No abstract

Most genome-wide association studies are based on samples of European descent. We assess whether the genetic determinants of blood lipids, a major cardiovascular risk factor, are shared across populations. Genetic correlations for lipids between European-ancestry and Asian cohorts are not significantly different from 1. A genetic risk score based on LDL-cholesterol-associated loci has consistent effects on serum levels in samples from the UK, Uganda and Greece (r = 0.23–0.28, p < 1.9 × 10−14). Overall, there is evidence of reproducibility for ~75% of the major lipid loci from European discovery studies, except triglyceride loci in the Ugandan samples (10% of loci). Individual transferable loci are identified using trans-ethnic colocalization. Ten of fourteen loci not transferable to the Ugandan population have pleiotropic associations with BMI in Europeans; none of the transferable loci do. The non-transferable loci might affect lipids by modifying food intake in environments rich in certain nutrients, which suggests a potential role for gene-environment interactions.

Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in Non-technical summaryRising administration costs and falling response rates mean that many surveys that would previously have been carried out in one preferred mode of data collection are having to consider the use of mixed modes. For example, increasing numbers of surveys use a mix of modes, starting with a cheaper mode (such as telephone interviewing) which typically produces lower response rates, and following up non-respondents with face-to-face interviews. In order to decide about suitable data collection designs, survey practitioners must assess the trade-off between the potential advantages (for example in terms of financial costs and response rates) and disadvantages (for example in terms of data comparability) of mixing modes.We discuss some of the challenges in evaluating the effects of using mixed modes on measurement and hence data comparability. The main argument is that it is very difficult to provide the information survey practitioners would need, about whether and to what extent using mixed modes would affect substantive conclusions. We briefly review theories about why different modes can lead to differences in survey responses. We then discuss the methods typically used to assess mode effects on measurement and then focus on some of the challenges. These include 1) the need to avoid confounding effects and what kinds of mode effects are actually identified, 2) the sensitivity of conclusions about the existence of mode effects to statistical methods used for the analysis of experimental mode comparison data, 3) the difficulty of assessing whether measurement differences matter in practice, and 4) the assessment of which mode provides better measurement. The main focus of the paper is on analysis methods. The points raised for discussion here arose in the context of the European Social Survey (ESS), which is conducting a programme of experimental research to inform the decision about whether to allow telephone interviewing in addition to face-to-face in its future rounds. We use some examples from the ESS experiments to illustrate how we tried to deal with these issues and to stimulate discussion. The paper concludes with an outlook of how the findings from the experimental studies are informing the decision process about whether or not to mix modes of data collection on the ESS and with general implications for mixed modes research. Assessing the Effect of Data Collection Mode on MeasurementAnnette Jäckle, Car...