The LifeLines Cohort Study is a large population-based cohort study and biobank that was established as a resource for research on complex interactions between environmental, phenotypic and genomic factors in the development of chronic diseases and healthy ageing. Between 2006 and 2013, inhabitants of the northern part of The Netherlands and their families were invited to participate, thereby contributing to a three-generation design. Participants visited one of the LifeLines research sites for a physical examination, including lung function, ECG and cognition tests, and completed extensive questionnaires. Baseline data were collected for 167 729 participants, aged from 6 months to 93 years. Follow-up visits are scheduled every 5 years, and in between participants receive follow-up questionnaires. Linkage is being established with medical registries and environmental data. LifeLines contains information on biochemistry, medical history, psychosocial characteristics, lifestyle and more. Genomic data are available including genome-wide genetic data of 15 638 participants. Fasting blood and 24-h urine samples are processed on the day of collection and stored at -80 °C in a fully automated storage facility. The aim of LifeLines is to be a resource for the national and international scientific community. Requests for data and biomaterials can be submitted to the LifeLines Research Office [LLscience@umcg.nl].

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Patients should be properly informed about the advantages and disadvantages of the treatment options for lateral epicondylitis. The decision to treat with physiotherapy or to adopt a wait-and-see policy might depend on available resources, since the relative gain of physiotherapy is small.

A lthough the number of test evaluations in the literature is increasing, much remains to be desired in terms of methodology. A series of surveys have shown that only a small number of studies of diagnostic accuracy fulfil essential methodologic standards. 1-3Shortcomings in the design of clinical trials are known to affect results. The biasing effects of inadequate randomization procedures and differential dropout have been discussed and demonstrated in several publications.4-6 A growing understanding of the potential sources of bias and variation has led to the development of guidelines to help researchers and readers in the reporting and appraisal of results from randomized trials.7,8 More recently, similar guidelines have been published to assess the quality of reporting and design of studies evaluating the diagnostic accuracy of tests. For many of the items in these guidelines, there is no or limited empirical evidence available on their potential for bias. 9In principle, such evidence can be collected by comparing studies that have design deficiencies with studies of the same test that have no such imperfections. Several large metaanalyses have used a meta-regression approach to account for differences in study design.10-12 Lijmer and colleagues examined a number of published meta-analyses and showed that studies that involved nonrepresentative patients or that used different reference standards tended to overestimate the diagnostic performance of a test.13 They looked at the influence of 6 methodologic criteria and 3 reporting features on the estimates of diagnostic accuracy in a limited number of clinical problems.We conducted this study of a larger and broader set of meta-analyses of diagnostic accuracy to determine the relative importance of 15 design features on estimates of diagnostic accuracy. Methods Data sources: systematic reviewsAn electronic search strategy was developed to identify all systematic reviews of studies evaluating the diagnostic accuracy of tests that were published between January 1999 and April 2002 in MEDLINE (OVID and PubMed), EMBASE (OVID), the Database of Abstracts of Reviews of Effect (DARE) of the Centre for Reviews and Dissemination (www.york.ac.uk/inst/crd Evidence of bias and variation in diagnostic accuracy studiesBackground: Studies with methodologic shortcomings can overestimate the accuracy of a medical test. We sought to determine and compare the direction and magnitude of the effects of a number of potential sources of bias and variation in studies on estimates of diagnostic accuracy. Methods:We identified meta-analyses of the diagnostic accuracy of tests through an electronic search of the databases MEDLINE, EMBASE, DARE and MEDION (1999-2002). We included meta-analyses with at least 10 primary studies without preselection based on design features. Pairs of reviewers independently extracted study characteristics and original data from the primary studies. We used a multivariable metaepidemiologic regression model to investigate the direction and strength of the a...

BackgroundLifeLines is a large prospective population-based three generation cohort study in the north of the Netherlands. Different recruitment strategies were adopted: recruitment of an index population via general practitioners, subsequent inclusion of their family members, and online self-registration. Our aim was to investigate the representativeness of the adult study population at baseline and to evaluate differences in the study population according to recruitment strategy.MethodsDemographic characteristics of the LifeLines study population, recruited between 2006–2013, were compared with the total adult population in the north of the Netherlands as registered in the Dutch population register. Socioeconomic characteristics, lifestyle, chronic diseases, and general health were further compared with participants of the Permanent Survey of Living Conditions within the region (2005–2011, N = 6,093). Differences according to recruitment strategy were assessed.ResultsCompared with the population of the north of the Netherlands, LifeLines participants were more often female, middle aged, married, living in a semi-urban place and Dutch native. Adjusted for differences in demographic composition, in LifeLines a smaller proportion had a low educational attainment (5% versus 14%) or had ever smoked (54% versus 66%). Differences in the prevalence of various chronic diseases and low general health scores were mostly smaller than 3%. The age profiles of the three recruitment groups differed due to age related inclusion criteria of the recruitment groups. Other differences according to recruitment strategy were small.ConclusionsOur results suggest that, adjusted for differences in demographic composition, the LifeLines adult study population is broadly representative for the adult population of the north of the Netherlands. The recruitment strategy had a minor effect on the level of representativeness. These findings indicate that the risk of selection bias is low and that risk estimates in LifeLines can be generalized to the general population.

Despite heterogeneity in study design and measures, our meta-analyses show that multiple aspects of social relationships are associated with cognitive decline. As evidence for publication bias was found, the association might be overestimated and should therefore be interpreted with caution. Future studies are needed to better define the mechanisms underlying these associations. Potential causality of this prognostic association should be examined in future randomized controlled studies.

ABSTRACT. Smidt N, van der Windt DA, Assendelft WJ, Mourits AJ, Devillé WL, de Winter AF, Bouter LM. Interobserver reproducibility of the assessment of severity of complaints, grip strength, and pressure pain threshold in patients with lateral epicondylitis. Arch Phys Med Rehabil 2002;83:1145-50.Objective: To evaluate the interobserver reproducibility of the assessment of severity of complaints, grip strength, and pressure pain threshold in patients with lateral epicondylitis in primary care.Design: Two physiotherapists assessed independently, and in randomized order, the severity of complaints scored on an 11-point numeric rating scale, pain-free grip strength, maximum grip strength, and pressure pain threshold.Setting: Primary care center in the Netherlands. Participants: Fifty patients were assessed by both physiotherapists.Interventions: Not applicable. Main Outcome Measures: Intraclass correlation coefficients (ICCs) and 95% confidence intervals (CIs) were calculated to assess interobserver reliability. The Bland and Altman method was used to assess interobserver agreement, which included calculation of the mean difference between the observers (d ), the 95% CI for d, the standard deviation of the differences, and the 95% limits of agreement. Finally, the smallest detectable difference (SDD) was calculated.Results: The ICC for the severity of complaints was .90. The ICCs for the pain-free grip strength and maximum grip strength were .97 and .98, respectively. The pressure pain threshold showed a lower reliability (ICCϭ.77). The interobserver agreement for all outcome measures was good, but systematic differences in assessment between the physiotherapists were found for the maximum grip strength and pressure pain threshold. For pressure pain threshold, the SDD was clearly larger than the predefined acceptable difference of 10% of the total range of measurement.Conclusions: The interobserver reliability of severity of complaints and grip strength was excellent, whereas the pressure pain threshold showed unsatisfactory reliability. Grip strength and overall assessment of the severity of complaints are useful and reliable measures for the assessment of lateral epicondylitis. Pain-free grip strength, in particular, is relatively easy to perform and has been shown to be associated with other measures of functional disability in patients with lateral epicondylitis. We, therefore, recommend the use of pain-free grip strength in both research and clinical practice.

AIM: To evaluate the available evidence of the AIM: To evaluate the available evidence of the effectiveness of physiotherapy for lateral epicondylitis effectiveness of physiotherapy for lateral epicondylitis of the elbow. of the elbow. METHOD: Randomised controlled trials (RCTs) identi-METHOD: Randomised controlled trials (RCTs) identi®ed by a highly sensitive search strategy in six ®ed by a highly sensitive search strategy in six databases in combination with reference checking. databases in combination with reference checking. Two independent reviewers selected RCTs that Two independent reviewers selected RCTs that included a physiotherapy intervention, patients with included a physiotherapy intervention, patients with lateral epicondylitis, and at least one clinically lateral epicondylitis, and at least one clinically relevant outcome measure. No language restrictions relevant outcome measure. No language restrictions were made. Methodological quality was independently were made. Methodological quality was independently assessed by two blinded reviewers. A best evidence assessed by two blinded reviewers. A best evidence synthesis, including a quantitative and qualitative synthesis, including a quantitative and qualitative analysis, was conducted, weighting the studies with analysis, was conducted, weighting the studies with respect to their internal validity, statistical signi®-respect to their internal validity, statistical signi®-cance, clinical relevance, and statistical power. cance, clinical relevance, and statistical power. RESULTS: 23 RCTs were included in the review, RESULTS: 23 RCTs were included in the review, evaluating the effects of lasertherapy, ultrasound evaluating the effects of lasertherapy, ultrasound treatment, electrotherapy, and exercises and mobilisatreatment, electrotherapy, and exercises and mobilisation techniques. Fourteen studies satis®ed at least tion techniques. Fourteen studies satis®ed at least 50% of the internal validity criteria. Except for 50% of the internal validity criteria. Except for ultrasound, pooling of data from RCTs was not ultrasound, pooling of data from RCTs was not possible because of insuf®cient data, or clinical or possible because of insuf®cient data, or clinical or statistical heterogeneity. The pooled estimate of the statistical heterogeneity. The pooled estimate of the treatment effects of two studies on ultrasound treatment effects of two studies on ultrasound compared to placebo ultrasound, showed statistically compared to placebo ultrasound, showed statistically signi®cant and clinically relevant differences in favour signi®cant and clinically relevant differences in favour of ultrasound. There is insuf®cient evidence either to of ultrasound. There is insuf®cient evidence either to demonstrate bene®t or lack of effect of lasertherapy, demonstrate bene®t or lack of effect of lasertherapy, electrotherapy, exercises and mobilisation techniques electrotherapy, exercises and mobilisation techniques for lateral epicondylitis. for lateral epicondylitis. CONC...