RESUMO
This paper reflects on the concept of the Plantationocene through an analysis of sugarcane plantations in Guangxi province, China. It argues that although these plantations are owned and operated by local villagers, they are de facto controlled by corporations, and subject to state intervention through a 'zoning scheme'. They are constructed and operated according to the same logic as other plantations all over the world, namely, the logic of extraction based on cheap land and labor. By demonstrating that plantations are not necessarily large-scale and do not always entail the alienation of land and labor, this paper hopes to empirically broaden the concept of the Plantationocene and to highlight the extractive nature of and the power relations around plantations.
RESUMO
BACKGROUND: Hypertension caused by air pollution exposure is a growing concern in China. The association between air pollutant exposure and hypertension has been found to be potentiated by obesity, however, little is known about the processes mediating this association. This study investigated the association between fine particulate matter (aerodynamic equivalent diameter ≤ 2.5 microns, PM2.5) exposure and the prevalence of hypertension in a representative population in southern China and tested whether obesity mediated this association. METHODS: A total of 14,308 adults from 48 communities/villages in southern China were selected from January 2015 to December 2015 using a stratified multistage random sampling method. Hourly PM2.5 measurements were collected from the China National Environmental Monitoring Centre. Restricted cubic splines were used to analyze the nonlinear dose-response relationship between PM2.5 exposure and hypertension risk. The mediating effect mechanism of obesity on PM2.5-associated hypertension was tested in a causal inference framework following the approach proposed by Imai and Keele. RESULTS: A total of 20.7% (2966/14,308) of participants in the present study were diagnosed with hypertension. Nonlinear exposure-response analysis revealed that exposure to an annual mean PM2.5 concentration above 41.8 µg/m3 was associated with increased hypertension risk at an incremental gradient. 9.1% of the hypertension burden could be attributed to exposure to elevated annual average concentrations of PM2.5. It is noteworthy that an increased body fat percentage positively mediated 59.3% of the association between PM2.5 exposure and hypertension risk, whereas body mass index mediated 34.3% of this association. CONCLUSIONS: This study suggests that a significant portion of the estimated effect of exposure to PM2.5 on the risk of hypertension appears to be attributed to its effect on alterations in body composition and the development of obesity. These findings could inform intersectoral actions in future studies to protect populations with excessive fine particle exposure from developing hypertension.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Hipertensão , Adulto , Humanos , Material Particulado/efeitos adversos , Material Particulado/análise , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Hipertensão/etiologia , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Obesidade/epidemiologia , Obesidade/complicações , China/epidemiologia , Tecido Adiposo , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análiseRESUMO
BACKGROUND: Resistant hypertension (RHTN), a clinically complex condition with profound health implications, necessitates considerable time and allocation of medical resources for effective management. Unraveling the environmental risk factors associated with RHTN may shed light on future interventional targets aimed at reducing its incidence. Exposure to heavy metal has been linked to an increased risk of hypertension, while the relationship with RHTN remains poorly understood. METHODS: Using the 1999-2018 National Health and Nutrition Examination Survey (NHANES) data, we examined the association of blood lead (Pb), cadmium (Cd), and mercury (Hg) with RHTN using a multinomial logistic regression model. The combined effects of the metals and the contribution of each metal were assessed using a weighted quantile sum (WQS) analysis. RESULTS: A total of 38281 participants were included in the analysis. Compared with no resistant hypertension (NRHTN), per 1 µg/dL increase in blood Pb concentration, the proportion of RHTN increased by 16% [adjusted odds ratio (aOR), 1.16; 95% confidence interval (CI) 1.01-1.32]. When analyzed by quartiles (Q), the aOR [95% CI] for Pd was 1.30[1.01,1.67] (Q4 vs. Q1); there was a significant dose-response relationship (p < 0.05). Likewise, as a continuous variable, each 1 µg/dL increase in blood Cd level was associated with a 13% increase in the proportion of RHTN (aOR: 1.13; 95%CI: [1.00,1.27]); when analyzed as quartile, aOR [95% CI] for Cd were 1.30[1.01,1.69] (Q3 vs. Q1), and 1.35[1.03,1.75] (Q4 vs. Q1); the dose-response relationship was significant (p < 0.05). WQS analysis showed a significant combined effects of Pb, Cd, and Hg on RHTN, with Pb as the highest weight (0.64), followed by Cd (0.25) and Hg (0.11). Stratified analysis indicated that the associations for the two heavy metals were significant for participants who were male, â¼ 60 years old, and with kidney dysfunction. CONCLUSION: Findings of this study with national data provide new evidence regarding the role of environmental heavy metal exposure in RHTN. The prevention strategies aimed at reducing heavy metal exposure should particularly focus on Americans who are middle-aged, male, and afflicted with kidney dysfunction.
Assuntos
Hipertensão , Mercúrio , Metais Pesados , Pessoa de Meia-Idade , Humanos , Masculino , Adulto , Feminino , Cádmio , Inquéritos Nutricionais , Chumbo , Hipertensão/induzido quimicamente , Hipertensão/epidemiologiaRESUMO
BACKGROUND: Exposure to ambient air pollution is associated with increased cardiovascular morbidity and mortality. Circulating microRNAs (miRNAs) may mediate cardiovascular effects of exposure to air pollution. This study aims to investigate whether circulating miRNAs mediate the associations between short-term human exposure to ambient air pollution and cardiovascular biomarkers. METHODS: Twenty-four healthy adults residing in the Research Triangle area of North Carolina, USA were enrolled between December 2016 and July 2019. Circulating miRNAs, protein, and lipid biomarkers were assessed repeatedly for 3 sessions separated by at least 7 days. Linear mixed-effects models were used to assess the associations between air pollutant concentrations obtained from nearby air quality monitoring stations and miRNAs controlling for covariates including omega-3 index, relative humidity, and temperature. miRNAs that were significantly altered were then matched with protein or blood lipid biomarkers using either Ingenuity Pathway Analysis or a literature search. A mediation analysis was performed to test the statistical significance of miRNA's mediating effects between exposure to air pollution and cardiovascular biomarkers. RESULTS: Short-term exposure to ambient fine particulate matter (PM2.5), ozone (O3), and nitrogen dioxide (NO2) was associated with changes in 11, 9, and 24 circulating miRNAs, respectively. Pathway analysis showed that several miRNAs including miR-125b-5p, miR-144-5p, miR-26a-5p, and miR-34a-5p may mediate the effects of air pollutant exposure on the changes of downstream protein / lipid biomarkers including serum amyloid A (SAA), C-reactive protein (CRP), soluble vascular adhesive molecules 1 (sICAM1), total cholesterol, and high-density lipoproteins (HDL). Mediation analysis showed that only miR-26a-5p significantly mediated air pollutant (PM2.5 and NO2)-induced effects on blood CRP and total cholesterol levels. For example, 34.1% of PM2.5-associated changes in CRP were significantly mediated by miR-26a-5p at lag4 [indirect effects, 0.06 (0.02, 0.10), P = 0.005]. Similarly, the proportions of indirect effects of miR-26a-5p on the association between NO2 exposure and CRP were 46.8% at lag2 [0.06 (0.02, 0.11), P = 0.003], 61.2% at lag3 [0.05 (0.00, 0.09), P = 0.04], and 30.8% at 5-day moving average [0.06 (0.02, 0.10), P = 0.01]. In addition, omega-3 index may be a significant modifying factor of the mediated effects of miRNAs. CONCLUSIONS: This study demonstrates that short-term exposure to ambient PM2.5, O3, and NO2 was associated with specific circulating miRNAs, and some of which may mediate their effects on the downstream inflammation and blood lipid markers.
Assuntos
Poluição do Ar , Doenças Cardiovasculares , MicroRNA Circulante , Adulto , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Biomarcadores/análise , Proteína C-Reativa/metabolismo , Colesterol , MicroRNA Circulante/análise , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Humanos , Lipídeos/análise , Dióxido de Nitrogênio/efeitos adversos , Dióxido de Nitrogênio/análise , Material Particulado/efeitos adversos , Material Particulado/análiseRESUMO
Diagnosis of HIV-associated neurocognitive impairment (NCI) continues to be a clinical challenge. The purpose of this study was to develop a prediction model for NCI among people with HIV using clinical- and magnetic resonance imaging (MRI)-derived features. The sample included 101 adults with chronic HIV disease. NCI was determined using a standardized neuropsychological testing battery comprised of seven domains. MRI features included gray matter volume from high-resolution anatomical scans and white matter integrity from diffusion-weighted imaging. Clinical features included demographics, substance use, and routine laboratory tests. Least Absolute Shrinkage and Selection Operator Logistic regression was used to perform variable selection on MRI features. These features were subsequently used to train a support vector machine (SVM) to predict NCI. Three different classification tasks were performed: one used only clinical features; a second used only selected MRI features; a third used both clinical and selected MRI features. Model performance was evaluated by area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity with a tenfold cross-validation. The SVM classifier that combined selected MRI with clinical features outperformed the model using clinical features or MRI features alone (AUC: 0.83 vs. 0.62 vs. 0.79; accuracy: 0.80 vs. 0.65 vs. 0.72; sensitivity: 0.86 vs. 0.85 vs. 0.86; specificity: 0.71 vs. 0.37 vs. 0.52). Our results provide preliminary evidence that combining clinical and MRI features can increase accuracy in predicting NCI and could be developed as a potential tool for NCI diagnosis in HIV clinical practice.
Assuntos
Complexo AIDS Demência/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Máquina de Vetores de Suporte , Humanos , Imageamento por Ressonância Magnética/métodosRESUMO
Neurocognitive impairment (NCI) remains a persistent complication of HIV disease that nearly half of persons with HIV experience, and rates are even higher in persons who use substances such as cocaine. Cognitive training is a promising intervention for HIV-associated NCI. In this randomized controlled trial, we examined the feasibility and effectiveness of a web-based cognitive training program to improve working memory in a sample of 58 persons with HIV and cocaine use disorder. Participants were randomly assigned to either the experimental working memory training arm or the attention control training arm and completed up to 48 daily sessions over 10 weeks. Overall, treatment completion (74%) and retention rates (97%) were high, and participant feedback indicated the intervention was acceptable. Our results show that the intervention successfully reduced working memory deficits in the experimental arm relative to the control arm. Our findings support both the feasibility and effectiveness of cognitive training in this population.
Assuntos
Cocaína , Infecções por HIV , Cognição , Infecções por HIV/complicações , Infecções por HIV/terapia , Humanos , Internet , Memória de Curto PrazoRESUMO
Background: Persons who use stimulant drugs have greater morbidity and mortality relative to non-users. HIV infection has the potential to contribute to even great disparity in health outcomes among persons who use stimulants. These health disparities likely result in part due to poorer access to healthcare. Our study used a cumulative risk model to examine the impact of multiple risk factors on healthcare access in a sample of persons with and without HIV who use stimulants. Method: Our sample included 453 persons who reported recent use of illicit stimulants (102 HIV+, 351 HIV-). Participants completed clinical interviews, questionnaires, and a rapid oral HIV test. We constructed an 8-item cumulative risk index that included factors related to socioeconomic status, homelessness, legal history, and substance use. Results: Participants with HIV (PHW) were older than participants without HIV and more likely to have health insurance. Participants with and without HIV reported similar prior treatment utilization, but PWH reported better healthcare access and lower cumulative risk scores. Regression analyses showed cumulative risk was a significant predictor of healthcare access (ß = -0.20, p < 0.001) even after controlling for age, HIV status, and health insurance status. We did not observe an interaction of HIV status by cumulative risk. Conclusions: Access to care among persons who use stimulants, both with and without HIV, is negatively impacted by the accumulation of risk factors from a number of different domains. Understanding the cumulative effects of these factors is critical for developing interventions to facilitate access to care, thus reducing health disparities and improving health outcomes.
Assuntos
Infecções por HIV , Pessoas Mal Alojadas , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Acessibilidade aos Serviços de Saúde , Humanos , Classe Social , Inquéritos e QuestionáriosRESUMO
Stimulant abuse is a major contributor to HIV transmission in the United States, yet HIV prevalence among persons who use illicit stimulants remains unknown. We implemented respondent driven sampling (RDS) to estimate the prevalence of HIV infection in this high-risk population. We also examined RDS-adjusted rates of risk behaviors among HIV-positive and HIV-negative participants. Recruited from seven seeds, our sample of 387 participants was 46% female, 89% African American, and 45.94 years old on average. Participants were predominantly non-injection cocaine users, had large networks of stimulant users, and reported an established relationship with their recruiter. The adjusted population proportion of HIV infection was 0.07 (0.04, 0.11). The majority of sexually active participants reported engagement in risk behaviors (73%), but rates generally did not differ by HIV status. Our results highlight that stimulant use is a risk factor for HIV infection. This study also demonstrates that RDS is a very effective strategy for reaching stimulant users in the community.
Assuntos
Infecções por HIV , Adulto , Cidades , Feminino , Infecções por HIV/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Assunção de Riscos , Inquéritos e Questionários , Estados Unidos/epidemiologiaRESUMO
Increased body mass index (BMI) and HIV are each associated with hypertension. This study tested interactions between BMI and detectable plasma viral load (pVL) on hypertension among 659 persons living with HIV (PLWH). All participants were categorized into four subgroups based on BMI (<25 and ≥25â kg/m2) and pVL (<200 and ≥200 copies/ml). Multiplicative interaction was assessed using logistic regression; addictive interaction was assessed using three measures: Relative Excess Risk due to Interaction (RERI), Attributable Proportion (AP), and Synergy index (S). Compared to the participants with normal BMI and undetectable pVL, those who had increased BMI with an undetectable pVL had an elevated risk of hypertension with OR [95%CI] = 1.80 [1.02, 3.20]; the risk was further increased for those who had increased BMI with detectable pVL with OR [95%CI] = 3.54 [1.71, 7.31]. The multiplicative interaction was significant (p = 0.01). Results from additive interaction indicated RERI [95%CI] =1.89 [0.76, 4.79] and AP [95%CI] = 0.64 [0.32, 0. 95]. The interaction effects of increased BMI and detectable pVL on hypertension on both multiplicative and additive scales suggested that PLWH with increased BMI and detectable pVL should be intensively managed and monitored for hypertension prevention and treatment.
Assuntos
Infecções por HIV , Hipertensão , Índice de Massa Corporal , Infecções por HIV/complicações , Humanos , Hipertensão/epidemiologia , Modelos Logísticos , Carga ViralRESUMO
Exposure to ambient air pollutants such as ozone (O3) and particulate matter (PM) is associated with increased cardiovascular morbidity and rate of mortality, but the underlying biological mechanisms have yet to be described. Emerging evidence shows that extracellular vehicle (EV) microRNAs (miRNAs) may facilitate cell-to-cell and organ-to-organ communications and play a role in the air pollution-induced cardiovascular effects. This study aims to explore the association between air pollutant exposure and miRNA changes related to cardiovascular diseases. Using a panel study design, 14 participants with coronary artery diseases were enrolled in this study. Each participant had up to 10 clinical visits and their plasma samples were collected and measured for expression of miRNA-21 (miR-21), miR-126, miR-146, miR-150, and miR-155. Mixed effects models adjusted for temperature, humidity, and season were used to examine the association between miRNA levels and exposure to 8-hr O3 or 24-hr PM2.5 up to 4 days prior. Results demonstrated that miR-150 expression was positively associated with O3 exposure at 1-4 days lag and 5day moving average while miR-155 expression tracked with O3 exposure at lag 0. No significant association was found between miRNA expression and ambient PM2.5 at any time point. ß-blocker and diabetic medication usage significantly modified the correlation between O3 exposure and miR-150 expression where the link was more prominent among non-users. In conclusion, evidence indicated an association between exposure to ambient O3 and circulating levels of EV miR-150 and miR-155 was observed. These findings pointed to a future research direction involving miRNA-mediated mechanisms of O3-induced cardiovascular effects.
Assuntos
MicroRNA Circulante/efeitos adversos , MicroRNA Circulante/genética , Doença da Artéria Coronariana/induzido quimicamente , Regulação da Expressão Gênica/efeitos dos fármacos , Ozônio/efeitos adversos , Ozônio/sangue , Transdução de Sinais/efeitos dos fármacos , Adulto , Idoso , Doença da Artéria Coronariana/fisiopatologia , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The number of people living with HIV (PLWH) increases rapidly with advancement in antiretroviral therapy. Suicide prevention is challenging, particularly for PLWH because of the negative impact of HIV-related stigma and social capital reduction. However, only a small proportion of the variance in suicide risk can be explained by these variables if a linear paradigm is used as guidance. In this study, we tested a nonlinear cusp catastrophe modeling. Participants (N = 523) were PLWH selected through a risk venue-based method in Wuhan, a provincial capital city in China. Suicidal ideation post HIV+ diagnosis and in the past 30 days and suicide plan and attempt were assessed. Data were collected using self-report questionnaire and were analyzed using both the direct and multivariate stochastic cusp catastrophe modeling methods with social capital as asymmetry variable and HIV-related stigma as bifurcation variable. The analysis was executed using R, including nls() function for the direct method and 'cusp' package for the stochastic modeling. Results from stochastic cusp modeling analysis indicated that social capital was significantly associated with risk of suicide after controlling for key covariates; the association was significantly bifurcated by HIV-related stigma. The data fit the cusp model better than the alternative linear model (R2 =.483 vs. .127). Findings of this study indicate suicide behaviors among Chinese PLWH follow a nonlinear dynamic system. In addition to enhancing our understanding of suicide risk, findings of this study underscore the significance in social capital enhancement and stigma reduction for suicide prevention among PLWH in China.
Assuntos
Infecções por HIV/epidemiologia , Infecções por HIV/psicologia , Estigma Social , Suicídio/psicologia , Suicídio/estatística & dados numéricos , China/epidemiologia , Humanos , Ideação SuicidaRESUMO
BACKGROUND: The effect of the Keep Moving toward Healthy Heart and Healthy Brain (KM2H2) program at 6-month post intervention has been assessed. The purpose of this study is to evaluate the KM2H2 program at 30-month post intervention. METHODS: A total of 450 senior hypertensive patients from 12 community health centers were randomized by center to either receive KM2H2 plus standard care (6 centers, n = 232) or standard care only (6 centers, n = 218). Data for outcome measures at 30-month post intervention were analyzed. New cases of stroke and heart attack were verified with medical records; levels of physical activity were assessed using self-reported questionnaire. In addition to comparative analysis, adjusted incidence rate and program effects were determined using mixed effects modeling method. RESULTS: At the 30-month follow-up, the adjusted incidence rate [95% CI] of stroke was 11.81% [5.90, 17.72] for patients in the intervention group and 19.78% [14.07, 25.50] (p = 0.03) for the control group. The adjusted incidence rate of heart attack was 3.34% [1.91, 8.58] and 6.68% [1.64, 11.73] for the intervention and control groups (p = 0.16), respectively; the proportion and the duration of engaging in regular physical activity were significantly greater for the intervention group than the control group. The reductions in blood pressure between the intervention and the control was not statistically significant. CONCLUSIONS: The KM2H2 program showed a persistent effect up to 30 months post intervention in enhancing physical activity and reducing the risk of cardio-cerebrovascular events, particularly stroke. These findings demonstrate the persistent effect of the KM2H2 and suggest the need for a full-scale evaluation of the intervention program for practical use. TRIAL REGISTRATION: ISRCTN Register ISRCTN12608966 . Registered 03 March 2015. Retrospectively registered.
Assuntos
Pressão Sanguínea , Exercício Físico , Hipertensão/terapia , Infarto do Miocárdio/prevenção & controle , Avaliação de Programas e Projetos de Saúde , Acidente Vascular Cerebral/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Hipertensão/complicações , Incidência , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/etiologia , Estudos Retrospectivos , Risco , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia , Inquéritos e QuestionáriosRESUMO
Receptive anal intercourse, multiple partners, condomless sex, sexually transmitted infections (STIs), and drug/alcohol addiction are familiar factors that correlate with increased human immunodeficiency virus (HIV) risk among men who have sex with men (MSM). To improve estimation to HIV acquisition, we created a composite score using questions from routine survey of 3588 MSM in Beijing, China. The HIV prevalence was 13.4%. A risk scoring tool using penalized maximum likelihood multivariable logistic regression modeling was developed, deploying backward step-down variable selection to obtain a reduced-form model. The full penalized model included 19 sexual predictors, while the reduced-form model had 12 predictors. Both models calibrated well; bootstrap-corrected c-indices were 0.70 (full model) and 0.71 (reduced-form model). Non-Beijing residence, short-term living in Beijing, illegal drug use, multiple male sexual partners, receptive anal sex, inconsistent condom use, alcohol consumption before sex, and syphilis infection were the strongest predictors of HIV infection. Discriminating higher-risk MSM for targeted HIV prevention programming using a validated risk score could improve the efficiency of resource deployment for educational and risk reduction programs. A valid risk score can also identify higher risk persons into prevention and vaccine clinical trials, which would improve trial cost-efficiency.
Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Infecções por HIV/epidemiologia , Comportamento Sexual/estatística & dados numéricos , Minorias Sexuais e de Gênero/estatística & dados numéricos , Sífilis/epidemiologia , Sexo sem Proteção/estatística & dados numéricos , Adolescente , Adulto , Idoso , China/epidemiologia , Preservativos , Estudos Transversais , Infecções por HIV/prevenção & controle , Homossexualidade Masculina/estatística & dados numéricos , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prevalência , Medição de Risco , Fatores de Risco , Assunção de Riscos , Sexo Seguro , Parceiros Sexuais , Inquéritos e Questionários , Adulto JovemRESUMO
INTRODUCTION: The complex relationships among HIV knowledge, condom-use skills, self-efficacy, peer influence and intention to use condoms have been rigorously investigated. However, studies guided by a linear behavior change model often explain only a limited amount of variances. This study aims to advance our understanding of the relationships through a nonlinear quantum change paradigm. METHODS: Data (nâ¯=â¯1970, 40.61% male, mean age 16.94⯱â¯0.74) from a behavioral intervention program among high school students in the Bahamas were analyzed with a chained cusp catastrophe model in two steps. In the first step, self-efficacy was analyzed as the outcome with HIV knowledge/condom-use skills as asymmetry variables and peer influence as bifurcation variable. In the second step, condom-use intention was analyzed as the outcome while self-efficacy (outcome in the first step) was used as bifurcation variable allowing peer influence as bifurcation, and HIV knowledge/condom-use skills were included as asymmetry. Cusp modeling analysis was conducted along with equivalent linear models. RESULTS: The cusp model performed better than the linear and logistic models. Cusp modeling analyses revealed that peer influence significantly bifurcated the relationships between HIV knowledge/condom-use skills and self-efficacy; while both self-efficacy and peer influence significantly bifurcated the relationship between HIV knowledge/condom-use skills and condom-use intention. CONCLUSION: Our findings support the central role of self-efficacy and peer influence as two chains in bridging the complex quantum relationships between HIV knowledge/condom-use skills and condom-use intention among adolescents. The nonlinear cusp catastrophe modeling provided a new method to advance HIV behavioral research.
Assuntos
Comportamento do Adolescente/psicologia , Preservativos/estatística & dados numéricos , Conhecimentos, Atitudes e Prática em Saúde , Intenção , Autoeficácia , Adolescente , Feminino , Humanos , Modelos Lineares , Modelos Logísticos , Masculino , Grupo Associado , Influência dos ParesRESUMO
This study tested the complex relationship among the perceived benefit from and cost of condom use, self-efficacy and condom use among adolescents as a nonlinear dynamic process. Participants were 12th graders in public Bahamian high schools who reported having had sex and frequency of condom use. Results revealed that the perceived benefit and perceived cost as asymmetry variables were significantly associated with condom use (p < 0.001) after controlling for covariates. The association was bifurcated by the variable self-efficacy (p < 0.001). Furthermore, the cusp model was better than linear and logistic regression models in predicting the dynamic changes in condom use behavior, judged by the AIC and BIC, and R2 criteria. These results suggest that adolescent condom use may follow a nonlinear rather than linear dynamic process. Emphasizing bifurcation variables such as self-efficacy that promote sudden change could be essential to strengthen current evidence-based intervention programs in encouraging condom use.
Assuntos
Preservativos/estatística & dados numéricos , Autoeficácia , Comportamento Sexual/psicologia , Adolescente , Preservativos/economia , Feminino , Humanos , Modelos Logísticos , Masculino , Percepção , Sexo SeguroRESUMO
Understanding barriers to consistent condom use among men who have sex with men (MSM) requires consideration of the context in which risk behaviors occur. Anal sex position is one such context. This pooled cross-sectional study used survey data from 1,230 MSM and their 2,618 reported male sexual partnerships. Overall, nearly half of the participants engaged in unprotected anal intercourse (UAI) with at least one of upto three partners in the past 6 months. "Insertive" men engaged in less UAI (39 %) than "receptive" (53 %) or "versatile" (51 %) men. Regardless of sexual position, UAI was associated with cohabiting with a male or female partner and perceiving great or moderate risk of HIV from male contact at the individual level, and steady (vs. casual) partnership at the dyad level. However, early MSM anal sex debut, high number of male partners, alcohol use, receiving and buying condoms, HIV testing, and MSM sex-seeking venues were found to be only statistically significantly correlated with UAI among some but not all sexual positions, implying that interventions to increase condom use should take into account how anal sex position may influence willingness and ability to engage in safer sex. Dyad level data appear to provide additional insight into the influence of sexual positions, and should be used to complement individual data for future intervention designs.
Assuntos
Homossexualidade Masculina , Comportamento Sexual , Sexo sem Proteção , Adolescente , Adulto , Idoso , Consumo de Bebidas Alcoólicas , China , Preservativos/estatística & dados numéricos , Estudos Transversais , Características da Família , Homossexualidade Masculina/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Comportamento Sexual/estatística & dados numéricos , Parceiros Sexuais , Adulto JovemRESUMO
There has been a consistent upward trend in ground-level ozone (O3) concentration in China. People living with HIV (PLWH) may be more vulnerable to the health impacts of O3 exposure due to their immunosuppressed state. This study aims to investigate the association between ambient O3 exposure and mortality among PLWH, as well as the potential exacerbating effects of a decreased CD4+ T cell level. Daily maximum 8-hour O3 concentrations were assigned to 7270 PLWH at a county level in Guangxi, China. Every 10-unit increase in ambient O3 concentration was associated with a significant rise in all-cause mortality ranging from 7.3 % to 28.7 % and a significant rise in AIDS-related mortality ranging from 8.4 % to 14.5 %. When PLWH had a higher CD4+ count (≥350 cells/µL), elevated O3 concentration was associated with increased blood CD4+ count at lag0 [percent change with 95 % confidence interval, 0.20(0.00, 0.40)], lag1 [0.26(0.06, 0.47)], and lag2 [0.23(0.03, 0.44)]; however, an opposite association was observed when CD4+ count was <350 cells/µL for half-year average [-2.45(-4.71, -0.14)] and yearly average [-3.42(-5.51, -1.29)] of O3 exposure. The association of O3 exposure with all-cause and AIDS-related mortality was more prominent among those with higher CD4+ count. Exploratory analysis revealed possible associations between O3 exposure and respiratory infections and clinical symptoms. These findings suggest potential synergistic effects between a compromised immune status and elevated O3 exposure levels on mortality risk among PLWH. Ambient O3 exposure should be considered as an emerging mortality risk factor for PLWH in the era of antiretroviral therapy, requiring further attention from researchers and healthcare professionals.
Assuntos
Síndrome da Imunodeficiência Adquirida , Poluentes Atmosféricos , Poluição do Ar , Ozônio , Humanos , Poluição do Ar/análise , Poluentes Atmosféricos/análise , Estudos Longitudinais , Linfócitos T , China/epidemiologia , Ozônio/efeitos adversos , Ozônio/análise , Linfócitos T CD4-Positivos/química , Exposição Ambiental/análise , Material Particulado/análiseRESUMO
BACKGROUND: Hypertensive adults are at a higher risk of cardiovascular morbidity and mortality. Dietary omega-3 polyunsaturated fatty acids (N3-PUFA) intake has been associated with cardiovascular benefits. However, few studies have specifically investigated whether dietary intake of N3-PUFA is associated with lower risk of all-cause and cardiovascular mortality among hypertensive adults in the U.S. METHODS: This prospective cohort study included 26,914 hypertensive individuals 18 years or older who participated in 10 NHANES cycles from 1999 to 2018. Dietary levels of N3-PUFA were obtained from the 24-hour dietary recalls. The dietary data were linked to mortality records from the National Death Index through December 31, 2019. The associations between dietary N3-PUFA levels and mortality were evaluated by constructing the Multivariable Cox Proportional Hazards models. RESULTS: We observed an increasing trend of dietary N3-PUFA intake levels over the years, mainly driven by alpha-linolenic acid (ALA). Lower all-cause mortality risk was observed among hypertensive adults with higher consumption of total N3-PUFA [adjusted hazards ratio, 95% confidence interval: 0.91 (0.86, 0.97)], plant-based ALA [0.88 (0.83, 0.93)], fish oil-based eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) [0.91 (0.83, 0.99)], EPA [0.93 (0.88, 0.98)], docosapentaenoic acid (DPA) [0.73 (0.58, 0.91)], or DHA [0.95 (0.90, 0.99)]. Hypertensive adults were at lower risk of cardiovascular mortality if their diet contained higher levels of total N3-PUFA [0.68 (0.53, 0.88)], ALA [0.89 (0.80, 0.99)], EPA [0.87 (0.79, 0.97)] or DPA [0.86 (0.78, 0.95)]. Weighted quantile sum analysis showed that ALA, EPA, and DPA were the main contributors of the N3-PUFA benefits against mortality among hypertensive adults. CONCLUSIONS: Dietary intake of N3-PUFA, particularly ALA, EPA, and DPA, was associated with lower risk of all-cause and cardiovascular mortality among U.S. hypertensive adults. These findings suggest that increasing dietary intake of N3-PUFA may serve as a potential strategy to lower hypertension-associated mortality risk.
Assuntos
Doenças Cardiovasculares , Ácidos Graxos Ômega-3 , Hipertensão , Adulto , Humanos , Inquéritos Nutricionais , Estudos Prospectivos , Ácidos Graxos Ômega-3/análise , Ácidos Graxos Insaturados , Ácido Eicosapentaenoico , Ácidos Docosa-Hexaenoicos , Hipertensão/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Ingestão de AlimentosRESUMO
Acquiring big-size datasets to raise the performance of deep models has become one of the most critical problems in representation learning (RL) techniques, which is the core potential of the emerging paradigm of federated learning (FL). However, most current FL models concentrate on seeking an identical model for isolated clients and thus fail to make full use of the data specificity between clients. To enhance the classification performance of each client, this study introduces the FDRL, a federated discriminative RL model, by partitioning the data features of each client into a global subspace and a local subspace. More specifically, FDRL learns the global representation for federated communication between those isolated clients, which is to capture common features from all protected datasets via model sharing, and local representations for personalization in each client, which is to preserve specific features of clients via model differentiating. Toward this goal, FDRL in each client trains a shared submodel for federated communication and, meanwhile, a not-shared submodel for locality preservation, in which the two models partition client-feature space by maximizing their differences, followed by a linear model fed with combined features for image classification. The proposed model is implemented with neural networks and optimized in an iterative manner between the server of computing the global model and the clients of learning the local classifiers. Thanks to the powerful capability of local feature preservation, FDRL leads to more discriminative data representations than the compared FL models. Experimental results on public datasets demonstrate that our FDRL benefits from the subspace partition and achieves better performance on federated image classification than the state-of-the-art FL models.
RESUMO
Introduction: Tartary buckwheat and adzuki bean, which are classified as coarse grain, has attracted increasing attention as potential functional ingredient or food source because of their high levels of bioactive components and various health benefits. Methods: This work investigated the effect of two different extrusion modes including individual extrusion and mixing extrusion on the phytochemical compositions, physicochemical properties and in vitro starch digestibility of instant powder which consists mainly of Tartary buckwheat and adzuki bean flour. Results: Compared to mixing extrusion, instant powder obtained with individual extrusion retained higher levels of protein, resistant starch, polyphenols, flavonoids and lower gelatinization degree and estimated glycemic index. The α-glucosidase inhibitory activity (35.45%) of the instant powder obtained with individual extrusion was stronger than that obtained with mixing extrusion (26.58%). Lower levels of digestibility (39.65%) and slower digestion rate coefficient (0.25 min-1) were observed in the instant powder obtained with individual extrusion than in mixing extrusion (50.40%, 0.40 min-1) by logarithm-of-slope analysis. Moreover, two extrusion modes had no significant impact on the sensory quality of instant powder. Correlation analysis showed that the flavonoids were significantly correlated with physicochemical properties and starch digestibility of the instant powder. Discussion: These findings suggest that the instant powder obtained with individual extrusion could be used as an ideal functional food resource with anti-diabetic potential.