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Williams-Blangero S, VandeBerg JL, Subedi J, Aivaliotis MJ, Rai DR, Upadhayay RP, Jha B, Blangero J. Genes on chromosomes 1 and 13 have significant effects on Ascaris infection. Proc Natl Acad Sci U S A 2002; 99:5533-8. [PMID: 11960011 PMCID: PMC122804 DOI: 10.1073/pnas.082115999] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2001] [Accepted: 02/27/2002] [Indexed: 11/18/2022] Open
Abstract
Nematode parasites show a characteristic aggregated distribution among hosts. This observation has important implications for pathogenesis, immunology, and control of these infections, but the relative roles of environment and genetics in determining these patterns have remained uncertain. This paper presents the results of the first genome scan for susceptibility to infection with roundworm (Ascaris lumbricoides). Data on 375 genetic markers were generated for each of 444 members of a genetically isolated Nepalese population, the Jirels. Ascaris worm burden as assessed by egg counts was measured in these same individuals by using the Kato Katz thick smear method. The extensive genealogical data available for the population allowed assignment of all 444 individuals to a single pedigree that contained 6,209 pairs of relatives that were informative for genetic analysis. A variance components linkage analysis resulted in the unequivocal localization of two genes (one on chromosome 1 and another on chromosome 13) with clear, significant effects on susceptibility to Ascaris infection. This is the first evidence that individual quantitative trait loci influence variation in Ascaris burden in humans.
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Williams-Blangero S, Subedi J, Upadhayay RP, Manral DB, Rai DR, Jha B, Robinson ES, Blangero J. Genetic analysis of susceptibility to infection with Ascaris lumbricoides. Am J Trop Med Hyg 1999; 60:921-6. [PMID: 10403321 DOI: 10.4269/ajtmh.1999.60.921] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Epidemiologic studies of helminthic infections have shown that susceptibility to these parasites frequently aggregates in families, suggesting the possible involvement of genetic factors. This paper presents a genetic epidemiologic analysis of Ascaris lumbricoides infection in the Jirel population of eastern Nepal. A total of 1,261 individuals belonging to a single pedigree were assessed for intensity of Ascaris infection at two time points. Following an initial assessment in which all individuals were treated with albendazole, a follow-up examination was performed one year later to evaluate reinfection patterns. Three measures of worm burden were analyzed, including eggs per gram of feces, direct worm counts, and worm biomass (weight). For all traits, variance component analysis of the familial data provided unequivocal evidence for a strong genetic component accounting for between 30% and 50% of the variation in worm burden. Shared environmental (i.e., common household) effects account for between 3% and 13% of the total phenotypic variance.
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Williams-Blangero S, Vandeberg JL, Subedi J, Jha B, Corrêa-Oliveira R, Blangero J. Localization of Multiple Quantitative Trait Loci Influencing Susceptibility to Infection withAscaris lumbricoides. J Infect Dis 2008; 197:66-71. [PMID: 18171287 DOI: 10.1086/524060] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Criscione CD, Anderson JD, Sudimack D, Subedi J, Upadhayay RP, Jha B, Williams KD, Williams-Blangero S, Anderson TJC. Landscape genetics reveals focal transmission of a human macroparasite. PLoS Negl Trop Dis 2010; 4:e665. [PMID: 20421919 PMCID: PMC2857643 DOI: 10.1371/journal.pntd.0000665] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 03/10/2010] [Indexed: 01/06/2023] Open
Abstract
Macroparasite infections (e.g., helminths) remain a major human health concern. However, assessing transmission dynamics is problematic because the direct observation of macroparasite dispersal among hosts is not possible. We used a novel landscape genetics approach to examine transmission of the human roundworm Ascaris lumbricoides in a small human population in Jiri, Nepal. Unexpectedly, we found significant genetic structuring of parasites, indicating the presence of multiple transmission foci within a small sampling area (∼14 km2). We analyzed several epidemiological variables, and found that transmission is spatially autocorrelated around households and that transmission foci are stable over time despite extensive human movement. These results would not have been obtainable via a traditional epidemiological study based on worm counts alone. Our data refute the assumption that a single host population corresponds to a single parasite transmission unit, an assumption implicit in many classic models of macroparasite transmission. Newer models have shown that the metapopulation-like pattern observed in our data can adversely affect targeted control strategies aimed at community-wide impacts. Furthermore, the observed metapopulation structure and local mating patterns generate an excess of homozygotes that can accelerate the spread of recessive traits such as drug resistance. Our study illustrates how molecular analyses complement traditional epidemiological information in providing a better understanding of parasite transmission. Similar landscape genetic approaches in other macroparasite systems will be warranted if an accurate depiction of the transmission process is to be used to inform effective control strategies. Currently, knowledge of transmission patterns of human helminth parasites is based on traditional epidemiological data such as the number of parasites within hosts. Genetic markers can greatly facilitate our understanding of the transmission process because they provide an indirect means to infer dispersal. Here, we apply novel landscape genetics methods to examine the transmission dynamics of the world's most common human macroparasite, Ascaris lumbricoides. Specifically, we tested for both the presence of multiple transmission foci in a single human village in Nepal and the epidemiological factors associated with such infection foci. On this very local scale, we were surprised to find multiple transmission foci that were centered on households and that reinfections were occurring from the same foci. Thus, our study illustrates the utility of population genetics analyses in epidemiology. Furthermore, our study challenges current dogma by revealing fragmentation of transmission rather than homogeneous parasite mixing within a single human community. Thus, the results have important implications for drug resistance evolution and parasite control.
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Research Support, N.I.H., Extramural |
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Williams-Blangero S, McGarvey ST, Subedi J, Wiest PM, Upadhayay RP, Rai DR, Jha B, Olds GR, Guanling W, Blangero J. Genetic component to susceptibility to Trichuris trichiura: evidence from two Asian populations. Genet Epidemiol 2002; 22:254-64. [PMID: 11921085 DOI: 10.1002/gepi.0187] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Trichuris trichiura is an helminthic infection with potentially severe health consequences. The hypothesis that host genetic factors can account for the distribution of Trichuris was tested using familial data on egg counts available for two populations, the Jirels of Nepal and the population of Jishan Island in Jiangxi Province of the People's Republic of China. Whipworm is highly prevalent in the Jishan Island population (86%), but occurs at a low rate in the Jirel population (14%). A quantitative genetic analysis was performed on each data set, using a variance component approach. Approximately 28% of the variation in Trichuris trichiura loads was attributable to genetic factors in both populations. Common household effects accounted for only 4% of the variation in the Jirels and none of the variation in the Jishan Island population. These concordant results from two separate populations provide strong evidence of the important role of genetics in determining differential susceptibility to whipworm infection.
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Williams-Blangero S, Vandeberg JL, Subedi J, Jha B, Dyer TD, Blangero J. Two quantitative trait loci influence whipworm (Trichuris trichiura) infection in a Nepalese population. J Infect Dis 2008; 197:1198-203. [PMID: 18462166 PMCID: PMC4122289 DOI: 10.1086/533493] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Whipworm (Trichuris trichiura) infection is a soil-transmitted helminth infection that affects >1 billion people. It is a serious public health problem in many developing countries and can result in deficits in growth and cognitive development. In a follow-up study of significant heritability for whipworm infection, we conducted the first genome scan for quantitative trait loci (QTL) influencing the heritability of susceptibility to this important parasitic disease. METHODS Whipworm egg counts were determined for 1,253 members of the Jirel population of eastern Nepal. All individuals in the study sample belonged to a single pedigree including >26,000 pairs of relatives that are informative for genetic analysis. RESULTS Linkage analysis of genome scan data generated for the pedigree provided unambiguous evidence for 2 QTL influencing susceptibility to whipworm infection, one located on chromosome 9 (logarithm of the odds ratio [LOD] score, 3.35; genomewide P = .0138) and the other located on chromosome 18 (LOD score, 3.29; genomewide P = .0159). There was also suggestive evidence that 2 loci located on chromosomes 12 and 13 influenced whipworm infection. CONCLUSION The results of this first genome scan for T. trichiura egg counts provides new information on the determinants of genetic predisposition to whipworm infection.
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Research Support, N.I.H., Extramural |
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Criscione CD, Anderson JD, Raby K, Sudimack D, Subedi J, Rai DR, Upadhayay RP, Jha B, Williams-Blangero S, Anderson TJC. Microsatellite markers for the human nematode parasite Ascaris lumbricoides: development and assessment of utility. J Parasitol 2007; 93:704-8. [PMID: 17626368 DOI: 10.1645/ge-1058r.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We describe 35 microsatellite markers from the human parasitic nematode Ascaris lumbricoides. We found 7 sex-linked markers and demonstrate that 26 autosomal loci can be scored reliably. These markers have high genetic variability and provide the tools to address multiple questions concerning the epidemiology, fine-scale genetic structure, host specificity, and mating systems of this parasite.
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Williams-Blangero S, Criscione CD, VandeBerg JL, Correa-Oliveira R, Williams KD, Subedi J, Kent JW, Williams J, Kumar S, Blangero J. Host genetics and population structure effects on parasitic disease. Philos Trans R Soc Lond B Biol Sci 2012; 367:887-94. [PMID: 22312056 PMCID: PMC3267115 DOI: 10.1098/rstb.2011.0296] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Host genetic factors exert significant influences on differential susceptibility to many infectious diseases. In addition, population structure of both host and parasite may influence disease distribution patterns. In this study, we assess the effects of population structure on infectious disease in two populations in which host genetic factors influencing susceptibility to parasitic disease have been extensively studied. The first population is the Jirel population of eastern Nepal that has been the subject of research on the determinants of differential susceptibility to soil-transmitted helminth infections. The second group is a Brazilian population residing in an area endemic for Trypanosoma cruzi infection that has been assessed for genetic influences on differential disease progression in Chagas disease. For measures of Ascaris worm burden, within-population host genetic effects are generally more important than host population structure factors in determining patterns of infectious disease. No significant influences of population structure on measures associated with progression of cardiac disease in individuals who were seropositive for T. cruzi infection were found.
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Subedi S, Tausig M, Subedi J, Broughton CL, Williams-Blangero S. Mental Illness and Disability among Elders in Developing Countries. J Aging Health 2016; 16:71-87. [PMID: 14979311 DOI: 10.1177/0898264303260446] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Objective: This article attempts to document the prevalence of psychiatric disorders among elders in a rural village in Nepal. In addition, we investigate the relationship between psychiatric illness and functional disability to assess the impact of disorder on social functioning. Method: A semistructured interview checklist to diagnose six disorders was used ( N = 182). In addition, elders older than age 60 were examined to assess the functional impact of mental health conditions by measuring functional disability. Results: Eighteen percent of elders seem to have a diagnosable psychiatric disorder. Furthermore, in general these elders were also less likely to receive assistance with the disabilities they report, compared with those who do not experience a psychiatric disorder. Discussion: Documenting the extent of psychiatric disorder among elders in developing societies sensitizes health planners to the growing reality of aging in their societies and the need for expanded physical and psychiatric health care services.
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Williams-Blangero S, Subedi J, Upadhayay RP, Manral DB, Khadka K, Jirel S, Robinson ES, Blangero J. Attitudes towards helminthic infection in the Jirel population of eastern Nepal. Soc Sci Med 1998; 47:371-9. [PMID: 9681907 DOI: 10.1016/s0277-9536(98)00073-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intestinal worm infections, including roundworm, hookworm, and whipworm, are major international health concerns, affecting approximately one fourth of the world's population. Many intervention schemes have been attempted to control these infections in heavily exposed populations, but success has been limited because individuals are readily reinfected upon renewed exposure. Few data are available concerning people's health beliefs about soil-transmitted helminthic infections in such populations. The purpose of this study was to assess health beliefs about common helminthiasis in a population experiencing moderate to high rates of infection. The focal population for the study was the Jirel population, a tribal group distributed across nine villages in the Jiri Region of Dolakha District, eastern Nepal. The results indicate that beliefs about the types, causes, and treatments of helminthic infections have been developed and reinforced by experience and empirical evidence. People's frequent inability to confirm the efficacy of drug therapy by observing worms in stools has led to dissatisfaction with biomedical approaches. Carefully planned education programs are required to alter prevailing attitudes and improve control of soil-transmitted helminthiasis in the region.
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Tausig M, Subedi S, Broughton CL, Subedi J, Williams-Blangero S. Measuring community mental health in developing societies: evaluation of a checklist format in Nepal. Int J Soc Psychiatry 2003; 49:269-86. [PMID: 14727694 DOI: 10.1177/0020764003494005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND There is growing recognition of the importance of mental health problems in developing countries. In large part, however, we have very limited epidemiological data at national and/or community levels about the prevalence of mental illnesses. AIMS The purpose of this paper is to describe the reliability and validity characteristics of an assessment tool that may be useful for conducting community-level surveys (particularly in rural communities of developing countries) to obtain prevalence rates of mental illnesses. METHODS We used a sample of adults residing in a rural village in Nepal to assess disorders with a modified version of the DSM-III-R Checklist. We evaluated construct validity, scale reliability, convergent validity and discriminant validity. RESULTS There is strong evidence for the construct validity of generalized anxiety and depression in our sample. By contrast, the symptoms associated with mania and schizophrenia were not empirically distinct. Convergent validity is acceptable. As a test of validity characteristics, the pattern of sociodemographic correlations suggests that the specific social origins of disorder in Nepal will require further investigation. CONCLUSION The first step in obtaining high quality information on the distribution of mental illness in developing countries is to establish some reliable and valid indicators of disorder. The checklist format for assessing disorder appears to meet this objective and offers the possibility that community-level prevalence studies can be reasonably conducted.
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Validation Study |
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Williams-Blangero S, Corrêa-Oliveira R, Vandeberg JL, Subedi J, Upadhayay RP, Rai DR, Jha B, Blangero J. Genetic influences on plasma cytokine variation in a parasitized population. Hum Biol 2005; 76:515-25. [PMID: 15754969 DOI: 10.1353/hub.2004.0062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The soil-transmitted helminths are the most common helminthic infections, affecting about one-fourth of the world's population. There is a significant genetic component to susceptibility to infection with these organisms. Substantial changes in plasma cytokine levels are associated with helminthic infections, and there may be significant genetic components to this cytokine variation. Six plasma cytokine levels were assessed for 367 members of a single pedigree from the Jirel population of eastern Nepal. This population experiences moderate rates of infection with geohelminths. Sex, age, helminthic infection, infection with Giardia, and presence of a household latrine were considered as covariates in all analyses of the cytokine data. The analyses of the single Jirel pedigree revealed significant heritabilities for IFN-gamma (h2 = 0.654+/-0.096), TNF-alpha (h2 = 0.458+/-0.101), IL-2 (h2 = 0.583+/-0.101), IL-4 (h2 = 0.700+/-0.095), IL-5 (h2 = 0.676+/-0.087), and IL-10 (h2 = 0.597+/-0.093). The ratios of IL-4 to IFN-gamma and of IL-10 to IFN-gamma were used as indicators of the degree of type 2 bias in immunological response; analyses of these variables indicated that approximately 40-60% of the variation (h2 = 0.400-0.577) in these derived measures of relative type 2/type 1 response is due to genetic factors.
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Research Support, U.S. Gov't, P.H.S. |
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Williams KD, Nahhas RW, Cottom CR, Lawrence S, Subedi J, Jha B, Czerwinski SA, Blangero J, Williams-Blangero S, Towne B. Evaluation of qualitative methods for phenotyping brachymesophalangia-V from radiographs of children. Am J Hum Biol 2011; 24:68-73. [PMID: 22131202 DOI: 10.1002/ajhb.22205] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 09/27/2011] [Accepted: 11/08/2011] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE Brachymesophalangia-V (BMP-V), the general term for a short and broad middle phalanx of the 5th digit, presents both alone and in a large number of complex brachydactylies and developmental disorders. Past anthropological and epidemiological studies of growth and development have examined the prevalence of BMP-V because small developmental disorders may signal more complex disruptions of skeletal growth and development. Historically, however, consensus on qualitative phenotype methodology has not been established. In large-scale, non-clinical studies such as the Fels Longitudinal Study and the Jiri Growth Study, quantitative assessment of the hand is not always the most efficient manner of screening for skeletal dysmorphologies. The current study evaluates qualitative phenotyping techniques for BMP-V used in past anthropological studies of growth and development to establish a useful and reliable screening method for large study samples. METHODS A total of 1,360 radiographs from Jiri Growth Study participants aged 3-18 years were evaluated. BMP-V was assessed using three methods: (1) subjective evaluation of length and width of the bone; (2) comparison with skeletal age-matched radiographs; and (3) subjective evaluation of the length of the middle 4th and 5th phalanges. RESULTS We found that the method that uses skeletal age-matched reference radiographs is the better tool for assessing BMP-V because it considers the shape, rather than solely the length and width of the bone, which can be difficult to judge accurately without measurement. This study highlights the complexity of phenotypic assessment of BMP-V and by extension other brachydactylies.
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Evaluation Study |
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Kart CS, Kinney JM, Subedi J, Basnyat KB, Vadakkan MF. Lay Explanations and Self-Management of Diabetes in Kathmandu, Nepal. J Aging Health 2016; 19:683-704. [PMID: 17682081 DOI: 10.1177/0898264307301183] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Objectives: This research explores the lay explanations and self-management of diabetes among residents in greater Kathmandu, Nepal. Methods: Interviews were done with 300 respondents drawn from diabetes patient listings and members of a national diabetes club. Sociodemographic and health-related data were collected with two standardized instruments: the Illness Perception Questionnaire and the Summary of Diabetes Self-Care Activities. Hierarchical ordinary least squares regression analyses were employed to examine predictors of self-management of diabetes. Results: Across seven equations, R2 values ranged from .020 to .221, and with the exception of one domain of self-management (blood sugar testing), one or more lay explanatory factors entered each equation. Discussion: Respondents from this sample appear to hold lay explanations of diabetes that are similar to those of their peers in developed nations. Findings are discussed, including the caveat that these mostly male, relatively educated, and urban-residing adults with diabetes are not necessarily representative of Nepali society.
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Williams KD, Blangero J, Subedi J, Jha B, Dyer T, VandeBerg JL, Towne B, Williams-Blangero S. Nonsyndromic brachydactyly type D and type E mapped to 7p15 in healthy children and adults from the Jirel ethnic group in eastern Nepal. Am J Hum Biol 2013; 25:743-50. [PMID: 24022874 PMCID: PMC3968259 DOI: 10.1002/ajhb.22441] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/14/2013] [Accepted: 07/15/2013] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVES There is phenotypic overlap between Brachydactyly Type D (BDD) and Brachydactyly Type E (BDE) that suggests a possible common underlying etiology. We seek to understand the genetic underpinnings of, and relationship between, these skeletal anomalies. METHODS The Jirel ethnic group of eastern Nepal participates in various genetic epidemiologic studies, including those in which hand-wrist radiographs have been taken to examine skeletal development. Nearly 2,130 individuals (969 males; 1,161 females) were phenotyped for BDD/BDE. Of these, 1,722 individuals (773 males; 949 females) were genotyped for 371 STR markers spanning the autosomal genome. Variance components-based linkage analysis was used to conduct a genome-wide linkage scan for QTL influencing the BDD/BDE phenotype. RESULTS BDD was present in 3.55%, and BDE was present in 0.39%, of the study sample. Because of the phenotypic overlap between two traits, affecteds of either type were considered as affected by a single combined phenotype (BDD/BDE) having a prevalence of 3.94%. The additive genetic heritability of BDD/BDE was highly significant (h(2) ± SE = 0.89 ± 0.13; P = 1.7 × 10(-11) ). Significant linkage of BDD/BDE was found to markers on chromosome 7p21-7p14 (peak LOD score = 3.74 at 7p15 between markers D7S493 and D7S516). CONCLUSIONS Possible positional candidate genes in the one-lod support interval of this QTL include TWIST and the HOXA1-A13 cluster. This is the first study to report significant linkage results for BDD/BDE using a large extended pedigree, and the first to suggest that mutations in TWIST and/or the HOXA1-A13 cluster may contribute to these specific skeletal anomalies.
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Williams KD, Blangero J, Cottom CR, Lawrence S, Choh AC, Czerwinski SA, Lee M, Duren DL, Sherwood RJ, Dyer TD, Jha B, Subedi J, Williams-Blangero S, Towne B. Heritability of brachydactyly type A3 in children, adolescents, and young adults from an endogamous population in eastern Nepal. Hum Biol 2008; 79:609-22. [PMID: 18494372 DOI: 10.1353/hub.2008.0016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Brachymesophalangia-V (BMP-V), a short and broad middle phalanx of the fifth digit, is the most common of all skeletal anomalies of the hand. When this feature appears alone, it is clinically known as brachydactyly type A3 (BDA3). A high prevalence of BDA3 has been observed among the children of the Jirel ethnic group in eastern Nepal. As part of the Jiri Growth Study, a hand-wrist radiograph is taken annually of each child to assess skeletal development. For this study the most recent radiographs of 1,357 Jirel children, adolescents, and young adults (676 boys, 681 girls), age 3-20 years, were examined for the presence or absence of BDA3, to report the prevalence and estimate the heritability of BDA3 in the Jirel population. The overall prevalence of BDA3 in this sample was 10.5% (12.9% of the males and 8.9% of the females were classified as BDA3 affected). The additive genetic heritability of BDA3 was statistically significant in this sample (h2 +/- SE = 0.87 +/- 0.16, p < 0.0001). This study is the first to estimate the prevalence and heritability of BDA3 in a large South Asian family-based sample.
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Tausig M, Selgelid MJ, Subedi S, Subedi J. Taking sociology seriously: a new approach to the bioethical problems of infectious disease. SOCIOLOGY OF HEALTH & ILLNESS 2006; 28:838-49. [PMID: 17184421 DOI: 10.1111/j.1467-9566.2006.00545.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
After a history of neglect, bioethicists have recently turned their attention to the topic of infectious disease. In this paper we link bioethicists' earlier neglect of infectious disease to their under-appreciation of the extent to which the problem of infectious disease is related to social factors and thus to questions of justice. We argue that a social causation of illness model - well-known to sociologists of medicine, but incompletely understood by bioethicists - will improve future bioethical analysis of issues related to infectious disease. By emphasising the relationships between social and economic structures of inequality and health, the social causation model provides a richer approach to ethical issues associated with infectious disease than the more commonly used biomedical model.
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Abstract
Sociologists have had only a marginal effect on the development of bioethical principles for medical research despite their interest in the effects of social and economic inequality on health and its implications for issues of social and individual justice. In this article we review existing bioethical standards for conducting medical research in very poor countries. Given the substantial differences in individual exposure to health risks and the availability of health protective resources as well as differences in the disease burden and mortality and morbidity at the population level, it is clear that illness in poor countries can be better understood using a social causation of illness perspective. In turn we suggest that such a perspective can be useful for identifying bioethical standards that better apply in this context.
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Abstract
Like many countries, the increase in the population of older adults in Nepal has led to national policies and programs to address their needs. It would, however, also be fair to say that not enough is yet known about older adults and hence it is unclear if government programs truly address those needs. Nepal is a very poor country that is still largely rural and characterized by extremes of inequality based on caste/ethnicity, gender, region, and income/wealth. In this paper, we describe the demographic and social conditions of older adults in Nepal, inequality, sources, and limitations of the data about older adults, and public policy and programs for older adults. We believe that studies of older adults in Nepal would benefit from adopting social determinants of health, healthy aging, and life course perspectives to both identify needs and formulate policy for older adults in Nepal.
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Williams KD, Blangero J, Mahaney MC, Subedi J, Jha B, Williams-Blangero S, Towne B. Axial quantitative ultrasound assessment of pediatric bone quality in eastern Nepal. Osteoporos Int 2015; 26:2319-28. [PMID: 25862355 DOI: 10.1007/s00198-015-3115-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 03/18/2015] [Indexed: 12/29/2022]
Abstract
UNLABELLED This study presents quantitative ultrasonography (QUS) bone quality data for an underrepresented, south Asian pediatric population from Nepal. Data were collected as part of a longitudinal study of growth and development. This study offers normative data and documents the effect of stunting, wasting, and underweight on the bone properties measured by QUS. INTRODUCTION The purpose of this study was to (1) examine the bone quality of a rural, non-Western pediatric population using QUS, (2) explore variation in the trajectory of bone quality development between males and females, and (3) examine the impact of growth disruption(s) on bone quality. METHODS A cross-sectional study of 860 children and adolescents aged 5-18 years from the Jirel ethnic group in eastern Nepal was performed. The Sunlight Omnisense 7000P was used to assess bone quality of the distal 1/3 radius and midshaft tibia. WHO reference standards were used to assess growth disruptions of height, weight, and BMI. RESULTS QUS bone quality data for an underrepresented, non-Western pediatric population are presented for the radius and tibia. A sizable portion of the study participants were classified as stunted, wasted, and/or underweight. Despite this prevalence of growth disruption in the study sample, bone quality data conform to other documented populations with less growth disruption. Thus, this study offers normative data and documents the minimal effect of stunting, wasting, and underweight on the bone properties measured by QUS. CONCLUSIONS Non-Western pediatric populations are significantly underserved with regard to simple, non-invasive screening tools that may help identify developmental disorders and assess bone health. The children and adolescents examined here represent normal growth and development for an underrepresented south Asian population. While this work demonstrates that stunting, wasting, or underweight status at time of QUS assessment is not associated with poor bone quality, we do suggest that further study is needed to examine possible cumulative effects of persistent disruptions that may lead to compromised bone quality in later adolescence.
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Johnson MP, Keyho R, Blackburn NB, Laston S, Kumar S, Peralta J, Thapa SS, Towne B, Subedi J, Blangero J, Williams-Blangero S. Glycated Serum Protein Genetics and Pleiotropy with Cardiometabolic Risk Factors. J Diabetes Res 2019; 2019:2310235. [PMID: 31089471 PMCID: PMC6476113 DOI: 10.1155/2019/2310235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/20/2018] [Accepted: 01/12/2019] [Indexed: 01/08/2023] Open
Abstract
Measurements of fasting glucose (FG) or glycated hemoglobin A1c (HbA1c) are two clinically approved approaches commonly used to determine glycemia, both of which are influenced by genetic factors. Obtaining accurate measurements of FG or HbA1c is not without its challenges, though. Measuring glycated serum protein (GSP) offers an alternative approach for assessing glycemia. The aim of this study was to estimate the heritability of GSP and GSP expressed as a percentage of total serum albumin (%GA) using a variance component approach and localize genomic regions (QTLs) that harbor genes likely to influence GSP and %GA trait variation in a large extended multigenerational pedigree from Jiri, Nepal (n = 1,800). We also performed quantitative bivariate analyses to assess the relationship between GSP or %GA and several cardiometabolic traits. Additive genetic effects significantly influence variation in GSP and %GA levels (p values: 1.15 × 10-5 and 3.39 × 10-5, respectively). We localized a significant (LOD score = 3.18) and novel GSP QTL on chromosome 11q, which has been previously linked to type 2 diabetes. Two common (MAF > 0.4) SNPs within the chromosome 11 QTL were associated with GSP (adjusted pvalue < 5.87 × 10-5): an intronic variant (rs10790184) in the DSCAML1 gene and a 3'UTR variant (rs8258) in the CEP164 gene. Significant positive correlations were observed between GSP or %GA and blood pressure, and lipid traits (p values: 0.0062 to 1.78 × 10-9). A significant negative correlation was observed between %GA and HDL cholesterol (p = 1.12 × 10-5). GSP is influenced by genetic factors and can be used to assess glycemia and diabetes risk. Thus, GSP measurements can facilitate glycemic studies when accurate FG and/or HbA1c measurements are difficult to obtain. GSP can also be measured from frozen blood (serum) samples, which allows the prospect of retrospective glycemic studies using archived samples.
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Hardin AM, Knigge RP, Duren DL, Williams-Blangero S, Subedi J, Mahaney MC, Sherwood RJ. Genetic influences on dentognathic morphology in the Jirel population of Nepal. Anat Rec (Hoboken) 2022; 305:2137-2157. [PMID: 34981668 PMCID: PMC9250551 DOI: 10.1002/ar.24857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022]
Abstract
Patterns of genetic variation and covariation impact the evolution of the craniofacial complex and contribute to clinically significant malocclusions in modern human populations. Previous quantitative genetic studies have estimated the heritabilities and genetic correlations of skeletal and dental traits in humans and nonhuman primates, but none have estimated these quantitative genetic parameters across the dentognathic complex. A large and powerful pedigree from the Jirel population of Nepal was leveraged to estimate heritabilities and genetic correlations in 62 maxillary and mandibular arch dimensions, incisor and canine lengths, and post-canine tooth crown areas (N ≥ 739). Quantitative genetic parameter estimation was performed using maximum likelihood-based variance decomposition. Residual heritability estimates were significant for all traits, ranging from 0.269 to 0.898. Genetic correlations were positive for all trait pairs. Principal components analyses of the phenotypic and genetic correlation matrices indicate an overall size effect across all measurements on the first principal component. Additional principal components demonstrate positive relationships between post-canine tooth crown areas and arch lengths and negative relationships between post-canine tooth crown areas and arch widths, and between arch lengths and arch widths. Based on these findings, morphological variation in the human dentognathic complex may be constrained by genetic relationships between dental dimensions and arch lengths, with weaker genetic correlations between these traits and arch widths allowing for variation in arch shape. The patterns identified are expected to have impacted the evolution of the dentognathic complex and its genetic architecture as well as the prevalence of dental crowding in modern human populations.
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Subedi J. Primary Health Care and Medical Pluralism Exemplified in Nepal: A Proposal for Maximizing Health Care Benefit. ACTA ACUST UNITED AC 1992. [DOI: 10.1080/00380237.1992.10570988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Williams KD, Subedi J, Jha B, Blangero J, Williams-Blangero S, Towne B. Quantitative physical activity assessment of children and adolescents in a rural population from Eastern Nepal. Am J Hum Biol 2015; 28:129-37. [PMID: 26179444 DOI: 10.1002/ajhb.22762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/27/2015] [Accepted: 06/16/2015] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES We report cross-sectional, objectively measured physical activity data for 399 children and adolescents aged 6 to 18 years. We evaluated physical activity of children and adolescents, considered time spent in each activity intensity category, and explored the impact of growth disruption (stunting and wasting) on physical activity patterns. METHODS Participants wore an Actical (Mini-Mitter, Bend, OR) omnidirectional accelerometer for one week as part of their annual visit to the Jiri Growth Study. The percentage of time spent in standard activity intensities were computed using standard metabolic equivalents (METS) cutpoints and compared by chronological age, sex, and school versus non-school days. RESULTS Primary findings include (1) children are more active on non-school days and adolescents are more active during the school week; (2) Jirel children do not exhibit the reduction in physical activity that most Western populations experience during the transition from childhood to adolescence; and (3) Jirel children and adolescents routinely meet the suggested one hour/day MVPA threshold; (4) Stunting is prevalent and factors leading to this growth disruption may contribute to the amount of time in sedentary or light physical activity. CONCLUSIONS We report child and adolescent physical activity patterns from the Jirel population of eastern Nepal. In this rural context, children and adolescents are more active than populations reported from Western contexts. This key finding has important biomedical implications for the maintenance of healthy body composition, skeletal health, and other health traits.
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