World Health Organization cardiovascular disease risk charts: revised models to estimate risk in 21 global regions

BACKGROUND: To help adapt cardiovascular disease risk prediction approaches to low-income and middle-income countries, WHO has convened an effort to develop, evaluate, and illustrate revised risk models. Here, we report the derivation, validation, and illustration of the revised WHO cardiovascular disease risk prediction charts that have been adapted to the circumstances of 21 global regions. METHODS: In this model revision initiative, we derived 10-year risk prediction models for fatal and non-fatal cardiovascular disease (ie, myocardial infarction and stroke) using individual participant data from the Emerging Risk Factors Collaboration. Models included information on age, smoking status, systolic blood pressure, history of diabetes, and total cholesterol. For derivation, we included participants aged 40-80 years without a known baseline history of cardiovascular disease, who were followed up until the first myocardial infarction, fatal coronary heart disease, or stroke event. We recalibrated models using age-specific and sex-specific incidences and risk factor values available from 21 global regions. For external validation, we analysed individual participant data from studies distinct from those used in model derivation. We illustrated models by analysing data on a further 123 743 individuals from surveys in 79 countries collected with the WHO STEPwise Approach to Surveillance. FINDINGS: Our risk model derivation involved 376 177 individuals from 85 cohorts, and 19 333 incident cardiovascular events recorded during 10 years of follow-up. The derived risk prediction models discriminated well in external validation cohorts (19 cohorts, 1 096 061 individuals, 25 950 cardiovascular disease events), with Harrell's C indices ranging from 0·685 (95% CI 0·629-0·741) to 0·833 (0·783-0·882). For a given risk factor profile, we found substantial variation across global regions in the estimated 10-year predicted risk. For example, estimated cardiovascular disease risk for a 60-year-old male smoker without diabetes and with systolic blood pressure of 140 mm Hg and total cholesterol of 5 mmol/L ranged from 11% in Andean Latin America to 30% in central Asia. When applied to data from 79 countries (mostly low-income and middle-income countries), the proportion of individuals aged 40-64 years estimated to be at greater than 20% risk ranged from less than 1% in Uganda to more than 16% in Egypt. INTERPRETATION: We have derived, calibrated, and validated new WHO risk prediction models to estimate cardiovascular disease risk in 21 Global Burden of Disease regions. The widespread use of these models could enhance the accuracy, practicability, and sustainability of efforts to reduce the burden of cardiovascular disease worldwide. FUNDING: World Health Organization, British Heart Foundation (BHF), BHF Cambridge Centre for Research Excellence, UK Medical Research Council, and National Institute for Health Research

Long-term fluctuations (1974-1999) of the salps Thalia democratica and Salpa fusiformis in the northwestern Mediterranean Sea: Relationships with hydroclimatic variability

We investigated the long-term variability of the salps Thalia democratica and Salpafusiformis during the period 1974-1999 at a coastal site in the Bay of Villefranche-sur-mer. During this period T. democratica varied both interannually and seasonally, whereas S. fusiformis showed only seasonal fluctuations. Weeks in which T. democratica and S. fusiformis populations were developing in situ (i.e., near the sampling station without advection) are defined as the informative periods. Different species-specific optima of temperature, salinity, and chlorophyll a concentration, as well as stability conditions of the water column, were related to informative periods for the two Thalia and Salpa species. Long-term temperature oscillations were significantly related to the interannual maxima of T. democratica. The link between positive anomalies of temperature and outbreaks of T. democratica stress the importance of primary consumers as indicators of changes occurring in the marine system

Numeric analysis of planktonic spatial patterns revealed by echograms

Observations of acoustic images made along a transect perpendicular to the Coast, off Villefranchesur-Mer, allow one to recognize the hydrological zone corresponding to a surface density gradient characterizing the Ligurian Sea front (Mediterranean Sea). Combinations of statistical and geometrical parameters from the digitized echoes enable discrimination between different classes of patches in relation to the frontal structure during one transect recorded on December 20, 1990. Patch recognition is based on the extraction of the general trend of each column and each row of the digitized data matrix by Eigenvector filtering. Multivariate analysis (principal component analysis and discriminant analysis) run on a 650 patches x 19 variables matrix shows a high negative relation between statistic and geometric parameters of the patches. The two main discriminant parameters are shape and echo strength of patches. From the convergence of our results in the Ligurian front with those of previous works made in other frontal region, it is suggested that this method could be generalized for quantifying and standardizing studies of the patchiness of plankton

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A new procedure to optimize the selection of groups in a classification tree: applications for ecological data

International audienceAgglomerative cluster analyses encompass many techniques, which have been widely used in various fields of science. In biology, and specifically ecology, datasets; are generally highly variable and may contain outliers, which increase the difficulty to identify the number of clusters. Here we present a new criterion to determine statistically the optimal level of partition in a classification tree. The criterion robustness is tested against perturbated data (outliers) using an observation or variable with values randomly generated. The technique, called Random Simulation Test (RST), is tested on (1) the well-known Iris dataset (Fisher, R.A., 1936. The use of multiple measurements in taxonomic problems. Ann. Eugenic. 7, 179-188], (2) simulated data with predetermined numbers of clusters following Milligan and Cooper [Milligan, G.W, Cooper, M.C., 1985. An examination of procedures for determining the number of clusters in a data set. Psychometrika SO, 159-1791 and finally (3) is applied on real copepod communities data previously analyzed in Beaugrand et al. (Beaugrand, G., Ibanez, F., Lindley, J.A., Reid, P.C., 2002. Diversity of calanoid copepods in the North Atlantic and adjacent seas: species associations and biogeography. Mar. Ecol. Prog. Ser. 232, 179-1951. The technique is compared to several standard techniques. RST performed generally better than existing algorithms on simulated data and proved to be especially efficient with highly variable datasets

Large scale spatial variations in the seasonal abundance of Calanus finmarchicus

Data collected by the Continuous Plankton Recorder (CPR) survey between 1962, and 1974 in the North Atlantic and adjacent seas were used to examine large scale spatial variations in the seasonal cycle of near-surface abundance of the copepod Calanus finmarchicus. Through most of this region, the dominant seasonal pattern was minimum abundance between November and February followed by an increase to maximum abundance in May. Two large (> 600 000 km(2)) areas had seasonal cycles that differed markedly from this dominant pattern. South of Newfoundland, maximum abundance occurred between February and May, while south of Greenland, maximum abundance occurred between April and October. This delayed seasonal cycle south of Greenland has not been identified previously, and it is speculated that regional changes in seasonal patterns may result from regional temperature and/or timing of food availability differences. (C) 1997 Elsevier Science Ltd

A multivariate approach to large-scale variation in marine planktonic copepod diversity and its environmental correlates

We have investigated the relationships between covariations in environmental variables and variations in distributions of marine copepod diversity over an extensive latitudinal range from 86.5 degrees N to 46.5 degrees S. For this purpose, 7 data sets (representing 13,713 samples) of copepod species composition data and 11 environmental data sets were assembled. Principal components analysis was applied to investigate the relationships among the mean and seasonal variations in environmental descriptors (ocean temperature, chlorophyll a [ Chl a], net primary production, and other physical and chemical properties of the ocean) and their relationships with spatial variations in copepod diversity. High copepod diversity corresponded to a combination of high ocean temperature and salinity and low Chl a and nutrient concentrations (nitrate, silicate, phosphate). To a lesser extent, high-diversity regions were also correlated to low seasonal variability in oxygen, ocean temperature, and mixed-layer depth. Regression on principal components provided a robust prediction of global copepod diversity (R-2 = 0.45, p < 0.001) as our subset of environmental data was representative of the full range of environmental variability that occurs globally

Phytoplankton biodiversity and NW Mediterranean Sea warming: changes in the dinoflagellate genus Ceratium in the 20th century

International audienceOur knowledge of the response of phytoplankton to climate change is restricted by the lack of phytoplankton long-term studies, especially those reporting species data. To circumvent this problem, we combined recent data from sampling at monitoring sites with old bibliographic data. The study was conducted on the genus Ceratium (planktonic dinoflagellates) in the NW Mediterranean, as numerous studies have been conducted in the area since the beginning of the 20th century. In addition, species of this highly diverse genus are known to be particularly sensitive to water temperature, and should thus be responsive to global warming. The temporal distribution of Ceratium species over the last century showed a progressive disappearance from the surface layer of likely stenothermic species, which may have moved to deeper layers in response to water warming, along with a decrease of species richness during the annual cycle. Seasonal and phenological aspects of Ceratium assemblages were also affected, as illustrated by the earlier timing in the minimum of richness. A change in the overall species assemblage also occurred from past to present in the Ligurian Sea, suggesting a warming in this area consistent with the development in surface water temperatures. Our results suggest that Ceratium species may constitute good biological indicators of warming in the NW Mediterranean Sea. In addition, the present study showed the importance of time-series data and the value of historical literature as the basis for ecological studies of long-term trends needed to substantiate our current understanding of the impact of global change on marine biodiversity