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Measurement error is a major issue in self-reported diet that can distort diet-disease relationships. Use of blood concentration biomarkers has the potential to mitigate the subjective bias inherent in self-reporting. As part of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) baseline visit (2008–2011), self-reported information on diet was collected from all participants (n  = 16,415). The HCHS/SOL also included annual telephone follow-up, as well as a second (2014–2017) and third (2020–2023) clinic visit. Blood concentration biomarkers for carotenoids, tocopherols, retinol, vitamin B12, and folate were measured in a subset of participants (n  = 476) as part of the Study of Latinos: Nutrition and Physical Activity Assessment Study (SOLNAS) (2010–2012). We examined the relationships among biomarker levels, self-reported intake, Hispanic/Latino background (Central American, Cuban, Dominican, Mexican, Puerto Rican, or South American), and other participant characteristics in this diverse cohort. We built regression calibration–based prediction equations for 10 nutritional biomarkers and used a simulation to study the power of detecting a diet-disease association in a multivariable Cox model using a predicted concentration level. Good statistical power was observed for some nutrients with high prediction model R 2 values, but further research is needed to understand how best to realize the potential of these dietary biomarkers. This study provides a comprehensive examination of several nutritional biomarkers within the HCHS/SOL, characterizing their associations with subject characteristics and the influence of the measurement characteristics on the power to detect associations with health outcomes. [ABSTRACT FROM AUTHOR]

Context: The interrelationships among the gut microbiome, the Mediterranean diet (MedDiet), and a clinical endpoint of diabetes is unknown. Objective: To identify gut microbial features of a MedDiet and examine whether the association between MedDiet and diabetes varies across individuals with different gut microbial profiles. Methods: This study included 543 diabetic, 805 prediabetic, and 394 normoglycemic participants from a cohort study of USA Hispanic/Latino men and women. Fecal samples were profiled using 16S rRNA gene sequencing. Adherence to MedDiet was evaluated by an index based on 2 24-hour dietary recalls. Results: A greater MedDiet adherence was associated with higher abundances of major dietary fiber metabolizers (e.g., Faecalibacterium prausnitzii, false-discoveryrate-adjusted P [q] = 0.01), and lower abundances of biochemical specialists (e.g., Parabacteroides, q = 0.04). The gut microbiomes of participants with greater MedDiet adherence were enriched for functions involved in dietary fiber degradation but depleted for those related to sulfur reduction and lactose and galactose degradation. The associations between MedDiet adherence and diabetes prevalence were significantly stronger among participants with depleted abundance of Prevotella (pinteraction = 0.03 for diabetes, 0.02 for prediabetes/diabetes, and 0.02 for prediabetes). A 1-SD deviation increment in the MedDiet index was associated with 24% (odds ratio [OR] 0.76; 95% CI, 0.59-0.98) and 7% (OR 0.93; 95% CI, 0.72-1.20) lower odds of diabetes in Prevotella noncarriers and carriers, respectively. Conclusion: Adherence to MedDiet is associated with diverse gut microorganisms and microbial functions. The inverse association between the MedDiet and diabetes prevalence varies significantly depending on gut microbial composition. [ABSTRACT FROM AUTHOR]

Objectives How insulin-like growth factor-1 (IGF-1) is related to OA is not well understood. We determined relationships between IGF-1 and hospital-diagnosed hand, hip and knee OA in UK Biobank, using Mendelian randomization (MR) to determine causality. Methods Serum IGF-1 was assessed by chemiluminescent immunoassay. OA was determined using Hospital Episode Statistics. One-sample MR (1SMR) was performed using two-stage least-squares regression, with an unweighted IGF-1 genetic risk score as an instrument. Multivariable MR included BMI as an additional exposure (instrumented by BMI genetic risk score). MR analyses were adjusted for sex, genotyping chip and principal components. We then performed two-sample MR (2SMR) using summary statistics from Cohorts for Heart and Aging Research in Genetic Epidemiology (CHARGE) (IGF-1, N  = 30 884) and the recent genome-wide association study meta-analysis (N  = 455 221) of UK Biobank and Arthritis Research UK OA Genetics (arcOGEN). Results A total of 332 092 adults in UK Biobank had complete data. Their mean (s. d.) age was 56.5 (8.0) years and 54% were female. IGF-1 was observationally related to a reduced odds of hand OA [odds ratio per doubling = 0.87 (95% CI 0.82, 0.93)], and an increased odds of hip OA [1.04 (1.01, 1.07)], but was unrelated to knee OA [0.99 (0.96, 1.01)]. Using 1SMR, we found strong evidence for an increased risk of hip [odds ratio per s. d. increase = 1.57 (1.21, 2.01)] and knee [1.30 (1.07, 1.58)] OA with increasing IGF-1 concentration. By contrast, we found no evidence for a causal effect of IGF-1 concentration on hand OA [0.98 (0.57, 1.70)]. Results were consistent when estimated using 2SMR and in multivariable MR analyses accounting for BMI. Conclusion We have found evidence that increased serum IGF-1 is causally related to higher risk of hip and knee OA. [ABSTRACT FROM AUTHOR]

Objectives: Antiretroviral therapy (ART) use is associated with disrupted lipid and glucose metabolism in people with HIV infection. We aimed to identify plasma lipid species associated with risk of diabetes in the context of HIV infection.Research Design and Methods: We profiled 211 plasma lipid species in 491 HIV-infected and 203 HIV-uninfected participants aged 35 to 55 years from the Women's Interagency HIV Study and the Multicenter AIDS Cohort Study. Cox proportional hazards model was used to examine associations between baseline lipid species and incident diabetes (166 diabetes cases were identified during a median follow-up of 12.6 years).Results: We identified 11 lipid species, representing independent signals for 8 lipid classes/subclasses, associated with risk of diabetes (P < 0.05 after FDR correction). After adjustment for multiple covariates, cholesteryl ester (CE) (22:4), lysophosphatidylcholine (LPC) (18:2), phosphatidylcholine (PC) (36:4), phosphatidylcholine plasmalogen (34:3), and phosphatidylethanolamine (PE) (38:2) were associated with decreased risk of diabetes (HRs = 0.70 to 0.82 per SD increment), while diacylglycerol (32:0), LPC (14:0), PC (38:3), PE (36:1), and triacylglycerol (50:1) were associated with increased risk of diabetes (HRs = 1.26 to 1.56 per SD increment). HIV serostatus did not modify any lipid-diabetes associations; however, most of these lipid species were positively associated with HIV and/or ART use, including 3 diabetes-decreased ( CE [22:4], LPC [18:2], PE [38:2]) and all 5 diabetes-increased lipid species.Conclusions: This study identified multiple plasma lipid species associated with incident diabetes. Regardless of the directions of their associations with diabetes, most diabetes-associated lipid species were elevated in ART-treated people with HIV infection. This suggests a complex role of lipids in the link between ART and diabetes in HIV infection. [ABSTRACT FROM AUTHOR]

Aims To test whether human immunodeficiency virus (HIV) infection and subclinical cardiovascular disease (sCVD) are associated with expression of CXCR4 and other surface markers on classical, intermediate, and non-classical monocytes in women. Methods and results sCVD was defined as presence of atherosclerotic lesions in the carotid artery in 92 participants of the Women's Interagency HIV Study (WIHS). Participants were stratified into four sets (n  = 23 each) by HIV and sCVD status (HIV−/sCVD−, HIV−/sCVD+, HIV+/sCVD−, and HIV+/sCVD+) matched by age, race/ethnicity, and smoking status. Three subsets of monocytes were determined from archived peripheral blood mononuclear cells. Flow cytometry was used to count and phenotype surface markers. We tested for differences by HIV and sCVD status accounting for multiple comparisons. We found no differences in monocyte subset size among the four groups. Expression of seven surface markers differed significantly across the three monocyte subsets. CXCR4 expression [median fluorescence intensity (MFI)] in non-classical monocytes was highest among HIV−/CVD− [628, interquartile range (IQR) (295–1389)], followed by HIV+/CVD− [486, IQR (248–699)], HIV−/CVD+ (398, IQR (89–901)), and lowest in HIV+/CVD+ women [226, IQR (73–519)), P  = 0.006 in ANOVA. After accounting for multiple comparison (Tukey) the difference between HIV−/CVD− vs. HIV+/CVD+ remained significant with P  = 0.005 (HIV−/CVD− vs. HIV+/CVD− P  = 0.04, HIV−/CVD− vs. HIV−/CVD+ P  = 0.06, HIV+/CVD+ vs. HIV+/CVD− P  = 0.88, HIV+/CVD+ vs. HIV−/CVD+ P  = 0.81, HIV+/CVD− vs. HIV−/CVD+, P  = 0.99). All pairwise comparisons with HIV−/CVD− were individually significant (P  = 0.050 vs. HIV−/CVD+, P  = 0.028 vs. HIV+/CVD−, P  = 0.009 vs. HIV+/CVD+). CXCR4 expression on non-classical monocytes was significantly higher in CVD− (501.5, IQR (249.5–887.3)) vs. CVD+ (297, IQR (81.75–626.8) individuals (P  = 0.028, n  = 46 per group). CXCR4 expression on non-classical monocytes significantly correlated with cardiovascular and HIV−related risk factors including systolic blood pressure, platelet and T cell counts along with duration of antiretroviral therapy (P  < 0.05). In regression analyses, adjusted for education level, study site, and injection drug use, presence of HIV infection and sCVD remained significantly associated with lower CXCR4 expression on non-classical monocytes (P  = 0.003), but did not differ in classical or intermediate monocytes. Conclusion CXCR4 expression in non-classical monocytes was significantly lower among women with both HIV infection and sCVD, suggesting a potential atheroprotective role of CXCR4 in non-classical monocytes. [ABSTRACT FROM AUTHOR]

Background: Associations of adult height with cardiometabolic and pulmonary traits have been studied in majority European ancestry populations using Mendelian randomization and polygenic risk score (PRS) analysis. The standard PRS approach entails creating a PRS for height using variants identified in prior genome-wide association studies (GWAS). It is unclear how well the standard PRS approach performs in non-European populations and whether height-trait associations observed in Europeans are also observed in other populations.Methods: In the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), we used: (i) the standard approach to create a PRS for height (PRS1) and (ii) a novel approach to optimize the selection of variants from previously established height association loci to better explain height in HCHS/SOL (PRS2). We also estimated the extent to which PRS-trait associations were independent or mediated by the PRS effect on height.Results: In 7539 women and 5245 men, PRS1 and PRS2 explained 9 and 29% of the variance in measured height, respectively. Both PRS1 and PRS2 were associated with forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/ FVC ratio, total cholesterol and 2-hour oral glucose-tolerance test insulin levels. Additionally, PRS2 was associated with estimated glomerular filtration rate and ankle brachial index. Both PRS1 and PRS2 had pleiotropic associations with FEV1/ FVC ratio in mediation analyses.Conclusions: Associations of polygenic scores of height with measures of lung function and cholesterol were consistent with those observed in prior studies of majority European ancestry populations. Mediation analysis may augment standard PRS approaches to disentangle pleiotropic and mediated effects. [ABSTRACT FROM AUTHOR]

Abstract: Global antibody glycosylation is dynamic and plays critical roles in shaping different immunological outcomes and direct antibody functionality during HIV infection. However, the relevance of global antibody or plasma glycosylation patterns to HIV persistence after antiretroviral therapy (ART) has not been characterized. First, we compared glycomes of total plasma and isolated immunoglobulin G (IgG) from HIV+ ART‐suppressed, HIV+ viremic, and HIV‐negative individuals. Second, in ART‐suppressed individuals, we examined the associations between glycomes and (1) levels of cell‐associated HIV DNA and RNA in PBMCs and isolated CD4+ T cells, (2) CD4 count and CD4%, and (3) expression of CD4+ T‐cell activation markers. HIV infection is associated with persistent alterations in the IgG glycome including decreased levels of disialylated glycans, which is associated with a lower anti‐inflammatory activity, and increased levels of fucosylated glycans, which is associated with lower antibody‐dependent cell‐mediated cytotoxicity (ADCC). We also show that levels of certain mono‐ and digalactosylated nonfucosylated glycomic traits (A2G1, A2G2, and A2BG2), which have been reported to be associated with higher ADCC and higher anti‐inflammatory activities, exhibit significant negative correlations with levels of cell‐associated total HIV DNA and HIV RNA in ART‐suppressed individuals. Finally, levels of certain circulating anti‐inflammatory glycans are associated with higher levels of CD4 T cells and lower levels of T‐cell activation. Our findings represent the first proof‐of‐concept evidence that glycomic alterations, known to be associated with differential states of inflammation and ADCC activities, are also associated with levels of HIV persistence in the setting of ART suppression. [ABSTRACT FROM AUTHOR]

Reports on the associations between multiple clinical and behavioral health indicators and major health outcomes among older adults are scarce. We prospectively examined concordance with guidelines from the American Cancer Society and American Heart Association for disease prevention in relation to cancer, cardiovascular disease (CVD), and mortality among Cardiovascular Health Study enrollees aged 65-98 years who, at baseline assessment in 1989-1996 (n = 3,491), were free of CVD and cancer. Total and cause-specific mortality, as well as incidence of cancer and CVD, were lower with higher guideline concordance. Independent of body mass index, blood pressure, total cholesterol, and fasting plasma glucose, better health behaviors (diet, physical activity, and alcohol consumption) were associated with lower mortality (2-sided P < 0.0001). Among individuals with ideal levels for 3-4 of these 4 cardiometabolic biomarkers, those with poor concordance with health behavior recommendations had higher mortality compared with those who had the highest concordance with these behavioral recommendations (adjusted mortality hazard ratio = 1.82,95% confidence interval: 1.25,2.67). Older adults who are concordant with recommendations for cancer and CVD prevention have reduced rates of chronic disease and mortality. Interventions to achieve and maintain healthy lifestyle behaviors may offer benefits both in the presence and absence of adverse traditional clinical risk factors. [ABSTRACT FROM AUTHOR]

Background. Intermittent smoking is prevalent amongHispanics, but little is known about whether this smoking pattern associates with increased chronic kidney disease (CKD) risk in this population. The objective of the present study is to identify patterns of exposure associated with CKD in US Hispanics. Methods. We used cross-sectional data on 15 410 participants of the Hispanics Community Health Study/the Study of Latinos, a population-based study of individuals aged 18-74 years, recruited in 2008 to 2011 from four US field centers (Bronx, NY; Chicago, IL; Miami, FL; San Diego, CA). Smoking exposure was obtained through a questionnaire. CKD was defined by an estimated glomerular filtration rate of <60 mL/min/ 1.73 m² or a urine albumin-to-creatinine ratio of ≥30 mg/g. Results. Approximately 14% of individuals were daily and 7% were intermittent smokers, and 16% were past smokers. There was a significant interaction between smoking status and packyears of exposure (P = 0.0003). In adjusted models, therewas an increased odds of CKD among daily, intermittent and past smokers by pack-years compared with never smokers. The association of intermittent smokers was significant at 10 pack-years [odds ratio (OR) = 1.38, 95% confidence intervals (CI) 1.06, 1.81], whereas for daily smokers this association was observed at 40 pack-years (OR = 1.43, 95% CI 1.09, 1.89). Conclusions. Our findings of increased risk of CKD among Hispanics who are intermittent smokers support screening and smoking cessation interventions targeted to this population for the prevention of CKD. It also suggests novel mechanistic pathways for kidney toxicity that should be further explored in future studies. [ABSTRACT FROM AUTHOR]

Background: Adipokines and inflammation may provide a mechanistic link between obesity and postmenopausal breast cancer, yet epidemiologic data on their associations with breast cancer risk are limited.Methods: In a case-cohort analysis nested within the Women's Health Initiative Observational Study, a prospective cohort of postmenopausal women, baseline plasma samples from 875 incident breast cancer case patients and 839 subcohort participants were tested for levels of seven adipokines, namely leptin, adiponectin, resistin, interleukin-6, tumor necrosis factor-α, hepatocyte growth factor, and plasminogen activator inhibitor-1, and for C-reactive protein (CRP), an inflammatory marker. Data were analyzed by multivariable Cox modeling that included established breast cancer risk factors and previously measured estradiol and insulin levels. All statistical tests were two-sided.Results: The association between plasma CRP levels and breast cancer risk was dependent on hormone therapy (HT) use at baseline (P interaction = .003). In a model that controlled for multiple breast cancer risk factors including body mass index (BMI), estradiol, and insulin, CRP level was positively associated with breast cancer risk among HT nonusers (hazard ratio for high vs low CRP levels = 1.67, 95% confidence interval = 1.04 to 2.68, P trend = .029). None of the other adipokines were statistically significantly associated with breast cancer risk. Following inclusion of CRP, insulin, and estradiol in a multivariable model, the association of BMI with breast cancer was attenuated by 115%.Conclusion: These data indicate that CRP is a risk factor for postmenopausal breast cancer among HT nonusers. Inflammatory mediators, together with insulin and estrogen, may play a role in the obesity-breast cancer relation. [ABSTRACT FROM AUTHOR]

Background. Individuals infected with human immunodeficiency virus (HIV) have increased risk of cardiovascular events. It is unknown whether T cell activation and senescence, 2 immunologic sequelae of HIV infection, are associated with vascular disease among HIV-infected adults. Methods. T cell phenotyping and carotid ultrasound were assessed among 115 HIV-infected women and 43 age- and race/ethnicity-matched HIV-uninfected controls participating in the Women's Interagency HIV Study. Multivariate analyses were used to assess the association of T cell activation (CD38+HLA-DR+) and senescence (CD28-CD57+) with subclinical carotid artery disease. Results. Compared with HIV-uninfected women, frequencies of CD4+CD38+HLA-DR+, CD8+CD38+HLA-DR+, and CD8+CD28-CD57+ T cells were higher among HIV-infected women, including those who achieved viral suppression while receiving antiretroviral treatment. Among HIV-infected women, adjusted for age, antiretroviral medications, and viral load, higher frequencies of activated CD4+ and CD8+ T cells and immunosenescent CD8+ T cells were associated with increased prevalence of carotid artery lesions (prevalence ratiolesions associated with activated CD4+ T cells, 1.6 per SD [95% confidence interval {CI}, 1.1-2.2]; P 5 .02; prevalence ratiolesions associated with activated CD8+ T cells, 2.0 per SD [95% CI, 1.2-3.3]; P < .01; prevalence ratiolesions associated with senescent CD8+ T cells, 1.9 per SD [95% CI, 1.1-3.1]; P = .01). Conclusions. HIV-associated T cell changes are associated with subclinical carotid artery abnormalities, which may be observed even among those patients achieving viral suppression with effective antiretroviral therapy. [ABSTRACT FROM AUTHOR]

Background The positive association between obesity and postmenopausal breast cancer has been attributed, in part, to the fact that estrogen, a risk factor for breast cancer, is synthesized in adipose tissue. Obesity is also associated with high levels of insulin, a known mitogen. However, no prospective studies have directly assessed associations between circulating levels of insulin and/or insulin-like growth factor (IGF)-l, a related hormone, and the risk of breast cancer independent of estrogen level. Methods We conducted a case-cohort study of incident breast cancer among nondiabetic women who were enrolled in the Women's Health Initiative Observational Study (WHI-OS), a prospective cohort of 93676 postmenopausal women. Fasting serum samples obtained at study entry from 835 incident breast cancer case subjects and from a subcohort of 816 randomly chosen WHI-OS subjects were tested for levels of insulin, glucose, total IGF-l, free IGF-l, insulin-like growth factor binding protein-3, and estradiol. Multivariable Cox proportional hazards models were used to estimate associations between levels of the serologic factors and baseline characteristics (including body mass index IBMI]) and the risk of breast cancer. All statistical tests were two-sided. Results Insulin levels were positively associated with the risk of breast cancer (hazard ratio [HR] for highest vs lowest quartile of insulin level = 1.46, 95% confidence interval [Cl] = 1.00 to 2.13, Ptrend = .02); however, the association with insulin level varied by hormone therapy (HT) use (Pintersection = .01). In a model that controlled for multiple breast cancer risk factors including estradiol, insulin level was associated with breast cancer only among nonusers of HT (HR for highest vs lowest quartile of insulin level = 2.40, 95% CI = 1.30 to 4.41, Ptrend < .001). Obesity (BMI ≥30 kg/m²) was also associated with the risk of breast cancer among nonusers of HT (HR for BMI ≥30 kg/m² vs 18.5 to <25 kg/m² = 2.12, 95% Cl = 1.26 to 3.58, Ptrend =.003); however, this association was attenuated by adjustment for insulin (Ptrend = .40). Conclusion These data suggest that hyperinsulinemia is an independent risk factor for breast cancer and may have a substantial role in explaining the obesity-breast cancer relationship. [ABSTRACT FROM AUTHOR]

Background. The insulin-like growth factor (IGF) axis has been hypothesized to influence the rate of human immunodeficiency virus (HIV) disease progression. This premise is based largely on laboratory models showing that IGF-l stimulates thymic growth and increases lymphocyte numbers and that IGF-binding protein (IGFBP)-3 has an opposing effect, inhibiting heniatopoietic stem cell development. Methods. We studied 1422 HIV-infected women enrolled in a large cohort that entailed semiannual follow-up (initiated in 1994). Baseline serum samples were tested for IGF-l and IGFBP-3 to determine their associations with incident clinical acquired immunodeficiency syndrome (AIDS) and CD4+ T cell count decline prior to April 1996 (before the era of highly active antiretroviral therapy [HAART]). Results. Low IGF-I levels (Ptrend = .02) and high IGFBP-3 levels (Ptrend = .02) were associated with rapid CD4+ T cell count decline. Only IGFBP-3, however, was significantly associated with AIDS incidence (hazard ratio for highest vs. lowest quartile, 2.65 [95% confidence interval, 1.30-5.421; Ptrend = .02) in multivariable models. Conclusions. These findings suggest that serum levels of IGFBP-3 (and possibly IGF-I) are associated with the rate of HIV disease progression in women and, more broadly, that interindividual heterogeneity in the IGE axis may influence HIV pathogenesis. If correct, the IGF axis could be a target for interventions to slow HIV disease progression and extend the time before use of HAART becomes necessary. [ABSTRACT FROM AUTHOR]

Background. Highly active antiretroviral therapy (HAART), in addition to traditional vascular risk factors, may affect coronary heart disease (CHD) risk in individuals with human immunodeficiency virus (HIV) infection. Methods. Among HIV-infected (931 men and 1455 women) and HIV-uninfected (1099 men and 576 women) adults, the predicted risk of CHD was estimated on the basis of age, sex, lipid and blood pressure levels, the presence of diabetes, and smoking status. Results. Among HIV-infected men, 2% had moderate predicted risk of CHD (10-year CHD risk, 15%-25%), and 17% had high predicted risk (10-year CHD risk of ⩾25% or diabetes). Among HIV-infected women, 2% had moderate predicted CHD risk, and 12% had high predicted CHD risk. Compared with users of protease inhibitor- based HAART, the adjusted odds ratio (OR) for moderate-to-high risk of CHD was significantly lower among HAART-naive individuals (OR, 0.57; 95% confidence interval [CI], 0.36-0.89). Users of HAART that was not protease inhibitor based (OR, 0.74; 95% CI, 0.53-1.01) and former HAART users (OR, 0.68; 95% CI, 0.46-1.03) were also less likely than users of protease inhibitor-based HAART to have moderate-to-high CHD risk, although 95% CIs overlapped the null. Low income was associated with increased likelihood of moderate-to-high CHD risk (for annual income <$10,000 vs. >$40,000: OR, 2.32; 95% CI, 1.51-3.56 ). Elevated body mass index (calculated as weight in kilograms divided by the square of height in meters) predicted increased likelihood of moderate-to- high CHD risk (for BMI of 18.5-24.9 vs. BMI of 25-30: OR, 1.41 [95% CI, 1.03-1.93]; for BMI of 18.5-24.9 vs. BMI ⩾30: OR, 1.79 [95% CI, 1.25-2.56]). Conclusions. Among HIV-infected adults, in addition to antiretroviral drug exposures, being overweight and having a low income level were associated with increased predicted CHD risk. This suggests a need to target HIV- infected men and women with these characteristics for vascular risk factor screening. [ABSTRACT FROM AUTHOR]

Discusses several topics related to geriatrics research. Calcium channel blocker use and gastrointestinal tract bleeding among older adults; Chronic pain and bereavement in a depressed elderly woman; Endocarditis in older people.

We estimated local ancestry on the autosomes and X chromosome in a large US-based study of 12,793 Hispanic/Latino individuals using the RFMix method, and we compared different reference panels and approaches to local ancestry estimation on the X chromosome by means of Mendelian inconsistency rates as a proxy for accuracy. We developed a novel and straightforward approach to performing ancestry-specific PCA after finding artifactual behavior in the results from an existing approach. Using the ancestry-specific PCA, we found significant population structure within African, European, and Amerindian ancestries in the Hispanic/Latino individuals in our study. In the African ancestral component of the admixed individuals, individuals whose grandparents were from Central America clustered separately from individuals whose grandparents were from the Caribbean, and also from reference Yoruba and Mandenka West African individuals. In the European component, individuals whose grandparents were from Puerto Rico diverged partially from other background groups. In the Amerindian ancestral component, individuals clustered into multiple different groups depending on the grandparental country of origin. Therefore, local ancestry estimation provides further insight into the complex genetic structure of US Hispanic/Latino populations, which must be properly accounted for in genotype-phenotype association studies. It also provides a basis for admixture mapping and ancestry-specific allele frequency estimation, which are useful in the identification of risk factors for disease. [ABSTRACT FROM AUTHOR]