Cigarette smoking and prostate cancer aggressiveness among African and European American men.

PURPOSE: Smoking is a modifiable lifestyle factor that has not been established as a prostate cancer risk factor, nor emphasized in prostate cancer prevention. Studies have shown that African American (AA) smokers have a poorer cancer prognosis than European Americans (EAs), while having a lower prevalence of heavy smoking. We examined the relationship between cigarette smoking and prostate cancer aggressiveness and assessed racial differences in smoking habits on the probability of high-aggressive prostate cancer. METHODS: Using data from the North Carolina-Louisiana Prostate Cancer Project (n = 1,279), prostate cancer aggressiveness was defined as high or low based on Gleason scores, serum prostate-specific antigen levels, and tumor stage. Cigarette smoking was categorized as current, former, or never smokers. Multivariable logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Self-reported current (OR = 1.99; 95% CI 1.30-3.06) smoking was associated with high-aggressive prostate cancer relative to never smokers. When stratified by self-reported race, the odds of having high-aggressive cancer increased among AA current (OR = 3.58; 95% CI 2.04-6.28) and former smokers (OR = 2.21; 95% CI 1.38-3.53) compared to AA never smokers, but the odds were diminished among the EA stratum (Pself-reported race x smoking status = 0.003). CONCLUSION: Cigarette smoking is associated with prostate cancer aggressiveness, a relationship modulated by self-reported race. Future research is needed to investigate types of cigarettes smoked and metabolic differences that may be contributing to the racial disparities observed.

Association of serum 25-hydroxyvitamin D with cardiovascular mortality and kidney outcome in patients with early stages of CKD.

PURPOSE: While serum 25-hydroxyvitamin D (25[OH]D) deficiency is prevalent in chronic kidney disease (CKD), the effects of 25(OH)D deficiency on cardiovascular mortality and kidney outcomes in patients with early-stage CKD remain incompletely understood. METHODS: This multicenter retrospective cohort study included adult patients with stages 1-3 CKD from 19 medical centers across China between January 2000 and May 2021. The primary outcome was cardiovascular mortality. The secondary study outcome included CKD progression (defined as a sustained > 40% eGFR decrease from baseline or progress to end-stage kidney disease), and annual percentage change of eGFR. RESULTS: Of 9229 adults with stages 1-3 CKD, 27.0% and 38.9% had severe (< 10 ng/mL) and moderate (10 to < 20 ng/mL) serum 25(OH)D deficiency, respectively. Compared with patients having 25(OH)D ≥ 20 ng/mL, a significantly higher risk of cardiovascular mortality (hazard ratio [HR] 1.90, 95% CI 1.37-2.63), CKD progression (HR 2.20, 95% CI 1.68-2.88), and a steeper annual decline in eGFR (estimate - 7.87%; 95% CI - 10.24% to - 5.51% per year) was found in those with serum 25(OH)D < 10 ng/mL. Similar results were obtained in subgroups and by sensitivity analyses. CONCLUSIONS: 25(OH)D deficiency is associated with increased risks of cardiovascular mortality and CKD progression in patients with early-stage CKD. Studies are needed to determine whether early intervention for 25(OH)D deficiency could improve the prognosis of patients with early-stage CKD.

Extreme terahertz magnon multiplication induced by resonant magnetic pulse pairs.

Nonlinear interactions of spin-waves and their quanta, magnons, have emerged as prominent candidates for interference-based technology, ranging from quantum transduction to antiferromagnetic spintronics. Yet magnon multiplication in the terahertz (THz) spectral region represents a major challenge. Intense, resonant magnetic fields from THz pulse-pairs with controllable phases and amplitudes enable high order THz magnon multiplication, distinct from non-resonant nonlinearities such as the high harmonic generation by below-band gap electric fields. Here, we demonstrate exceptionally high-order THz nonlinear magnonics. It manifests as 7th-order spin-wave-mixing and 6th harmonic magnon generation in an antiferromagnetic orthoferrite. We use THz two-dimensional coherent spectroscopy to achieve high-sensitivity detection of nonlinear magnon interactions up to six-magnon quanta in strongly-driven many-magnon correlated states. The high-order magnon multiplication, supported by classical and quantum spin simulations, elucidates the significance of four-fold magnetic anisotropy and Dzyaloshinskii-Moriya symmetry breaking. Moreover, our results shed light on the potential quantum fluctuation properties inherent in nonlinear magnons.

Variations in Student Approaches to Problem Solving in Undergraduate Biology Education.

Existing research has investigated student problem-solving strategies across science, technology, engineering, and mathematics; however, there is limited work in undergraduate biology education on how various aspects that influence learning combine to generate holistic approaches to problem solving. Through the lens of situated cognition, we consider problem solving as a learning phenomenon that involves the interactions between internal cognition of the learner and the external learning environment. Using phenomenography as a methodology, we investigated undergraduate student approaches to problem solving in biology through interviews. We identified five aspects of problem solving (including knowledge, strategy, intention, metacognition, and mindset) that define three qualitatively different approaches to problem solving; each approach is distinguishable by variations across the aspects. Variations in the knowledge and strategy aspects largely aligned with previous work on how the use or avoidance of biological knowledge informed both concept-based and nonconcept-based strategies. Variations in the other aspects revealed intentions spanning complete disengagement to deep interest with the course material, different degrees of metacognitive reflections, and a continuum of fixed to growth mindsets. We discuss implications for how these characterizations can improve instruction and efforts to support development of problem-solving skills.

[Correlations between the average Young's modulus and histopathological characteristics of papillary thyroid carcinoma].

Objective: To explore the histopathological factors affecting the stiffness of papillary thyroid carcinoma (PTC). Methods: Ninety-six patients with PTC confirmed by surgery and pathology in Shanxi Bethune Hospital from January 2019 to December 2020 were selected, including 101 nodules. Two-dimensional ultrasound and shear-wave elastography (SWE) were performed before surgery and the average Young's modulus (Emean) of PTC nodules were measured. Histopathological examinations on the nodules were conducted after surgery to decide the lesion size, number of lesions, calcification type, presence or absence of capsular and extracapsular invasion, degree of fibrosis, microvessel density, and number of tumor cells. The correlations between the lesion size, degree of fibrosis, microvessel density, and number of tumor cells and the Emean were analyzed. The Emeans of nodules with different numbers of lesions, presence or absence of capsular and extracapsular invasion, and different pathological calcification types were compared. The multiple linear regression analysis was used to evaluate the histopathological factors influencing the Emean. Results: The ranges of the lesion sizes, degrees of fibrosis, microvascular density, numbers of tumor cells, and the Emeans of the 101 investigated PTC nodules were (1.29±0.95) cm, (30.64±18.37)%, (101.64±30.7) vessels per high power field, (373.52±149.87) cells per high power field, and (36.47±19.62) kPa, respectively. Correlation analysis showed that the lesion size of PTC and the degree of fibrosis were positively correlated with the Emean (r=0.660, P＜0.001; r=0.789, P＜0.001), while the microvessel density was negatively correlated with the Emean (r=-0.198, P=0.047). The Emean of the group with capsular and extracapsular invasion was higher than that of the group without (P=0.014). There were statistical differences in the Emeans among different types of pathological calcification (P＜0.001). The multiple linear regression analysis showed that the lesion size (ß=0.325, P＜0.001), degree of fibrosis (ß=0.563, P＜0.001), psammoma bodies (ß=0.177, P=0.001), stromal calcification (ß=0.164, P=0.003), and mixed calcification of both psammoma bodies and stroma (ß=0.163, P=0.003) were independent influencing factors for the Emean. The degree of fibrosis had the greatest impact on the Emean. Conclusions: The Emean of PTC lesions was correlated with the histopathological characteristics of PTC. The lesion size, degree of fibrosis, and calcification had significant impact on the Emean, among which the degree of fibrosis had the greatest impact.

Postpandemic immunity debt of influenza in the USA and England: an interrupted time series study.

OBJECTIVES: The concept of "immunity debt" has gained attention in the public sphere, and some have argued that the recent out-of-season resurgence of respiratory syncytial virus demonstrates the presence of immunity debt. This study investigates the existence of immunity debt in the context of influenza. STUDY DESIGN: Interrupted time series analysis. METHODS: The positivity rate of influenza in the USA and England was gathered from the Centers for Disease Control and Prevention and the UK Health Security Agency. A time series model with an autoregressive approach was used to model the dynamics of positivity rate. Binary indicator variables were included in the model to account for the impact of non-pharmaceutical interventions (NPIs) and immunity debt. RESULTS: The impact of NPIs and immunity debt on the positivity rate of influenza was found to be statistically significant. CONCLUSIONS: This present work provides evidence supporting the existence of immunity debt in influenza in both the USA and England in the immediate month following the removal of NPIs such as lockdowns and facemask mandates.

Uric acid is negatively associated with cognition in the first- episode of schizophrenia.

BACKGROUND: We explored the relationship between levels of serum uric acid (UA) and cognitive impairment in people with schizophrenia to order to better protect and improve cognitive function in such patients. METHODS: A uricase method evaluated serum UA levels in 82 individuals with first-episode schizophrenia and in 39 healthy controls. The Brief Psychiatric Rating Scale (BPRS) and the event-related potential P300 were used to assess the patient's psychiatric symptoms and cognitive functioning. The link between serum UA levels, BPRS scores, and P300 was investigated. RESULTS: Prior to treatment, serum UA levels and latency N3 in the study group were significantly higher than in the control group, whereas the amplitude P3 was considerably lower. After therapy, the study group's BPRS scores, serum UA levels, latency N3, and amplitude P3 were lower than before treatment. According to correlation analysis, serum UA levels in the pre-treatment study group significantly positively correlated with BPRS score and latency N3 but not amplitude P3. After therapy, serum UA levels were no longer substantially related to the BPRS score or amplitude P3 but strongly and positively correlated with latency N3. CONCLUSIONS: First-episode schizophrenia patients have higher serum UA levels than the general population which partly reflects poor cognitive performance. Improving patients' cognitive function may be facilitated by lowering serum UA levels.

Testosterone promotes the migration, invasion and EMT process of papillary thyroid carcinoma by up-regulating Tnnt1.

PURPOSE: To explore the key genes and molecular pathways in the progression of thyroid papillary carcinoma (PTC) promoted by testosterone using RNA-sequencing technology, and to provide new drug targets for improving the therapeutic effect of PTC. METHODS: Orchiectomy (ORX) was carried out to construct ORX mouse models. TPC-1 cells were subcutaneously injected for PTC formation in mice, and the tumor tissues were collected for RNA-seq. The key genes were screened by bioinformatics technology. Tnnt1 expression in PTC cells was knocked down or overexpressed by transfection. Cell counting kit-8 (CCK-8), colony formation assay, scratch assay and transwell assay were adopted, respectively, for the detection of cell proliferation, colony formation, migration and invasion. Besides, quantification real-time polymerase chain reaction (qRT-PCR) and western blot were utilized to determine the mRNA and protein expression levels of genes in tissues or cells. RESULTS: Both estradiol and testosterone promoted the growth of PTC xenografts. The key gene Tnnt1 was screened and obtained by bioinformatics technology. Functional analysis revealed that overexpression of Tnnt1 could markedly promote the proliferation, colony formation, migration, invasion, and epithelial-to-mesenchymal transition (EMT) process of PTC cells, as well as could activate p38/JNK pathway. In addition, si-Tnt1 was able to inhibit the cancer-promoting effect of testosterone. CONCLUSION: Based on the outcomes of bioinformatics and basic experiments, it is found that testosterone can promote malignant behaviors such as growth, migration, invasion and EMT process of PTC by up-regulating Tnnt1 expression. In addition, the function of testosterone may be achieved by activating p38/JNK signaling pathway.

Sex-Related Effect of Aging in Gingival Gamma-Delta T Cells.

Aging affects the number and function of gamma-delta (γδ) T cells in a tissue-specific manner, modifying the risk for inflammatory disease. These aging-related γδT-cell variations in gingival tissues that could increase the risk for inflammation and periodontal disease remain unknown. Here we sought to identify quantitative and qualitative variations in gingival γδT cells associated with aging that could have an impact in oral immunoinflammatory responses. For this, gingival tissues from young (4 mo) and aged (24 mo) male and female mice were collected and analyzed by flow cytometry. Cell suspensions were stimulated and stained with eFluor450 (cell viability), anti-CD45 (hematopoietic cells), anti-CD3 (lymphocytes), anti-TCRγδ (γδT cells), anti-IL-15rα (cell proliferation), and anti-Notch-3 (senescence marker). Detection of intracellular cytokines IL-17A and interferon γ (IFNγ) was performed. Gingival expression of specific γ- and δ-chains and cytokines was evaluated by quantitative reverse transcription polymerase chain reaction. A significantly higher number of IL-17A-producing γδT cells and IL-17A expression levels were observed in gingival tissues from aged females but not males. Similarly, the number of gingival Notch-3+ γδT cells increased with aging only in females. IL-15rα was not detected in gingival γδT cells. Chains γ1, 2, 4, 5, 6, and 7 as well as δ1, 2, 4, and 6 were detected. Detection levels of all γ chains except γ1 as well as δ1 and δ2 changed with aging in males, females, or both. Interestingly, number of IL-17A-producing conventional T cells similarly increased with aging only in females. Both sexes showed increased IFNγ+ conventional T-cell numbers with aging; however, it reached significance only in females. In conclusion, the number of gingival IL-17A-producing γδT cells and IL-17A expression increase naturally with aging specifically in females. This sexual dimorphism in gingival γδT and conventional Th17 cell numbers and phenotypes suggests distinct aging-related mechanisms of periodontitis in males and females.

The expression of annexin-A1 in esophageal squamous cell carcinoma and its association with the biological behavior of the primary human esophageal squamous carcinoma cell line.

This study aimed to observe the differential expression of Annexin-A1 in esophageal squamous cell carcinoma (ESCC) and explored the effect of small interfering ribonucleic acid (RNAi)-Annexin-A1 on the biological behavior of CE81T-0 cells. An immunohistochemical approach was used to detect the expression of Annexin-A1 in 86 pairs of ESCC samples. Quantitative reverse transcription polymerase chain reaction was used to detect the expression of Annexin-A1 in CE81T-0 and CE81T-4 cells, and the expression of Annexin-A1 in CE81T-0 cells was knocked out by RNAi. A methyl-thiazolyl-tetrazolium assay was used to observe the effect of Annexin-A1 on cell proliferation, and flow cytometry was conducted to analyze its effect on cell cycles and apoptosis. A scratch assay and a Transwell chamber were used to detect changes in cell migration and invasion. From the results, compared with the Annexin-A1 expression rate of 59.3% in para-carcinoma tissues, the expression of Annexin-A1 in cancer was reduced to only 32.6% in ESCC cells. Annexin-A1 was strongly expressed in highly differentiated ESCC cells without lymphatic metastasis and highly expressed in the CE81T-0 cell group with low metastasis. Annexin-A1 gene silencing promoted cell proliferation and inhibited apoptosis, blocked cells in the S-phase, and increased cell migration, leading to an increase in the number of invaded cells. Above all, Annexin-A1 could reflect the differentiation degree and lymph node metastasis of ESCC cells to some extent and was involved in the invasion, metastasis, proliferation, and other biological behaviors of ESCC cells, indicating an experimental basis for Annexin-A1 as a molecular marker in the early diagnosis of ESCC and the prediction of cell metastasis, invasion, and differentiation degree.

[PLXNA1 is highly expressed in hepatocellular carcinoma and affects patients' survival and immune microenvironment].

OBJECTIVE: To investigate PLXNA1 expression in hepatocellular carcinoma (HCC) and explore its biological function and impacts on patients' survival outcomes and immune microenvironment. METHODS: Bioinformatic analysis of highly expressed immune-related genes in HCC were performed using TCGA database and Immport website, and 7 genes associated with the survival outcomes of the patients were identified using univariate Cox regression analysis, Gene Expression Profiling Interactive Analysis, and Kaplan Meier plotter website. The expression profile of PLXNA1 in HCC was verified using GEO database. The impact of PLXNA1 expression on survival outcomes of HCC patients was analyzed using TCGA database, Kaplan Meier, and timeROC curve analyses, and its association with immune cell infiltration was explored using TIMER website, CIBERSORT, and ssGSEA. Immunohistochemmistry was used to detect PLXNA1 expression in clinical specimens of HCC and adjacent tissues, and the correlation of PLXNA1 expression level with the patients' survival was analyzed. RT-qPCR was used to examine PLXNA1 expressions in different HCC cell lines, and the effects of PLXNA1 knockdown on proliferation and migration of SMMC-7721 cells were evaluated using CCK-8 and Transwell assays. RESULTS: Bioinformatic analyses suggested that PLXNA1 was highly expressed in HCC, and its high expression was associated with poor survival outcomes of the patients. PLXNA1 expression level was significantly correlated with immune cell infiltration in HCC. Immunohistochemmistry showed that compared with the adjacent tissues, HCC tissues had significantly higher PLXNA1 expressions, which were associated with a poor patient survival and served also as a diagnostic indicator for HCC (AUC= 0.9346). In cultured HCC cell lines, SMMC-7721 cells showed a higher PLXNA1 expression than HL-7702 cells, and PLXNA1 knockdown significantly suppressed proliferation and migration of SMMC-7721 cells. CONCLUSION: PLXNA1 is highly expressed in HCC to promote tumor cell migration and proliferation and affect the patients' survival outcomes and immune microenvironment.

Tuberculosis and Risk of Emphysema among US Adults in the NHANES I Epidemiologic Follow-Up Study Cohort, 1971-1992.

(1) Background: History of TB is a known risk factor for long-term respiratory impairment affecting lung functions in both restrictive and obstructive lung disease. (2) Methods: We analyzed data from the NHANES I Epidemiologic Follow-up Study (NHEFS), a longitudinal study conducted on a noninstitutionalized adult US population aged 25-74 years. Approximately 93 percent of the original NHANES I cohort was successfully traced by the end of the survey period and was available for analysis. The final adjusted model included age groups, gender, family income, lifetime smoking, body mass index (BMI), and frequency of alcohol consumption as potential confounders. (3) Results: The estimated hazards ratio of developing emphysema during follow-up for individuals with a past diagnosis of TB was 54% lower (95% CI = 0.35, 0.61) that that in individuals with no past TB, after controlling for potential confounders and using proportional hazards regression appropriate to the complex sample design. The association, however, was not statistically significant (HR = 0.86, p-value = 0.38) when only a self-reported history of TB was considered as the exposure in an unadjusted model. (4) Conclusions: Tuberculosis (self-reported or LTBI) was strongly (but inversely) associated with emphysema incidence. The association was not statistically significant with only a self-reported history of TB as exposure.

[Animal study on left bundle branch current of injury and anatomic location of leads in His-purkinje conduction system pacing].

Objective: Explore the relationship between tip of the left bundle branch pacing lead and anatomic location of left bundle branch as well as the mechanism of left bundle branch current of injury. To clarify the clinical value of left bundle branch current of injury during operation. Methods: The pacing leads were implanted in the hearts of two living swines. Intraoperative electrophysiological study confirmed that the left bundle branch or only the deep left ventricular septum was captured at low output. Immediately after operation, the gross specimen of swine hearts was stained with iodine to observe the gross distribution of His-purkinje conduction system on the left ventricular endocardium and its relationship with the leads. Subsequently, the swine hearts were fixed with formalin solution, and the pacing leads were removed after the positions were marked. The swine hearts were then sectioned and stained with Masson and Goldner trichrome, and the relationship between the anatomic location of the conduction system and the tip of the lead was observed under a light microscope. Results: After iodine staining of the specimen, the His-purkinje conduction system was observed with the naked eye in a net-like distribution, and the lead tip was screwed deeply and fixed in the left bundle branch area of the left ventricular subendocardium in the ventricular septum. Masson and Goldner trichrome staining showed that left bundle branch pacing lead directly passed through the left bundle branch when there was left bundle branch potential with left bundle branch current of injury, while it was not directly contact the left bundle branch when there was left bundle branch potential without left bundle branch current of injury. Conclusion: The left bundle branch current of injury observed on intracardiac electrocardiogram during His-purkinje conduction system pacing suggests that the pacing lead directly contacted the conduction bundle or its branches, therefore, the captured threshold was relatively low. Left bundle branch current of injury can be used as an important anatomic and electrophysiological evidence of left bundle branch capture.

Increased Utilization of Low-Dose CT for Lung Cancer Screening at an Arkansas Community Oncology Clinic.

BACKGROUND: Low-dose CT (LDCT) is underused in Arkansas for lung cancer screening, a rural state with a high incidence of lung cancer. The objective was to determine whether offering free LDCT increased the number of high-risk individuals screened in a rural catchment area. METHODS: There were 5,402 patients enrolled in screening at Highlands Oncology, a community oncology clinic in Northwest Arkansas, from 2013 to 2020. Screenings were separated into time periods: period 1 (10 months for-fee), period 2 (10 months free with targeted advertisements and primary care outreach), and period 3 (62 months free with only primary care outreach). In all, 5,035 high-risk participants were eligible for analysis based on National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology. Enrollment rates, incidence densities (IDs), Cox proportional hazard models, and Kaplan-Meier curves were performed to investigate differences between enrollment periods and high-risk groups. RESULTS: Patient volume increased drastically once screenings were offered free of charge (period 1 = 4.6 versus period 2 = 66.0 and period 3 = 69.8 average patients per month). Incidence density per 1,000 person-years increased through each period (IDPeriod 1 = 17.2; IDPeriod 2 = 20.8; IDPeriod 3 = 25.5 cases). Cox models revealed significant differences in lung cancer risk between high-risk groups (P = .012) but not enrollment periods (P = .19). Kaplan-Meier lung cancer-free probabilities differed significantly between high-risk groups (log-rank P = .00068) but not enrollment periods (log-rank P = .18). CONCLUSIONS: This study suggests that eligible patients are more receptive to free LDCT screening, despite most insurances not having a required copay for eligible patients.

[Establishment of a digital remote platform for respiratory support and intelligent early warning in intensive care units].

During the disease progression or treatment of critically ill patients with lung injury, the changes in respiratory mechanics are continuous and dynamic. Establishing a digital platform for respiratory support in the ICU, which enables the continuous recording, dynamic analysis, and real-time alerting of numerical and waveform data from mechanical ventilation, can help intensivists improve their understanding of "dynamic respiratory mechanics", improve respiratory therapy and patient outcomes, as well as reduce workload and increase work efficiency. The construction of a dedicated database for mechanical ventilation, based on ventilator waveforms provides essential data support for projects such as respiratory mechanics data algorithm models. This will facilitate the establishment of an auxiliary decision-making system, enable the realization of intelligent mechanical ventilation, and create a new era of dynamic respiratory mechanics.

[Applications and challenges of large language models in critical care medicine].

The rapid development of big data methods and technologies has provided more and more new ideas and methods for clinical diagnosis and treatment. The emergence of large language models (LLM) has made it possible for human-computer interactive dialogues and applications in complex medical scenarios. Critical care medicine is a process of continuous dynamic targeted treatment. The huge data generated in this process needs to be integrated and optimized through models for clinical application, interaction in teaching simulation, and assistance in scientific research. Using the LLM represented by generative pre-trained transformer ChatGPT can initially realize the application in the diagnosis of severe diseases, the prediction of death risk and the management of medical records. At the same time, the time and space limitations, illusions and ethical and moral issues of ChatGPT emerged as the times require. In the future, it is undeniable that it may play a huge role in the diagnosis and treatment of critical care medicine, but the current application should be combined with more clinical knowledge reserves of critical care medicine to carefully judge its conclusions.

Association of DNA methylation signatures with cognitive performance among smokers and ex-smokers.

INTRODUCTION: Alterations in DNA methylation profiles have been associated with cancer, and can be influenced by environmental factors such as smoking. A small but growing literature indicates there are reproducible and robust differences in methylation levels among smokers, never smokers, and ex-smokers. Here, we compared differences in salivary DNA methylation levels among current and ex-smokers (at least 2 years abstinent). METHODS: Smokers (n=26) and ex-smokers (n=30) provided detailed smoking histories, completed the Paced Auditory Serial Addition Test (PASAT), and submitted a saliva sample. Whole-genome DNA methylation from saliva was performed, and ANCOVA models and a receiver operating characteristic (ROC) curve were used for the differences between groups and the performance of significant CpG sites. RESULTS: After controlling for race, age, and gender, smokers had significantly lower methylation levels than ex-smokers in two CpG sites: cg05575921 (AHRR) and cg21566642 (ALPPL2). Based on the ROC analyses, both CpGs had strong classification potentials (cg05575921 AUC=0.97 and cg21566642 AUC=0.93) in differentiating smoking status. Across all subjects, the percent methylation of cg05575921 (AHRR) and cg21566642 (ALPPL2) positively correlated with the length of the last quit attempt (r=0.65 and 0.64, respectively, p<0.001) and PASAT accuracy (r=0.29 and 0.30, respectively, p<0.05). CONCLUSIONS: In spite of the small sample size and preliminary research, our results replicate previously reported differences in AHRR hypomethylation among smokers. Furthermore, we show that the duration of smoking abstinence is associated with a recovery of methylation in ex-smokers, which may be linked to a reduced risk of smoking-associated diseases. The association with cognitive performance suggests that the hypomethylation of AHRR in saliva may reflect systemic exposure to cigarette-related toxicants that negatively affect cognitive performance, and should be validated in larger studies.