39 research outputs found

    Comportamento de desova e paternidade múltipla em ninhos de "Podocnemis sextuberculata" (Testudines:Podocnemididae) na reserva biológica do rio Trombetas, Pará, Brasil

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    Podocnemis sextuberculata genus belongs to the family Podocnemididae is considered “Vulnerable” according to the International Union for Conservation of Nature - IUCN, largely due to the human harvest of their eggs and adults. Several studies reported the occurrence of multiple clutches of the turtles from the Podocnemis genus, including P. sextuberculata. However, direct observation (capture-mark-recapture) were not mad. Most studies report multiple clutches indirectly, through the analysis of gonads. Multiple clutches in turtles are considered important for the survival of the offspring. A polyandrous mating system and multiple paternity in turtles contributes to genetic heterozygosity in offspring and promotes greater genetic variability in the population. This study aims to analyze directly the nesting behavior and the occurrence of multiple clutches during a breeding season of P. sextuberculata as well as their ecological and genetic effects on the offspring. The study area is located in the Trombetas Biological Reserve, in the municipality of Oriximiná, Pará, Brazil. The nests were identified on the Farias Beach (1º15'S), from October to November 2013. During the nesting season, the beach was monitored from 1900h to 0700h for 60 nights. Females were captured, measured and blood samples collected after nesting. Radio transmitters were attached their carapaces to monitor their movements and potential nesting in nearby areas. The nests were marked. After the eclosion of the eggs, we collected data on reproductive characteristics. We also took a blood sample from the hatchling femoral vein. We used six primers from the studied species, five primers from P. unifilis and a primer from P. expansa to perform the PCR analysis (the Polymerase Chain Reaction) and genotyping. There were no reports of a second clutch for any of the females monitored in this study. Female size (track width) was significantly smaller (ANOVA; df = 2.15 F = 4.22, p < 0.05; Tukey: p <0.05) at the beginning of the breeding season (mean = 110mm ± 8.4) than in the middle of the breeding season (mean = 148mm ± 19). There were no significant differences between the hatching success (ANOVA; df = 2.35; F = 0.85; p = 0.44) and clutch size (ANOVA; df = 2.31; F = 0.29; p = 0.75) for the different periods of the breeding season (beginning, middle and end). Mean incubation time was 55 days (50 - 73). The hatchling remained in the nest after hatching for a mean of 6 days (2-14). We observed a strong synchronization between the descent and the ascent of the river water level with the nesting 11 and hatching period, respectively. We analyzed all hatchlings from 23 nests, and confirmed multiple paternity in 100% of the sample. There was a mean of six fathers per nest. There were no significant difference between the number of parents and the period of the nesting season (Kruskal-Wallis; df = 2, H = 2.193, p = 0.33). There were also no significant differences between the relative size of females (Correlation of Spearman; rho = -0.10; p = 0.76) and the hatching success (Correlation of Spearman; rho = 0.04; p = 0.85) compared with the number of males fathering the clutch. However, clutch size was significantly related to the number of father found (Correlation of Spearman; rho = 0.47; p < 0.05).Podocnemis sextuberculata, da família Podocnemididae, é listada como espécie vulnerável (União Internacional para a Conservação da Natureza – IUCN), em grande parte devido ao consumo de seus ovos e adultos pela população humana. A ocorrência de posturas múltiplas de quelônios do gênero Podocnemis, inclusive de P.sextuberculata está documentada. Entretanto, as verificações diretas (captura-marcação-recaptura) referentes a este fato são raras, sendo na maioria das vezes relatadas de forma indireta, como a partir da análise das gônadas das fêmeas. A desova múltipla em quelônios é importante para a sobrevivência da prole. O sistema de acasalamento poliândrico e paternidade múltipla em tartarugas também consistem em uma importante estratégia de sobrevivência para a população, pois contribui para o aumento da heterozigosidade genética nas proles e promove maior variabilidade genética na população. O presente trabalho teve como objetivo analisar, diretamente, o comportamento de nidificação e a ocorrência de desovas múltiplas durante uma estação de desova de P.sextuberculata e seus efeitos ecológicos e genéticos na prole. A área deste estudo localiza-se na Reserva Biológica do Rio Trombetas, no município de Oriximiná, Pará, Brasil. Os ninhos foram amostrados na praia do Farias (1º15’S e 56º50’O), entre outubro e novembro de 2013. Durante a estação de nidificação, a praia foi monitorada das 19h às 7h do dia seguinte, durante aproximadamente 60 noites. Após a desova 10 fêmeas foram capturadas, medidas e amostras de sangue foram coletadas. Rádios transmissores foram colocados na porção superior das carapaças para observação dos próximos locais de desovas. Os ninhos foram marcados e, após o nascimento dos filhotes, dados referentes aos aspectos reprodutivos e uma amostra de sangue da veia femoral foram coletados. Utilizou-se seis locos heterólogos à espécie, cinco locos de P. unifilis e um loco de P. expansa para realização das análises de PCR (Reação em cadeia da Polimerase) e genotipagem. Não houve registro de uma segunda desova para nenhuma das fêmeas monitoradas. O tamanho das fêmeas (largura do rastro) foi significativamente menor (ANOVA; d.f. = 2,15; F=4,22, p < 0,05; Tukey: p < 0,05) no início da estação de desova (média=110mm ±8,4) quando comparada ao meio da estação de desova (média = 148mm ± 19). Não houve diferenças significativas entre o sucesso de eclosão (ANOVA; d.f. = 2,35; F = 0,85; p = 0,44) e o tamanho da ninhada (ANOVA; d.f. = 2,31; F = 0,29; p = 0,75) com relação aos diferentes períodos da estação de desova (início, meio e fim). O período de incubação dos ovos de P.sextuberculata foi em média 55 dias (50 – 73). O período de tempo em que os filhotes permaneceram nos ninhos após a eclosão foi, em média, 6 dias (2-14). Observamos uma forte sincronia entre a descida e a subida do nível das águas do rio com o período de desovas e nascimento dos filhotes, respectivamente. Analisamos todos os filhotes de 23 ninhos de P.sextuberculata, dos quais foram verificados 100% de paternidade múltipla. Em média foram encontrados seis pais por ninho. Não houve diferença significativa entre o número de pais encontrados e o período da estação de desova (Kruskal-Wallis; d.f. = 2; H = 2,193; p = 0,33). Não houve diferenças significativas entre o tamanho das fêmeas (Correlação de Spearman; rho = -0,10; p = 0,76) e o sucesso de eclosão (Correlação de Spearman; rho = 0,04; p = 0,85) em relação ao número de pais encontrados nos ninhos. Contudo, o tamanho da ninhada apresentou significativamente correlação positiva com o número de pais encontrados (Correlação de Spearman; rho = 0,47; p < 0,05)

    Vulnerability of giant South American turtle (Podocnemis expansa) nesting habitat to climate-change-induced alterations to fluvial cycles

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    A change in seasonal flooding cycles in the Amazon may negatively impact nesting success of the Giant South American Turtle (Podocnemis expansa). Our aim was to devise a technique that could be replicated in the entire Amazon basin, for monitoring alterations in fluvial cycles and their effects on turtle nest mortality. We mapped the spatial distribution and height of P. expansa nests and tested the effects of different inundation scenarios within the Trombetas River Biological Reserve, Para state, Brazil. We also used historical data on water level and hatchling production to test whether the sharp decline in the Trombetas River P. expansa population over the past thirty years was related to detected changes in the flood pulse. Our models indicate that an increase of 1.5m in the water level is sufficient to decrease the time of exposure to less than the minimum required for incubation and hatching (55 days above the water) in 50% of the nesting area. This model explains the low hatchling production in dry seasons when the total nesting site exposure was less than 200 days. Since 1971, there was an average decline of 15 days per decade in sandbank exposure during the nesting season (a total of 62 days from 1971 to 2015). However, the decrease in sandbank exposure was not significantly correlated with the sharp decline in hatchling production. Changes to the water cycle in combination with the main sources of decline (overharvest, construction of dams, and dredging of riverbeds) might have an accumulative effect on P. expansa populations. © The Author(s) 2016

    Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

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    © The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

    Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

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    Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can 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-standardized 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 age-standardized 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 was 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 shortfall in diabetes diagnosis and surveillance

    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

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    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

    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

    Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

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    Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI &lt;18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For school&#x2;aged children and adolescents, we report thinness (BMI &lt;2 SD below the median of the WHO growth reference) and obesity (BMI &gt;2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit

    A century of trends in adult human height

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

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    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

    Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants.

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    BACKGROUND: Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories. METHODS: We used data from 1990 to 2019 on people aged 30-79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age. FINDINGS: The number of people aged 30-79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306-359) million women and 317 (292-344) million men in 1990 to 626 (584-668) million women and 652 (604-698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55-62) of women and 49% (46-52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43-51) of women and 38% (35-41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20-27) for women and 18% (16-21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran. INTERPRETATION: Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings. FUNDING: WHO
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