Cohort studies

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Opioids contribute to fracture risk: a meta-analysis of 8 cohort studies.

Opioids contribute to fracture risk: a meta-analysis of 8 cohort studies.

Despite the advantages of this study, some limitations should be mentioned. First, although we searched all cohort studies describing the association of opioids with fractures, the eligible studies were restricted to the English language. The number of relevant studies was still rela- tively small, which implies that some studies may have been missed due to their publication in non-English language journals or publication in a book or a journal that is not included in the computer databases. Second, studies with nonsignificant results, especially those that show an absence of effect, may not be published because they are rejected by the journals or because the investigators are unwilling to submit them for publication [36]. Although we controlled for publication bias using statistical methods, publication bias could not be completely ruled out. Thus, the pooled effect measure may be overestimated. Third, the degree of control for con- founding variables, such as age, gender, body mass index and comorbidity, also varied between studies. Fourth, in this meta-analysis, we were not able to investigate the effect of different opi- oid doses because relevant data were available in only a few studies. Fifth, it was unfortunate that we were not able to define contributing factors because all of the included papers were from Western countries and all of th pe participants were Caucasian. Therefore, our results cannot be generalized to worldwide populations, especially non-Western populations. As a re- sult, more investigations of contributing factors, such as ethnicity, participant education level and socioeconomic class, especially in non-Western populations, are required. Sixth, we were not able to determine the fracture timing, whether medication sedation effects would be more
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Strong association between serological status and probability of progression to clinical visceral leishmaniasis in prospective cohort studies in India and Nepal.

Strong association between serological status and probability of progression to clinical visceral leishmaniasis in prospective cohort studies in India and Nepal.

Contrary to what has been reported in some smaller cohort studies and among studies of other Leishmania species, our study populations exhibited a strong association between serological markers and progression to symptomatic VL among asymptomatic individuals [16,17,18]. Among the 235 VL cases that developed in our 32,529-person strong study population, 88 arose from a subgroup of 1,103 individuals with high initial DAT titers. Even using a very low cut-off for a positive DAT titer (1:800), Sundar et al. found no seropositive individuals among 100 Indian controls living in non-endemic regions, providing further evidence for the fact that positive serology is a result of infection with VL parasites and not due to cross reactivity [25]. Although the vast majority of individuals who are seropositive do not progress to disease, seroprevalence and seroconversion remain good markers for prevalence and incidence of Leishmania infection in epidemiological studies, and as tools to monitor the impact of interventions, especially when high titer cut offs are used.
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Systematic review of birth cohort studies in South East Asia and Eastern Mediterranean regions

Systematic review of birth cohort studies in South East Asia and Eastern Mediterranean regions

In addition to infections, the incidence of non-communi- cable diseases such as cardiovascular disease, diabetes, can- cers, cognitive defects and mental illness, are also increas- ing in low and middle-income countries (2,10). Thus, the developed world faces a dual burden of communicable and non-communicable disease. The diseases of adulthood have known associations with risk factors in earlier life. A life-course perspective of health determinants is now well outlined with understanding being drawn from previous longitudinal studies. Data from the UK NCDS study (3) for example outlined the association between maternal smok- ing and low birth weight (20). Risk factors even for the same non-communicable diseases are likely to differ some- what between developed and developing countries. There- fore, any future birth cohort studies in the developing world would be more informative than those in the devel- oped world.
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What are the health benefits of active travel? A systematic review of trials and cohort studies.

What are the health benefits of active travel? A systematic review of trials and cohort studies.

In light of this, users of the findings of this and similar reviews need to consider the extent to which we can generalise between studies conducted in different countries or settings. In particular, the amount of exertion required to travel actively may be greater in some settings than others for the same journey time, due to differences in congestion, terrain and climate. In countries where current levels of physical activity are low (such as the UK, where only 39% of men and 29% of women achieve 30 minutes of moderate intensity physical activity of any type five times a week [60] [61]) adding 30 minutes of active travel per day might well produce much larger changes in health at a population level than were measured in non-UK studies. The prospective cohort studies also tended to focus on travel to work or school rather than active travel for general transportation, which again may limit generali- sability.
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Fish intake and ovarian cancer risk: a meta-analysis of 15 case-control and cohort studies.

Fish intake and ovarian cancer risk: a meta-analysis of 15 case-control and cohort studies.

Figure 1 illustrates the search process and the final selection of relevant studies. 1,222 records were identified through database searching, and 30 additional records were identified through other sources. On the basis of the titles and abstracts, we identified 23 full-text articles. After further evaluation, eight studies were excluded for lack of available data. At last, a total of 15 eligible studies published between 1984 and 2011 were identified, including 10 case–control studies[12,15,24–31] and five cohort studies[32–36] (Baseline data and other details of included case– control studies and cohort studies are shown in Table 1 and Table 2, respectively). Among the ten case-control studies, five studies were population based, and the other five studies were hospital based. A total of 889,033 female subjects, including 6,087 ovarian cancer cases were involved. Of the 15 included studies, six studies were conducted in Europe, three studies in Asia, five studies in North America, and remaining one in Australia. Most studies used food frequency questionnaires(FFQ) for the assess- ment of fish consumption. Most studies matched or adjusted for some potential confounders, including age, total energy intake, and use of oral contraceptives. Table S1 summarizes the quality scores of cohort studies and case-control studies. The Newcastle- Ottawa Scale scores for the included studies ranged from 4 to 9, with a median 7.5. The median scores of cohort studies and case-
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Adult consequences of late adolescent alcohol consumption: a systematic review of cohort studies.

Adult consequences of late adolescent alcohol consumption: a systematic review of cohort studies.

There is evidence from a single population-based cohort that late adolescent drinking can cause early death among men, principally through car crashes and suicides [12,15]. There is a large evidence base attesting to the ongoing impacts of late adolescent drinking on adult drinking behaviours, though most studies cannot strongly support causal inferences because of their designs. There is robust evidence from one national cohort that apparent effects on later alcohol consumption persist beyond the age of 30, which is longer than had previously been understood [43]. Possible effects on subsequent alcohol problems including dependence are somewhat more complex than effects upon subsequent alcohol consumption per se. Evidence from multiple well-designed cohort studies indicates that other factors indicative of heightened psychosocial risk more broadly are also implicated. It is nonetheless striking that effects on alcohol problems assessed in the mid 30s appear to have been produced by elevated consumption in late adolescence in both SCS and MFCS, and to earlier ages in other studies. Findings from a rigorous birth cohort study on nonalcohol outcomes, however, demonstrate that many apparent effects of late adolescent drinking may be due to uncontrolled confounding [60]. Certainty about the long-term consequences of late adolescent drinking is thus not easily achieved.
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Profile of three Brazilian birth cohort studies in Ribeirão Preto, SP and São Luís, MA

Profile of three Brazilian birth cohort studies in Ribeirão Preto, SP and São Luís, MA

We describe three birth cohort studies, respectively carried out in 1978/79 and 1994 in Ribeirão Preto, a city located in the most developed region of Brazil, and in 1997/98 in São Luís, a city located in a less developed region. The objective of the present report was to describe the methods used in these three studies, presenting their history, methodological design, objectives, developments, and diffi- culties faced along 28 years of research. The first Ribeirão Preto study, initially perinatal, later encompassed questions regarding the reper- cussions of intrauterine development on future growth and chronic adult diseases. The subjects were evaluated at birth (N = 6827), at school age (N = 2861), at the time of recruitment for military service (N = 2048), and at 23/25 years of age (N = 2063). The study of the second cohort, which started in 1994 (N = 2846), permitted compari- son of aspects of perinatal health between the two groups in the same region, such as birth weight, mortality and health care use. In 1997/98, a new birth cohort study was started in São Luís (N = 2443), capital of the State of Maranhão. The 1994 Ribeirão Preto cohort and the São Luís cohort are in the second phase of joint follow-up. These studies permit comparative temporal analyses in the same place (Ribeirão Preto 1978/79 and 1994) and comparisons of two contrasting popula- tions regarding cultural, economic and sociodemographic conditions (Ribeirão Preto and São Luís).
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Latestage diagnosis of HIV infection in Brazilian children : evidence from two national cohort studies

Latestage diagnosis of HIV infection in Brazilian children : evidence from two national cohort studies

study cohort/year of HIV diagnosis (1983 to 1998 or 1999 to 2002), age at time of HIV diagnosis (< one, one to five, and six to 12 years). We stratified year of birth into three groups according to the history of pre-HAART and HAART in Brazil: be- fore 1988 (ART not available); 1989 to 1995 (lim- ited ART availability); 1996 to 2002 (ART avail- able nation-wide, more consistent use of ART with Brazilian children (HAART available), and widespread implementation of first national ART guidelines and of strategies to prevent mother- to-child transmission 11 . For year of HIV diagno-
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The use of new technologies in Cohort studies

The use of new technologies in Cohort studies

Diferentes fatores de risco e suas relações no tempo determinado à ocorrência da doença ou de um desfecho só podem ser detectados no desenho de coorte, pois esta interação temporal [r]

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Gestational weight gain and body mass index in children: results from three german cohort studies.

Gestational weight gain and body mass index in children: results from three german cohort studies.

The US Institute of Medicine (IOM) established GWG recommendations for women by different BMI classes in 1990 [15], which were slightly revised in 2009 [16]. With respect to the long term effects on childhood obesity adherence might be of particular importance for children of overweight and obese mothers, whose risk for later childhood obesity is increased irrespective of GWG [17]. Previous studies suggested that most environmental risk factors for childhood overweight might not only account for a shift of the total BMI distribution, but have a stronger effect in overweight children compared to normal- weight peers (18–20). To our knowledge, however, no study assessed whether high GWG is associated with BMI in a similar way.
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Rev. bras.oftalmol.  vol.75 número3

Rev. bras.oftalmol. vol.75 número3

Objective: For nearly a century, penetrating keratoplasty has been the surgical technique of choice in the management of corneal changes. However, in recent years, several lamellar keratoplasty techniques have been developed, modified or improved, especially techniques for replacing the posterior portion, for the correction of bullous keratopathy. The aim of this study was to evaluate the effectiveness and safety of endothelial keratoplasty versus penetrating keratoplasty for pseudophakic and aphakic bullous keratopathy. Methods: A systematic review of the literature was carried out, and the main electronic databases were searched. The date of the most recent search was from the inception of the electronic databases to December 11, 2015. Two authors independently selected relevant clinical trials, assessed their methodological quality and extracted data. Results: The electronic search yielded a total of 893 published papers from the electronic databases. Forty-four full-text articles were retrieved for further consideration. Of these 44 full-text articles, 33 were excluded because they were all case series studies; therefore, ten studies (with one further publication) met the inclusion criteria: one randomized clinical trial with two publications; three controlled studies; and six cohort studies. The clinical and methodological diversity found in the included studies meant that it was not possible to combine studies in a meta- analysis. Conclusions: There is no robust evidence that endothelial keratoplasty is more effective and safe than penetrating keratoplasty for improving visual acuity and decreasing corneal rejection for pseudophakic and aphakic bullous keratopathy. There is a need for further randomized controlled trials.
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Fisioter. Pesqui.  vol.23 número3

Fisioter. Pesqui. vol.23 número3

ABSTRACT | Lymphedema is characterized by accumulation of proteins and luids in the interstice, with physical and psychological changes. Among the physiotherapeutic techniques used to reduce lymphedema we have the complex decongestive therapy. The objective of this review is to identify evidence for the practice of complex decongestive therapy for intensive care of lymphedema. A search was carried out in the PubMed, EMBASE and PEDro databases. The articles chosen were randomized and cohort studies, which have been evaluated and selected independently by two reviewers who evaluated the methodological quality of the studies within the PEDro Scale. The search resulted in 414 studies, reduced to seven eligible studies for quality analysis, classiied by PEDro scale as high quality and moderate efectiveness studies. The analyzed articles showed good methodological quality and their results showed the efectiveness of complex decongestive therapy in reducing the volume of lymphedema in intensive care. Keywords | Drainage; Lymphedema; Lymphatic Diseases; Breast Neoplasms.
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Cad. Saúde Pública  vol.25 suppl.3

Cad. Saúde Pública vol.25 suppl.3

first occurrence of breast cancer in cohort studies and in case-control studies with the appearance of the first breast cancer; (c) mean follow-up time – minimum of ten years in cohort studies, while in case-control studies no limit was set on the pe- riod between exposure and diagnosis; (d) type of variable – studies in which the stress variable was measured quantitatively; stress measured with a numerical scale, questionnaire, and checklist; stress measured against frequency of exposure and intensity of the event; (e) statistical type and analysis – studies that calculated relative risk (RR) for the first episode of breast cancer in relation to the stress variable, adjusting for the following confounding factors (age, use of oral contracep- tives, any type of hormone replacement, meno- pause, alcohol intake, smoking, socioeconomic status, and family history of breast cancer).
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Fat Intake Is Not Linked to Prostate Cancer: A Systematic Review and Dose-Response Meta-Analysis.

Fat Intake Is Not Linked to Prostate Cancer: A Systematic Review and Dose-Response Meta-Analysis.

A previous meta-analysis [12], of 29 observational studies with 5 cohort studies, found that only total fat consumption was associated with an increased risk for Pca (RR = 1.2). Consum- ing 45g of total fat per day (5 studies, combined RR = 1.12, 95%CI: 1.01, 1.25) or saturated fat (4 studies, combined RR = 1.38, 95%CI: 1.13, 1.70) increased the risk for advanced stage Pca. The meta-analysis was well-designed, but most of the studies included were case-controlled with considerable heterogeneity, which may account for the low grade of evidence. Another systematic review [48] that contained only 5 studies (including one cohort study) claimed that saturated fat consumption was associated with advanced Pca. However, their limited study numbers and sample size may explain the low statistical power of their results. The present meta-analysis is based on large numbers of cohort studies and we found no association between fat intake and the risk for Pca. Our results are similar to a meta-analysis by Chua et al [15]. Our meta-analysis included more high quality cohorts and prepared with more flexible design, may be credible. There were also reviews on this topic [13, 14], but the lack of systematic statistical analysis and less rigorous design may lead to a loss of credibility.
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A Meta-Analysis on Prehypertension and Chronic Kidney Disease.

A Meta-Analysis on Prehypertension and Chronic Kidney Disease.

Two reviewers (Yang Li and Peng Xia) independently identified potentially relevant studies by using the previously described search strategy. The titles and abstracts of each article were reviewed to ascertain the inclusion criteria, and the full text was carefully reviewed if the con- formity was unclear. The data were extracted according to a standardized form, and disagree- ment was resolved by consensus when the data differed between the investigators. The following study characteristics were extracted: country of origin, publication year, sample size, gender, age, median follow-up time, prevalence of prehypertension, type of risk and adjusted confounding factors. We assessed the quality of the studies using the Newcastle-Ottawa Scale (NOS). In terms of study quality, the cohort studies were considered to be of fair (scores of 4–6) to good (scores of 7–9) quality.
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A comparison of technique modifications in laparoscopic donor nephrectomy: a systematic review and meta-analysis.

A comparison of technique modifications in laparoscopic donor nephrectomy: a systematic review and meta-analysis.

The major strengths of this SRMA is the systematic approach with a protocol published in ad- vance and a relatively large number of studies included. A comprehensive assessment is provid- ed of 4 different technique modifications of laparoscopic donor nephrectomy that is relevant to both clinicians and patients. The presented data provide a complete overview of current litera- ture and reveals the gaps in evidence. Several limitations should be discussed. First, the results should be interpreted cautiously, in general, the quality of the included cohort studies and RCTs was low to intermediate or unclear. For 3 randomized clinical trials the risk of bias was high [18, 25, 43], for the remaining 2 trials the risk of bias was unclear [17, 42]. Assessment of the cohort studies revealed that the overall quality was low to intermediate. Second, consider- able heterogeneity in most studies was observed. This may be explained by differences in expe- rience and learning curve. In all studies, very limited or no information regarding experience of the surgeons of each separate technique modification was provided. Third, publication bias cannot be excluded, as asymmetry in one funnel plot was found, while most funnel plots
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Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review.

Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review.

In the meta-analysis, the assessment of whole grain intake and its classification varied between the different included cohorts (Table 4). The use of an FFQ with less-detailed questions on whole grain foods [9] and the use of a classification that weighted all foods with at least 25% of whole grains equally [6–8] may have contributed to measure- ment error. In addition, the level of whole grain intakes differed substantially for the different cohorts. For example, the intake of whole grains and rye bread in particular was substantially higher for the Finnish population than for the US populations. Our results suggest that the benefit of adding a serving of whole grains may be greater for populations with a low intake than for those who already have a high intake, but this finding requires further research. Given the measure- ment error in the assessment of whole grain intake, the potential for residual confounding, and the difference in characteristics of the study populations, the estimated magnitude of associations should be interpreted with caution. However, all cohort studies were consistent with a substantial protective effect of whole grain consumption in relation to type 2 diabetes and excluding any one study did not substantially change the pooled estimate. Publication bias can affect the findings of any meta-analysis, but standard tests did not indicate the presence of publication bias in the current analysis.
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Thyrotropin and free thyroxine levels and coronary artery disease: cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Thyrotropin and free thyroxine levels and coronary artery disease: cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

We have also found that lower levels of TSH were not associated with CAD. Our data contrasts with findings from a large meta-analysis by Collet et al. (2), which evaluated CHD events among subjects with SCHyper in comparison with euthyroid ones. They included 52,674 participants from 10 cohort studies with available data about SCHyper, incident CHD, and mortality. However, none of these cohorts detected occult CAD using CCTA (2). SCHyper was independently associated with CHD events (HR=1.21; 95%CI=0.99–1.46), all-cause mortality (HR= 1.29; 95%CI=1.02–1.62), and cardiovascular mortality (HR= 1.24, 95%CI=1.06–1.46) (2). Another prospective study with a mean follow-up around 3 years, 76 middle-aged sub- jects with SCHyper and 1062 euthyroid ones, all of them with type 2 diabetes mellitus, showed a higher incidence of CHD events with lower TSH levels. Subjects with TSH o 0.1 mIU/L presented HR=4.96 (95%CI=1.01–25.66, P for trend=0.049) for CHD events in comparison with subjects in the reference category, or with TSH between 0.45 and 4.49 mIU/L, regardless of glycemic control (22). In our sample, only 0.5% (n=4) of the total number of subjects were SCHyper with TSH values lower than 0.1 mUI/L.
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Socioeconomic status and the 25 × 25 risk factors as determinants of premature mortality

Socioeconomic status and the 25 × 25 risk factors as determinants of premature mortality

We used individual-level data from more than 1·7 million individuals in 48 independent cohort studies to compare the association of low socio economic status with mortality to those of six WHO 25 × 25 risk factor targets for the reduction of premature mortality. We found that the independent association between socioeconomic status and mortality is com parable in strength and consistency across countries to those for the 25 × 25 risk factors. Low socioeconomic status was associated with 2·1 YLLs between ages 40 and 85 years, while the corresponding years of life lost were 0·5 for high alcohol intake, 0·7 for obesity, 3·9 for diabetes, 1·6 for hyper- tension, 2·4 for physical inactivity and 4·8 for current smoking in men and women combined. These fi ndings are largely consistent with previous studies, 17–19 which
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Systematic assessment of environmental risk factors for bipolar disorder : an umbrella review of systematic reviews and meta analyses

Systematic assessment of environmental risk factors for bipolar disorder : an umbrella review of systematic reviews and meta analyses

We systematically searched the PubMed/MEDLINE, EMBASE and PsycINFO databases from inception to 7 October 2016 to identify systematic reviews and meta- analyses of observational studies ex- amining associations of environmental (non- genetic) risk factors with BD. The search strategy used the keywords “bipolar disorder” and “meta- analyses or systematic reviews” applied to the title/abstract/ keywords fields. Two authors (B.B. and J.L.C.) independently screened the titles/abstracts of retrieved publications, and discrepancies were resolved through consensus. If a final decision could not be reached, a third investigator made the decision regarding possible eligibility (A.F.C. or C.A.K.). The full texts of publications selected after title/ abstract screening were then reviewed by the same investigators to determine final eligibility. We included systematic reviews and meta- analyses of observational studies (i.e., cross- sectional, case−control and cohort studies) which investigated environmental risk factors for BD. No language restrictions were applied. Systematic reviews and meta- analyses of genetic risk factors, peripheral biomarkers of BD, factors related to recurrence/relapse of BD or intervention studies were excluded. A published umbrella review evaluated possible hints of bias in the literature of peripheral biomarkers for BD. 20 We also
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