Publications
90 results found
Piel FB, Adamkiewicz TV, Amendah D, et al., 2015, Observed and expected frequencies of structural hemoglobin variants in newborn screening surveys in Africa and the Middle East: Deviations from Hardy-Weinberg equilibrium, Genetics in Medicine, Vol: 18, Pages: 265-274, ISSN: 1530-0366
Purpose:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural hemoglobin variants.Methods:We conducted a systematic review of newborn screening surveys of hemoglobins S and C in Africa and the Middle East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data.Results:Sixty samples reported genotype counts for hemoglobin variants in Africa and the Middle East. Observed and expected counts matched in 27%. The observed number of sickle cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (P < 0.05) in 24. High FIS values were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, was 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East.Conclusion:Differences between observed and expected genotype frequencies are common in surveys of hemoglobin variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA-affected newborns (up to one-third in sub-Saharan Africa and one-half in the Middle East).
Murray CJL, Barber RM, Foreman KJ, et al., 2015, Global, regional, and national disability-adjusted life years (DALYs) for 306 diseases and injuries and healthy life expectancy (HALE) for 188 countries, 1990-2013: quantifying the epidemiological transition, Lancet, Vol: 386, Pages: 2145-2191, ISSN: 1474-547X
BackgroundThe Global Burden of Disease Study 2013 (GBD 2013) aims to bring together all available epidemiological data using a coherent measurement framework, standardised estimation methods, and transparent data sources to enable comparisons of health loss over time and across causes, age–sex groups, and countries. The GBD can be used to generate summary measures such as disability-adjusted life-years (DALYs) and healthy life expectancy (HALE) that make possible comparative assessments of broad epidemiological patterns across countries and time. These summary measures can also be used to quantify the component of variation in epidemiology that is related to sociodemographic development.MethodsWe used the published GBD 2013 data for age-specific mortality, years of life lost due to premature mortality (YLLs), and years lived with disability (YLDs) to calculate DALYs and HALE for 1990, 1995, 2000, 2005, 2010, and 2013 for 188 countries. We calculated HALE using the Sullivan method; 95% uncertainty intervals (UIs) represent uncertainty in age-specific death rates and YLDs per person for each country, age, sex, and year. We estimated DALYs for 306 causes for each country as the sum of YLLs and YLDs; 95% UIs represent uncertainty in YLL and YLD rates. We quantified patterns of the epidemiological transition with a composite indicator of sociodemographic status, which we constructed from income per person, average years of schooling after age 15 years, and the total fertility rate and mean age of the population. We applied hierarchical regression to DALY rates by cause across countries to decompose variance related to the sociodemographic status variable, country, and time.FindingsWorldwide, from 1990 to 2013, life expectancy at birth rose by 6·2 years (95% UI 5·6–6·6), from 65·3 years (65·0–65·6) in 1990 to 71·5 years (71·0–71·9) in 2013, HALE at birth rose by 5·4 years (4&midd
Hockham C, Piel FB, Gupta S, et al., 2015, Understanding the contrasting spatial haplotype patterns of malaria-protective β-globin polymorphisms, Infection, Genetics and Evolution, Vol: 36, Pages: 174-183, ISSN: 1567-7257
The malaria-protective β-globin polymorphisms, sickle-cell (β(S)) and β(0)-thalassaemia, are canonical examples of human adaptation to infectious disease. Occurring on distinct genetic backgrounds, they vary markedly in their patterns of linked genetic variation at the population level, suggesting different evolutionary histories. β(S) is associated with five classical restriction fragment length polymorphism haplotypes that exhibit remarkable specificity in their geographical distributions; by contrast, β(0)-thalassaemia mutations are found on haplotypes whose distributions overlap considerably. Here, we explore why these two polymorphisms display contrasting spatial haplotypic distributions, despite having malaria as a common selective pressure. We present a meta-population genetic model, incorporating individual-based processes, which tracks the evolution of β-globin polymorphisms on different haplotypic backgrounds. Our simulations reveal that, depending on the rate of mutation, a large population size and/or high population growth rate are required for both the β(S)- and the β(0)-thalassaemia-like patterns. However, whilst the β(S)-like pattern is more likely when population subdivision is high, migration low and long-distance migration absent, the opposite is true for β(0)-thalassaemia. Including gene conversion has little effect on the overall probability of each pattern; however, when inter-haplotype fitness variation exists, gene conversion is more likely to have contributed to the diversity of haplotypes actually present in the population. Our findings highlight how the contrasting spatial haplotype patterns exhibited by β(S) and β(0)-thalassaemia may provide important indications as to the evolution of these adaptive alleles and the demographic history of the populations in which they have evolved.
Newton JN, Briggs ADM, Murray CJL, et al., 2015, Changes in health in England, with analysis by English regions and areas of deprivation, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013, Lancet, Vol: 386, Pages: 2257-2274, ISSN: 1474-547X
Piel FB, Adamkiewicz TV, Amendah D, et al., 2015, Observed and expected frequencies of structural hemoglobin variants in newborn screening surveys in Africa and the Middle East: Deviations from Hardy-Weinberg equilibrium, Genetics in Medicine, ISSN: 1530-0366
Purpose:Our objective was to compare observed and expected genotype proportions from newborn screening surveys of structural hemoglobin variants. Methods: We conducted a systematic review of newborn screening surveys of hemoglobins S and C in Africa and the Middle-East. We compared observed frequencies to those expected assuming Hardy-Weinberg equilibrium (HWE). Significant deviations were identified by an exact test. The fixation index FIS was calculated to assess excess homozygosity. We compared newborn estimates corrected and uncorrected for HWE deviations using demographic data. Results: Sixty samples reported genotype counts for hemoglobin variants in Africa and the Middle-East. Observed and expected counts matched in 27%. The observed number of sickle-cell anemia (SCA) individuals was higher than expected in 42 samples, reaching significance (p<0.05) in 24. High FIS were common across the study regions. The estimated total number of newborns with SCA, corrected based on FIS, were 33,261 annual births instead of 24,958 for the 38 samples across sub-Saharan Africa and 1,109 annual births instead of 578 for 12 samples from the Middle East.Conclusion: Differences between observed and expected genotype frequencies are common in surveys of hemoglobin variants in the study regions. Further research is required to identify and quantify factors responsible for such deviations. Estimates based on HWE might substantially underestimate the annual number of SCA affected newborns (up to one third in sub-Saharan Africa and one half in the Middle East).
Vos T, Barber RM, Bell B, et al., 2015, Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013, The Lancet, Vol: 386, Pages: 743-800, ISSN: 0140-6736
BackgroundUp-to-date evidence about levels and trends in disease and injury incidence, prevalence, and years lived with disability (YLDs) is an essential input into global, regional, and national health policies. In the Global Burden of Disease Study 2013 (GBD 2013), we estimated these quantities for acute and chronic diseases and injuries for 188 countries between 1990 and 2013.MethodsEstimates were calculated for disease and injury incidence, prevalence, and YLDs using GBD 2010 methods with some important refinements. Results for incidence of acute disorders and prevalence of chronic disorders are new additions to the analysis. Key improvements include expansion to the cause and sequelae list, updated systematic reviews, use of detailed injury codes, improvements to the Bayesian meta-regression method (DisMod-MR), and use of severity splits for various causes. An index of data representativeness, showing data availability, was calculated for each cause and impairment during three periods globally and at the country level for 2013. In total, 35 620 distinct sources of data were used and documented to calculated estimates for 301 diseases and injuries and 2337 sequelae. The comorbidity simulation provides estimates for the number of sequelae, concurrently, by individuals by country, year, age, and sex. Disability weights were updated with the addition of new population-based survey data from four countries.FindingsDisease and injury were highly prevalent; only a small fraction of individuals had no sequelae. Comorbidity rose substantially with age and in absolute terms from 1990 to 2013. Incidence of acute sequelae were predominantly infectious diseases and short-term injuries, with over 2 billion cases of upper respiratory infections and diarrhoeal disease episodes in 2013, with the notable exception of tooth pain due to permanent caries with more than 200 million incident cases in 2013. Conversely, leading chronic sequelae were largely attributable to non-communic
Piel FB, Weatherall DJ, 2015, Sickle-cell disease: a call to action, Transactions of the Royal Society of Tropical Medicine and Hygiene, Vol: 109, Pages: 355-356, ISSN: 0035-9203
Mayer F, Piel FB, Cassel-Lundhagen A, et al., 2015, Comparative multilocus phylogeography of two Palaearctic spruce bark beetles: influence of contrasting ecological strategies on genetic variation, MOLECULAR ECOLOGY, Vol: 24, Pages: 1292-1310, ISSN: 0962-1083
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- Citations: 29
Hollm-Delgado M-G, Piel FB, Weiss DJ, et al., 2015, Vitamin A supplements, routine immunization, and the subsequent risk ofinfection among children under 5 years in sub-Saharan Africa, eLife, Vol: 4, ISSN: 2050-084X
Recent studies, partly based on murine models, suggest childhood immunization and vitamin A supplements may confer protection against malaria infection, although strong evidence to support these theories in humans has so far been lacking. We analyzed national survey data from children aged 6–59 months in four sub-Saharan African countries over an 18-month time period, to determine the risk of Plasmodium spp. parasitemia (n=8390) and Plasmodium falciparum HRP-2 (PfHRP-2)-related antigenemia (n=6121) following vitamin A supplementation and standard vaccination. Bacille Calmette Guerin-vaccinated children were more likely to be PfHRP-2 positive (relative risk [RR]=4.06, 95% confidence interval [CI]=2.00–8.28). No association was identified with parasitemia. Measles and polio vaccination were not associated with malaria. Children receiving vitamin A were less likely to present with parasitemia (RR=0.46, 95% CI=0.39–0.54) and antigenemia (RR=0.23, 95% CI=0.17–0.29). Future studies focusing on climate seasonality, placental malaria and HIV are needed to characterize better the association between vitamin A and malaria infection in different settings.
GBD 2013 Mortality and Causes of Death Collaborators, 2015, Global, regional, and national age–sex specific all-cause and cause-specific mortality for 240 causes of death, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013, The Lancet, Vol: 385, Pages: 117-171, ISSN: 0140-6736
SummaryBackground Up-to-date evidence on levels and trends for age-sex-specific all-cause and cause-specific mortality is essential for the formation of global, regional, and national health policies. In the Global Burden of Disease Study 2013 (GBD 2013) we estimated yearly deaths for 188 countries between 1990, and 2013. We used the results to assess whether there is epidemiological convergence across countries. Methods We estimated age-sex-specific all-cause mortality using the GBD 2010 methods with some refinements to improve accuracy applied to an updated database of vital registration, survey, and census data. We generally estimated cause of death as in the GBD 2010. Key improvements included the addition of more recent vital registration data for 72 countries, an updated verbal autopsy literature review, two new and detailed data systems for China, and more detail for Mexico, UK, Turkey, and Russia. We improved statistical models for garbage code redistribution. We used six different modelling strategies across the 240 causes; cause of death ensemble modelling (CODEm) was the dominant strategy for causes with sufficient information. Trends for Alzheimer's disease and other dementias were informed by meta-regression of prevalence studies. For pathogen-specific causes of diarrhoea and lower respiratory infections we used a counterfactual approach. We computed two measures of convergence (inequality) across countries: the average relative difference across all pairs of countries (Gini coefficient) and the average absolute difference across countries. To summarise broad findings, we used multiple decrement life-tables to decompose probabilities of death from birth to exact age 15 years, from exact age 15 years to exact age 50 years, and from exact age 50 years to exact age 75 years, and life expectancy at birth into major causes. For all quantities reported, we computed 95% uncertainty intervals (UIs). We constrained cause-specific fractions within each age-sex-co
Longo DL, Piel FB, Weatherall DJ, 2014, The α-Thalassemias, New England Journal of Medicine, Vol: 371, Pages: 1908-1916, ISSN: 0028-4793
Piel FB, Rees DC, Williams TN, 2014, Managing the burden of sickle-cell disease in Africa, The Lancet. Haematology, Vol: 1, Pages: e11-e12, ISSN: 2352-3026
Sickle-cell disease is a genetic disorder of growing public health importance worldwide.1 More than 300 000 homozygous neonates with sickle-cell anaemia (HbSS)—the most common form of sickle-cell disease worldwide1—are born every year, with three-quarters born in sub-Saharan Africa.2 Estimates based on demographic projections suggest that this number could increase to 400 000 by 2050.3 Little is known about the natural history of sickle-cell anaemia, especially in Africa, or the epidemiology of other clinically relevant forms of sickle-cell disease, such as HbSC disease and HbS-β-thalassaemia.
Hockham C, Penman B, Piel F, et al., 2014, Understanding the haplotypic diversity and distribution of malaria-protective β-globin mutations, Malaria Journal, Vol: 13
Piel FB, Tatem AJ, Huang Z, et al., 2014, Global migration and the changing distribution of sickle haemoglobin: A quantitative study of temporal trends between 1960 and 2000, The Lancet Global Health, Vol: 2, Pages: e80-e89, ISSN: 2214-109X
BackgroundChanges in the geographical distribution of genetic disorders are often thought to happen slowly, especially when compared with infectious diseases. Whereas mutations, genetic drift, and natural selection take place over many generations, epidemics can spread through large populations within a few days or weeks. Nevertheless, population movements can interfere with these processes, and few studies have been done of their effect on genetic disorders. We aimed to investigate the effect of global migration on the distribution of the sickle-cell gene—the most common and clinically significant haemoglobin structural variant.MethodsFor each country, we extracted data from the World Bank's Global Bilateral Migration Database about international human migrations between 1960 and 2000. We combined this information with evidence-based estimates of national HbS allele frequencies, generated within a Bayesian geostatistical framework, to analyse temporal changes in the net numbers of migrants, and classified countries with an index summarising these temporal trends.FindingsThe number of international migrants increased from 92·6 million in 1960, to 165·2 million in 2000. The estimated global number of migrants with HbS increased from about 1·6 million in 1960, to 3·6 million in 2000. This increase was largely due to an increase in the number of migrants from countries with HbS allele frequencies higher than 10%, from 3·1 million in 1960, to 14·2 million in 2000. Additionally, the mean number of countries of origin for each destination country increased from 70 (SE 46) in 1960, to 98 (48) in 2000, showing an increasing diversity in the network of international migrations between countries. Our index of change map shows a patchy distribution of the magnitude of temporal changes, with the highest positive and negative values scattered across all continents.InterpretationGlobal human population movements have had a substanti
Piel FB, 2013, Sickle-cell disease: geographical distribution and population estimates, M S-MEDECINE SCIENCES, Vol: 29, Pages: 965-967, ISSN: 0767-0974
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- Citations: 8
Howes RE, Dewi M, Piel FB, et al., 2013, Spatial distribution of G6PD deficiency variants across malaria-endemic regions, Malaria Journal, Vol: 12
Piel FB, Howes RE, Patil AP, et al., 2013, The distribution of haemoglobin C and its prevalence in newborns in Africa, Scientific Reports, Vol: 3
Piel FB, Patil AP, Howes RE, et al., 2013, Global epidemiology of Sickle haemoglobin in neonates: A contemporary geostatistical model-based map and population estimates, The Lancet, Vol: 381, Pages: 142-151, ISSN: 0140-6736
Piel FB, Hay SI, Gupta S, et al., 2013, Global Burden of Sickle Cell Anaemia in Children under Five, 2010-2050: Modelling Based on Demographics, Excess Mortality, and Interventions, PLoS Medicine, Vol: 10
Piel FB, Howes RE, Nyangiri OA, et al., 2013, Online Biomedical Resources for Malaria-Related Red Cell Disorders, Human Mutation, Vol: 34, Pages: 937-944
Howes RE, Piel FB, Patil AP, et al., 2012, G6PD Deficiency Prevalence and Estimates of Affected Populations in Malaria Endemic Countries: A Geostatistical Model-Based Map, PLOS MEDICINE, Vol: 9, ISSN: 1549-1277
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- Citations: 331
Grosse SD, Atrash HK, Odame I, et al., 2012, The Jamaican historical experience of the impact of educational interventions on sickle cell disease child mortality, American Journal of Preventive Medicine, Vol: 42, Pages: e101-e103
Patil AP, Gething PW, Piel FB, et al., 2011, Bayesian geostatistics in health cartography: the perspective of malaria, TRENDS IN PARASITOLOGY, Vol: 27, Pages: 245-252, ISSN: 1471-4922
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- Citations: 59
Howes RE, Patil AP, Piel FB, et al., 2011, The global distribution of the Duffy blood group, Nature Communications, Vol: 2
Grosse SD, Odame I, Atrash HK, et al., 2011, Sickle cell disease in Africa: A neglected cause of early childhood mortality, American Journal of Preventive Medicine, Vol: 41, Pages: S398-S405
Piel FB, Patil AP, Howes RE, et al., 2010, Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis, Nature Communications, Vol: 1
Piel F, Gilbert M, De Canniere C, et al., 2008, Coniferous round wood imports from Russia and Baltic countries to Belgium.: A pathway analysis for assessing risks of exotic pest insect introductions, DIVERSITY AND DISTRIBUTIONS, Vol: 14, Pages: 318-328, ISSN: 1366-9516
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- Citations: 32
Piel F, Grégoire JC, Knížek M, 2006, New occurrence of Ips duplicatus Sahlberg in Herstal (Liege, Belgium), EPPO Bulletin, Vol: 36, Pages: 529-530, ISSN: 0250-8052
The double-spined spruce engraver Ips duplicatus is not present in Belgium and France. In summer 2003, several adult Ips duplicatus beetles were caught near quays in Herstal (Liege) during a survey. Large volumes of spruce logs, from Russia and the Baltic countries, had been imported to the immediate locality where the beetles had been caught. Thus, it is most likely that the capture specimens were introduced with these consignments. © The Authors (2006).
Piel F, Gilbert M, Franklin A, et al., 2005, Occurrence of <i>Ips typographus</i> (Col., Scolytidae) along an urbanization gradient in Brussels, Belgium, AGRICULTURAL AND FOREST ENTOMOLOGY, Vol: 7, Pages: 161-167, ISSN: 1461-9555
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- Citations: 16
Grégoire JC, Piel F, De Proft M, et al., 2001, Spatial distribution of ambrosia-beetle catches: A possibly useful knowledge to improve mass-trapping, Integrated Pest Management Reviews, Vol: 6, Pages: 237-242, ISSN: 1353-5226
Several species of ambrosia beetles (Coleoptera: Scolytidae) have recently started attacking standing, living beeches (Fagus sylvatica) in southern Belgium. In 2001, 1.3 million m3 of apparently healthy trees were struck. So far the outbreak has been limited to the Ardenne, and partly the Gaume, areas, and Brussels has been untouched. The city of Brussels is surrounded by a vast 4300 ha forest, mainly planted with beech, the Forêt de Soignes, of invaluable ecological and recreational value, of which 1600 ha belong to the regional authorities. In the spring 2001, these latter commissionned a study to assess the new threat to the forest. A 500 m x 500 m grid of small traps, baited with ethanol and lineatin, was deployed over the regional part of the forest. The main species caught were Trypodendron domesticum, Anisandrus dispar and, in high numbers, Xylosandrus germanus, an exotic species of Asian origin found for the first time in Belgium in 1994. Whilst there was a consistent homogeneity between catches within the same sites (2 traps/site, distant by 2-6 m), there were no spatial relationships between catches at larger distances for T. domesticum and A. dispar. For X. germanus, spatial autocorrelations were observed within distances of 2000 m, suggesting that this species has sufficient mobility to cover this range. The planning of the 2002 trapping campaign will take this information into account: the traps will be deployed within a smaller grid.
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