with earlier reference panels, consistent with resolution of causal signals to common risk haplotypes. Stratification of T2D-associated loci based on T2D-related quantitative trait associations revealed tissue-specific enrichment of regulatory annotations in pancreatic islet enhancers for loci influencing insulin secretion and in adipocytes, monocytes, and hepatocytes for insulin action-associated loci. These findings highlight the predominant role played by common variants of modest effect and the diversity of biological mechanisms influencing T2D pathophysiology.


Assuntos
Diabetes Mellitus Tipo 2/genética , Grupo com Ancestrais do Continente Europeu , Regulação da Expressão Gênica/fisiologia , Estudo de Associação Genômica Ampla , Variação Genética , Humanos
9.
Nat Genet ; 47(12): 1415-25, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26551672

RESUMO

We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct signal mapped predominantly to noncoding sequence, implying that association with T2D is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine mapping implicated rs10830963 as driving T2D association. We confirmed that the T2D risk allele for this SNP increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease.


Assuntos
Mapeamento Cromossômico , Diabetes Mellitus Tipo 2/genética , Loci Gênicos , Predisposição Genética para Doença , Fator 3-beta Nuclear de Hepatócito/genética , Polimorfismo de Nucleotídeo Único/genética , Receptor MT2 de Melatonina/genética , Sítios de Ligação , Estudos de Casos e Controles , Imunoprecipitação da Cromatina , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Genômica , Fator 3-beta Nuclear de Hepatócito/metabolismo , Humanos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Fígado/metabolismo , Fígado/patologia , Anotação de Sequência Molecular , Receptor MT2 de Melatonina/metabolismo
10.
Eur J Endocrinol ; 173(5): 655-64, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26423473

RESUMO

OBJECTIVE: Pituitary adenomas (PA) are among the most common human neoplasms. To describe the epidemiology and assess the disease burden of clinically significant PAs, population-based studies are needed. Iceland has a small well-defined population. The aim of this study is to describe the epidemiology of PAs in Iceland over an expanded period of time. DESIGN: This is a retrospective observational study, including all PAs diagnosed in Iceland from 1955 to 2012. METHODS: Extensive clinical information was gathered in a database. Prevalence rates for all PA subtypes were calculated along with standardized incidence rates (SIR). Sex ratios and relationships with adenoma size, age, and symptoms were assessed. RESULTS: We identified 471 individuals: 190 men and 281 women. Total prevalence in 2012 was 115.57/100, 000, prolactinomas were most prevalent (54.37/100, 000) followed by non-functioning adenomas (NFPAs) (42.32/100 ,000). Throughout the period, NFPAs were most common (43.0%) followed by prolactinomas (39.9%) and 11.3% had acromegaly and 5.7% Cushing's disease. Women are diagnosed younger with smaller adenomas. Total SIR has increased significantly and is now 5.8/100 000 per year. CONCLUSION: In this nationwide study spanning six decades, we have confirmed PAs rising prevalence and incidence rates noted in recent studies. We demonstrated higher overall prevalence and incidence rates than ever previously recorded with an increasing predominance of NFPAs, which is not explained by incidental findings alone. There is a relationship with the introduction of imaging modalities, but the vast majority of patients are symptomatic at diagnosis. This underlines the importance of increased awareness, education, and appropriate allocation of resources for this growing group of patients.


Assuntos
Acromegalia/epidemiologia , Adenoma/epidemiologia , Hipersecreção Hipofisária de ACTH/epidemiologia , Neoplasias Hipofisárias/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Islândia/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Prolactinoma/epidemiologia , Estudos Retrospectivos , Adulto Jovem
11.
Diabetes Care ; 37(12): 3213-9, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25315206

RESUMO

OBJECTIVE: Studies in type 2 diabetes report both increased mortality for normal weight and no evidence of an obesity paradox. We aimed to examine whether adipose tissue, muscle size, and physical function, which are known to vary by weight, mediate associations between BMI and mortality. RESEARCH DESIGN AND METHODS: The AGES-Reykjavik cohort comprised participants aged 66-96 years with diabetes defined by fasting glucose, medications, or self-report. BMI was determined from measured height and weight and classified as normal (18.5-24.9 kg/m(2), n = 117), overweight (25.0-29.9 kg/m(2), n = 293, referent group) or obese (≥30.0 kg/m(2), n = 227). Thigh muscle area and intermuscular, visceral, and subcutaneous adipose tissues were assessed with computed tomography. Function was assessed from gait speed and knee extensor strength. Hazard ratios (HRs) and 95% CIs were estimated by Cox proportional hazards regression adjusted for demographics and diabetes-related risk factors. RESULTS: The median follow-up was 6.66 years, and there were 85, 59, and 44 deaths among normal weight, overweight, and obese participants, respectively. There was no mortality risk for obese participants and an increased risk among normal weight compared with overweight participants (HR 1.72 [95% CI 1.12-2.64]). Associations remained with adjustment for adipose tissues and knee extensor strength; however, mortality risk for normal weight was attenuated following adjustment for thigh muscle (HR 1.36 [95% CI 0.87-2.11]) and gait speed (HR 1.44 [95% CI 0.91-2.27]). Linear regression confirmed with bootstrapping indicated that thigh muscle size mediated 46% of the relationship between normal weight and mortality. CONCLUSIONS: Normal weight participants had elevated mortality risk compared with overweight participants. This paradoxical association was mediated in part by muscle size.


Assuntos
Composição Corporal , Peso Corporal/fisiologia , Diabetes Mellitus Tipo 2/mortalidade , Atividade Motora , Tecido Adiposo/patologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Humanos , Masculino , Músculo Esquelético/patologia , Obesidade/complicações , Obesidade/metabolismo , Obesidade/mortalidade , Sobrepeso/complicações , Sobrepeso/metabolismo , Sobrepeso/mortalidade , Fatores de Risco
12.
Nat Genet ; 46(4): 357-63, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24584071

RESUMO

Loss-of-function mutations protective against human disease provide in vivo validation of therapeutic targets, but none have yet been described for type 2 diabetes (T2D). Through sequencing or genotyping of ~150,000 individuals across 5 ancestry groups, we identified 12 rare protein-truncating variants in SLC30A8, which encodes an islet zinc transporter (ZnT8) and harbors a common variant (p.Trp325Arg) associated with T2D risk and glucose and proinsulin levels. Collectively, carriers of protein-truncating variants had 65% reduced T2D risk (P = 1.7 × 10(-6)), and non-diabetic Icelandic carriers of a frameshift variant (p.Lys34Serfs*50) demonstrated reduced glucose levels (-0.17 s.d., P = 4.6 × 10(-4)). The two most common protein-truncating variants (p.Arg138* and p.Lys34Serfs*50) individually associate with T2D protection and encode unstable ZnT8 proteins. Previous functional study of SLC30A8 suggested that reduced zinc transport increases T2D risk, and phenotypic heterogeneity was observed in mouse Slc30a8 knockouts. In contrast, loss-of-function mutations in humans provide strong evidence that SLC30A8 haploinsufficiency protects against T2D, suggesting ZnT8 inhibition as a therapeutic strategy in T2D prevention.


Assuntos
Proteínas de Transporte de Cátions/genética , Diabetes Mellitus Tipo 2/genética , Mutação de Sentido Incorreto/genética , Animais , Sequência de Bases , Glicemia/genética , Estudos de Associação Genética , Genótipo , Humanos , Transporte de Íons/genética , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Proinsulina/sangue , Análise de Sequência de DNA , Transportador 8 de Zinco
13.
Nat Genet ; 46(3): 234-44, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24509480

RESUMO

To further understanding of the genetic basis of type 2 diabetes (T2D) susceptibility, we aggregated published meta-analyses of genome-wide association studies (GWAS), including 26,488 cases and 83,964 controls of European, east Asian, south Asian and Mexican and Mexican American ancestry. We observed a significant excess in the directional consistency of T2D risk alleles across ancestry groups, even at SNPs demonstrating only weak evidence of association. By following up the strongest signals of association from the trans-ethnic meta-analysis in an additional 21,491 cases and 55,647 controls of European ancestry, we identified seven new T2D susceptibility loci. Furthermore, we observed considerable improvements in the fine-mapping resolution of common variant association signals at several T2D susceptibility loci. These observations highlight the benefits of trans-ethnic GWAS for the discovery and characterization of complex trait loci and emphasize an exciting opportunity to extend insight into the genetic architecture and pathogenesis of human diseases across populations of diverse ancestry.


Assuntos
Diabetes Mellitus Tipo 2/genética , Alelos , Grupo com Ancestrais do Continente Asiático/genética , Estudos de Casos e Controles , Grupo com Ancestrais do Continente Europeu/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Hispano-Americanos/genética , Humanos , Polimorfismo de Nucleotídeo Único , Fatores de Risco
14.
Nat Genet ; 46(3): 294-8, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24464100

RESUMO

Through whole-genome sequencing of 2,630 Icelanders and imputation into 11,114 Icelandic cases and 267,140 controls followed by testing in Danish and Iranian samples, we discovered 4 previously unreported variants affecting risk of type 2 diabetes (T2D). A low-frequency (1.47%) variant in intron 1 of CCND2, rs76895963[G], reduces risk of T2D by half (odds ratio (OR) = 0.53, P = 5.0 × 10(-21)) and is correlated with increased CCND2 expression. Notably, this variant is also associated with both greater height and higher body mass index (1.17 cm per allele, P = 5.5 × 10(-12) and 0.56 kg/m(2) per allele, P = 6.5 × 10(-7), respectively). In addition, two missense variants in PAM, encoding p.Asp563Gly (frequency of 4.98%) and p.Ser539Trp (frequency of 0.65%), confer moderately higher risk of T2D (OR = 1.23, P = 3.9 × 10(-10) and OR = 1.47, P = 1.7 × 10(-5), respectively), and a rare (0.20%) frameshift variant in PDX1, encoding p.Gly218Alafs*12, associates with high risk of T2D (OR = 2.27, P = 7.3 × 10(-7)).


Assuntos
Amidina-Liases/genética , Ciclina D2/genética , Diabetes Mellitus Tipo 2/genética , Variação Genética , Proteínas de Homeodomínio/genética , Oxigenases de Função Mista/genética , Transativadores/genética , Estatura/genética , Peso Corporal/genética , Estudos de Casos e Controles , Dinamarca , Diabetes Mellitus Tipo 2/patologia , Feminino , Frequência do Gene , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Islândia , Irã (Geográfico) , Masculino , Polimorfismo de Nucleotídeo Único , Fatores de Risco
15.
BMC Public Health ; 13: 36, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23320535

RESUMO

BACKGROUND: A decline in mortality rates due to cardiovascular diseases and all-cause mortality has led to increased life expectancy in the Western world in recent decades. At the same time, the prevalence of type 2 diabetes, a disease associated with a twofold excess risk of cardiovascular disease and mortality, has been increasing. The objective of this study was to estimate the secular trend of cardiovascular and all-cause mortality rates in two population-based cohorts of older persons, with and without type 2 diabetes, examined 11 years apart. METHODS: 1506 participants (42% men) from the population-based Reykjavik Study, examined during 1991-1996 (median 1993), mean age 75.0 years, and 4814 participants (43% men) from the AGES-Reykjavik Study, examined during 2002-2006 (median 2004), mean age 77.2 years, age range in both cohorts 70-87 years. The main outcome measures were age-specific mortality rates due to cardiovascular disease and all causes, over two consecutive 5.7- and 5.3-year follow-up periods. RESULTS: A 32% decline in cardiovascular mortality rate and a 19% decline in all-cause mortality rate were observed between 1993 and 2004. The decline was greater in those with type 2 diabetes, as illustrated by the decline in the adjusted hazard ratio of cardiovascular mortality in individuals with diabetes compared to those without diabetes, from 1.88 (95% CI 1.24-2.85) in 1993 to 1.46 (95% CI 1.11-1.91) in 2004. We also observed a concurrent decrease in major cardiovascular risk factors in both those with and without diabetes. A higher proportion of persons with diabetes received glucose-lowering, hypertensive and lipid-lowering medication in 2004. CONCLUSIONS: A decline in cardiovascular and all-cause mortality rates was observed in older persons during the period 1993-2004, in both those with and without type 2 diabetes. This decline may be partly explained by improvements in cardiovascular risk factors and medical treatment over the period studied. However, type 2 diabetes still persists as an independent risk factor for cardiovascular mortality.


Assuntos
Doenças Cardiovasculares/mortalidade , Diabetes Mellitus Tipo 2/mortalidade , Idoso , Idoso de 80 Anos ou mais , Causas de Morte/tendências , Estudos de Coortes , Feminino , Humanos , Islândia/epidemiologia , Masculino
16.
Laeknabladid ; 98(12): 639-44, 2012 Dec.
Artigo em Islandês | MEDLINE | ID: mdl-23232723

RESUMO

INTRODUCTION: Sedentary lifestyle and energy rich food have been associated with the risk of developing type 2 diabetes; limited data are available on environmental conditions in childhood on this risk later in life. The objective was to study if residency in the first 20 years of life affected the risk of developing type 2 diabetes. METHODS: In a cohort of 17811 men (48%) and women, mean age 53 years (range 33-81) participating in the population-based Reykjavík Study from 1967-91, 29% grew up in rural and 35% in coastal areas for an average of 20 years before moving to urban Reykjavík, but 36% lived in Reykjavík from birth. The prevalence of type 2 diabetes according to residency in early life was examined. RESULTS: The relative risk of developing type 2 diabetes was 43% lower in men (RR 0.57; 95% CI 0.43-0.77) and 26% lower (RR 0.74; 95% CI 0.56-0.99) in women living in rural areas for the first 20 years of their life compared with those living in urban Reykjavík from birth. The low prevalence among those that grew up in rural areas was maintained through the age categories of 55-64 years and 65 years and older. CONCLUSIONS: Our findings indicate that persons growing up in rural areas in early 20th century Iceland had lower risk of developing type 2 diabetes later in life when compared with peers living in Reykjavík from birth. We postulate a prolonged effect of early development on glucose metabolism and risk of developing type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Características de Residência , Saúde da População Rural , Saúde da População Urbana , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Inquéritos Epidemiológicos , Humanos , Islândia/epidemiologia , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Medição de Risco , Fatores de Risco , Adulto Jovem
17.
PLoS Genet ; 8(5): e1002741, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22693455

RESUMO

Common diseases such as type 2 diabetes are phenotypically heterogeneous. Obesity is a major risk factor for type 2 diabetes, but patients vary appreciably in body mass index. We hypothesized that the genetic predisposition to the disease may be different in lean (BMI<25 Kg/m²) compared to obese cases (BMI≥30 Kg/m²). We performed two case-control genome-wide studies using two accepted cut-offs for defining individuals as overweight or obese. We used 2,112 lean type 2 diabetes cases (BMI<25 kg/m²) or 4,123 obese cases (BMI≥30 kg/m²), and 54,412 un-stratified controls. Replication was performed in 2,881 lean cases or 8,702 obese cases, and 18,957 un-stratified controls. To assess the effects of known signals, we tested the individual and combined effects of SNPs representing 36 type 2 diabetes loci. After combining data from discovery and replication datasets, we identified two signals not previously reported in Europeans. A variant (rs8090011) in the LAMA1 gene was associated with type 2 diabetes in lean cases (P = 8.4×10⁻9, OR = 1.13 [95% CI 1.09-1.18]), and this association was stronger than that in obese cases (P = 0.04, OR = 1.03 [95% CI 1.00-1.06]). A variant in HMG20A--previously identified in South Asians but not Europeans--was associated with type 2 diabetes in obese cases (P = 1.3×10⁻8, OR = 1.11 [95% CI 1.07-1.15]), although this association was not significantly stronger than that in lean cases (P = 0.02, OR = 1.09 [95% CI 1.02-1.17]). For 36 known type 2 diabetes loci, 29 had a larger odds ratio in the lean compared to obese (binomial P = 0.0002). In the lean analysis, we observed a weighted per-risk allele OR = 1.13 [95% CI 1.10-1.17], P = 3.2×10⁻¹4. This was larger than the same model fitted in the obese analysis where the OR = 1.06 [95% CI 1.05-1.08], P = 2.2×10⁻¹6. This study provides evidence that stratification of type 2 diabetes cases by BMI may help identify additional risk variants and that lean cases may have a stronger genetic predisposition to type 2 diabetes.


Assuntos
Índice de Massa Corporal , Diabetes Mellitus Tipo 2/genética , Proteínas de Grupo de Alta Mobilidade/genética , Laminina/genética , Obesidade/genética , Idoso , Alelos , Grupo com Ancestrais do Continente Asiático/genética , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/complicações , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Polimorfismo de Nucleotídeo Único , Fatores de Risco
19.
BMJ Open ; 1(1): e000132, 2011 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-22021772

RESUMO

OBJECTIVE: To examine if the beneficial effect of statin medication on mortality seen in randomised clinical trials of type 2 diabetes applies equally to observational studies in the general population of older people. DESIGN: A prospective, population-based cohort study. SETTING: Reykjavik, Iceland. PARTICIPANTS: 5152 men and women from the Age, Gene/Environment Susceptibility-Reykjavik Study, mean age 77 years, range of 66-96 years. MAIN OUTCOME MEASURE: Cardiovascular and all-cause mortalities and the RR of dying according to statin use and history of coronary heart disease (CHD) in persons with type 2 diabetes and those without diabetes with a median follow-up time of 5.3 years, until end of 2009. RESULTS: The prevalence of type 2 diabetes was 12.4% of which 35% used statins. Statin use was associated with a 50% (95% CI 8% to 72%) lower cardiovascular mortality and 53% (29% to 68%) lower all-cause mortalities in persons with diabetes. For those without diabetes, statin use was associated with a 16% (-24% to 43%) lower cardiovascular and 30% (11% to 46%) lower all-cause mortalities. Persons with diabetes using statins had a comparable risk of cardiovascular and all-cause mortality to that of the general population without diabetes. The effect was independent of the level of glycaemic control. CONCLUSION: This observational study lends important support to existing data from randomised clinical trials. These data suggest that in the general population of older people with diabetes, statin medication markedly reduces the excess cardiovascular and all-cause mortality risk, irrespective of the presence or absence of coronary heart disease or glucose-lowering medication.

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