Evolution challenges. Integrating research and practice in teaching and learning about evolution

Abstract and Keywords Scientists frequently attribute public misunderstanding of evolution to religious or political influences. Ineffective undergraduate teaching has also contributed. Faculty often ignored strong pedagogical evidence. Five research conclusions are discussed: The traditional lecture approach is inadequate. Active learning is much more effective. Fundamental reasoning difficulties limit students' understanding. Simple steps help overcome these. Misconceptions typically persist unless directly addressed with a conceptual-change approach. Evolution is a complex set of ideas that cannot be adequately understood without advanced critical thinking. This is infrequently mastered without intentionally designed learning tasks. Understanding evolution is typically insufficient for its acceptance. But acceptance as valid for real-world decisions is important. This requires helping students consider social and affective factors related to evolution. Keywords: misconceptions, conceptual-change, intentional design, evolution acceptance Scientists frequently attribute the public misunderstanding of evolution largely to conservative religious influences or dubious political motivations. Indeed, Mazur (2004 found Christian religiosity to be the strongest correlate of "disbelief" in evolution with low educational attainment and political conservatism also important. How science is taught in undergraduate education is a powerful additional factor that usually has been ignored in analyses of Why Don't Undergraduates Really "Get" Evolution? What Can ... http://www.oxfordscholarship.com.ezproxy.lib.indiana.edu/vie... of 27 6/25/13 5:37 PM public misunderstanding of evolution. Rejection and misunderstanding of evolution are not simply the results of some facets of American culture. Rather, they are also the predictable results of traditional, didactic teaching strategies. Postsecondary science teaching often ignores strong evidence on ways to make instruction much more effective (e.g., The first part of this chapter focuses on four broadly applicable results of research on teaching undergraduate science. The latter part turns to strategies that take account of factors that apply more strongly to evolution than to much of the rest of science. Key Result 1: Active Learning Is More Effective Active learning substantially increases achievement when compared with traditional pedagogy in undergraduate science, a conclusion featured in a review in Science The inadequacy of the traditional lecture approach in undergraduate science has been demonstrated most extensively in physics, where active methods roughly doubled average normalized pretest to posttest gains in learning, an effect approximating a two standard deviation difference Thus, one answer to the question "What can faculty do to increase the proportion of students who 'get' evolution?" is to switch further toward structured active learning in lieu of more didactic pedagogies. The implications of this conclusion can be both distressing and elating. This conclusion can be distressing because time already spent on improving lectures would often have been spent much more effectively on improving pedagogy. The conclusion can be elating because changes can be fairly easy and can have large effects. Unfortunately, faculty often have reservations about adopting active learning. These reservations include loss of content coverage, possible loss of control over the class, and possible failure of the activities. Tanner (2009) addressed a number of these. Similarly, several dysfunctional illusions that falsely suggest a lack of rigor for more effective pedagogies probably have slowed their adoption However one chooses to label these reasoning abilities, scores on reasoning tests have often been shown to predict achievement in undergraduate science courses and, sometimes, in precollege science (e.g., These findings have profound implications for understanding and teaching molecular aspects of biology generally, and of evolution specifically, as shown by studies of undergraduate chemistry. For example, Herron (1975) listed startling differences between core ideas in chemistry that the concrete students can and cannot understand without altered pedagogy. These students will be a large fraction of any first-year class. (p.314) Scores on reasoning tests were also related to the acceptance of evolution. Students who scored lower on tests of basic reasoning were less likely to accept evolution on the pretest and were more likely to continue to reject evolution on the posttest than individuals who performed better on the reasoning assessment A major advance for understanding how differences in reasoning play out in learning biology was recently provided by 1. Descriptive predictions could be mastered by most students whatever their scores on reasoning tests. 2. Tasks requiring understanding and testing hypotheses involving perceptible causal agents (e.g., light, moisture) were usually mastered only by students with higher reasoning scores. 3. Tasks using hypotheses involving causal agents that cannot be as directly perceived (e.g., genetic versus environmental causation, chemical communication) were usually mastered only by students with even higher reasoning abilities. Much greater pedagogical support is needed for tasks requiring the use of causal hypotheses, especially those using inferred causal agents. These distinctions are fundamental to students' difficulties in understanding evolution and to the development of effective ways to help them master it. Unfortunately, the underlying reasoning patterns are not changed easily with conventional teaching. Other researchers have made additional suggestions for fostering more complex reasoning. For example, a nice example of the use of hands-on modeling to support more complex thinking in a large molecular biology class was provided by In summary, the answer to the question "What can faculty do to increase the proportion of students who 'get' evolution?" from this second perspective is that faculty often need to pay more attention to students' basic reasoning and to teach in ways that better support (rather than just require) scientific understanding and reasoning. Without such support many students cannot understand what is being taught even when they are trying quite hard to do so. Although these problems and many of the solutions have been clear for decades, they have not been widely adopted. "Because we [as faculty] are at the point that concrete experience … is superfluous, we tend to forget that it was not always so [for us] and in our rush to 'cover the material,' we omit the very kind of experiences that can make our subject meaningful to beginning students" (Herron, 1978, p. 167). Many faculty will be skeptical (as I was) that well-performing students are deficient in understanding the basic concepts that should underlie their successes in class. It may be hard to accept that even "facility in solving standard quantitative problems is not an adequate criterion for functional understanding" (Thornton, 1999). In order to see the limitations of current approaches and the effects of changes we need more sophisticated ways of writing in-class and exam assessments About the Index Search across all sources Show related links Why Don't Undergraduates Really "Get" Evolution? What Can ... http://www.oxfordscholarship.com.ezproxy.lib.indiana.edu/vie... of 27 6/25/13 5:37 PM macroevolution is central to an understanding of the strength of the evidence showing that evolution has occurred (Padian, 2010). Further, macroevolution "is perhaps the primary stumbling block" for students, teachers, and other adults who have difficulty accepting evolution (M. U. Smith, 2010b, p. 541). The switch in students' understanding from misconceptions or alternative conceptions to scientifically valid views is termed conceptual change (for evolution: Banet & Ayuso, 2003; Various approaches to teaching evolution have attempted to produce major conceptual change and understanding generally. M. U. Smith (2010b) provided a concise (p.317) overview. Six examples merit special discussion. Although these mostly address microevolution, they could be modified for topics in macroevolution. 1. An Exemplary Conceptual Change Approach. Banet and Ayuso About the Index Search across all sources Show related links Why Don't Undergraduates Really "Get" Evolution? What Can ... http://www.oxfordscholarship.com.ezproxy.lib.indiana.edu/vie... of 27 6/25/13 5:37 PM Roscoe, this volume). 5. Participatory Action Research. In a multiyear study, Grant (2008) examined the misconceptions his first-year biology students held about natural selection. "Many students who presented evidence on pre-tests that they harbored substantial misconceptions in fact remained highly resistant to instruction, and often defended their misconceptions using course appropriate terminology, but incorrectly, on the course final exam. In other words, many had hijacked course content in service of their misconceptions" (Grant, 2008, p. 15). He iteratively designed ways to address these in a large class setting. Key changes included repeatedly presenting summaries of in-class surveys of prior knowledge and misconceptions. He also asked students to discuss with their neighbors what evidence and arguments would be needed to foster the replacement of these misconceptions with expert knowledge. He termed this "participatory action research." It required substantial reductions in content and rearrangements of topics. There were large increases over previous years in the grades on the final examination questions on evolution: On a key question assessing natural selection, good answers (8 to10 of 10 points) increased from about 3% of students (2000)(2001)(2002)(2003)(2004)(2005) to 54% (2006)(2007), and very low scores (0-2 points) were eliminated. This approach has considerable promise for improving undergraduate science learning generally. Whole Course Transformation. In what is essentially a deep conceptual change approach, BioQUEST has emphasized computer-facilitated, case-based learning with a focus on problem-posing, problem-solving, and peer persuasion, often addressing topics in evolution In summary, the answer to the question "What can faculty do to increase the proportion of students who 'get' evolution?" from this third perspective is that faculty often need to give even more attention to students' persistent misunderstandings and to teach in ways that better support conceptual change (rather than falsely assuming that telling students the right idea or showing them the data will be sufficient to elicit change). Without explicit, active support for conceptual change, most students will retain their initial misunderstandings. (p.319) Key Result 4: Complex Thinking Is Requisite for Understanding Evolution Many of the difficulties we encounter in getting students to understand evolution are well explained by differences in their approaches to knowledge, specifically to how they expect to understand new topics. These approaches range from "just tell me what to memorize" to expecting us to help them understand the applications, implications, and trade-offs in various contexts. These different approaches are usefully understood as differences in adult cognitive development. There is a substantial body of research on cognitive development in college and its implications for learning and teaching. This approach began with Perry's (1970) study of "intellectual and ethical development" in undergraduates. Perry's work has been cited by hundreds of subsequent studies (partially reviewed by Cognitive development beyond that typically found in undergraduates is a prerequisite for an adequate understanding of evolution. Sinatra, Southerland, McConaughy, and Demastes About the Index Search across all sources Show related links Why Don't Undergraduates Really "Get" Evolution? What Can ... http://www.oxfordscholarship.com.ezproxy.lib.indiana.edu/vie... 6 of 27 6/25/13 5:37 PM they termed absolutism, relativism, and evaluativism. Perry's terms for these three approaches (dualism, multiplicity, and relativism) have been widely used, although some studies have used alternative terminologies. A simplified summary of these major cognitive differences will make clearer the implications for teaching evolution. (p.320) Absolutism (Perry's Dualism) About two-thirds of first-year students and half of sophomores had absolutism as their core approach Relativism (Perry's Multiplicity) When students first encounter meaningful uncertainty in a new area they typically have no idea how it might be resolved. In the face of uncertainty all opinions seem to be equally valid-any answer that one prefers on whatever grounds is fine. Personal experience, personally interpreted, has the preeminent role. This is the approach most of us usually use in picking a flavor of ice cream, but it is a terrible approach to critical thinking About one-third of first-year students and perhaps 80% of seniors were "transitional": they regarded knowledge in some areas as absolute and knowledge in others as uncertain and, hence, arbitrary Burgoyne and Downey (2011) have suggested that we ask students to see absolutism and relativism as two misconceptions: Contextual Knowing (Bendixen and Rule's Evaluativism; Perry's Relativism) The approach where students have learned to make context-framed, criteria-based comparisons has also been termed contextual relativism (e.g., Knefelkamp, 1999) (p.321) and contextual knowing As students become more cognitively sophisticated, they (like many older adults) typically use a mosaic of approaches, perhaps treating some topics in dualism/absolutism and some in multiplicity even while struggling to master contextual knowing in others Beyond Contextual Knowing The limitations of simple contextual knowing are evident when we consider complex problems. The core difficulty is that students who have learned to operate within a series of individual disciplines often have no coherent way to deal with differences that arise when a variety of disciplines apply to a complex problem. They consequently see any choice among combinations of disciplinary For example, even a local environmental issue, such as the appropriateness of a nuclear power plant, requires a consideration of trade-offs across multiple perspectives including science, waste disposal, environmental economics, politics, and environmental racism, to name just a few To deal with such issues constructively, students must learn to consider the benefits and negative consequences illuminated by each perspective. As students learn to make such analyses they begin thinking in a way that Perry termed "Commitment [within contextual relativism]" and Baxter Magolda termed "self-authorship." This approach is exceedingly rare among undergraduates except under transformed curricula Applications to Teaching Evolution "Perhaps the most useful developmental theory to be applied to evolution instruction is that of Perry" (M. U. Smith, 2010b, p. 541; also Nelson, 1986, etc.). Classroom applications that strive to foster cognitive development can profitably focus on key aspects of the three transitions between the four main approaches to understanding. (p.322) These are: initially understanding uncertainty, then using comparisons and criteria to address uncertainty (contextual knowing) and, later, using consequences and values to frame arguments and justify choices. Uncertainty in evolution can be invoked, for example, by listing (or having the class list) currently viable alternative hypotheses, listing ones that were historically viable or by asking for deep understanding of experimental designs (Why is this control included? Are any controls missing? What untested hypotheses might have produced the same results?). Once some important uncertainty has been made clear, the alternative hypotheses or design considerations or other factors need to be compared, and possibly resolved, using appropriate criteria. Unless both the alternatives and the criteria are made explicit, most of the critical thinking will be tacit and therefore incomprehensible-and the students' approaches to thinking will be unaffected. For comparisons of historically grounded alternatives in evolution, such as what sequences should have been expected from the fossil record, an appropriate criterion is the result of a fair test. A fair test is a new set of data that could have confirmed any of the alternatives and that is different from (and not tightly tied to) the data sets on which they were proposed. We can ask: What patterns of change in the fossil record might have been expected of the fossil record when the geological column was first put into its modern order in the 1840s, noting that evolution was not really available except to Darwin. Alternatives included: all kinds at the beginning with just extinction, Lyell's large cycles with great reptiles perhaps returning again (and again), Sedgwick's extinctions and new recreations, vertebrates first and invertebrates by degeneration, and, of course, evolution starting, as Darwin noted, with one or a few very simple kinds. Students will suggest some of these ideas, if asked. The fossil record itself provides a fair test of these alternatives, as most of them were not based on the ordered sequence of rocks in the newly emerging geological column and as any of the alternative patterns could have been found. A number of other criteria are also important. These include accounting for apparently conflicting scientific data and the availability of causal explanations (e.g., However, even when we understand that one alternative is much more probable than another we may choose not to accept it. It is often appropriate to reject hypotheses that are probably true when there are serious risks to accepting the hypothesis and being wrong. Thus, for many considerations of safety in the face of severe consequences we demand not just that safety be very probable but that it be overwhelmingly probable (basic decision theory, below). This requires moving beyond contextual knowing. For students studying evolution, going beyond contextual knowing would require that students understand the force of the evidence in the context of the nature of science generally; understand and know how to weigh the consequences (p.323) from the applications of evolution, both positive and negative; and understand how to fit evolution into larger cultural contexts. It thus becomes crucial for faculty members who teach evolution to help students address its consequences and applications. Faculty also need to consider whether to address the cultural contexts for evolution and, if so, how to do so effectively. About the Index Search across all sources Show related links Why Don't Undergraduates Really "Get" Evolution? What Can ... http://www.oxfordscholarship.com.ezproxy.lib.indiana.edu/vie... of 27 6/25/13 5:37 PM If we step back from focusing just on conceptual understanding or scientific reasoning, things become more complicated. Baxter Magolda (e.g., 2004a) noted that students make meaning of their experiences using their own perspectives rather than accepting the instructor's meaning and perspective. Further, the development of more complex ways of understanding is inextricably intertwined with the development of a different and more complex sense of self and of different and of more complex ways of relating to others. "Interviewees who developed complex ways of knowing [after graduation] often could not live those ways of knowing until they had developed complex ways of seeing themselves and their relations with others" (Baxter Magolda, 2004a, p. 39). Let me stress again the importance of making extensive use of structured active learning and not just because it fosters content mastery. Appropriately structured collaborative and cooperative learning also helps foster increased cognitive sophistication and the other changes that are essential to that cognitive development. I found two techniques to be especially powerful in fostering cognitive development: 1. In teaching evolution to seniors, I developed a worksheet based on Perry's descriptions of the cognitive tasks required for deep understanding (Nelson, 2010a), and had students complete the worksheet outside of class. Then, I implemented a whole-period discussion of applications of Perry's principles, a discussion that fostered deep rethinking with peers. 2. In courses ranging from first-year to graduate, I had the students either discuss excerpts from Perry's (1970) book including his summary of the student's experience (Nelson, 2010a) or presented and had them discuss and repeatedly refer back to a graphical synopsis of Perry (as in Nelson, 2010b). Using either approach, I repeatedly asked students how a person would respond to the evolution-creation controversy (and to other issues) from the perspective of an absolutist, versus from multiplicity, versus, in turn, from contextual knowing and, later, from self-authorship In summary, the answer to the question "What can faculty do to increase the proportion of students who 'get' evolution?" from this fourth perspective is that faculty need to design their courses to foster greater cognitive sophisticati

The selection landscape and genetic legacy of ancient Eurasians

The Holocene (beginning around 12,000 years ago) encompassed some of the most significant changes in human evolution, with far-reaching consequences for the dietary, physical and mental health of present-day populations. Using a dataset of more than 1,600 imputed ancient genomes, we modelled the selection landscape during the transition from hunting and gathering, to farming and pastoralism across West Eurasia. We identify key selection signals related to metabolism, including that selection at the FADS cluster began earlier than previously reported and that selection near the LCT locus predates the emergence of the lactase persistence allele by thousands of years. We also find strong selection in the HLA region, possibly due to increased exposure to pathogens during the Bronze Age. Using ancient individuals to infer local ancestry tracts in over 400,000 samples from the UK Biobank, we identify widespread differences in the distribution of Mesolithic, Neolithic and Bronze Age ancestries across Eurasia. By calculating ancestry-specific polygenic risk scores, we show that height differences between Northern and Southern Europe are associated with differential Steppe ancestry, rather than selection, and that risk alleles for mood-related phenotypes are enriched for Neolithic farmer ancestry, whereas risk alleles for diabetes and Alzheimer’s disease are enriched for Western hunter-gatherer ancestry. Our results indicate that ancient selection and migration were large contributors to the distribution of phenotypic diversity in present-day Europeans

Cardiovascular disease, risk factors and heart rate variability in the elderly general population: Design and objectives of the CARdiovascular disease, Living and Ageing in Halle (CARLA) Study

BACKGROUND: The increasing burden of cardiovascular diseases (CVD) in the ageing population of industrialized nations requires an intensive search for means of reducing this epidemic. In order to improve prevention, detection, therapy and prognosis of cardiovascular diseases on the population level in Eastern Germany, it is necessary to examine reasons for the East-West gradient of CVD morbidity and mortality, potential causal mechanisms and prognostic factors in the elderly. Psychosocial and nutritional factors have previously been discussed as possible causes for the unexplained part of the East-West gradient. A reduced heart rate variability appears to be associated with cardiovascular disease as well as with psychosocial and other cardiovascular risk factors and decreases with age. Nevertheless, there is a lack of population-based data to examine the role of heart rate variability and its interaction with psychosocial and nutritional factors regarding the effect on cardiovascular disease in the ageing population. There also is a paucity of epidemiological data describing the health situation in Eastern Germany. Therefore, we conduct a population-based study to examine the distribution of CVD, heart rate variability and CVD risk factors and their associations in an elderly East German population. This paper describes the design and objectives of the CARLA Study. METHODS/DESIGN: For this study, a random sample of 45–80 year-old inhabitants of the city of Halle (Saale) in Eastern Germany was drawn from the population registry. By the end of the baseline examination (2002–2005), 1750 study participants will have been examined. A multi-step recruitment strategy aims at achieving a 70 % response rate. Detailed information is collected on own and family medical history, socioeconomic, psychosocial, behavioural and biomedical factors. Medical examinations include anthropometric measures, blood pressure of arm and ankle, a 10-second and a 20-minute electrocardiogram, a general physical examination, an echocardiogram, and laboratory analyses of venous blood samples. On 200 participants, a 24-hour electrocardiogram is recorded. A detailed system of quality control ensures high data quality. A follow-up examination is planned. DISCUSSION: This study will help to elucidate pathways to CVD involving autonomic dysfunction and lifestyle factors which might be responsible for the CVD epidemic in some populations

Physiological response to firefighting activities of various work cycles using extended duration and prototype SCBA

Firefighters’ self-contained breathing apparatus (SCBA) protects the respiratory system during firefighting but increases the physiological burden. Extended duration SCBA (>30 min) have increased air supply, potentially increasing the duration of firefighting work cycles. To examine the effects of SCBA configuration and work cycle (length and rest), 30 firefighters completed seven trials using different SCBA and one or two bouts of simulated firefighting following work cycles common in the United States. Heart rate, core temperature, oxygen consumption, work output and self-reported perceptions were recorded during all activities. Varying SCBA resulted in few differences in these parameters. However, during a second bout, work output significantly declined while heart rates and core temperatures were elevated relative to a single bout. Thirty seven per cent of the subjects were unable to complete the second bout in at least one of the two-bout conditions. These firefighters had lower fitness and higher body mass than those who completed all assigned tasks. Practitioner Summary: The effects of extended duration SCBA and work/rest cycles on physiological parameters and work output have not been examined. Cylinder size had minimal effects, but extended work cycles with no rest resulted in increased physiological strain and decreased work output. This effect was more pronounced in firefighters with lower fitness.This work was supported by the Department of Homeland Security Fire Prevention and Safety, Federal Emergency Management Agency [grant number EMW-2010-FP-01606].Ope

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function.

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways

Global variations in diabetes mellitus based on fasting glucose and haemogloblin A1c

Fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c) are both used to diagnose diabetes, but may identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening had elevated FPG, HbA1c, or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardised proportion of diabetes that was previously undiagnosed, and detected in survey screening, ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the agestandardised proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global gap in diabetes diagnosis and surveillance.peer-reviewe