WorldCat Identities

Ripatti, Samuli

Overview
Works: 15 works in 19 publications in 1 language and 23 library holdings
Roles: Author, Other
Publication Timeline
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Most widely held works by Samuli Ripatti
Simulation-based maximum likelihood estimation in linear latent variable models with normal and ordinal outcomes by Klaus Larsen( Book )

3 editions published in 2000 in English and held by 5 WorldCat member libraries worldwide

Estimation of multivariate frailty models using penalized partial likelihood by Samuli Ripatti( Book )

2 editions published in 1999 in English and held by 3 WorldCat member libraries worldwide

Estimation of multivariate frailty models using penalized partial likelihood( Book )

1 edition published in 1999 in English and held by 2 WorldCat member libraries worldwide

Latent variable models for multivariate survival and count data by Samuli Ripatti( Book )

2 editions published in 2001 in English and held by 2 WorldCat member libraries worldwide

The Role of Adiposity in Cardiometabolic Traits a Mendelian Randomization Analysis by Tove Fall( )

1 edition published in 2013 in English and held by 1 WorldCat member library worldwide

Background: The association between adiposity and cardiometabolic traits is well known from epidemiological studies. Whilst the causal relationship is clear for some of these traits, for others it is not. We aimed to determine whether adiposity is causally related to various cardiometabolic traits using the Mendelian randomization approach. Methods and Findings: We used the adiposity-associated variant rs9939609 at the FTO locus as an instrumental variable (IV) for body mass index (BMI) in a Mendelian randomization design. Thirty-six population-based studies of individuals of European descent contributed to the analyses. Age-and sex-adjusted regression models were fitted to test for association between (i) rs9939609 and BMI (n = 198,502), (ii) rs9939609 and 24 traits, and (iii) BMI and 24 traits. The causal effect of BMI on the outcome measures was quantified by IV estimators. The estimators were compared to the BMI-trait associations derived from the same individuals. In the IV analysis, we demonstrated novel evidence for a causal relationship between adiposity and incident heart failure (hazard ratio, 1.19 per BMI-unit increase; 95% CI, 1.03-1.39) and replicated earlier reports of a causal association with type 2 diabetes, metabolic syndrome, dyslipidemia, and hypertension (odds ratio for IV estimator, 1.1-1.4; all p<0.05). For quantitative traits, our results provide novel evidence for a causal effect of adiposity on the liver enzymes alanine aminotransferase and gamma-glutamyl transferase and confirm previous reports of a causal effect of adiposity on systolic and diastolic blood pressure, fasting insulin, 2-h post-load glucose from the oral glucose tolerance test, C-reactive protein, triglycerides, and high-density lipoprotein cholesterol levels (all p<0.05). The estimated causal effects were in agreement with traditional observational measures in all instances except for type 2 diabetes, where the causal estimate was larger than the observational estimate (p = 0.001). Conclusions: We provide novel evidence for a causal relationship between adiposity and heart failure as well as between adiposity and increased liver enzymes
Association of vitamin D status with arterial blood pressure and hypertension risk a mendelian randomisation study by Karani S Vimaleswaran( )

1 edition published in 2014 in English and held by 1 WorldCat member library worldwide

A genome-wide association search for type 2 diabetes genes in African Americans by Nicholette D Palmer( )

1 edition published in 2012 in English and held by 1 WorldCat member library worldwide

African Americans are disproportionately affected by type 2 diabetes (T2DM) yet few studies have examined T2DM using genome-wide association approaches in this ethnicity. The aim of this study was to identify genes associated with T2DM in the African American population. We performed a Genome Wide Association Study (GWAS) using the Affymetrix 6.0 array in 965 African-American cases with T2DM and end-stage renal disease (T2DM-ESRD) and 1029 population-based controls. The most significant SNPs (n = 550 independent loci) were genotyped in a replication cohort and 122 SNPs (n = 98 independent loci) were further tested through genotyping three additional validation cohorts followed by meta-analysis in all five cohorts totaling 3,132 cases and 3,317 controls. Twelve SNPs had evidence of association in the GWAS (P<0.0071), were directionally consistent in the Replication cohort and were associated with T2DM in subjects without nephropathy (P<0.05). Meta-analysis in all cases and controls revealed a single SNP reaching genome-wide significance (P<2.5×10( -8)). SNP rs7560163 (P = 7.0×10( -9), OR (95% CI) = 0.75 (0.67-0.84)) is located intergenically between RND3 and RBM43. Four additional loci (rs7542900, rs4659485, rs2722769 and rs7107217) were associated with T2DM (P<0.05) and reached more nominal levels of significance (P<2.5×10( -5)) in the overall analysis and may represent novel loci that contribute to T2DM. We have identified novel T2DM-susceptibility variants in the African-American population. Notably, T2DM risk was associated with the major allele and implies an interesting genetic architecture in this population. These results suggest that multiple loci underlie T2DM susceptibility in the African-American population and that these loci are distinct from those identified in other ethnic populations
Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture by Sonja I Berndt( )

1 edition published in 2013 in English and held by 1 WorldCat member library worldwide

Approaches exploiting trait distribution extremes may be used to identify loci associated with common traits, but it is unknown whether these loci are generalizable to the broader population. In a genome-wide search for loci associated with the upper versus the lower 5th percentiles of body mass index, height and waist-to-hip ratio, as well as clinical classes of obesity, including up to 263,407 individuals of European ancestry, we identified 4 new loci (IGFBP4, H6PD, RSRC1 and PPP2R2A) influencing height detected in the distribution tails and 7 new loci (HNF4G, RPTOR, GNAT2, MRPS33P4, ADCY9, HS6ST3 and ZZZ3) for clinical classes of obesity. Further, we find a large overlap in genetic structure and the distribution of variants between traits based on extremes and the general population and little etiological heterogeneity between obesity subgroups
Sex-stratified Genome-wide Association Studies Including 270,000 Individuals Show Sexual Dimorphism in Genetic Loci for Anthropometric Traits by Joshua C Randall( )

1 edition published in 2013 in English and held by 1 WorldCat member library worldwide

Given the anthropometric differences between men and women and previous evidence of sex-difference in genetic effects, we conducted a genome-wide search for sexually dimorphic associations with height, weight, body mass index, waist circumference, hip circumference, and waist-to-hip-ratio (133,723 individuals) and took forward 348 SNPs into follow-up (additional 137,052 individuals) in a total of 94 studies. Seven loci displayed significant sex-difference (FDR<5%), including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were genome-wide significant in women (P<5x10( -8)), but not in men. Sex-differences were apparent only for waist phenotypes, not for height, weight, BMI, or hip circumference. Moreover, we found no evidence for genetic effects with opposite directions in men versus women. The PPARG locus is of specific interest due to its role in diabetes genetics and therapy. Our results demonstrate the value of sex-specific GWAS to unravel the sexually dimorphic genetic underpinning of complex traits
Large meta-analysis of genome-wide association studies identifies five loci for lean body mass by M. Carola Zillikens( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Lean body mass, consisting mostly of skeletal muscle, is important for healthy aging. We performed a genome-wide association study for whole body (20 cohorts of European ancestry with n = 38,292) and appendicular (arms and legs) lean body mass (n = 28,330) measured using dual energy X-ray absorptiometry or bioelectrical impedance analysis, adjusted for sex, age, height, and fat mass. Twenty-one single-nucleotide polymorphisms were significantly associated with lean body mass either genome wide (p <5 x 10( -8)) or suggestively genome wide (p <2.3 x 10( -6)). Replication in 63,475 (47,227 of European ancestry) individuals from 33 cohorts for whole body lean body mass and in 45,090 (42,360 of European ancestry) subjects from 25 cohorts for appendicular lean body mass was successful for five single-nucleotide polymorphisms in/ near HSD17B11, VCAN, ADAMTSL3, IRS1, and FTO for total lean body mass and for three single-nucleotide polymorphisms in/ near VCAN, ADAMTSL3, and IRS1 for appendicular lean body mass. Our findings provide new insight into the genetics of lean body mass
Fitting exponential family mixed models by Juni Palmgren( Book )

1 edition published in 2001 in English and held by 1 WorldCat member library worldwide

Metabolite Profiling and Cardiovascular Event Risk( )

1 edition published in 2015 in English and held by 1 WorldCat member library worldwide

Abstract : Background--: High-throughput profiling of circulating metabolites may improve cardiovascular risk prediction over established risk factors. Methods and Results--: We applied quantitative nuclear magnetic resonance metabolomics to identify the biomarkers for incident cardiovascular disease during long-term follow-up. Biomarker discovery was conducted in the National Finnish FINRISK study (n=7256; 800 events). Replication and incremental risk prediction was assessed in the Southall and Brent Revisited (SABRE) study (n=2622; 573 events) and British Women's Health and Heart Study (n=3563; 368 events). In targeted analyses of 68 lipids and metabolites, 33 measures were associated with incident cardiovascular events at P <0.0007 after adjusting for age, sex, blood pressure, smoking, diabetes mellitus, and medication. When further adjusting for routine lipids, 4 metabolites were associated with future cardiovascular events in meta-analyses: higher serum phenylalanine (hazard ratio per standard deviation, 1.18; 95% confidence interval, 1.12-1.24; P =4×10 -10) and monounsaturated fatty acid levels (1.17; 1.11-1.24; P =1×10 -8) were associated with increased cardiovascular risk, while higher omega-6 fatty acids (0.89; 0.84-0.94; P =6×10 -5) and docosahexaenoic acid levels (0.90; 0.86-0.95; P =5×10 -5) were associated with lower risk. A risk score incorporating these 4 biomarkers was derived in FINRISK. Risk prediction estimates were more accurate in the 2 validation cohorts (relative integrated discrimination improvement, 8.8% and 4.3%), albeit discrimination was not enhanced. Risk classification was particularly improved for persons in the 5% to 10% risk range (net reclassification, 27.1% and 15.5%). Biomarker associations were further corroborated with mass spectrometry in FINRISK (n=671) and the Framingham Offspring Study (n=2289). Conclusions--: Metabolite profiling in large prospective cohorts identified phenylalanine, monounsaturated fatty acids, and polyunsaturated fatty acids as biomarkers for cardiovascular risk. This study substantiates the value of high-throughput metabolomics for biomarker discovery and improved risk assessment. Abstract : Supplemental Digital Content is available in the text
Research report. Estimation of multivariate frailty models using penalized partial likelihood( )

in English and held by 1 WorldCat member library worldwide

Pharmacogenomics of Hypertension: A Genome‐Wide, Placebo‐Controlled Cross‐Over Study, Using Four Classes of Antihypertensive Drugs( )

1 edition published in 2015 in English and held by 1 WorldCat member library worldwide

Abstract : Background: Identification of genetic markers of antihypertensive drug responses could assist in individualization of hypertension treatment. Methods and Results: We conducted a genome‐wide association study to identify gene loci influencing the responsiveness of 228 male patients to 4 classes of antihypertensive drugs. The Genetics of Drug Responsiveness in Essential Hypertension (GENRES) study is a double‐blind, placebo‐controlled cross‐over study where each subject received amlodipine, bisoprolol, hydrochlorothiazide, and losartan, each as a monotherapy, in a randomized order. Replication analyses were performed in 4 studies with patients of European ancestry (PEAR Study, N=386; GERA I and II Studies, N=196 and N=198; SOPHIA Study, N=372). We identified 3 single‐nucleotide polymorphisms within the ACY3 gene that showed associations with bisoprolol response reaching genome‐wide significance ( P <5×10 −8 ); however, this could not be replicated in the PEAR Study using atenolol. In addition, 39 single‐nucleotide polymorphisms showed P values of 10 −5 to 10 −7 . The 20 top‐associated single‐nucleotide polymorphisms were different for each antihypertensive drug. None of these top single‐nucleotide polymorphisms co‐localized with the panel of >40 genes identified in genome‐wide association studies of hypertension. Replication analyses of GENRES results provided suggestive evidence for a missense variant (rs3814995) in the NPHS1 (nephrin) gene influencing losartan response, and for 2 variants influencing hydrochlorothiazide response, located within or close to the ALDH1A3 (rs3825926) and CLIC5 (rs321329) genes. Conclusions: These data provide some evidence for a link between biology of the glomerular protein nephrin and antihypertensive action of angiotensin receptor antagonists and encourage additional studies on aldehyde dehydrogenase–mediated reactions in antihypertensive drug action
 
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Alternative Names
Samuli Ripatti Finnish statistician, researcher, professor of biostatistics (Institute for Molecular Medicine Finland (FIMM), University of Helsinki)

Languages
English (19)