Systolic blood pressure and 6-year mortality in South Africa: a country-wide, population-based cohort study

Background: Improving hypertension control is an important global health priority, yet, to our knowledge, there is no direct evidence on the relationship between blood pressure and mortality in sub-Saharan Africa. We aimed to investigate the relationship between systolic blood pressure and mortality in South Africa and to assess the comparative effectiveness of different systolic blood pressure targets for clinical care and population-wide hypertension management efforts. Methods: In this country-wide, population-based cohort study, we used longitudinal data on adults aged 30 years and older from five waves (2008, 2010–11, 2012, 2014–15, and 2017) of the South African National Income Dynamics Study. We estimated the relationship between systolic blood pressure and 6-year all-cause mortality and compared the mortality reductions associated with lowering systolic blood pressure to different targets (120 mm Hg, 130 mm Hg, 140 mm Hg, 150 mm Hg). We also estimated the mean blood pressure reduction required to achieve each target, the share of the population in need of management, and the number needed to treat (NNT) to avert one death under different hypothetical population-wide scale-up scenarios. Findings: Of the 8338 age-eligible respondents in the 2010–11 survey, 4993 had all required data and were included in our study. We found a weak, non-linear relationship between systolic blood pressure and 6-year mortality, with larger incremental mortality benefits at higher systolic blood pressure values: reducing systolic blood pressure from 160 mm Hg to 150 mm Hg was associated with a relative risk of mortality of 0·95 (95% CI 0·90 to 0·99; p=0·033), reducing systolic blood pressure from 150 mm Hg to 140 mm Hg had a relative risk of 0·96 (0·91 to 1·01; p=0·12), with no evidence of incremental benefits of reducing systolic blood pressure below 140 mm Hg. At the population level, reducing systolic blood pressure to 150 mm Hg among all those with a starting systolic blood pressure of more than 150 mm Hg was associated with the lowest NNT (n=50), 3·3 deaths averted (95% CI −0·6 to 0·3) per 1000 population, blood pressure management for 16% (95% CI 15·2 to 17·3) of individuals, and a −2·7 mm Hg mean change in systolic blood pressure required to achieve the 150 mm Hg scale-up target (−3·0 to −2·5; p<0·0001). Interpretation: The relationship between systolic blood pressure and mortality is weaker in South Africa than in high-income and many low-income and middle-income countries. As such, we do not find compelling evidence in support of targets below 140 mm Hg and find that scaling up management based on a 150 mm Hg target is more efficient in terms of the NNT compared with strategies to reduce systolic blood pressure to lower values. Funding: Non

Yield of Photoperiod-sensitive Sorghum Hybrids Based on Guinea-race Germplasm under Farmers’ Field Conditions in Mali

The first sorghum [Sorghum bicolor (L.) Moench] hybrids based on West African Guinea-race-derived parents were created to enhance farmer’s food security and income through increased yields. To assess their performance, eight hybrids, six experimental pure-line cultivars, one pure-line check (Lata), and a highly adapted landrace cultivar (Tieble) were evaluated in 27 farmer-managed and two on-station yield trials in Mali, West Africa, from 2009 to 2011. The hybrids were confirmed to have photoperiod sensitivity similar to the well-adapted Guinea landrace check cultivar. Genotypic differences for on-farm grain yield were highly significant and genotype × environment crossover interactions were limited. The yield superiorities of individual hybrids, relative to the landrace check, ranged from 17 to 37% over the 27 on-farm trials. The three top yielding hybrids showed 30% yield advantages across productivity levels, with absolute yield advantages averaging 380 kg ha−1 under lower (1.0–1.5 t ha−1) and 660 kg ha−1 under higher (2.0–3.5 t ha−1) productivity conditions. A mean male-parent (better parent) heterosis of 26% was observed for the four hybrids having Lata as a male parent. As the hybrids studied here were obtained with a low intensity of selection using a limited number of parents, even greater yield superiorities may be attained with development of distinct parental pools and scaled-up hybrid breeding

Global, regional, national, and selected subnational levels of stillbirths, neonatal, infant, and under-5 mortality, 1980�2015: a systematic analysis for the Global Burden of Disease Study 2015

Background Established in 2000, Millennium Development Goal 4 (MDG4) catalysed extraordinary political, financial, and social commitments to reduce under-5 mortality by two-thirds between 1990 and 2015. At the country level, the pace of progress in improving child survival has varied markedly, highlighting a crucial need to further examine potential drivers of accelerated or slowed decreases in child mortality. The Global Burden of Disease 2015 Study (GBD 2015) provides an analytical framework to comprehensively assess these trends for under-5 mortality, age-specific and cause-specific mortality among children under 5 years, and stillbirths by geography over time. Methods Drawing from analytical approaches developed and refined in previous iterations of the GBD study, we generated updated estimates of child mortality by age group (neonatal, post-neonatal, ages 1�4 years, and under 5) for 195 countries and territories and selected subnational geographies, from 1980�2015. We also estimated numbers and rates of stillbirths for these geographies and years. Gaussian process regression with data source adjustments for sampling and non-sampling bias was applied to synthesise input data for under-5 mortality for each geography. Age-specific mortality estimates were generated through a two-stage age�sex splitting process, and stillbirth estimates were produced with a mixed-effects model, which accounted for variable stillbirth definitions and data source-specific biases. For GBD 2015, we did a series of novel analyses to systematically quantify the drivers of trends in child mortality across geographies. First, we assessed observed and expected levels and annualised rates of decrease for under-5 mortality and stillbirths as they related to the Soci-demographic Index (SDI). Second, we examined the ratio of recorded and expected levels of child mortality, on the basis of SDI, across geographies, as well as differences in recorded and expected annualised rates of change for under-5 mortality. Third, we analysed levels and cause compositions of under-5 mortality, across time and geographies, as they related to rising SDI. Finally, we decomposed the changes in under-5 mortality to changes in SDI at the global level, as well as changes in leading causes of under-5 deaths for countries and territories. We documented each step of the GBD 2015 child mortality estimation process, as well as data sources, in accordance with the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Findings Globally, 5·8 million (95 uncertainty interval UI 5·7�6·0) children younger than 5 years died in 2015, representing a 52·0% (95% UI 50·7�53·3) decrease in the number of under-5 deaths since 1990. Neonatal deaths and stillbirths fell at a slower pace since 1990, decreasing by 42·4% (41·3�43·6) to 2·6 million (2·6�2·7) neonatal deaths and 47·0% (35·1�57·0) to 2·1 million (1·8-2·5) stillbirths in 2015. Between 1990 and 2015, global under-5 mortality decreased at an annualised rate of decrease of 3·0% (2·6�3·3), falling short of the 4·4% annualised rate of decrease required to achieve MDG4. During this time, 58 countries met or exceeded the pace of progress required to meet MDG4. Between 2000, the year MDG4 was formally enacted, and 2015, 28 additional countries that did not achieve the 4·4% rate of decrease from 1990 met the MDG4 pace of decrease. However, absolute levels of under-5 mortality remained high in many countries, with 11 countries still recording rates exceeding 100 per 1000 livebirths in 2015. Marked decreases in under-5 deaths due to a number of communicable diseases, including lower respiratory infections, diarrhoeal diseases, measles, and malaria, accounted for much of the progress in lowering overall under-5 mortality in low-income countries. Compared with gains achieved for infectious diseases and nutritional deficiencies, the persisting toll of neonatal conditions and congenital anomalies on child survival became evident, especially in low-income and low-middle-income countries. We found sizeable heterogeneities in comparing observed and expected rates of under-5 mortality, as well as differences in observed and expected rates of change for under-5 mortality. At the global level, we recorded a divergence in observed and expected levels of under-5 mortality starting in 2000, with the observed trend falling much faster than what was expected based on SDI through 2015. Between 2000 and 2015, the world recorded 10·3 million fewer under-5 deaths than expected on the basis of improving SDI alone. Interpretation Gains in child survival have been large, widespread, and in many places in the world, faster than what was anticipated based on improving levels of development. Yet some countries, particularly in sub-Saharan Africa, still had high rates of under-5 mortality in 2015. Unless these countries are able to accelerate reductions in child deaths at an extraordinary pace, their achievement of proposed SDG targets is unlikely. Improving the evidence base on drivers that might hasten the pace of progress for child survival, ranging from cost-effective intervention packages to innovative financing mechanisms, is vital to charting the pathways for ultimately ending preventable child deaths by 2030. Funding Bill & Melinda Gates Foundation. © 2016 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY license