Background:The P-wave duration (PWD) is an electrocardiographic measurement that represents cardiac conduction in the atria. Shortened or prolonged PWD is associated with atrial fibrillation (AF).... Show moreBackground:The P-wave duration (PWD) is an electrocardiographic measurement that represents cardiac conduction in the atria. Shortened or prolonged PWD is associated with atrial fibrillation (AF). We used exome-chip data to examine the associations between common and rare variants with PWD.Methods:Fifteen studies comprising 64 440 individuals (56 943 European, 5681 African, 1186 Hispanic, 630 Asian) and approximate to 230 000 variants were used to examine associations with maximum PWD across the 12-lead ECG. Meta-analyses summarized association results for common variants; gene-based burden and sequence kernel association tests examined low-frequency variant-PWD associations. Additionally, we examined the associations between PWD loci and AF using previous AF genome-wide association studies.Results:We identified 21 common and low-frequency genetic loci (14 novel) associated with maximum PWD, including several AF loci (TTN, CAND2, SCN10A, PITX2, CAV1, SYNPO2L, SOX5, TBX5, MYH6, RPL3L). The top variants at known sarcomere genes (TTN, MYH6) were associated with longer PWD and increased AF risk. However, top variants at other loci (eg, PITX2 and SCN10A) were associated with longer PWD but lower AF risk.Conclusions:Our results highlight multiple novel genetic loci associated with PWD, and underscore the shared mechanisms of atrial conduction and AF. Prolonged PWD may be an endophenotype for several different genetic mechanisms of AF. Show less
Akinyoade, A.; Damen, J.C.M.; Dietz, A.J.; Kilama, B.B.; Omme, G. van 2014
Africa's population has grown extremely rapidly over the last fifty years from 289 million inhabitants in 1961 to more than 1 billion today. This is a growth rate of 350% in just half a century... Show moreAfrica's population has grown extremely rapidly over the last fifty years from 289 million inhabitants in 1961 to more than 1 billion today. This is a growth rate of 350% in just half a century and the number of urban residents has increased even more quickly: from 65 million in 1960 to 460 million today, or from 20% to 46% of the population as a whole. Demographers predict that soon more than 50% of all Africans will be living in cities. The average life expectancy, literacy rates and primary-school attendance figures in Africa have also all increased spectacularly. And today there are large numbers of relatively healthy, well-educated young people with a more international view of the world. Changes in the structure of Africa's population are evident in the continent's population pyramid. A 'youth bulge' can be seen in Southern Africa's population statistics, with those aged between 10 and 30 far outnumbering those in the 0-10 age group and those over 30 years of age. In other parts of Africa, and for Africa as a whole, the population statistics still have a pyramid structure and have not yet created the sort of onion shape seen in Southern Africa. The expectation is, however, that a declining birth rate across Africa over the next few decades will lead to a change in the continent's population structure and there will be a relatively high number of 10-30 year olds compared to other parts of the world. The fact that there are so many youth in Africa today and that they are much better educated than their parents ever were is having a big impact on the labour market. The youth are starting to feel disillusioned about the lack of job opportunities and are realizing that their (reasonably good) level of education is not going to allow them direct or easy access to greater prosperity and a better life. Show less
