Helen Keller International

About: Helen Keller International is a nonprofit organization based out in New York, New York, United States. It is known for research contribution in the topics: Population & Micronutrient. The organization has 423 authors who have published 538 publications receiving 15888 citations. The organization is also known as: HKI.

A century of trends in adult human height

Abstract: Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.

Impact of vitamin A supplementation on childhood mortality. A randomised controlled community trial.

Abstract: 450 villages in northern Sumatra were randomly assigned to either participate in a vitamin A supplementation scheme (n = 229) or serve for 1 year as a control (n = 221). 25 939 preschool children were examined at baseline and again 11 to 13 months later. Capsules containing 200 000 IU vitamin A were distributed to preschool children aged over 1 year by local volunteers 1 to 3 months after baseline enumeration and again 6 months later. Among children aged 12-71 months at baseline, mortality in control villages (75/10 231, 7.3 per 1000) was 49% greater than in those where supplements were given (53/10 919, 4.9 per 1000) (p less than 0.05). The impact of vitamin A supplementation seemed to be greater in boys than in girls. These results support earlier observations linking mild vitamin A deficiency to increased mortality and suggest that supplements given to vitamin A deficient populations may decrease mortality by as much as 34%.

Refractive error and visual impairment in school children in rural southern China.

Abstract: Purpose To assess the prevalence of refractive error and visual impairment in school children in a rural area of southern China. Design Prospective cross-sectional survey. Participants Two thousand four hundred children from junior high schools in Yangxi County. Methods Random selection of classes from the 3 junior high school grade levels was used to identify the study sample. Children from 36 classes in 13 schools were examined in April 2005. The examination included visual acuity (VA) testing; ocular motility evaluation; cycloplegic autorefraction; and examination of the external eye, anterior segment, media, and fundus. Main Outcome Measures Distance VA and cycloplegic refraction. Results Among 2515 enumerated children, 2454 (97.6%) were examined. The study population consisted of the 2400 children between 13 and 17 years old. Prevalences of uncorrected, presenting, and best-corrected VA ≤ 20/40 in the better eye were 27.0%, 16.6%, and 0.46%, respectively. Sixty percent of those who could achieve acuity ≥20/32 in at least one eye with best correction were without the necessary spectacles. Refractive error was the cause in 97.1% of eyes with reduced vision; amblyopia, 0.81%; other causes, 0.67%; and unexplained causes, 1.4%. Myopia (spherical equivalent, −0.50 diopters [D] or more in either eye) affected 36.8% of 13-year-olds, increasing to 53.9% of 17-year-olds. Myopia was associated with higher grade level, female gender, schooling in the county urban center, and higher parental education. Hyperopia (+2.00 D or more) affected approximately 1.0% in all age groups. Astigmatism (≥0.75 D) was present in 25.3% of all children. Conclusions Reduced vision because of uncorrected myopia is a public health problem among school-age children in rural China. Effective VA screening strategies are needed to eliminate this easily treated cause of visual impairment.

The anemia of vitamin A deficiency: epidemiology and pathogenesis

Abstract: Objective: To gain insight into vitamin A deficiency as a cause of anemia. Methods: Comprehensive review of the scientific literature. Results: Although vitamin A deficiency is recognized to cause anemia, ‘vitamin A deficiency anemia’ lacks complete characterization as a distinct clinical entity. Vitamin A appears to be involved in the pathogenesis of anemia through diverse biological mechanisms, such as the enhancement of growth and differentiation of erythrocyte progenitor cells, potentiation of immunity to infection and reduction of the anemia of infection, and mobilization of iron stores from tissues. Epidemiological surveys show that the prevalence of anemia is high in populations affected by vitamin A deficiency in developing countries. Improvement of vitamin A status has generally been shown to reduce anemia, but the actual public health impact on anemia is unclear. Conclusions: Further work is needed to elucidate the biological mechanisms by which vitamin A causes anemia. The inclusion of anemia as an outcome measure in future micronutrient intervention studies should help provide further insight into the anemia of vitamin A deficiency.

Effect of parental formal education on risk of child stunting in Indonesia and Bangladesh: a cross-sectional study

Abstract: Summary Background Child stunting is associated with poor child development and increased mortality. Our aim was to determine the effect of length of maternal and paternal education on stunting in children under the age of 5 years. Methods Data for indicators of child growth and of parental education and socioeconomic status were gathered from 590 570 families in Indonesia and 395 122 families in Bangladesh as part of major nutritional surveillance programmes. Findings The prevalence of stunting in families in Indonesia was 33·2%, while that in Bangladesh was 50·7%. In Indonesia, greater maternal formal education led to a decrease of between 4·4% and 5% in the odds of child stunting (odds ratio per year 0·950, 95% CI 0·946–0·954 in rural settings; 0·956, 0·950–0·961 in urban settings); greater paternal formal education led to a decrease of 3% in the odds of child stunting (0·970, 0·967–0·974). In Bangladesh, greater maternal formal education led to a 4·6% decrease in the odds of child stunting (0·954, 0·951–0·957), while greater paternal formal education led to a decrease of between 2·9% and 5·4% in the odds of child stunting (0·971, 0·969–0·974 in rural settings; 0·946, 0·941–0·951 in urban settings). In Indonesia, high levels of maternal and paternal education were both associated with protective caregiving behaviours, including vitamin A capsule receipt, complete childhood immunisations, better sanitation, and use of iodised salt (all p Interpretation Both maternal and paternal education are strong determinants of child stunting in families in Indonesia and Bangladesh.