A Tête-à-tête with ChatGPT on the impact of artificial intelligence in medical education.

Chat Generative Pre-Trained Transformer (ChatGPT) is an artificial intelligence (AI) language model developed by OpenAI. It is trained to process vast amounts of text and engage in human-like conversational interaction with users. Being accessible by all, it is widely used and its capabilities range from language translation, summarising long texts and creative writing. This article explores the potential role of ChatGPT in medical education and the possible concerns about the misuse of this technology through a conversation with ChatGPT itself via text prompts. The implications of this technology in medical education as told by ChatGPT are interesting and seemingly helpful for both the students and the tutors. However, this could be a double-edged sword considering the risks of compromised students' integrity and concerns of over-reliance. This also calls for counter strategies and policies in place to mitigate these risks.

Occult HBV infection in HIV-infected adults and evaluation of pooled NAT for HBV.

The study aimed to determine the prevalence of occult hepatitis B virus infection among HIV-infected persons and to evaluate the use of a pooling strategy to detect occult HBV infection in the setting of HIV infection. Five hundred and two HIV-positive individuals were tested for HBV, occult HBV and hepatitis C and D with serologic and nucleic acid testing (NAT). We also evaluated a pooled NAT strategy for screening occult HBV infection among the HIV-positive individuals. The prevalence of HBV infection among HIV-positive individuals was 32 (6.4%), and occult HBV prevalence was 10%. The pooling HBV NAT had a sensitivity of 66.7% and specificity of 100%, compared to HBV DNA NAT of individual samples. In conclusion, this study found a high prevalence of occult HBV infection among our HIV-infected population. We also demonstrated that pooled HBV NAT is highly specific, moderately sensitive and cost-effective. As conventional HBV viral load assays are expensive in resource-limited settings such as India, pooled HBV DNA NAT might be a good way for detecting occult HBV infection and will reduce HBV-associated complications.

GCKR and PPP1R3B identified as genome-wide significant loci for plasma lactate: the Atherosclerosis Risk in Communities (ARIC) study.

AIM: To investigate the genetic influence of circulating lactate level, a marker of oxidative capacity associated with diabetes. METHODS: We conducted a genome-wide association study of log-transformed plasma lactate levels in 6901 European-American participants in the Atherosclerosis Risk in Communities study. For regions that achieved genome-wide significance in European-American participants, we conducted candidate region analysis in African-American subjects and tested for interaction between metformin use and the index single nucleotide polymorphisms for plasma lactate in European-American subjects. RESULTS: The genome-wide association study in European-American subjects identified two genome-wide significant loci, GCKR (rs1260326, T allele ß=0.08; P=1.8×10(-47) ) and PPP1R3B/LOC157273 (rs9987289, A allele ß=0.06; P=1.6×10(-9) ). The index single nucleotide polymorphisms in these two loci explain 3.3% of the variance in log-transformed plasma lactate levels among the European-American subjects. In the African-American subjects, based on a region-significant threshold, the index single nucleotide polymorphism at GCKR was associated with plasma lactate but that at PPP1R3B/LOC157273 was not. Metformin use appeared to strengthen the association between the index single nucleotide polymorphism at PPP1R3B/LOC157273 and plasma lactate in European-American subjects (P for interaction=0.01). CONCLUSIONS: We identified GCKR and PPP1R3B/LOC157273 as two genome-wide significant loci of plasma lactate. Both loci are associated with other diabetes-related phenotypes. These findings increase our understanding of the genetic control of lactate metabolism.

Confirming genes influencing risk to cleft lip with/without cleft palate in a case-parent trio study.

A collection of 1,108 case-parent trios ascertained through an isolated, nonsyndromic cleft lip with or without cleft palate (CL/P) was used to replicate the findings from a genome-wide association study (GWAS) conducted by Beaty et al. (Nat Genet 42:525-529, 2010), where four different genes/regions were identified as influencing risk to CL/P. Tagging SNPs for 33 different genes were genotyped (1,269 SNPs). All four of the genes originally identified as showing genome-wide significance (IRF6, ABCA4 and MAF, plus the 8q24 region) were confirmed in this independent sample of trios (who were primarily of European and Southeast Asian ancestry). In addition, eight genes classified as 'second tier' hits in the original study (PAX7, THADA, COL8A1/FILIP1L, DCAF4L2, GADD45G, NTN1, RBFOX3 and FOXE1) showed evidence of linkage and association in this replication sample. Meta-analysis between the original GWAS trios and these replication trios showed PAX7, COL8A1/FILIP1L and NTN1 achieved genome-wide significance. Tests for gene-environment interaction between these 33 genes and maternal smoking found evidence for interaction with two additional genes: GRID2 and ELAVL2 among European mothers (who had a higher rate of smoking than Asian mothers). Formal tests for gene-gene interaction (epistasis) failed to show evidence of statistical interaction in any simple fashion. This study confirms that many different genes influence risk to CL/P.

Treatment of triclosan through enhanced microbial biodegradation.

Triclosan (TCS) is extensively used in healthcare and personal care products as an antibacterial agent. Due to the persistent and toxic nature of TCS, it is not completely degraded in the biological wastewater treatment process. In this research work, identification of TCS degrading bacteria from municipal wastewater sludge and applying the same as bioaugmentation treatment for wastewater have been reported. Based on the 16S rRNA analysis of wastewater sludge, it was found that Providencia rettgeri MB-IIT strain was active and able to grow in higher TCS concentration. The identified bacterial strain was able to use TCS as carbon and energy source for its growth. The biodegradation experiment was optimized for the operational parameters viz. pH (5-10), inoculum size (1-5% (v/v)) and different initial concentration (2, 5, and 10 mg/L) of TCS. During the TCS degradation process, manganese peroxidase (MnP) and laccase (LAC) enzyme activity and specific growth rate of P. rettgeri strain were maximum at pH=7% and 2% (v/v) inoculum size, resulting in 98% of TCS removal efficiency. A total of six intermediate products were identified from the Liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analysis, and the two mechanisms responsible for the degradation of TCS have been elucidated. The study highlights that P. rettgeri MB-IIT strain could be advantageously used to degrade triclosan present in the wastewater.

Lung Cancer Detection and Improving Accuracy Using Linear Subspace Image Classification Algorithm.

The ability to identify lung cancer at an early stage is critical, because it can help patients live longer. However, predicting the affected area while diagnosing cancer is a huge challenge. An intelligent computer-aided diagnostic system can be utilized to detect and diagnose lung cancer by detecting the damaged region. The suggested Linear Subspace Image Classification Algorithm (LSICA) approach classifies images in a linear subspace. This methodology is used to accurately identify the damaged region, and it involves three steps: image enhancement, segmentation, and classification. The spatial image clustering technique is used to quickly segment and identify the impacted area in the image. LSICA is utilized to determine the accuracy value of the affected region for classification purposes. Therefore, a lung cancer detection system with classification-dependent image processing is used for lung cancer CT imaging. Therefore, a new method to overcome these deficiencies of the process for detection using LSICA is proposed in this work on lung cancer. MATLAB has been used in all programs. A proposed system designed to easily identify the affected region with help of the classification technique to enhance and get more accurate results.

Risk factors for HIV transmission among heterosexual discordant couples in South India.

OBJECTIVE: To assess the risk factors associated with heterosexual HIV transmission among South Indian discordant couples enrolled in clinical care. METHODS: A nested matched case-control study of serodiscordant couples in which the HIV-infected partner (index case) was enrolled in care. Demographic and clinical characteristics, sexual behaviours, CD4 cell count and plasma HIV-1 RNA loads were measured at enrollment and longitudinally over 12 months of follow-up. The study included 70 cases who seroconverted during study follow-up and 167 matched controls who remained persistently serodiscordant. RESULTS: The incidence of HIV infection among the initially seronegative partners was 6.52 per 100 person-years. Persistently discordant patients were more likely to have initiated highly active antiretroviral therapy (HAART) than patients in seroconverting relationships (62.9%vs. 42.9%) (P=0.001). Patients in seroconverting relationships had significantly higher plasma viral loads (PVLs) than patients in discordant relationships at enrolment, at 6 months and at 12 months (P<0.05). Patients in seroconverting relationships were less likely to use condoms with their primary partners than patients in discordant relationships (P<0.05). Patients in relationships that seroconverted between 6 and 12 months were diagnosed more often with genital Herpes simplex than patients in discordant relationships (P=0.001). In the univariate and multivariate logistic regression, the following variables were associated with seroconversion: PVL >100,000 [odds ratio (OR): 1.82; 95% confidence interval (CI): 1.1-2.8], non-disclosure of HIV status (OR: 5.5; 95% CI: 4.3-6.2) and not using condoms (OR: 2.8; 95% CI: 2.4-3.6). CONCLUSIONS: Couples-based intervention models are crucial in preventing HIV transmission to seronegative spouses. Providing early treatment for sexually transmitted infections, HAART and enhancing condom use and disclosure could potentially decrease the risk of HIV transmission within Indian married couples.

Couples at risk for HIV infection in Southern India: characteristics of HIV-infected patients in concordant and discordant heterosexual relationships.

The aim of the article is to compare the clinical and behavioural characteristics of HIV-infected South Indian patients in concordant and discordant heterosexual relationships. A cross-sectional analysis of married couples in concordant and discordant relationships was carried out. Demographic and clinical characteristics, sexual behaviours, CD4 cell count and plasma HIV-1 RNA loads were assessed. A total of 839 concordant patients and 996 discordant patients were included in this analysis. Significantly more men were in discordant than concordant relationships (97% versus 59%; P = 0.002). More discordant patients had never initiated highly active antiretroviral treatment (HAART) than concordant patients (14.1% versus 8.5%; P = 0.004). Concordant patients had significantly higher CD4 cell counts than discordant patients at the time of enrolling to care (205 versus 139 cells/microL; P = 0.001). Discordant patients had significantly higher plasma viral loads than concordant patients (100,000 copies/mL versus 89,154 copies/mL; P = 0.002). Discordant patients were more likely to use condoms with their spouses than concordant patients (49% versus 28.8%; P = 0.01). In conclusion, couples-based interventions and the provision of HAART could substantially decrease behavioural and clinical correlates of HIV transmission among discordant South Indian married couples. The spouses of HIV-infected index patients are at increased risk for HIV infection, and further preventive measures are needed.

Evolutionary disruption of S&P 500 trading concentration: An intriguing tale of a financial innovation.

The novel finding of Balakrishnan, Miller & Shankar (2008) that investors, overwhelmed by the plethora of stock investment offerings, limit their analysis and daily choices to only a small subset of stocks (i.e., herding behavior) now seems to be common wisdom (Iosebashvili, 2019). We investigate whether the introduction of an innovation in financial products designed to allow investors to trade the entire product bundle of S&P 500 stocks, namely S&P 500 index funds, altered "herding behavior" by creating a new class of index investors. We model the distribution of daily trading concentration as a power law function and examine changes over the last six decades. Intriguingly, we discover a unique pattern in the trading concentration distribution that exhibits two distinct trends. For the period 1960-75, the trading concentration of the S&P 500 stocks tracks the increasing trend for the entire market, i.e., the unevenness in trading has steadily increased. However, after the introduction of S&P 500 index funds in 1975, concentration of trading in the S&P 500 stocks has steadily decreased, i.e., trading distribution has become more even across all 500 stocks, contrary to the current belief of equity analysts. This is also in sharp contrast to the case of U.S. stocks that are not in the S&P 500 index where trading concentration has steadily increased. We further corroborate the uniqueness of the inverted V-shape by a counterfactual investigation of the trading concentration patterns for other sets of 500 stock portfolios. This uniquely distinctive trading concentration pattern for S&P 500 stocks appears to be driven by the increasing dominance of bundle trading by index investors.

High frequency of clinically significant mutations after first-line generic highly active antiretroviral therapy failure: implications for second-line options in resource-limited settings.

Continuation of failed highly active antiretroviral therapy regimens can lead to the accumulation of mutations that may limit options for second-line treatment. We studied the pattern of drug resistance mutations among 138 Indian patients who experienced failure of nonnucleotide reverse-transcriptase-containing first-line highly active antiretroviral therapy. This study demonstrates a high frequency of drug resistance mutations in human immunodeficiency virus-infected Indians who experience immunologic treatment failure and suggests the need for viral load monitoring.

Establishment of T-lymphocyte subset reference intervals in a healthy adult population in Chennai, India.

Estimation of CD4+ T-lymphocytes continues to be an important aspect for monitoring HIV disease progression and response to antiretroviral therapy. Most of the diagnostic laboratories often rely on western text books for CD4+ T-lymphocyte reference values, which could, often be unreliable for usage in local settings. Therefore, we attempted to establish the reference values for T-lymphocyte subsets among healthy adults in a cross-sectional study carried out at the YRG Centre for AIDS Research and Education (YRG CARE) in Chennai, south India, in 213 (84 female and 129 male) healthy, HIV-1/2 seronegative adults as volunteers. Whole blood specimens were processed for CD4+, CD8+ T-lymphocyte estimation and haematological parameters. The established range of CD4+ T-lymphocyte counts for men and women were 383-1347 cells/microl (mean 865 and median 845 cells/microl) and 448-1593 cells/microl (mean 1021 and median 954 cells/microl), respectively. Women had significantly higher absolute CD4+ Tlymphocyte counts (P<0.001) and CD4+:CD8+ T-lymphocyte ratio as compared to men. The established normal range of CD4+ T-lymphocyte % was 21-59 (mean 40.2 and median 40.1). The influence of age was not observed in any of the parameters except CD4+/CD8+ T-lymphocyte ratio with the >45 yr age group. Further studies with greater sample size may be required to define the staging of HIV disease in relation to the normal CD4 T-lymphocyte count in the general population.

Cofactors for low serum albumin levels among HIV-infected individuals in Southern India.

BACKGROUND AND AIMS: Malnutrition and low serum albumin among human immunodeficiency virus (HIV)-infected individuals are cofactors for HIV disease progression. The present study aimed to identify the proportion of HIV-infected individuals with low serum albumin and the possible cofactors among highly active antiretroviral therapy (HAART) experienced and HAART naïve individuals. METHODS: A total of 835 HIV-infected individuals (HAART-experienced, HAART-naïve) were included in the study. RESULTS: Of the 835 individuals, 44.6% had normal (4.2-5.2 g/dL) and 55.4% had abnormal (<4.2 g/dL) albumin levels. The abnormal group had significantly lower body mass index (BMI) compared with the normal group (P = .02). Among those with abnormal albumin, 388 (84%) were HAART experienced compared with 239 (64%) with normal albumin (P < .001). Among the abnormal group, 259 (55.9%) had CD4 count <200 cells/mL as compared with 124 (33.3%) in the normal group (P < .001). CONCLUSIONS: CD4 count and lower were the major cofactors for low serum albumin among HIV-infected individuals. Therefore, serum albumin would be a useful biochemical test for HIV disease in resource-limited settings.

Primary HIV-1 drug resistance and polymorphic patterns among injecting drug users (IDUs) in Chennai, Southern India.

BACKGROUND AND OBJECTIVE: India has 1.1 million injecting drug users (IDUs) with an HIV prevalence rate as high as 64%. Drug resistance screening before therapy is beneficial to the individual. Here, we have studied primary drug resistance among IDUs in Chennai. METHODS: Specimens (n = 55) collected between March 2005 and April 2006 were subjected to genotyping assay. The mutations for the drug resistance were interpreted using the Stanford HIV Drug Resistance Database. RESULTS: M41LM (1.8%), K65KN (1.8%), and G73GS (2.7%) were found to be associated with low-level resistance to zidovudine (ZDV), stavudine (d4T), abacavir (ABC), didanosine (ddI), emtricitabine (FTC), tenofovir (TDF), and saquinavir (SQV) in each specimen. The rate of polymorphisms is significantly different from universally established subtype ''C''-specific polymorphisms (P < .0001). CONCLUSION: The presence of drug resistance mutations, though minimal, is alarming as it could spread easily between IDUs and from them to their sexual partners. The genetic variation is of importance in vaccine design.

Diversity of hepatitis C virus infection among HIV-infected people who inject drugs in India.

The availability of generic direct acting antivirals (DAAs) for hepatitis C virus (HCV) treatment has prompted many low-and-middle-income countries to launch HCV elimination programs. Because the efficacy of some of these generic DAAs varies by HCV viral subtype, information on subtype distribution can contribute important information to these elimination programs. We conducted a cross-sectional serosurvey to characterize HCV subtype diversity among HIV positive people who inject drugs (PWID) across 14 cities in India. Of 801 HIV positive PWID sampled, 639 tested HCV antibody positive (78.9%). Among 105 samples sequenced, genotype 3 (58.1%) was the most commonly observed followed by genotype 1 (36.2%) and genotype 6 (5.7%). Of the genotype 3 infections, 65% were subtype 3a and 35% were subtype 3b. Of the genotype 1 infections, 94% were subtype 1a and 6% were subtype 1b. All genotype 6 samples were subtype 6n. There was some variability in genotype diversity depending on geographic region and PWID epidemic stage with greater diversity observed in older PWID epidemics. One sequence, HY018, did not cluster with any known reference sequences in phylogenetic analysis. Nearly 80% of HIV infected PWID across India are co-infected with HCV, and subtype prevalence and genetic diversity varied by region and PWID epidemic stage. HCV elimination programs in India will need to consider HCV subtype.

Moulded Osteomyofascial Pedicled Split (MOPS) Craniotomy Flap in Reconstruction of Anterior Cranial Fossa Defects: Pilot Study of a Novel Technique.

INTRODUCTION: Anterior cranial fossa (ACF) defects still remains a reconstructive challenge to neurosurgeons due to the difficult location, inaccessibility, and unfavorable vascular anatomy. Usual reconstructive methods reported complications such as recurrent cerebrospinal fluid leak due to bone resorption and tissue breakdown. This is mainly due to the avascularity of the bone graft and inability to provide bony structural support for the skull base. An ideal reconstructive modality should provide a rigid bony support to prevent brain herniation as well as ensure a water tight barrier between sinonasal tract and intracranial compartment. METHODOLOGY: Hence, we thought of a novel technique of taking the outer table of the primary craniotomy flap with its intact myofascial pedicle and moulded it with multiple osteotomies (moulded osteomyofascial pedicled split (MOPS) craniotomy flap) to fit into uneven ACF defects. Advantages of our flap include (1) It is a pedicled vascularized bone flap. (2) It is taken from primary craniotomy flap; hence, no separate craniotomy is required. (3) The inner table is intact and leaves no secondary calvarial bone defect on the donor site. (4) Osteoplastic flap is moulded to fit into the defect, thus providing good contour. RESULTS: MOPS flap was used in five patients with ACF defects due to varied etiologies such as encephalocele defect, frontal mucocele, skull base meningioma, and complex naso ethmoid fracture. Age of the patients included in the study varied from 21 to 60 years. Male:female ratio was 4:1. ACF defects were reconstructed using MOPS flap in all cases. There were no postoperative complications and 1-month postoperative computerized tomography scan showed no evidence of bone resorption with acceptable cosmesis. CONCLUSION: MOPS craniotomy flap provides a novel, easily mastered, and cost-effective technique with minimal complication in reconstruction of complex ACF defects with acceptable esthetic and functional outcome.

Is there synergy in syndemics? Psychosocial conditions and sexual risk among men who have sex with men in India.

Syndemic theory describes the clustering and synergistic interaction of disease driven by contextual and social factors, which worsen health outcomes for a population, and has been applied to men who have sex with men (MSM) and their risk for HIV and other sexually transmitted infections. Recent reviews, however, have critiqued prevailing approaches in syndemic studies that assess only additive associations without evaluation of synergy. Following these suggestions, we compared the traditional additive approach with a test for synergistic association of 5 syndemic conditions (alcohol dependence, illicit drug use, depression, intimate partner violence (IPV), and childhood sexual abuse (CSA)) with unprotected anal intercourse (UAI) and active syphilis infection among 11,771 MSM recruited through respondent driven sampling from 12 cities in India. UAI was assessed via self-report and active syphilis infection was diagnosed by RPR and THPA tests. An additive association was explored using a condition count (range 0-5), and synergy was tested using relative excess risk due to interactions (RERIs) calculated from all 2-way and common 3-way interactions between conditions in adjusted regression models. There was a significant dose response associated with the syndemic count and UAI, and a similar pattern for syphilis, though not statistically significant. RERIs showed synergy for only one pair of conditions for UAI and syphilis, respectively: IPV + depression and alcohol dependence + illicit drug use. In this study, we found an additive association between syndemic conditions and UAI with evidence of synergistic interaction between a pair of psychosocial conditions, and no significant additive association, but a synergistic interaction between another pair of psychosocial conditions for syphilis. Our results lend further support to a critical reassessment of syndemic analyses. Closer attention to the cumulative development, underlying causal pathways, and possible synergistic interaction of co-occurring epidemics through combined qualitative and quantitative methodologies may yield more effective interventions for vulnerable, marginalized populations.

Use of an HIV-1 reverse-transcriptase enzyme-activity assay to measure HIV-1 viral load as a potential alternative to nucleic acid-based assay for monitoring antiretroviral therapy in resource-limited settings.

An inexpensive and technically less-demanding methodology to quantify HIV-1 viral load would be of great value for resource-limited settings, where the nucleic-acid amplification technique (NAAT) is impractical and/or resource-prohibitive. In this study, an HIV-1 reverse-transcriptase enzyme-activity assay (ExaVir Load assay, version 1) was compared with the gold standard RT-PCR assay, Roche HIV-1 Amplicor Monitor, version 1.5. A total of 121 plasma specimens were used for the evaluation. ExaVir Load had a sensitivity of 97 % and a specificity of 71 % in identifying specimens with <400 copies ml(-1) in the Roche RT-PCR assay as being less than the detection limit of the assay (5500 copies ml(-1)). The mean difference (95 % limits of agreement) between Roche RT-PCR and ExaVir Load was -0.23 (-1.59 to 1.13) log(10)(copies ml(-1)) by Bland-Altman analysis. Significant negative correlations were seen between CD4(+) T-cell counts and the ExaVir Load assay (r=-0.32, P<0.05), and between CD4(+) T-cell counts and the Roche RT-PCR (r=-0.38, P<0.01). The present study with HIV-1 showed a strong correlation between the ExaVir Load assay and the RT-PCR assay. Hence, the ExaVir Load assay could be considered for use in resource-limited settings as an alternative viral-load assay to the standard NAAT-based assay after further evaluation with prospective specimens.

Hydrothorax in association with Scopulariopsis brumptii in an AIDS patient in Chennai, India.

Over the past decade, an increasing number of opportunistic fungal infections have been reported in immunocompromised subjects. Microascus spp. and their anamorphs Scopulariopsis spp. have been recovered from a wide geographical range. We report a case of Scopulariopsis brumptii in a 27-year-old man with AIDS presenting with breathlessness, pericardial effusion and hydrothorax in Chennai, southern India, in February 2007. Because of respiratory arrest, the patient was intubated. However, the patient developed obstructive shock and died due to cardiac dysfunctions. This report underlines the need for a direct, intensive approach to investigations in immunocompromised patients, especially those with AIDS.

Histopathological Analysis of Brain Tumours- A Seven Year Study from a Tertiary Care Centre in South India.

INTRODUCTION: Tumours of central nervous system constitute 1%-2% of tumours in adults. The incidence of brain tumours has been reported to be around 3.9 and 3.0/one lac/year in males and females respectively. A few studies are available from India which show a lower incidence of brain tumours compared to the developed countries. Not much is known about the epidemiology of brain tumours in the population from South India. AIM: To identify the age groups, gender distribution, topography and different histological types of brain tumours. MATERIALS AND METHODS: A total of 510 cases of brain tumours were identified over a period of seven years which were included in the present study. We retrieved the slides of these cases and reviewed them. Immunohistochemistry in required cases were done. Age and gender distribution, clinical presentation, site of tumour and histopathologic patterns with grade were noted and the data was analysed with SPSS software version 17.0. RESULTS: Our analysis showed that most of the brain tumours occur between 40-60 years of age, with a male to female ratio of 0.9:1. Majority of cases involved dura and cerebral lobes except for the occipital lobe, and meningioma and glial tumours were the most common broad histological types. WHO grade IV tumours and metastasis were common in males compared to females. CONCLUSION: This study revealed the distribution of brain tumours in patients attending our institution. The results obtained were comparable with available worldwide data.

Cadmium body burden and increased blood pressure in middle-aged American Indians: the Strong Heart Study.

Cadmium (Cd) is an environmental pollutant that has been associated with cardiovascular disease in populations, but the relationship of Cd with hypertension has been inconsistent. We studied the association between urinary Cd concentrations, a measure of total body burden, and blood pressure in American Indians, a US population with above national average Cd burden. Urinary Cd was measured using inductively coupled plasma mass spectrometry, and adjusted for urinary creatinine concentration. Among 3714 middle-aged American Indian participants of the Strong Heart Study (mean age 56 years, 41% male, 67% ever-smokers, 23% taking antihypertensive medications), urinary Cd ranged from 0.01 to 78.48 µg g-1 creatinine (geometric mean=0.94 µg g-1) and it was correlated with smoking pack-year among ever-smokers (r2=0.16, P<0.0001). Participants who were smokers were on average light-smokers (mean 10.8 pack-years), and urinary Cd was similarly elevated in light- and never-smokers (geometric means of 0.88 µg g-1 creatinine for both categories). Log-transformed urinary Cd was significantly associated with higher systolic blood pressure in models adjusted for age, sex, geographic area, body mass index, smoking (ever vs never, and cumulative pack-years) and kidney function (mean blood pressure difference by lnCd concentration (ß)=1.64, P=0.002). These associations were present among light- and never-smokers (ß=2.03, P=0.002, n=2627), although not significant among never-smokers (ß=1.22, P=0.18, n=1260). Cd was also associated with diastolic blood pressure among light- and never-smokers (ß=0.94, P=0.004). These findings suggest that there is a relationship between Cd body burden and increased blood pressure in American Indians, a population with increased cardiovascular disease risk.