A genome-wide linkage scan identifies multiple chromosomal regions influencing serum lipid levels in the population on the Samoan islands

A stop-gain variant in BTNL9 is associated with atherogenic lipid profiles

Current understanding of lipid genetics has come mainly from studies in European-ancestry populations; limited effort has focused on Polynesian populations, whose unique population history and high prevalence of dyslipidemia may provide insight into the biological foundations of variation in lipid levels. Here, we performed an association study to fine map a suggestive association on 5q35 with high-density lipoprotein cholesterol (HDL-C) seen in Micronesian and Polynesian populations. Fine-mapping analyses in a cohort of 2,851 Samoan adults highlighted an association between a stop-gain variant (rs200884524; c.652C>T, p.R218∗; posterior probability = 0.9987) in BTNL9 and both lower HDL-C and greater triglycerides (TGs). Meta-analysis across this and several other cohorts of Polynesian ancestry from Samoa, American Samoa, and Aotearoa New Zealand confirmed the presence of this association (βHDL-C = -1.60 mg/dL, p HDL-C = 7.63 × 10-10; βTG = 12.00 mg/dL, p TG = 3.82 × 10-7). While this variant appears to be Polynesian specific, there is also evidence of association from other multiancestry analyses in this region. This work provides evidence of a previously unexplored contributor to the genetic architecture of lipid levels and underscores the importance of genetic analyses in understudied populations.

Using Community Based Research Frameworks to Develop and Implement a Church-Based Program to Prevent Diabetes and Its Complications for Samoan Communities in South Western Sydney

Pasifika communities bear a disproportionate burden of diabetes compared to the general Australian population. Community-based participatory research (CBPR), which involves working in partnership with researchers and communities to address local health needs, has gained prominence as a model of working with underserved communities. This paper describes how Le Taeao Afua (LTA) Samoan diabetes prevention program was underpinned by two CBPR frameworks to develop a culturally tailored church-based lifestyle intervention to prevent diabetes and its complications in the Australian Samoan community. The name LTA, which means ‘a new dawn,’ was chosen by the community to signify a new dawn without diabetes in the Australian Samoan community. Strategies for engaging with the Australian Samoan community in South Western Sydney are discussed mapped to the key principles from the CBPR frameworks. In particular, this paper highlights the steps involved in building relationships with Samoan community leaders and the vital role of community activators and peer support facilitators in the success of delivering the program. Lessons learnt, such as the importance of church and maintaining a Samoan way of life in daily activities, and processes to build effective partnerships and maintain long-term relationships with the Australian Samoan community, are also discussed. Our paper, through providing a case example of how to apply CBPR frameworks, will help guide future community-based health promotion programs for underserved communities.

Cardiometabolic disease risk among siblings of patients with major depressive disorder

Studies have suggested an association between metabolic and cerebrocardiovascular diseases and major depressive disorder (MDD). However, the risk of metabolic and cerebrocardiovascular diseases in the unaffected siblings of patients with MDD remains uncertain. Using the Taiwan National Health Insurance Research Database, 22,438 unaffected siblings of patients with MDD and 89,752 age-/sex-matched controls were selected and followed up from 1996 to the end of 2011. Individuals who developed metabolic and cerebrocardiovascular diseases during the follow-up period were identified. Compared with the controls, the unaffected siblings of patients with MDD had a higher prevalence of metabolic diseases, such as hypertension (5.0% vs. 4.5%, p = 0.007), dyslipidemia (5.6% vs. 4.8%, p < 0.001), and obesity (1.7% vs. 1.5%, p = 0.028), and cerebrocardiovascular diseases, such as ischemic stroke (0.6% vs. 0.4%, p < 0.005) and ischemic heart disease (2.1% vs. 1.7%, p < 0.001). Logistic regression analyses revealed that the unaffected siblings of patients with MDD were more likely to develop hypertension, dyslipidemia, ischemic stroke, and ischemic heart diseases during the follow-up period than the controls. Our study revealed a familial coaggregation between MDD and metabolic and cerebrocardiovascular diseases. Additional studies are required to investigate the shared pathophysiology of MDD and metabolic and cerebrocardiovascular diseases.

Genome-wide association studies in Samoans give insight into the genetic architecture of fasting serum lipid levels

The current understanding of the genetic architecture of lipids has largely come from genome-wide association studies (GWAS). To date, few GWAS have examined the genetic architecture of lipids in Polynesians, and none have in Samoans, whose unique population history, including many population bottlenecks, may provide insight into the biological foundations of variation in lipid levels. Here we performed a GWAS of four fasting serum lipid levels: total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TG) in a sample of 2849 Samoans, with validation genotyping for associations in a replication cohort comprising 1798 Samoans and American Samoans. We identified multiple genome-wide significant associations (P < 5 × 10^-8) previously seen in other populations-APOA1 with TG, CETP with HDL, and APOE with TC and LDL-and several suggestive associations (P < 1 × 10^-5), including an association of variants downstream of MGAT1 and RAB21 with HDL. However, we observed different association signals for variants near APOE than what has been previously reported in non-Polynesian populations. The association with several known lipid loci combined with the newly identified associations with variants near MGAT1 and RAB21 suggest that while some of the genetic architecture of lipids is shared between Samoans and other populations, part of the genetic architecture may be Polynesian-specific.

A missense variant in CREBRF is associated with taller stature in Samoans

OBJECTIVES

Studies have demonstrated that rs373863828, a missense variant in CREBRF, is associated with a number of anthropometric traits including body mass index (BMI), obesity, percent body fat, hip circumference, and abdominal circumference. Given the biological relationship between height and adiposity, we hypothesized that the effect of this variant on BMI might be due in part to an association of this variant with height.

METHODS

We tested the hypothesis that minor allele of rs373863828 is associated with height in a Samoan population in two adult cohorts and in a separate cohort of children (age 5-18 years old) using linear mixed modeling.

RESULTS

We found evidence of a strong relationship between rs373863828 and greater mean height in Samoan adults (0.77 cm greater average height for each copy of the minor allele) with the same direction of effect in Samoan children.

CONCLUSIONS

These results suggest that the missense variant rs373863828 in CREBRF, first identified through an association with larger BMI, may be related to an underlying biological mechanism affecting overall body size including stature.

Co-shared genetics and possible risk gene pathway partially explain the comorbidity of schizophrenia, major depressive disorder, type 2 diabetes, and metabolic syndrome

Schizophrenia (SCZ) and major depressive disorder (MDD) in treatment-naive patients are associated with increased risk for type 2 diabetes (T2D) and metabolic syndrome (MetS). SCZ, MDD, T2D, and MetS are often comorbid and their comorbidity increases cardiovascular risk: Some risk genes are likely co-shared by them. For instance, transcription factor 7-like 2 (TCF7L2) and proteasome 26S subunit, non-ATPase 9 (PSMD9) are two genes independently reported as contributing to T2D and SCZ, and PSMD9 to MDD as well. However, there are scarce data on the shared genetic risk among SCZ, MDD, T2D, and/or MetS. Here, we briefly describe T2D, MetS, SCZ, and MDD and their genetic architecture. Next, we report separately about the comorbidity of SCZ and MDD with T2D and MetS, and their respective genetic overlap. We propose a novel hypothesis that genes of the prolactin (PRL)-pathway may be implicated in the comorbidity of these disorders. The inherited predisposition of patients with SCZ and MDD to psychoneuroendocrine dysfunction may confer increased risk of T2D and MetS. We illustrate a strategy to identify risk variants in each disorder and in their comorbid psychoneuroendocrine and mental-metabolic dysfunctions, advocating for studies of genetically homogeneous and phenotype-rich families. The results will guide future studies of the shared predisposition and molecular genetics of new homogeneous endophenotypes of SCZ, MDD, and metabolic impairment.

T2D and Depression Risk Gene Proteasome Modulator 9 is Linked to Insomnia

Insomnia increases type-2 diabetes (T2D) risk. The 12q24 locus is linked to T2D, depression, bipolar disorder and anxiety. At the 12q24 locus, the Proteasome-Modulator 9 (PSMD9) single nucleotide polymorphisms (SNPs) rs74421874 [intervening sequence (IVS) 3+nt460-G>A], rs3825172 (IVS3+nt437-C>T) and rs14259 (E197G-A>G) are linked to: T2D, depression, anxiety, maturity-onset-diabetes-of the young 3/MODY3, obesity, waist circumference, hypertension, hypercholesterolemia, T2D-macrovascular disease, T2D-microvascular disease, T2D-neuropathy, T2D-carpal-tunnel syndrome, T2D-nephropathy, T2D-retinopathy and non-diabetic retinopathy. PSMD9 SNP rs1043307/rs14259 (E197G-A>G) plays a role in anti-depressant therapy response, depression and schizophrenia. We aimed at determining PSMD9 rs74421874/rs3825172/rs14259 SNPs potential linkage to primary insomnia and sleep hours in T2D families. We recruited 200 Italian T2D families phenotyping them for primary insomnia and sleep hours per night. PSMD9-T2D-risk SNPs rs74421874/rs3825172 and rs1043307/rs14259 were tested for linkage with insomnia and sleep hours. Non-parametric-linkage analysis, linkage-disequilibrium-model analysis, single-SNP analysis, cluster-based-parametric analysis, quantitative-trait and variant-component analysis were performed using Merlin software. To validate data, 1000 replicates were executed for the significant non-parametric data. PSMD9 rs74421874 (IVS3+nt460-G>A), rs3825172 (IVS3+nt437-C>T) and rs1043307/rs14259 (E197G-A>G) SNPs are linked to insomnia in our Italian families.

Translating the semi-structured assessment for drug dependence and alcoholism in the Western Pacific: rationale, study design and reliability of alcohol dependence

AIMS

The aims of this study were to develop a bilingual version of the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) in English and Samoan and determine the reliability of assessments of alcohol dependence in American Samoa.

METHODS

The study consisted of development and reliability-testing phases. In the development phase, the SSADDA alcohol module was translated and the translation was evaluated through cognitive interviews. In the reliability-testing phase, the bilingual SSADDA was administered to 40 ethnic Samoans, including a sub-sample of 26 individuals who were retested.

RESULTS

Cognitive interviews indicated the initial translation was culturally and linguistically appropriate except items pertaining to alcohol tolerance, which were modified to reflect Samoan concepts. SSADDA reliability testing indicated diagnoses of DSM-III-R and DSM-IV alcohol dependence were reliable. Reliability varied by language of administration.

CONCLUSION

The English/Samoan version of the SSADDA is appropriate for the diagnosis of DSM-III-R alcohol dependence, which may be useful in advancing research and public health efforts to address alcohol problems in American Samoa and the Western Pacific. The translation methods may inform researchers translating diagnostic and assessment tools into different languages and cultures.

Proteasome modulator 9 gene SNPs, responsible for anti-depressant response, are in linkage with generalized anxiety disorder

Proteasome modulator 9 (PSMD9) gene single nucleotide polymorphism (SNP) rs1043307/rs2514259 (E197G) is associated with significant clinical response to the anti-depressant desipramine. PSMD9 SNP rs74421874 [intervening sequence (IVS) 3 + nt460 G>A], rs3825172 (IVS3 + nt437 C>T) and rs1043307/rs2514259 (E197G A>G) are all linked to type 2 diabetes (T2D), maturity-onset-diabetes-of the young 3 (MODY3), obesity and waist circumference, hypertension, hypercholesterolemia, T2D-macrovascular and T2D-microvascular disease, T2D-neuropathy, T2D-carpal tunnel syndrome, T2D-nephropathy, T2D-retinopathy, non-diabetic retinopathy and depression. PSMD9 rs149556654 rare SNP (N166S A>G) and the variant S143G A>G also contribute to T2D. PSMD9 is located in the chromosome 12q24 locus, which per se is in linkage with depression, bipolar disorder and anxiety. In the present study, we wanted to determine whether PSMD9 is linked to general anxiety disorder in Italian T2D families. Two-hundred Italian T2D families were phenotyped for generalized anxiety disorder, using the diagnostic criteria of DSM-IV. When the diagnosis was unavailable or unclear, the trait was reported as unknown. The 200 Italians families were tested for the PSMD9 T2D risk SNPs rs74421874 (IVS3 + nt460 G>A), rs3825172 (IVS3 +nt437 T>C) and for the T2D risk and anti-depressant response SNP rs1043307/rs2514259 (E197G A>G) for evidence of linkage with generalized anxiety disorder. Non-parametric linkage analysis was executed via Merlin software. One-thousand simulation tests were performed to exclude results due to random chance. In our study, the PSMD9 gene SNPs rs74421874, rs3825172, and rs1043307/rs2514259 result in linkage to generalized anxiety disorder. This is the first report describing PSMD9 gene SNPs in linkage to generalized anxiety disorder in T2D families.

Prevalence of adiposity and associated cardiometabolic risk factors in the Samoan genome-wide association study

OBJECTIVE

To describe the prevalence of obesity-related noncommunicable diseases (NCDs) and associated risk factors in a sample of Samoan adults studied in 2010 as part of a genome-wide assocation study (GWAS) for obesity related traits.

METHODS

Anthropometric and biochemical data collected from n = 3,475 participants (n = 1,437 male; n = 2,038 female) aged 24.5 to <65 years were used to describe the prevalence of obesity, diabetes, hypertension, and dyslipidemia within the study sample. One way analysis of variance, χ(2) tests, and binary logistic regression were used to identify differences in disease and risk factor prevalence by 10-year age group, gender, or by census region of residence.

RESULTS

Obesity was highly prevalent among the study sample; 64.6% of females and 41.2% of males were obese according to Polynesian cutoffs (BMI ≥ 32 kg/m(2) ). Females were less likely than males to have hypertension (31.7% vs. 36.7%) but equally likely to have diabetes (17.8% vs. 16.4%). With the exception of obesity and low HDL-cholesterol in females only, there were significant differences in the prevalence of all NCDs and associated risk factors by age group, with the oldest age group (55 to <65 years) most affected. In both sexes, residents of the Apia Urban Area were at significantly greater risk of obesity, diabetes, low HDL-cholesterol, and high triglycerides than residents of the more rural Savaii region.

CONCLUSIONS

The phenotypic characteristics of this sample provide evidence of a continuation of previously reported temporal trends toward obesity and its associated disorders. Attention must be paid to the critical NCD situation in Samoa.

Overweight condition and waist circumference and a candidate gene within the 12q24 locus

Aims

Obesity and obesity-associated phenotypes are linked to the chromosome12q24 locus, the non-insulin-dependent-diabetes 2 (NIDDM2) locus. The gene of proteasome modulator 9 (PSMD9) lies in the NIDDM2 region and is linked to type 2 diabetes (T2D), microvascular and macrovascular complications of T2D.

We aimed at studying whether the PSMD9 T2D risk single nucleotide polymorphisms (SNPs) IVS3+nt460, IVS3+nt437, and 197G are linked to obesity, overweight status and waist circumference in Italian T2D families.

Methods and results

We screened 200 Italians T2D siblings/families for PSMD9 variants. Using Merlin software, we performed non-parametric linkage analysis to test for linkage with obesity and overweight condition and variance component analysis to test for linkage with waist circumference in our T2D siblings/families dataset.

Our study shows that the PSMD9 SNPs IVS3+nt460, IVS3+nt437, and 197G are in linkage with overweight condition and waist circumference in Italians. The statistical power tests performed via simulations on real data confirm that the results are not due to random chance.

Conclusions

In summary, the linkage strategy using a homogeneous family/subject dataset can identify a gene contributing to a complex trait. PMSD9 may be at least one of the genes responsible for the linkage to obesity and obesity-associated phenotypes at the locus 12q24 in other populations.

Epigenetics, and human biology and health responses to modernization in the Samoan archipelago

Epigenetic mechanisms offer explanations for how environmental exposures at critical life periods may affect human biological and disease phenotypes. Incorporation of epigenetic approaches into research on health consequences of societal transitions may increase understanding of the complex biobehavioral factors influencing changing populations. Description of present and planned genetic epidemiology research, including epigenetic studies, among Samoans experiencing economic modernization and globalization offer examples for progress in knowledge of population health transitions.

Cardiovascular disease risk factors and DNA methylation at the LINE-1 repeat region in peripheral blood from Samoan Islanders

Lower levels of LINE-1 methylation in peripheral blood have been previously associated with risk of developing non-communicable conditions, the most well-explored of these being cancer, although recent research has begun to link altered LINE-1 methylation and cardiovascular disease. We examined the relationship between LINE-1 methylation and factors associated with metabolic and cardiovascular diseases through quantitative bisulfite pyrosequencing in DNA from peripheral blood samples from participants of the Samoan Family Study of Overweight and Diabetes (2002-03). The sample included 355 adult Samoans (88 men and 267 women) from both American Samoa and Samoa. In a model including all sample participants, men had significantly higher LINE-1 methylation levels than women (p=0.04), and lower levels of LINE-1 methylation were associated with higher levels of fasting LDL (p=0.02) and lower levels of fasting HDL (p=0.009). The findings from this study confirm that DNA "global" hypomethylation, (as measured by methylation at LINE-1 repeats) observed previously in cardiovascular disease is associated with altered levels of LDL and HDL in peripheral blood. Additionally, these findings strongly argue the need for further research, particularly including prospective studies, in order to understand the relationship between LINE-1 DNA methylation measured in blood and risk factors for cardiovascular disease.

First assessment of menstrual cycle function and reproductive endocrine status in Samoan women

BACKGROUND

American Samoa and Samoa are now characterized by one of the world's highest levels of adult overweight and obesity. Our objective was to investigate patterns of menstrual cyclicity reported by Samoan women and examine the relationship to adiposity and select hormone levels.

METHODS

A cross-sectional analysis was performed among Samoan women, aged 18-39 years (n = 322), using anthropometric and biomarker measures of adiposity and reproductive health, including insulin, adiponectin, testosterone, sex hormone-binding globulin, free androgen index (FAI) and mullerian-inhibiting substance (MIS). Menstrual regularity was assessed from self-reported responses. Multivariable models were estimated to adjust for potential confounding of the associations between menstrual patterns and other measures.

RESULTS

A high proportion of the women (13.7%) reported oligomenorrhea or amenorrhea (OM/AM). More than three-quarters, 80.7%, of women were either overweight or obese, using Polynesian-specific criteria, and OM/AM was significantly associated with higher BMI. Abdominal circumference and insulin levels were significantly higher, and adiponectin levels were lower, in those who reported OM/AM versus regular menstruation. The FAI was higher in women with increased BMI. MIS levels declined with age, more slowly in those reporting OM/AM.

CONCLUSIONS

Self-reported OM/AM was associated with an elevated BMI, abdominal adiposity and serum insulin, and with reduced adiponectin levels. These findings support a high rate of metabolic syndrome, and perhaps PCOS and reproductive dysfunction, among Samoan women.

Genetic loci for blood lipid levels identified by linkage and association analyses in Caribbean Hispanics

To identify genetic loci influencing blood lipid levels in Caribbean Hispanics, we first conducted a genome-wide linkage scan in 1,211 subjects from 100 Dominican families on five lipid quantitative traits: total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglycerides (TG), and LDL-C/HDL-C ratio. We then investigated the association between blood lipid levels and 21,361 single nucleotide polymorphisms (SNP) under the 1-logarithm of odds (LOD) unit down regions of linkage peaks in an independent community-based subcohort (N = 814, 42% Dominican) from the Northern Manhattan Study (NOMAS). We found significant linkage evidence for LDL-C/HDL-C on 7p12 (multipoint LOD = 3.91) and for TC on 16q23 (LOD = 3.35). In addition, we identified suggestive linkage evidence of LOD > 2.0 on 15q23 for TG, 16q23 for LDL-C, 19q12 for TC and LDL-C, and 20p12 for LDL-C. In the association analysis of the linkage peaks, we found that seven SNPs near FLJ45974 were associated with LDL-C/HDL-C with a nominal P < 3.5 × 10(-5), in addition to associations (P < 0.0001) for other lipid traits with SNPs in or near CDH13, SUMF2, TLE3, FAH, ARNT2, TSHZ3, ZNF343, RPL7AL2, and TMC3. Further studies are warranted to perform in-depth investigations of functional genetic variants in these regions.

PRELIMINARY BLOOD LIPID, LIPOPROTEIN AND GLUCOSE FINDINGS FROM THE GENOME-WIDE ASSOCIATION STUDY OF ADIPOSITY IN SAMOANS

Samoans have been shown to exhibit alarmingly high rates of non-communicable disease such as obesity, diabetes and cardiovascular disease (CVD). A high NCD burden is usually characterized by high rates of biological risk factors within the population, such as elevated lipid, lipoprotein, and blood glucose levels. This report describes the prevalence of these biological risk factors in a population of 800 Samoan adults (39% male, n=312), aged 25-64 years. High levels of total cholesterol were found in 11.5% of men and 10.0% of women. Of the 800 individuals studied 617 (77.1%) had levels of LDL-cholesterol that were too high. A substantially greater proportion of women had levels of HDL-cholesterol, which is protective against CVD risk, that were too low (62.1% of women as compared to 27.9% of men). Men showed higher average levels of triglycerides, with more men than women being classified as having increased risk for CVD. High blood glucose was, conversely, more prevalent in women than men (12.5% of women, 7.7% of men). These biochemical findings support reports of a high NCD burden in Samoa. This disease burden has implications not only for the individual, but also the family and the national economy as the healthcare system is placed under increasing pressure. Primary prevention strategies for these diseases must be multifold, addressing the multiple determinants of NCDs.

A fourth locus for autosomal dominant hypercholesterolemia maps at 16q22.1

Autosomal dominant hypercholesterolemia (ADH) is characterized by isolated increase in plasmatic low-density lipoprotein (LDL) cholesterol levels associated with high risk of premature cardiovascular disease. Mutations in LDLR, APOB, and PCSK9 genes have been shown to cause ADH. We now report further genetic heterogeneity of ADH through the study of a large French family in which the involvement of these three genes was excluded. A genome-wide scan mapped the disease-causing gene, named HCHOLA4, at 16q22.1 in a 7.89-Mb interval containing 154 genes with a maximum LOD score of 3.9. To reduce the linked region, we genotyped 18 smaller non-LDLR/non-APOB/non-PCSK9-ADH families at the HCHOLA4 locus. Six families did not exclude linkage to the locus, but none allowed reduction of the disease interval. The 154 regional genes were sorted according to the function of the encoded protein and tissue expression profiles, and 57 genes were analyzed through sequencing of their coding region and close flanking intronic parts. No disease-causing mutation was identified in these families, particularly in the LCAT gene. Finally, our results also show the existence of other ADH genes as nine families were neither linked to LDLR, APOB, and PCSK9 genes nor to the new HCHOLA4 locus.

Genome-wide linkage scan for loci associated with epilepsy in Belgian shepherd dogs

BACKGROUND

Idiopathic epilepsy in the Belgian shepherd dog is known to have a substantial genetic component. The objective of this study was to identify genomic regions associated with the expression of generalized seizures in the Belgian Tervuren and Sheepdog.

RESULTS

DNA from 366 dogs, of which 74 were classified as epileptic, representing two extended families were subjected to a genome-wide linkage scan using 410 microsatellite markers yielding informative coverage averaging 5.95 +/- 0.21 Mb. Though previous studies based on pedigree analyses proposed a major gene of influence, the present study demonstrated the trait to be highly polygenic. Studies of complex disorders in humans indicate that a liberal composite evaluation of genetic linkage is needed to identify underlying quantitative trait loci (QTLs). Four chromosomes yielded tentative linkage based upon LOD scores in excess of 1.0. Possible QTLs within these regions were supported also by analyses of multipoint linkage, allele frequency, TDT, and transmission of haplotype blocks.

CONCLUSIONS

Taken together the data tentatively indicate six QTLs, three on CFA 2, and one on each of CFA 6, 12, and 37, that support fine mapping for mutations associated with epilepsy in the Belgian shepherd. The study also underscores the complexity of genomic linkage studies for polygenic disorders.

Suggestive linkage detected for blood pressure related traits on 2q and 22q in the population on the Samoan islands

Background

High blood pressure or hypertension is a major risk factor involved in the development of cardiovascular diseases. We conducted genome-wide variance component linkage analyses to search for loci influencing five blood pressure related traits including the quantitative traits systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP), the dichotomous trait hypertension (HT) and the bivariate quantitative trait SBP-DBP in families residing in American Samoa and Samoa, as well as in the combined sample from the two polities. We adjusted the traits for a number of environmental covariates such as smoking, alcohol consumption, physical activity and material life style.

Results

We found suggestive univariate linkage for SBP on chromosome 2q35-q37 (LOD 2.4) and for PP on chromosome 22q13 (LOD 2.2), two chromosomal regions that recently have been associated with SBP and PP, respectively.

Conclusion

We have detected additional evidence for a recently reported locus associated with SBP on chromosome 2q and a susceptibility locus for PP on chromosome 22q. However, differences observed between the results from our three partly overlapping genetically homogenous study samples from the Samoan islands suggest that additional studies should be performed in order to verify these results.

Interdisciplinary Translational Research in Anthropology, Nutrition, and Public Health

This review focuses on several human population health research topics that exemplify interdisciplinary concepts and approaches from anthropology, nutrition, and public health with an emphasis on applied or translational global health implications. First, a recent study on neonatal survival in a resource-poor region emphasizes how health can be markedly improved with detailed translation and implementation of evidence from all three disciplines. Second, schistosomiasis, a parasitic worm infection, is reviewed with an emphasis on developing a consensus of its nutritional health burdens and the next translational research steps needed to improve control of both infection transmission and disease. Last, the author's long-term Samoan nutrition and health studies are described with a focus on new translational research to improve diabetes. This selective review attempts to provide a rationale for the intersections of anthropology, nutrition, and public health to proceed with fundamental biological, cultural, and behavioral research to reduce health inequalities globally and domestically.

Dietary patterns are associated with metabolic syndrome in adult Samoans

The prevalence of metabolic syndrome has reached epidemic levels in the Samoan Islands. In this cross-sectional study conducted in 2002-2003, dietary patterns were described among American Samoan (n = 723) and Samoan (n = 785) adults (> or =18 y) to identify neo-traditional and modern eating patterns and to relate these patterns to the presence of metabolic syndrome using Adult Treatment Panel III criteria. The neo-traditional dietary pattern, similar across both polities, was characterized by high intake of local foods, including crab/lobster, coconut products, and taro, and low intake of processed foods, including potato chips and soda. The modern pattern, also similar across both polities, was characterized by high intake of processed foods such as rice, potato chips, cake, and pancakes and low intake of local foods. The neo-traditional dietary pattern was associated with significantly higher serum HDL-cholesterol in American Samoa (P-trend = 0.05) and a decrease in abdominal circumference in American Samoa and Samoa (P-trend = 0.004 and 0.01, respectively). An inverse association was found with metabolic syndrome, although it did not reach significance (P = 0.23 in American Samoa; P = 0.13 in Samoa). The modern pattern was significantly positively associated with metabolic syndrome in Samoa (prevalence ratio = 1.21 for the fifth compared with first quintile; 95% CI: 0.93.1.57; P-trend = 0.05) and with increased serum triglyceride levels in both polities (P < 0.05). Reduced intake of processed foods high in refined grains and adherence to a neo-traditional eating pattern characterized by plant-based fiber, seafood, and coconut products may help to prevent growth in the prevalence of metabolic syndrome in the Samoan islands.

Adiponectin and type 2 diabetes in Samoan adults

OBJECTIVE

Previous studies have established an association between adiponectin and type 2 diabetes. It is unclear whether adiponectin will be useful among Samoan Islanders, characterized by markedly elevated levels of obesity, in differentiating those at risk of developing type 2 diabetes.

METHODS

Cross-sectional, genetic epidemiology study of obesity in American Samoa and Samoa 2002-2003 (n = 1,599). Logistic regression provided adjusted odds ratios and 95% confidence intervals for the association between adiponectin, diabetes, and prediabetes (impaired fasting glucose).

RESULTS

There is a significant decreasing trend in the odds of diabetes and prediabetes across increasing quintiles of adiponectin with an OR of 2.8 (95% CI: 1.6, 5.0) and 2.9 (95% CI: 1.5, 5.7), respectively, in the lowest relative to the highest quintile of adiponectin (P-for-trend = 0.004 and 0.001).

CONCLUSIONS

Adiponectin is an important correlate, independent of other risk factors, of the pathogenesis of type 2 diabetes among Samoan islanders and may help distinguish those at higher risk of developing this disease.

Identification of quantitative trait loci for fibrin clot phenotypes: the EuroCLOT study

OBJECTIVE

Fibrin makes up the structural basis of an occlusive arterial thrombus, and variability in fibrin phenotype relates to cardiovascular risk. The aims of the current study from the EU consortium EuroCLOT were to (1) determine the heritability of fibrin phenotypes and (2) identify QTLs associated with fibrin phenotypes.

METHODS AND RESULTS

447 dizygotic (DZ) and 460 monozygotic (MZ) pairs of healthy UK white female twins and 199 DZ twin pairs from Denmark were studied. D-dimer, an indicator of fibrin turnover, was measured by ELISA and measures of clot formation, morphology, and lysis were determined by turbidimetric assays. Heritability estimates and genome-wide linkage analysis were performed. Estimates of heritability for d-dimer and turbidometric variables were in the range 17% to 46%, with highest levels for maximal absorbance which provides an estimate of clot density. Genome-wide linkage analysis revealed 6 significant regions with LOD >3 on 5 chromosomes (5, 6, 9, 16, and 17).

CONCLUSIONS

The results indicate a significant genetic contribution to variability in fibrin phenotypes and highlight regions in the human genome which warrant further investigation in relation to ischemic cardiovascular disorders and their therapy.