Qualidade de artigos científicos

The paper discusses the difficulties in judging the quality of scientific manuscripts and describes some common pitfalls that should be avoided when preparing a paper for submission to a peer-reviewed journal. Peer review is an imperfect system, with less than optimal reliability and uncertain validity. However, as it is likely that it will remain as the principal process of screening papers for publication, authors should avoid some common mistakes when preparing a report based on empirical findings of human research. Among these are: excessively long abstracts, extensive use of abbreviations, failure to report results of parsimonious data analyses, and misinterpretation of statistical associations identified in observational studies as causal. Another common problem in many manuscripts is their excessive length, which makes them more difficult to be evaluated or read by the intended readers, if published. The evaluation of papers after their publication with a view towards their inclusion in a systematic review is also discussed. The limitations of the impact factor as a criterion to judge the quality of a paper are reviewed.O artigo discute as dificuldades em julgar a qualidade de manuscritos científicos e descreve algumas das armadilhas comuns que devem ser evitadas ao preparar um artigo para submissão a um periódico. A revisão por pares é um sistema imperfeito, com confiabilidade abaixo da ideal e validade duvidosa. Entretanto, como provavelmente continuará sendo o principal processo de seleção de artigos para publicação, os autores devem evitar alguns erros ao preparar um manuscrito baseado em achados empíricos da pesquisa humana. Entre eles estão: resumos excessivamente longos, amplo uso de abreviações, falha ao relatar resultados de análise de dados parcimoniosa, e interpretação equivocada de associações estatísticas encontradas em estudos observacionais como sendo causais. Outro problema comum em muitos manuscritos é sua excessiva extensão, o que os torna mais difíceis de serem avaliados ou lidos por leitores-alvo, se publicados. Discute-se a avaliação de artigos após sua publicação e inclusão em revisão sistemática. São revisadas as limitações do fator de impacto como um critério para julgar a qualidade de um artigo

Determinantes dos níveis de cotinina salivar: um estudo de base populacional no Brasil

OBJECTIVE: A cross-sectional population-based study was conducted to assess, in active smokers, the relationship of number of cigarettes smoked and other characteristics to salivary cotinine concentrations. METHODS: A random sample of active smokers aged 15 years or older was selected using a stepwise cluster sample strategy, in the year 2000 in Rio de Janeiro, Brazil. The study included 401 subjects. Salivary cotinine concentration was determined using gas chromatography with nitrogen-phosphorus detection. A standard questionnaire was used to collect demographic and smoking behavioral data. The relation between the number of cigarettes smoked in the last 24h and cotinine level was examined by means of a nonparametric fitting technique of robust locally weighted regression. RESULTS: Significantly (p;40 ng/mL per cigarette were excluded. CONCLUSIONS: There was found a positive association between self-reporting smoking five minutes after waking up, and inhaling more than ½ the time are consistent and higher cotinine levels. These can be markers of dependence and higher nicotine intake. Salivary cotinine proved to be a useful biomarker of recent smoking and can be used in epidemiological studies and smoking cessation programs.OBJETIVO: Realizou-se um estudo transversal para analisar a relação entre número de cigarros fumados e outras características com a concentração de cotinina salivar entre fumantes. MÉTODOS: Fumantes ativos de 15 anos ou mais foram selecionados por meio de amostra probabilística em múltiplos estágios no ano 2000, município do Rio de Janeiro, Brasil. O estudo incluiu 401 fumantes. A concentração de cotinina salivar foi determinada utilizando-se cromatografia gasosa com detector de nitrogênio/fósforo. Coletaram-se informações demográficas e sobre o comportamento tabágico utilizando-se questionário padronizado. A relação entre o número de cigarros fumados nas últimas 24h e o nível de cotinina foi analisada utilizando técnica não paramétrica baseada em regressões robustas locais ponderadas. RESULTADOS: O nível médio ajustado de cotinina foi significativamente (

Association Between Homocysteine and Vascular Calcification Incidence, Prevalence, and Progression in the MESA Cohort.

Background While elevated homocysteine has been associated with calcification in several studies, its importance as a cardiovascular risk factor remains unclear. This study examines the relationship between homocysteine and vascular and valve calcification in the MESA (Multi-ethnic Study of Atherosclerosis) cohort. Methods and Results MESA participants with baseline homocysteine measurements and cardiac computed tomography scans were included (N=6789). Baseline and follow-up assessment of vascular (coronary artery [CAC], descending thoracic aorta [DTAC]) and valve (aortic valve [AVC], mitral annular [MAC]) calcification was performed. Prevalence ratio/relative risk regression was used to assess the relationship of homocysteine with prevalent and incident calcification, and multivariable logistic regression was used to assess associations between homocysteine and calcification progression. Elevated homocysteine was associated with greater relative risk of prevalent and incident CAC and incident DTAC. We also identified a strong association between elevated homocysteine and CAC and DTAC progression. Elevated homocysteine was found to confer a >2-fold increased risk of severe CAC progression (defined as ΔCAC ≥100/year) and an ≈1.5-fold increased risk for severe DTAC progression (defined as ΔDTAC ≥100/year). Conclusions To our knowledge, this is the first study demonstrating an association between elevated homocysteine and both incidence and progression of coronary and extra-coronary vascular calcification. Our findings suggest a potential role for elevated homocysteine as a risk factor for severe vascular calcification progression. Future studies are warranted to further assess the utility of homocysteine as a biomarker for vascular calcification incidence and progression. Clinical Trial Registration https://www.clinicaltrials.gov/. Unique identifier: NCT00005487

ERICA: prevalência de tabagismo em adolescentes brasileiros

OBJECTIVE To estimate the prevalences of tobacco use, tobacco experimentation, and frequent smoking among Brazilian adolescents. METHODS We evaluated participants of the cross-sectional, nation-wide, school-based Study of Cardiovascular Risks in Adolescents (ERICA), which included 12- to 17-year-old adolescents from municipalities of over 100 thousand inhabitants. The study sample had a clustered, stratified design and was representative of the whole country, its geographical regions, and all 27 state capitals. The information was obtained with self-administered questionnaires. Tobacco experimentation was defined as having tried cigarettes at least once in life. Adolescents who had smoked on at least one day over the previous 30 days were considered current cigarette smokers. Having smoked cigarettes for at least seven consecutive days was an indicator for regular consumption of tobacco. Considering the complex sampling design, prevalences and 95% confidence intervals were estimated according to sociodemographic and socio-environmental characteristics. RESULTS We evaluated 74,589 adolescents. Among these, 18.5% (95%CI 17.7-19.4) had smoked at least once in life, 5.7% (95%CI 5.3-6.2) smoked at the time of the research, and 2.5% (95%CI 2.2-2.8) smoked often. Adolescents aged 15 to 17 years had higher prevalences for all indicators than those aged 12 to 14 years. The prevalences did not differ significantly between sexes. The highest prevalences were found in the South region and the lowest ones, in the Northeast region. Regardless of sex, the prevalences were found to be higher for adolescents who had had paid jobs, who lived with only one parent, and who reported having been in contact with smokers either inside or outside their homes. Female public school adolescents were found to smoke more than the ones from private schools. CONCLUSIONS Tobacco use among adolescents is still a challenge. Intending to reduce the prevalence of tobacco use among young people, especially the ones under socioeconomic vulnerability conditions, Brazil must consolidate and increase effective public health care measures.OBJETIVO Estimar as prevalências de tabagismo, experimentação e fumo frequente em adolescentes brasileiros. MÉTODOS Foram avaliados os participantes do Estudo de Riscos Cardiovasculares em Adolescentes (ERICA), estudo transversal de base escolar e abrangência nacional. Participaram adolescentes de 12 a 17 anos de municípios com mais de 100 mil habitantes. A amostra foi estratificada e conglomerada e tem representatividade nacional, regional e para as 27 capitais. As informações foram obtidas usando-se questionário autopreenchível. Experimentação foi definida como: ter experimentado cigarros alguma vez na vida. Foram considerados fumantes atuais de cigarros aqueles que fumaram pelo menos um dia nos últimos 30 dias. Utilizou-se como indicador de uso frequente de tabaco ter fumado cigarros por pelo menos sete dias seguidos. Considerando-se o desenho complexo da amostra, prevalências e intervalos de confiança de 95% foram estimados segundo características sociodemográficas e socioambientais. RESULTADOS Foram avaliados 74.589 adolescentes; dentre esses, 18,5% (IC95% 17,7-19,4) fumaram pelo menos uma vez na vida, 5,7% (IC95% 5,3-6,2) fumavam no momento da pesquisa e 2,5% (IC95% 2,2-2,8) fumavam com frequência. Adolescentes de 15 a 17 anos tiveram prevalências mais elevadas de todos os indicadores comparados aos de 12 a 14 anos. As prevalências não apresentaram diferenças significativas entre sexos. Maiores prevalências foram observadas na região Sul e menores na região Nordeste. Independentemente de sexo, as prevalências foram maiores para adolescentes que tinham tido trabalho remunerado, nos que não moravam com os dois pais e que referiram ter tido contato com fumante em casa ou fora. Adolescentes do sexo feminino de escolas públicas fumavam mais do que as de escolas privadas. CONCLUSÕES O tabagismo entre adolescentes ainda é um desafio. Visando a redução da prevalência de tabagismo entre jovens, em especial os que se encontram em situação de vulnerabilidade socioeconômica, o Brasil deve consolidar e ampliar medidas de saúde pública efetivas

Positive additive and multiplicative interactions among clustered components of metabolic syndrome with type 2 diabetes mellitus among Brazilian adolescent students

Background: It is still controversial whether the joint effect of Metabolic syndrome (MetS) components is greater than that expected based on their independent effects, regarding type 2 diabetes mellitus in adolescents. We evaluated additive and multiplicative interactions between pair-wise combinations of metabolic syndrome components regarding type 2 diabetes mellitus. Methods: We studied 37,815 Brazilian adolescents from a national school-based survey, The Study of Cardiovascular Risk Factors in Adolescents (Portuguese acronym, ERICA). A Poisson regression model was used to calculate sex-, age-, obesity-, smoking status-, sedentary behavior-, physical inactivity-, alcoholic consumption- and socioeconomic status-adjusted prevalence ratios to evaluate both additive and multiplicative interactions. Results: In the comparison of observed and expected joint effects, relative excess risk due to additive interaction (RERI) for high triglycerides and low high-density lipoprotein-cholesterol, high triglycerides and elevated waist circumference, elevated waist circumference and low high-density lipoprotein-cholesterol and elevated waist circumference and high blood pressure were 2.53 (−0.41, 5.46), 2.86 (−2.89, 8.61), 1.71 (−1.05, 4.46) and 0.97 (0.15, 1.79), respectively, thus suggesting additive interactions. Multiplicative interactions for those pairs of components were also observed, as expressed by interaction ratios > 1.0. Conclusions: The joint presence of some of the components of MetS showed a greater association with the prevalence of type 2 diabetes mellitus in adolescents than expected from the sum of their isolated effects. From a public health perspective, preventing one of the components of the pairs that interact may result in a greater reduction in the prevalence of T2DM than focusing on an individual component that does not interact with another component

Body-Mass Index and Mortality Risk in US Blacks Compared to Whites

Objective: To compare body-mass index (BMI)-related mortality risk in US Blacks vs. Whites as the relationship appears to differ across race/ethnicity groups. Design and Methods We pooled cross-sectional surveys of nationally representative samples of 11,934 Blacks and 59,741 Whites aged 35–75 in the National Health Interview Survey from 1997–2002 with no history of cardiovascular disease or cancer. Mortality follow-up was available through 2006. BMI was calculated from self-reported height and weight. We used adjusted Cox regression analysis to adjust for potential confounders. Results: Over 9 years of follow-up, there were 4,303 deaths (1,205 among never smokers). Age-adjusted mortality rates were higher in Blacks compared to Whites at BMI < 25 kg/m2 and showed no increase at higher levels of BMI. In men, adjusted hazard ratios for all-cause death rose in a similar fashion across upper BMI quintiles in Blacks and Whites; in women, however, BMI was positively associated with mortality risk in Whites, but inversely associated in Blacks (p interaction = 0.01). Racial disparities were amplified in subsidiary analyses that introduced a 12-month lag for mortality or focused on CVD mortality. Conclusions: The relationship of elevated BMI to mortality appears weaker in US Blacks than in Whites, especially among women

The Sex and Race Specific Relationship between Anthropometry and Body Fat Composition Determined from Computed Tomography: Evidence from the Multi-Ethnic Study of Atherosclerosis.

BackgroundFew studies have investigated the relationship of anthropometric measurements with computed tomography (CT) body fat composition, and even fewer determined if these relationships differ by sex and race.MethodsCT scans from 1,851 participants in the population based Multi-Ethnic Study of Atherosclerosis were assessed for visceral and subcutaneous fat areas by semi-automated segmentation of body compartments. Regression models were used to investigate relationships for anthropometry with visceral and subcutaneous fat separately by sex and race/ethnicity.ResultsParticipants were 50% female, 41% Caucasian, 13% Asian, 21% African American, and 25% Hispanic. For visceral fat, the positive relationship with weight (p = 0.028), waist circumference (p&lt;0.001), waist to hip ratio (p&lt;0.001), and waist to height ratio (p = 0.05) differed by sex, with a steeper slope for men. That is, across the range of these anthropometric measures the rise in visceral fat is faster for men than for women. Additionally, there were differences by race/ethnicity in the relationship with height (p&lt;0.001), weight (p&lt;0.001), waist circumference (p&lt;0.001), hip circumference (p = 0.006), and waist to hip ratio (p = 0.001) with the Hispanic group having shallower slopes. For subcutaneous fat, interaction by sex was found for all anthropometric indices at p&lt;0.05, but not for race/ethnicity.ConclusionThe relationship between anthropometry and underlying adiposity differs by sex and race/ethnicity. When anthropometry is used as a proxy for visceral fat in research, sex-specific models should be used