Semiparametric Bayesian Density Estimation with Disparate Data Sources: A Meta-Analysis of Global Childhood Undernutrition

Undernutrition, resulting in restricted growth, and quantified here using height-for-age z-scores, is an important contributor to childhood morbidity and mortality. Since all levels of mild, moderate and severe undernutrition are of clinical and public health importance, it is of interest to estimate the shape of the z-scores' distributions. We present a finite normal mixture model that uses data on 4.3 million children to make annual country-specific estimates of these distributions for under-5-year-old children in the world's 141 low- and middle-income countries between 1985 and 2011. We incorporate both individual-level data when available, as well as aggregated summary statistics from studies whose individual-level data could not be obtained. We place a hierarchical Bayesian probit stick-breaking model on the mixture weights. The model allows for nonlinear changes in time, and it borrows strength in time, in covariates, and within and across regional country clusters to make estimates where data are uncertain, sparse, or missing. This work addresses three important problems that often arise in the fields of public health surveillance and global health monitoring. First, data are always incomplete. Second, different data sources commonly use different reporting metrics. Last, distributions, and especially their tails, are often of substantive interest.Comment: 41 total pages, 6 figures, 1 tabl

Reproductive Biology of Blue Runner (Caranx crysos) from the Eastern Gulf of Mexico

Blue runner were obtained from commercial fisheries in south Florida, northwest Florida, and the Mississippi Delta. Monthly mean gonadosomatic indices indicated that peak spawning occurred in June, July, and August for all areas with a secondary peak in October for northwest Florida. The spawning season was confirmed for the south Florida collection by histological examination of gonads. Probit analysis of 185 northwest Florida blue runner captured during peak spawning months indicated a length-at-maturity of 267 mm. Fecundity varied from 41,000 ova in a 243·mm·FL, 288-gram fish to 1,546,000 ova in a 385·mm·FL, 1,076-gram fish. Sex ratios were 1.15F:1M for Mississippi Delta, 1.66F:1M for northwest Florida and 1.91F:1M for south Florida

Children’s height and weight in rural and urban populations in low-income and middle-income countries: a systematic analysis of population-representative data

Background Urban living aff ects children’s nutrition and growth, which are determinants of their survival, cognitive development, and lifelong health. Little is known about urban–rural diff erences in children’s height and weight, and how these diff erences have changed over time. We aimed to investigate trends in children’s height and weight in rural and urban settings in low-income and middle-income countries, and to assess changes in the urban–rural diff erentials in height and weight over time. Methods We used comprehensive population-based data and a Bayesian hierarchical mixture model to estimate trends in children’s height-for-age and weight-for-age Z scores by rural and urban place of residence, and changes in urban–rural diff erentials in height and weight Z scores, for 141 low-income and middle-income countries between 1985 and 2011. We also estimated the contribution of changes in rural and urban height and weight, and that of urbanisation, to the regional trends in these outcomes. Findings Urban children are taller and heavier than their rural counterparts in almost all low-income and middleincome countries. The urban–rural diff erential is largest in Andean and central Latin America (eg, Peru, Honduras, Bolivia, and Guatemala); in some African countries such as Niger, Burundi, and Burkina Faso; and in Vietnam and China. It is smallest in southern and tropical Latin America (eg, Chile and Brazil). Urban children in China, Chile, and Jamaica are the tallest in low-income and middle-income countries, and children in rural areas of Burundi, Guatemala, and Niger the shortest, with the tallest and shortest more than 10 cm apart at age 5 years. The heaviest children live in cities in Georgia, Chile, and China, and the most underweight in rural areas of Timor-Leste, India, Niger, and Bangladesh. Between 1985 and 2011, the urban advantage in height fell in southern and tropical Latin America and south Asia, but changed little or not at all in most other regions. The urban–rural weight diff erential also decreased in southern and tropical Latin America, but increased in east and southeast Asia and worldwide, because weight gain of urban children outpaced that of rural children.Interpretation Further improvement of child nutrition will require improved access to a stable and aff ordable food supply and health care for both rural and urban children, and closing of the the urban–rural gap in nutritional status