Iodine deficiency and functional performance of schoolchildren in Benin

The notion that iodine deficiency may lead not only to goiter and cretinism, but to a much wider range of disorders, from stillbirth and abortions, to hearing problems and mental and physical underdevelopment began to be accepted beyond the research community since the early 1980's. In 1990 it was estimated that these problems, collectively called iodine deficiency disorders (IDD), presented a public health problem in 118 countries and that over 40 million people were affected by some degree of mental impairment. Children who have been exposed to iodine deficiency in the pre- and early post-natal phases of life show varying degrees of mental and psychomotor retardation, depending on the duration and degree of the deficiency. Adequate maternal iodine intake before and during pregnancy prevents such disorders. The question however whether or not deficits in mental and psychomotor performance of iodine deficient children may be reversed by supple-mentation with iodine later in life has not yet been answered unequivocally.The research described in this thesis was set up to address this question. A double-blind placebo-controlled intervention was carried out in an iodine deficient area of northern Benin in the period 1995-1996. A single oral dose of iodized oil or placebo was administrated to 2 groups of schoolchildren, aged 7-11 years. The observation period was 10-11 months. However, 3 to 4 months after supple-mentation the population started to have access to iodized salt, in addition to non-iodized salt. Because iodine became available to both groups, the main hypothesis, i.e. that iodine supplementation would improve mental performance had to be modified. It was decided to take children whose iodine status, as measured by different indicators, did not change during the observation period as the "control" group. In addition to mental and psychomotor performance, other aspects associated with iodine deficiency were studied, including behavioral change and hearing thresholds and their relation with mental performance. The suitability of several indicators for measuring iodine status and thyroid function was evaluated.Results showed that an improvement in iodine status as measured by urinary iodine concentration, was reflected in a significantly improved performance on the combination of mental tests, 10 months after supplementation. Moreover, children with better iodine status could hear better than their peers with a poorer iodine status, while hearing thresholds were negatively correlated with performance on all mental tests, but one. The serum concentration of thyroglobulin and the urinary iodine concentration were found to be indicators most suitable for measuring change in iodine status in this age group. Although the influx of iodine into the area precludes the drawing of "hard" conclusions, the results presented suggest that iodine supplementation is likely to promote a catch-up process in functional performance of iodine deficient schoolchildren.</p

Whole blood NAD and NADP concentrations are not depressed in subjects with clinical pellagra

Population surveys for niacin deficiency are normally based on clinical signs or on biochemical measurements of urinary niacin metabolites. Status may also be determined by measurement of whole blood NAD and NADP concentrations. To compare these methods, whole blood samples and spot urine samples were collected from healthy subjects (n = 2) consuming a western diet, from patients (n = 34) diagnosed with pellagra and attending a pellagra clinic in Kuito (central Angola, where niacin deficiency is endemic), and from female community control subjects (n = 107) who had no clinical signs of pellagra. Whole blood NAD and NADP concentrations were measured by microtiter plate-based enzymatic assays and the niacin urinary metabolites 1-methyl-2-pyridone-5-carboxamide (2-PYR) and 1-methylnicotinamide (1-MN) by HPLC. In healthy volunteers, inter- and intra-day variations for NAD and NADP concentrations were much lower than for the urinary metabolites, suggesting a more stable measure of status. However, whole blood concentrations of NAD and NADP or the NAD:NADP ratio were not significantly depressed in clinical pellagra. In contrast, the concentrations of 2-PYR and 1-MN, expressed relative to either creatinine or osmolality, were lower in pellagra patients and markedly higher following treatment. The use of the combined cut-offs (2-PYR <3.0 micromol/mmol creatinine and 1-MN <1.3 micromol/mmol creatinine) gave a sensitivity of 91% and specificity of 72%. In conclusion, whole blood NAD and NADP concentrations gave an erroneously low estimate of niacin deficiency. In contrast, spot urine sample 2-PYR and 1-MN concentrations, relative to creatinine, were a sensitive and specific measure of deficiency

Low-dose RUTF protocol and improved service delivery lead to good programme outcomes in the treatment of uncomplicated SAM: a programme report from Myanmar.

The treatment of uncomplicated severe acute malnutrition (SAM) requires substantial amounts of ready-to-use therapeutic food (RUTF). In 2009, Action Contre la Faim anticipated a shortfall of RUTF for their nutrition programme in Myanmar. A low-dose RUTF protocol to treat children with uncomplicated SAM was adopted. In this protocol, RUTF was dosed according to beneficiary's body weight, until the child reached a Weight-for-Height z-score of ≥-3 and mid-upper arm circumference ≥110 mm. From this point, the child received a fixed quantity of RUTF per day, independent of body weight until discharge. Specific measures were implemented as part of this low-dose RUTF protocol in order to improve service quality and beneficiary support. We analysed individual records of 3083 children treated from July 2009 to January 2010. Up to 90.2% of children recovered, 2.0% defaulted and 0.9% were classified as non-responders. No deaths were recorded. Among children who recovered, median [IQR] length of stay and weight gain were 42 days [28; 56] and 4.0 g kg(-1) day(-1) [3.0; 5.7], respectively. Multivariable logistic regression showed that children older than 48 months had higher odds of non-response to treatment than younger children (adjusted odds ratio: 3.51, 95% CI: 1.67-7.42). Our results indicate that a low-dose RUTF protocol, combined with specific measures to ensure good service quality and beneficiary support, was successful in treating uncomplicated SAM in this setting. This programmatic experience should be validated by randomised studies aiming to test, quantify and attribute the effect of the protocol adaptation and programme improvements presented here

Low and deficient niacin status and pellagra are endemic in postwar Angola

BACKGROUND: Outbreaks of pellagra were documented during the civil war in Angola, but no contemporary data on the incidence of pellagra or the prevalence of niacin deficiency were available. OBJECTIVE: The objective was to investigate the incidence of pellagra and the prevalence of niacin deficiency in postwar Angola and their relation with dietary intake, poverty, and anthropometric status. DESIGN: Admissions data from 1999 to 2004 from the pellagra treatment clinic in Kuito, Angola, were analyzed. New patients admitted over 1 wk were examined, and urine and blood samples were collected. A multistage cluster population survey collected data on anthropometric measures, household dietary intakes, socioeconomic status, and clinical signs of pellagra for women and children. Urinary excretion of 1-methylnicotinamide, 1-methyl-2-pyridone-5-carboxymide, and creatinine was measured and hemoglobin concentrations were measured with a portable photometer. RESULTS: The incidence of clinical pellagra has not decreased since the end of the civil war in 2002. Low excretion of niacin metabolites was confirmed in 10 of 11 new clinic patients. Survey data were collected for 723 women aged 15-49 y and for 690 children aged 6-59 mo. Excretion of niacin metabolites was low in 29.4% of the women and 6.0% of the children, and the creatinine-adjusted concentrations were significantly lower in the women than in the children (P < 0.001, t test). In children, niacin status was positively correlated with the household consumption of peanuts (r = 0.374, P = 0.001) and eggs (r = 0.290, P = 0.012) but negatively correlated with socioeconomic status (r = -0.228, P = 0.037). CONCLUSIONS: The expected decrease in pellagra incidence after the end of the civil war has not occurred. The identification of niacin deficiency as a public health problem should refocus attention on this nutritional deficiency in Angola and other areas of Africa where maize is the staple

Dwarf galaxy populations in present-day galaxy clusters: I. Abundances and red fractions

We compare the galaxy population in the Virgo, Fornax, Coma and Perseus cluster to a state-of-the-art semi-analytic model, focusing on the regime of dwarf galaxies with luminosities from approximately 10^8 L_sun to 10^9 L_sun. We find that the number density profiles of dwarfs in observed clusters are reproduced reasonably well, and that the red fractions of model clusters provide a good match to Coma and Perseus. On the other hand, the red fraction among dwarf galaxies in Virgo is clearly lower than in model clusters. We argue that this is mainly caused by the treatment of environmental effects in the model. This explanation is supported by our finding that the colours of central ("field") dwarf galaxies are reproduced well, in contrast to previous claims. Finally, we find that the dwarf-to-giant ratio in model clusters is too high. This may indicate that the current model prescription for tidal disruption of faint galaxies is still not efficient enough.Comment: 20 pages, 10 figures. Accepted by MNRAS. Includes the modifications after referee report. Main results unchanged, interpretation slightly change

Can annihilating Dark Matter be lighter than a few GeVs?

We estimate the gamma ray fluxes from the residual annihilations of Dark Matter particles having a mass mdm \in [MeV, O(GeV)] and compare them to observations. We find that particles lighter than O(100 MeV) are excluded unless their cross section is S-wave suppressed.Comment: 4 pages. No figure. Values corrected (last column Table.1). Text clarified. Conclusions unchange

ORIGIN OF THE HIGH ENERGY EXTRAGALACTIC DIFFUSE GAMMA RAY BACKGROUND

We show that cosmic rays in external galaxies, groups and clusters rich in gas, with an average flux similar to that observed in the Milky Way, could have produced the observed extragalactic diffuse gamma radiation.Comment: 9 pages, latex, 1 faxable figure available upon request from [email protected]. Submitted to Phys Rev Lett

Dependence of atmospheric muon flux on seawater depth measured with the first KM3NeT detection units: The KM3NeT Collaboration

KM3NeT is a research infrastructure located in the Mediterranean Sea, that will consist of two deep-sea Cherenkov neutrino detectors. With one detector (ARCA), the KM3NeT Collaboration aims at identifying and studying TeV–PeV astrophysical neutrino sources. With the other detector (ORCA), the neutrino mass ordering will be determined by studying GeV-scale atmospheric neutrino oscillations. The first KM3NeT detection units were deployed at the Italian and French sites between 2015 and 2017. In this paper, a description of the detector is presented, together with a summary of the procedures used to calibrate the detector in-situ. Finally, the measurement of the atmospheric muon flux between 2232–3386 m seawater depth is obtained