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1.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 33(1): 113-116, 2021 Jan.
Artículo en Chino | MEDLINE | ID: mdl-33565414

RESUMEN

Causal inference research is a causal test designed to assess the impact of exposures on outcomes.Both experimental and observational studies can be used to examine causal associations between exposure factors and outcomes. Experimental studies are sometimes limited by factors such as ethics or experimental conditions. Observational studies account for a large proportion in clinical studies, but the effectiveness and research value of observational studies will be affected if the design of observational studies is not rigorous and the confounding factors are not well controlled.The Guidelines for controlling confounding factors and reporting results in causal inference studie formulated by a special group of 47 editors from 35 journals from all over the world provide good guidance to researchers. This article interprets the guidelines and hopes to provide help for clinical researchers.


Asunto(s)
Causalidad , Estudios Observacionales como Asunto , Factores de Confusión Epidemiológicos
2.
Genome Med ; 12(1): 115, 2020 12 28.
Artículo en Inglés | MEDLINE | ID: mdl-33371892

RESUMEN

The identification of genetic variation that directly impacts infection susceptibility to SARS-CoV-2 and disease severity of COVID-19 is an important step towards risk stratification, personalized treatment plans, therapeutic, and vaccine development and deployment. Given the importance of study design in infectious disease genetic epidemiology, we use simulation and draw on current estimates of exposure, infectivity, and test accuracy of COVID-19 to demonstrate the feasibility of detecting host genetic factors associated with susceptibility and severity in published COVID-19 study designs. We demonstrate that limited phenotypic data and exposure/infection information in the early stages of the pandemic significantly impact the ability to detect most genetic variants with moderate effect sizes, especially when studying susceptibility to SARS-CoV-2 infection. Our insights can aid in the interpretation of genetic findings emerging in the literature and guide the design of future host genetic studies.


Asunto(s)
/epidemiología , Estudios de Casos y Controles , Genómica/métodos , Pandemias , Proyectos de Investigación , /genética , Simulación por Computador , Factores de Confusión Epidemiológicos , Exposoma , Reacciones Falso Negativas , Predisposición Genética a la Enfermedad , Variación Genética , Interacciones Huésped-Patógeno/genética , Humanos , Proyectos de Investigación/estadística & datos numéricos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Riesgo , Sensibilidad y Especificidad
4.
J Urol ; 204(6): 1305-1311, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32924780

RESUMEN

PURPOSE: Most international practice guidelines recommend screening for chronic kidney disease among older men with lower urinary tract symptoms. However, prior studies supporting these guidelines are insufficient due to incomplete assessments of kidney function and inadequate adjustment for confounding factors. MATERIALS AND METHODS: We conducted a cross-sectional study among 5,530 American men older than 65 years in the multicenter Osteoporotic Fractures in Men Study. Chronic kidney disease was defined per international guidelines as estimated glomerular filtration rate less than 60 ml/minute/1.73 m2 based on serum creatinine or cystatin C, or urinary albumin-to-creatinine ratio 30 mg/gm or greater. Lower urinary tract symptoms were assessed with the American Urological Association Symptom Index. Associations were estimated using multivariable linear and modified Poisson regression models. RESULTS: Chronic kidney disease prevalence was 16% among 5,530 men with serum creatinine, 24% among 1,504 men with serum cystatin C and 14% among 1,487 men with urinary albumin-to-creatinine measurements. Lower urinary tract symptoms were not associated with lower estimated glomerular filtration rate based on serum creatinine or cystatin C. Although symptom severity was modestly associated with a higher prevalence of chronic kidney disease in age/site adjusted analyses, confidence intervals were wide and associations using all 3 definitions were not statistically significant after adjustment for important confounders, including cardiovascular disease and analgesic use. CONCLUSIONS: Lower urinary tract symptoms are not independently associated with multiple measures of kidney dysfunction or prevalence of chronic kidney disease among older community dwelling men. Our results do not support recommendations for kidney function testing among older men with lower urinary tract symptoms.


Asunto(s)
Vida Independiente/estadística & datos numéricos , Síntomas del Sistema Urinario Inferior/epidemiología , Insuficiencia Renal Crónica/epidemiología , Anciano , Anciano de 80 o más Años , Albuminuria/diagnóstico , Factores de Confusión Epidemiológicos , Creatinina/sangre , Creatinina/orina , Estudios Transversales , Cistatina C/sangre , Tasa de Filtración Glomerular/fisiología , Humanos , Síntomas del Sistema Urinario Inferior/complicaciones , Síntomas del Sistema Urinario Inferior/diagnóstico , Síntomas del Sistema Urinario Inferior/fisiopatología , Masculino , Prevalencia , Insuficiencia Renal Crónica/sangre , Insuficiencia Renal Crónica/diagnóstico , Insuficiencia Renal Crónica/etiología , Índice de Severidad de la Enfermedad , Micción/fisiología
5.
PLoS One ; 15(8): e0237865, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32866187

RESUMEN

BACKGROUND: Illness-related costs experienced by tuberculosis patients produce a severe economic impact on households, especially poor families. Few studies have investigated the full costs, including direct and indirect costs, at the patient and household levels in south-east China. METHODS: A case follow-up study was conducted in the Bao'an district of Shenzhen City, China. Eligible new and previously treated individuals with pulmonary tuberculosis (TB) during January 1st 2013 to June 30th 2013 were enrolled. Medical and non-medical costs as well as income loss were calculated in diagnosis and treatment periods, respectively. Factors associated with costs due to TB diagnosis, treatment and TB care (diagnosis + treatment) were explored respectively with a linear regression model. RESULTS: Of the total 514 TB patients enrolled, 95% were from the migrant population, and 65% were males, with a mean age of 32.25 (±10.11). The median costs due to TB diagnosis and TB treatment were 79 United States dollar (USD), 748USD (6.2897 China Yuan (CNY) = 1USD, 2013) per patient, respectively. The median costs due to TB care (diagnosis and treatment) per patient was 1218USD, corresponding to 26% of patients' annual income pre-illness. Those who visited more times to health facilities, hospitalized, received higher education, or occupied in national civil servant/services/retired staff might expense more before diagnosis. Costs due to TB treatment was significantly higher among migrant patients, sputum smear positive patients, and widowed/divorced population. Factors associated with less total costs were native patients, fewer times of visiting to health-care facilities and those with no hospitalization history due to TB. CONCLUSIONS: Although a free TB control policy is in force, patients with TB are still facing a heavy economic burden. More available interventions to reduce the financial burden on tuberculosis patients are urgently needed.


Asunto(s)
Costo de Enfermedad , Tuberculosis/diagnóstico , Tuberculosis/economía , Adulto , China/epidemiología , Factores de Confusión Epidemiológicos , Femenino , Costos de la Atención en Salud , Humanos , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud , Tuberculosis/epidemiología , Tuberculosis/terapia , Adulto Joven
6.
Acta bioquím. clín. latinoam ; 54(3): 257-266, set. 2020. graf, tab
Artículo en Español | LILACS | ID: biblio-1130600

RESUMEN

EL HOMA-IR (homeostasis model assessment-insulin-resistance) es un estimador de insulinorresistencia (IR) pero depende de la determinación de insulina. Los índices triglicéridos-glucosa (T-G)-circunferencia de la cintura (CC) (T-G-CC) o triglicéridos-glucosa-índice de masa corporal (TG- IMC) podrían ser sustitutos. Los objetivos de este trabajo consistieron en investigar en personas con riesgo de desarrollar diabetes tipo 2 (DT2): a) los índices T-G, T-G-CC y T-G-IMC como estimadores de HOMA-IR>2,1; b) determinar su poder discriminante. Se realizó un estudio prospectivo en el que se estudiaron 223 individuos ≥45 años con riesgo de desarrollar diabetes tipo 2 (DT2). La relación T-G se calculó como ln [triglicéridos (mg/dL) x glucemia (mg/dL)/2]. La relación T-G-CC y T-G-IMC fue el producto de T-G por CC o IMC. Se utilizó análisis de regresión logística y se calcularon las áreas bajo las curvas ROC (receiver operating characteristic curves) (ABC) para comparar las asociaciones de T-G, T-G-CC y T-G-IMC con HOMA-IR>2,1. Mediante análisis discriminante se evaluó la clasificación de los sujetos entre HOMA-IR>2,1 y HOMA-IR≤2,1. ABC, sensibilidad, especificidad, poder predictivo positivo y negativo para T-G-CC y T-G-IMC fueron mayores que para T-G, con los siguientes valores de corte: T-G=8,75, T-G-CC=821 y T-G-IMC=255. Los odds ratios (OR) para HOMA-IR>2,1, ajustados para confusores, fueron: T-G>8,75, OR: 4,85 (IC 95% 2,73-8,62); T-G-CC>821, OR: 10,41 (IC 95% 5,55-19,53); T-GIMC> 255, OR: 10,41 (IC 95% 5,55-19,53). Con el análisis discriminante T-G>8,75 clasificó correctamente 69,2% individuos con HOMA-IR≤2,1 y 68,3% con HOMA-IR>2,1; T-G-CC y T-G-IMC clasificaron 74,4% y 78,2% respectivamente (p<0,001 en todos los casos). Se concluyó que T-GCC> 821 y T-G-IMC>255 fueron mejores estimadores de HOMA-IR>2,1 que T-G>8,75. Estas son determinaciones simples y accesibles y podrían ser útiles en la práctica clínica y en estudios epidemiológicos.


HOMA-IR ((homeostasis model assessment-insulin-resistance) is a surrogate estimator of insulin resistance (IR) but it depends on insulin determination. Triglyceride-glucose-waist circumference (T-G-WC) or triglyceride-glucose-body mass index (BMI) (T-G-BMI) could be substitutes. The objectives of this work were: to investigate in people at risk of developing type 2 diabetes (T2D): a) T-G, T-G-CC and T-G-BMI as estimators of HOMA-IR>2.1 and b) to determine their discriminating power. A prospective study was conducted studying 223 individuals ≥45 years of age at risk of developing type 2 diabetes (T2D). The T-G ratio was calculated as ln [triglycerides (mg/dL) x glycemia (mg/dL)/2]. The T-G-CC and T-G-BMI ratio was the product of T-G by CC or BMI. Logistic regression analysis was used and the areas under the receiver operating characteristic curves (ROC) curves were calculated to compare the associations of T-G, T-G-CC and T-G-BMI with HOMA-IR>2.1. Using a discriminant analysis, the classification of the subjects between HOMA-IR>2.1 or HOMA-IR≤2.1 was evaluated. AUC, sensitivity, specificity, positive and negative predictive powers for T-G-CC and T-G-BMI were higher than for T-G, with the following cut-off values: TG=8.75, T-G-CC=821 and T-G-BMI=255. Odds ratios (OR) for HOMA-IR>2.1, adjusted for confounders, were: T-G>8.75, OR 4.85 (95% CI 2.73-8.62); T-G-CC>821, OR 10.41 (95% CI 5.55-19.53); T-G-BMI>255, OR 10.41 (95% CI 5.55-19.53). With the discriminant analysis T-G>8.75, 69.2% correctly classified with HOMA-IR≤2.1 and 68.3% with HOMA-IR>2.1; T-G-CC and T-G-BMI correctly classified 74.4% and 78.2% respectively (p <0.001 in all cases). It is concluded that T-G-CC>821 and T-G-BMI>255 were better estimators of HOMA-IR>2.1 than T-G>8.75. T-G-WC and T-G-BMI are simple and reliable determinations and could be useful in clinical practice and epidemiological studies.


O HOMA-IR (homeostasis model assessment-insulin-resistance) e um estimador de resistencia a insulina (RI), mas depende da determinacao da insulina. Triglicerideos-glicose (T-G), circunferencia da cintura (CC) (T-G-CC) ou triglicerideos-glicose-indice de massa corporal (T-G-IMC) poderiam ser substitutos. Os objetivos desse trabalho foram investigar em pessoas com risco de desenvolver diabetes tipo 2 (DT2): a) os indices T-G, T-G-CC e T-G-IMC como estimadores de HOMA-IR> 2,1; b) determinar seu poder discriminante. Um estudo prospectivo foi realizado em 223 pessoas ≥45 anos com risco de desenvolver diabetes tipo 2 (DT2). A razao T-G foi calculada como ln [triglicerideos (mg/dL) x glicemia (mg/dL)/2]. A razao T-G-CC e T-G-IMC foi o produto de T-G por CC ou IMC. A analise de regressao logistica foi utilizada e as areas sob as curvas ROC (receiver operating features) ABC foram calculadas para comparar as associacoes de T-G, T-G-CC e T-G-IMC com HOMA-IR>2.1. Por meio de analise discriminante, avaliou-se a classificacao dos sujeitos entre HOMA-IR>2,1 e HOMA-IR≤2,1. ABC, sensibilidade, especificidade, poder preditivo positivo e negativo para TG-CC e TG-IMC foram maiores que para TG, com os seguintes valores de corte: TG=8,75, TG-CC=821 e TG-IMC=255. Odds Ratios (OR) para HOMA-IR>2,1, ajustados para fatores de confusao, foram: TG>8,75, OR 4,85 (IC95% 2,73-8,62); T-G-CC>821, OR 10,41 (IC 95% 5,55-19,53); T-G-IMC>255, OR 10,41 (IC 95% 5,55-19,53). Com a analise discriminante T-G>8,75, 69,2% foram classificados corretamente com HOMA-IR≤2,1 e 68,3% com HOMA-IR>2,1; T-G-CC e T-G-IMC classificaram 74,4% e 78,2%, respectivamente (p<0,001 em todos os casos). Conclui-se que T-G-CC>821 e TG- IMC>255 foram melhores estimadores de HOMA-IR>2,1 que T-G>8,75. Elas sao determinacoes simples e acessiveis e poderiam ser uteis na pratica clinica e em estudos epidemiologicos.


Asunto(s)
Humanos , Triglicéridos , Poder Psicológico , Estudios Epidemiológicos , Modelos Logísticos , Oportunidad Relativa , Factores de Confusión Epidemiológicos , Curva ROC , Sensibilidad y Especificidad , Clasificación , Área Bajo la Curva , Cortejo , Diabetes Mellitus Tipo 2 , Diabetes Mellitus Tipo 2/complicaciones , Glucosa , Objetivos , Insulina , Personas , Organización y Administración , Asociación , Glucemia , Resistencia a la Insulina , Índice de Masa Corporal , Análisis Discriminante , Riesgo , Análisis de Regresión , Circunferencia de la Cintura
7.
Am J Gastroenterol ; 115(10): 1707-1715, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32852340

RESUMEN

INTRODUCTION: Proton pump inhibitors (PPIs) increase the risk for enteric infections that is likely related to PPI-induced hypochlorhydria. Although the impact of acid suppression on severe acute respiratory syndrome coronavirus 2 is unknown thus far, previous data revealed that pH ≤3 impairs the infectivity of the similar severe acute respiratory syndrome coronavirus 1. Thus, we aimed to determine whether use of PPIs increases the odds for acquiring coronavirus disease 2019 (COVID-19) among community-dwelling Americans. METHODS: From May 3 to June 24, 2020, we performed an online survey described to participating adults as a "national health survey." A multivariable logistic regression was performed on reporting a positive COVID-19 test to adjust for a wide range of confounding factors and to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: Of 53,130 participants, 3,386 (6.4%) reported a positive COVID-19 test. In regression analysis, individuals using PPIs up to once daily (aOR 2.15; 95% CI, 1.90-2.44) or twice daily (aOR 3.67; 95% CI, 2.93-4.60) had significantly increased odds for reporting a positive COVID-19 test when compared with those not taking PPIs. Individuals taking histamine-2 receptor antagonists were not at elevated risk. DISCUSSION: We found evidence of an independent, dose-response relationship between the use of antisecretory medications and COVID-19 positivity; individuals taking PPIs twice daily have higher odds for reporting a positive test when compared with those using lower-dose PPIs up to once daily, and those taking the less potent histamine-2 receptor antagonists are not at increased risk. These findings emphasize good clinical practice that PPIs should only be used when indicated at the lowest effective dose, such as the approved once-daily label dosage of over-the-counter and prescription PPIs. Further studies examining the association between PPIs and COVID-19 are needed.


Asunto(s)
Betacoronavirus/patogenicidad , Infecciones por Coronavirus/epidemiología , Ácido Gástrico/metabolismo , Encuestas Epidemiológicas/estadística & datos numéricos , Neumonía Viral/epidemiología , Inhibidores de la Bomba de Protones/efectos adversos , Adolescente , Adulto , Betacoronavirus/aislamiento & purificación , Técnicas de Laboratorio Clínico/estadística & datos numéricos , Factores de Confusión Epidemiológicos , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/fisiopatología , Infecciones por Coronavirus/virología , Prescripciones de Medicamentos/estadística & datos numéricos , Femenino , Mucosa Gástrica/efectos de los fármacos , Mucosa Gástrica/metabolismo , Reflujo Gastroesofágico/tratamiento farmacológico , Microbioma Gastrointestinal/efectos de los fármacos , Microbioma Gastrointestinal/fisiología , Pirosis/tratamiento farmacológico , Humanos , Concentración de Iones de Hidrógeno/efectos de los fármacos , Persona de Mediana Edad , Pandemias , Neumonía Viral/diagnóstico , Neumonía Viral/fisiopatología , Neumonía Viral/virología , Adulto Joven
8.
Pediatrics ; 146(2)2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32632021

RESUMEN

OBJECTIVES: To examine how overweight and obesity at specific ages and overall BMI growth patterns throughout childhood predict cardiometabolic phenotypes at 11 to 12 years. METHODS: In a population-based sample of 5107 infants, BMI was measured every 2 years between ages 2 to 3 and 10 to 11 years. We identified 5 BMI trajectories using growth curve models. At ages 11 to 12 years, 1811 children completed assessments for metabolic syndrome risk scores, carotid-femoral pulse wave velocity, and carotid intima-media thickness. Multivariable regression models were used to estimate associations, adjusted for potential confounders (eg, age, sex, smoking exposure, and small for gestational age). RESULTS: Overweight and obesity from early childhood onward were strongly associated with higher cardiometabolic risk at 11 to 12 years of age. At age 6 to 7 years, compared with those with a healthy weight, children with overweight had higher metabolic syndrome risk scores by 0.23 SD units (95% confidence interval 0.05 to 0.41) and with obesity by 0.76 SD units (0.51-1.01), with associations almost doubling by age 10 to 11 years. Obese (but not overweight) children had higher outcome pulse wave velocity (0.64-0.73 SD units) from ages 6 to 7 years and slightly higher outcome carotid intima-media thickness (0.20-0.30 SD units) at all ages. Cumulative exposure to high BMI from 2 to 3 years of age carried the greatest cardiometabolic risk, with a gradient of risk across trajectories. CONCLUSIONS: High early-childhood BMI is already silently associated with the development of cardiometabolic risk by 11 to 12 years, highlighting the urgent need for effective action to reduce overweight and obesity in early childhood.


Asunto(s)
Índice de Masa Corporal , Diagnóstico Precoz , Tamizaje Masivo , Obesidad Pediátrica/epidemiología , Australia/epidemiología , Grosor Intima-Media Carotídeo , Niño , Preescolar , Factores de Confusión Epidemiológicos , Metabolismo Energético , Femenino , Estudios de Seguimiento , Trastornos del Crecimiento/epidemiología , Humanos , Lactante , Recién Nacido Pequeño para la Edad Gestacional , Masculino , Síndrome Metabólico/epidemiología , Sobrepeso/epidemiología , Pandemias , Fenotipo , Análisis de la Onda del Pulso , Riesgo
9.
JAMA ; 324(1): 68-78, 2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32633800

RESUMEN

Importance: Data are limited regarding statin therapy for primary prevention of atherosclerotic cardiovascular disease (ASCVD) in adults 75 years and older. Objective: To evaluate the role of statin use for mortality and primary prevention of ASCVD in veterans 75 years and older. Design, Setting, and Participants: Retrospective cohort study that used Veterans Health Administration (VHA) data on adults 75 years and older, free of ASCVD, and with a clinical visit in 2002-2012. Follow-up continued through December 31, 2016. All data were linked to Medicare and Medicaid claims and pharmaceutical data. A new-user design was used, excluding those with any prior statin use. Cox proportional hazards models were fit to evaluate the association of statin use with outcomes. Analyses were conducted using propensity score overlap weighting to balance baseline characteristics. Exposures: Any new statin prescription. Main Outcomes and Measures: The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes included a composite of ASCVD events (myocardial infarction, ischemic stroke, and revascularization with coronary artery bypass graft surgery or percutaneous coronary intervention). Results: Of 326 981 eligible veterans (mean [SD] age, 81.1 [4.1] years; 97% men; 91% white), 57 178 (17.5%) newly initiated statins during the study period. During a mean follow-up of 6.8 (SD, 3.9) years, a total 206 902 deaths occurred including 53 296 cardiovascular deaths, with 78.7 and 98.2 total deaths/1000 person-years among statin users and nonusers, respectively (weighted incidence rate difference [IRD]/1000 person-years, -19.5 [95% CI, -20.4 to -18.5]). There were 22.6 and 25.7 cardiovascular deaths per 1000 person-years among statin users and nonusers, respectively (weighted IRD/1000 person-years, -3.1 [95 CI, -3.6 to -2.6]). For the composite ASCVD outcome there were 123 379 events, with 66.3 and 70.4 events/1000 person-years among statin users and nonusers, respectively (weighted IRD/1000 person-years, -4.1 [95% CI, -5.1 to -3.0]). After propensity score overlap weighting was applied, the hazard ratio was 0.75 (95% CI, 0.74-0.76) for all-cause mortality, 0.80 (95% CI, 0.78-0.81) for cardiovascular mortality, and 0.92 (95% CI, 0.91-0.94) for a composite of ASCVD events when comparing statin users with nonusers. Conclusions and Relevance: Among US veterans 75 years and older and free of ASCVD at baseline, new statin use was significantly associated with a lower risk of all-cause and cardiovascular mortality. Further research, including from randomized clinical trials, is needed to more definitively determine the role of statin therapy in older adults for primary prevention of ASCVD.


Asunto(s)
Aterosclerosis/prevención & control , Enfermedades Cardiovasculares/mortalidad , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Veteranos , Anciano , Anciano de 80 o más Años , Enfermedades Cardiovasculares/prevención & control , Causas de Muerte , Factores de Confusión Epidemiológicos , Femenino , Humanos , Masculino , Mortalidad , Puntaje de Propensión , Estudios Retrospectivos , Estados Unidos/epidemiología , Servicios de Salud para Veteranos
14.
PLoS One ; 15(6): e0233960, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32584812

RESUMEN

The causal effect of an exposure on an outcome of interest in an observational study cannot be estimated directly if the confounding variables are not controlled. Many approaches are available for estimating the causal effect of an exposure. In this manuscript, we demonstrate the advantages associated with using inverse probability weighting (IPW) and doubly robust estimation of the odds ratio in terms of reduced bias. IPW approach can be used to adjust for confounding variables and provide unbiased estimates of the exposure's causal effect. For cluster-structured data, as is common in animal populations, inverse conditional probability weighting (ICPW) approach can provide a robust estimation of the causal effect. Doubly robust estimation can provide a robust method even when the specification of the model form is uncertain. In this paper, the usage of IPW, ICPW, and doubly robust approaches are illustrated with a subset of data with complete covariates from the Australian-based National Bovine Respiratory Disease Initiative as well as simulated data. We evaluate the causal effect of prior bovine viral diarrhea exposure on bovine respiratory disease in feedlot cattle. The results show that the IPW, ICPW and doubly robust approaches would provide a more accurate estimation of the exposure effect than the traditional outcome regression model, and doubly robust approaches are the most preferable overall.


Asunto(s)
Complejo Respiratorio Bovino/epidemiología , Diarrea Mucosa Bovina Viral/epidemiología , Simulación por Computador , Modelos Estadísticos , Animales , Australia , Sesgo , Biometría , Complejo Respiratorio Bovino/complicaciones , Diarrea Mucosa Bovina Viral/etiología , Bovinos , Factores de Confusión Epidemiológicos , Oportunidad Relativa
15.
BMC Public Health ; 20(1): 673, 2020 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-32404075

RESUMEN

BACKGROUND: Smoking is the most preventable cause of most chronic diseases such as cardiovascular disease (CVD). Dyslipidemia is also an important risk factor for CVD. Yet, research has provided contradicting findings regarding the association between smoking and blood lipids. This paper examines the relationship between dyslipidemia and smoking based on the results of a cross-sectional sample of a Kurdish population in western Iran. METHODS: This population-based study was derived from the recruitment phase of Ravansar Non-Communicable Disease (RaNCD) cohort study. Logistic regression model adjusted by confounding variables was used to determine the relationship between smoking and blood lipid components. In addition, dose-response relationship between blood lipids and the number of smoked cigarettes was evaluated. RESULTS: For the purpose of this study, 7586 participants were examined. The lifetime prevalence of smoking was 19.9%, and 11.8% were current smokers. The prevalence of dyslipidemia in current smokers (54.9%) was higher than former smokers (43.9%) and in turn former smokers higher than non-smokers (38.0%). Current smokers had greater risk of abnormal HDL cholesterol [OR (95% CI), 2.28(1.98 -2.62)] and triglyceride [OR (95% CI), 1.37(1.15 -1.67)] compared to non-smokers. There was no significant difference in total cholesterol and LDL cholesterol between the two groups. A dose-response relationship was found between the number of cigarettes smoked and HDL-C and TG but no relationship was observed in terms of total cholesterol and LDL-C. CONCLUSIONS: As compared to non-smokers, current smokers and former smokers had abnormal HDL-C and triglyceride and abnormal total cholesterol and triglyceride, respectively. After quitting smoking, heavy smokers showed a more normal HDL-C and total cholesterol levels than the people who tended to smoke a lower number of cigarettes per day.


Asunto(s)
Dislipidemias/etnología , Lípidos/sangre , Fumar Tabaco/etnología , Adulto , Anciano , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Estudios de Cohortes , Factores de Confusión Epidemiológicos , Estudios Transversales , Femenino , Humanos , Irán/epidemiología , Modelos Logísticos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Triglicéridos/sangre
16.
Epidemiol Infect ; 148: e151, 2020 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-32364110

RESUMEN

With a case-crossover design, a case's exposure during a risk period is compared to the case's exposures at referent periods. The selection of referents for this self-controlled design is determined by the referent selection strategy (RSS). Previous research mainly focused on systematic bias associated with the RSS. We additionally focused on how RSS determines the number of referents per risk, sensitivity to overdispersion and time-varying confounding.We illustrated the consequences of different RSS using a simulation study informed by data on meteorological variables and Legionnaires' disease. By randomising the events and exposure time series, we explored statistical power associated with time-stratified and fixed bidirectional RSS and their susceptibility to systematic bias and confounding bias. In addition, we investigated how a high number of events on the same date (e.g. outbreaks) affected coefficient estimation. As illustrated by our work, referent selection alone can be insufficient to control for a time-varying confounding bias. In contrast to systematic bias, confounding bias can be hard to detect. We studied potential solutions: varying the model parameters and link-function, outlier-removal and aggregating the input-data over smaller areas. Our simulation study offers a framework for researchers looking to detect and to avoid bias in case-crossover studies.


Asunto(s)
Exposición a Riesgos Ambientales , Proyectos de Investigación , Sesgo , Estudios de Casos y Controles , Factores de Confusión Epidemiológicos , Estudios Cruzados , Interpretación Estadística de Datos , Estudios Epidemiológicos , Humanos , Enfermedad de los Legionarios/epidemiología , Medición de Riesgo , Tiempo (Meteorología)
17.
J Clin Hypertens (Greenwich) ; 22(6): 943-948, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32472662

RESUMEN

The pandemic of COVID-19, a disease caused by a novel coronavirus SARS-CoV-2, is associated with significant morbidity and mortality. Recent data showed that hypertension, diabetes mellitus, cardiovascular diseases, and chronic obstructive pulmonary disease were the most prevalent comorbidities in COVID-19 patients. Additionally, data indicate that hypertension, diabetes, and cardiovascular diseases are important risk factors for progression and unfavorable outcome in COVID-19 patients. There is only limited amount of data regarding follow-up of these patients, and they provided conflicting results. The main limitation is a small number of participants and particularly those who experienced primary composite outcome (admission in intensive care unit, use of mechanical ventilation, or death). Additionally, the limited number of patients was essential obstacle for performing analysis that would include many confounding factors such as advanced age, smoking status, and obesity and potentially change conclusion. So far, there is no study that demonstrated independent predictive value of diabetes on mortality in COVID-19 patients, but there are many speculations about the association between diabetes and susceptibility to novel coronavirus, as well as its impact on progression and prognosis of COVID-19. The aim of this review article was to summarize the current knowledge about the relationship between diabetes and COVID-19 and its role in outcome in these patients.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus , Diabetes Mellitus , Pandemias , Neumonía Viral , Pronóstico , Betacoronavirus/aislamiento & purificación , Betacoronavirus/patogenicidad , Comorbilidad , Factores de Confusión Epidemiológicos , Infecciones por Coronavirus/mortalidad , Infecciones por Coronavirus/terapia , Diabetes Mellitus/epidemiología , Diabetes Mellitus/terapia , Progresión de la Enfermedad , Humanos , Evaluación de Resultado en la Atención de Salud , Neumonía Viral/mortalidad , Neumonía Viral/terapia , Factores de Riesgo
19.
PLoS One ; 15(4): e0231670, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32298347

RESUMEN

BACKGROUND: In stroke studies, ordinal logistic regression (OLR) is often used to analyze outcome on the modified Rankin Scale (mRS), whereas the non-parametric Mann-Whitney measure of superiority (MWS) has also been suggested. It is unclear how these perform comparatively when confounding adjustment is warranted. AIMS: Our aim is to quantify the performance of OLR and MWS in different confounding variable settings. METHODS: We set up a simulation study with three different scenarios; (1) dichotomous confounding variables, (2) continuous confounding variables, and (3) confounding variable settings mimicking a study on functional outcome after stroke. We compared adjusted ordinal logistic regression (aOLR) and stratified Mann-Whitney measure of superiority (sMWS), and also used propensity scores to stratify the MWS (psMWS). For comparability, OLR estimates were transformed to a MWS. We report bias, the percentage of runs that produced a point estimate deviating by more than 0.05 points (point estimate variation), and the coverage probability. RESULTS: In scenario 1, there was no bias in both sMWS and aOLR, with similar point estimate variation and coverage probabilities. In scenario 2, sMWS resulted in more bias (0.04 versus 0.00), and higher point estimate variation (41.6% versus 3.3%), whereas coverage probabilities were similar. In scenario 3, there was no bias in both methods, point estimate variation was higher in the sMWS (6.7%) versus aOLR (1.1%), and coverage probabilities were 0.98 (sMWS) versus 0.95 (aOLR). With psMWS, bias remained 0.00, with less point estimate variation (1.5%) and a coverage probability of 0.95. CONCLUSIONS: The bias of both adjustment methods was similar in our stroke simulation scenario, and the higher point estimate variation in the MWS improved with propensity score based stratification. The stratified MWS is a valid alternative for adjusted OLR only when the ratio of number of strata versus number of observations is relatively low, but propensity score based stratification extends the application range of the MWS.


Asunto(s)
Accidente Cerebrovascular/epidemiología , Simulación por Computador , Factores de Confusión Epidemiológicos , Humanos , Modelos Logísticos , Modelos Biológicos , Modelos Estadísticos , Probabilidad , Pronóstico , Puntaje de Propensión , Accidente Cerebrovascular/diagnóstico
20.
BMC Public Health ; 20(1): 554, 2020 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-32334556

RESUMEN

BACKGROUND: Although it has been established that low socioeconomic status is linked to increased risk of death after stroke, the mechanisms behind this link are still unclear. In this study we aim to shed light on the relationship between income level and survival after stroke by investigating the extent to which differences in stroke severity account for differences in survival. METHODS: The study was based on patients registered in Riksstroke (the Swedish stroke register) with first time ischemic stroke (n = 51,159) or intracerebral hemorrhage (n = 6777) in 2009-2012. We used causal mediation analysis to decompose the effect of low income on 3-month case fatality into a direct effect and an indirect effect due to stroke severity. Since causal mediation analysis relies on strong assumptions regarding residual confounding of the relationships involved, recently developed methods for sensitivity analysis were used to assess the robustness of the results to unobserved confounding. RESULTS: After adjustment for observed confounders, patients in the lowest income tertile had a 3.2% (95% CI: 0.9-5.4%) increased absolute risk of 3-month case fatality after intracerebral hemorrhage compared to patients in the two highest tertiles. The corresponding increase for case fatality after ischemic stroke was 1% (0.4-1.5%). The indirect effect of low income, mediated by stroke severity, was 1.8% (0.7-2.9%) for intracerebral hemorrhage and 0.4% (0.2-0.6%) for ischemic stroke. Unobserved confounders affecting the risk of low income, more severe stroke and case fatality in the same directions could explain the indirect effect, but additional adjustment to observed confounders did not alter the conclusions. CONCLUSIONS: This study provides evidence that as much as half of income-related inequalities in stroke case fatality is mediated through differences in stroke severity. Targeting stroke severity could therefore lead to a substantial reduction in inequalities and should be prioritized. Sensitivity analysis suggests that additional adjustment for a confounder of greater impact than age would be required to considerably alter our conclusions.


Asunto(s)
Disparidades en el Estado de Salud , Clase Social , Accidente Cerebrovascular/mortalidad , Anciano , Factores de Confusión Epidemiológicos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Análisis de Supervivencia , Suecia/epidemiología
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