Electronegative Electroretinograms in the United Arab Emirates

PURPOSE

An electronegative electroretinogram (ERG), defined as having a b:a wave ratio ≤1 in the scotopic flash ERG response, indicates relative inner retinal dysfunction. Causes vary depending upon the study population. In the Arabian Gulf, where inherited retinal disease is relatively prevalent, common diagnoses associated with electronegative ERGs have not been described. In this study, we report the frequency and causes of electronegative ERGs in a cohort of Emirati patients with inherited retinal disease.

METHODS

A retrospective review was performed of all full-field ERGs done for Emirati patients in the Ocular Genetics Service of Cleveland Clinic Abu Dhabi from January 2017 to December 2019. Those who had an electronegative ERG in at least one eye were included in the study.

RESULTS

Out of 137 patients, 9 probands (6.6%) had an electronegative ERG. The mean age at presentation was 24 years (range 5-48 years), and five patients (55.6%) were male. The final clinical diagnoses were congenital stationary night blindness (CSNB) (two TRPM1-related and one Oguchi disease), X-linked retinoschisis (XLRS) (one genetically confirmed and two not genetically tested), cone-rod dystrophy (one CRX-related and one not genetically tested), and enhanced S-cone syndrome (ESCS) (one NRL-related). The one patient who did not have bilateral electronegative ERGs was a male with XLRS whose fellow eye had an unrecordable ERG.

CONCLUSIONS

In this series of Emirati patients, an electronegative ERG was most commonly associated with the inherited retinal diseases recessive CSNB and XLRS. An electronegative ERG was noted in a case of NRL-related ESCS.

High prevalence of gestational night blindness and maternal anemia in a population-based survey of Brazilian Amazonian postpartum women

Nutrition during pregnancy is one of the key elements to good maternal and child health, as well as to lifetime landmarks. However, many pregnant women go undernourished in less developed settings. The purpose of this study was to estimate the prevalence and factors associated with gestational night blindness (GXN) and maternal anemia in a cross-sectional population-based study in Cruzeiro do Sul, Acre State, Western Brazilian Amazon. All women living in the municipality admitted at the only maternity-hospital in the city to delivery of a singleton infant were eligible to this study (n = 1,525). Recruitment of participants took place between July 2015 to June 2016. GXN was assessed in the postpartum period by WHO standardized interview. Maternal anemia was defined as hemoglobin at delivery < 110.0 g/L. We estimated prevalence rates and adjusted prevalence ratios (aPR), alongside 95% confidence intervals (95% CI), of the factors associated with the outcomes through multiple Poisson regression models with robust variance. Alarming prevalence of GXN (11.5%; 95% CI, 9.97-13.25) and maternal anemia (39.4%; 95% CI, 36.84-41.95) were found. Factors associated with GXN were (aPR; 95% CI): ≥ 5 residents in the household (2.06; 1.24-3.41), smoking during pregnancy (1.78; 1.15-2.78), and attending < 6 antenatal care visits (1.61; 1.08-2.40). Factors associated with maternal anemia were (aPR; 95% CI): maternal age < 19 years (1.18; 1.01-1.38), gestational malaria (1.22; 1.01-1.49), not taking micronutrient supplements during pregnancy (1.27; 1.01-1.62), and attending < 6 antenatal care visits (1.40; 1.15-1.70). High prevalence rates of GXN and maternal anemia in these postpartum women may reflect poor assistance during antenatal care, underlying the importance of rethinking current protocols related to nutrition in pregnancy.

Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age

BACKGROUND

Vitamin A deficiency (VAD) is a major public health problem in low- and middle-income countries, affecting 190 million children under five years of age and leading to many adverse health consequences, including death. Based on prior evidence and a previous version of this review, the World Health Organization has continued to recommend vitamin A supplementation for children aged 6 to 59 months. There are new data available from recently published randomised trials since the previous publication of this review in 2010, and this update incorporates this information and reviews the evidence.

OBJECTIVES

To assess the effects of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged six months to five years.

SEARCH METHODS

In March 2016 we searched CENTRAL, Ovid MEDLINE, Embase, six other databases, and two trials registers. We also checked reference lists and contacted relevant organisations and researchers to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-RCTs evaluating the effect of synthetic VAS in children aged six months to five years living in the community. We excluded studies involving children in hospital and children with disease or infection. We also excluded studies evaluating the effects of food fortification, consumption of vitamin A rich foods, or beta-carotene supplementation.

DATA COLLECTION AND ANALYSIS

For this update, two reviewers independently assessed studies for inclusion and abstracted data, resolving discrepancies by discussion. We performed meta-analyses for outcomes, including all-cause and cause-specific mortality, disease, vision, and side effects. We used the GRADE approach to assess the quality of the evidence.

MAIN RESULTS

We identified 47 studies (4 of which are new to this review), involving approximately 1,223,856 children. Studies took place in 19 countries: 30 (63%) in Asia, 16 of these in India; 8 (17%) in Africa; 7 (15%) in Latin America, and 2 (4%) in Australia. About one-third of the studies were in urban/periurban settings, and half were in rural settings; the remaining studies did not clearly report settings. Most of the studies included equal numbers of girls and boys and lasted about a year. The included studies were at variable overall risk of bias; however, evidence for the primary outcome was at low risk of bias. A meta-analysis for all-cause mortality included 19 trials (1,202,382 children). At longest follow-up, there was a 12% observed reduction in the risk of all-cause mortality for vitamin A compared with control using a fixed-effect model (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.83 to 0.93; high-quality evidence). This result was sensitive to choice of model, and a random-effects meta-analysis showed a different summary estimate (24% reduction: RR 0.76, 95% CI 0.66 to 0.88); however, the confidence intervals overlapped with that of the fixed-effect model. Nine trials reported mortality due to diarrhoea and showed a 12% overall reduction for VAS (RR 0.88, 95% CI 0.79 to 0.98; 1,098,538 participants; high-quality evidence). There was no significant effect for VAS on mortality due to measles, respiratory disease, and meningitis. VAS reduced incidence of diarrhoea (RR 0.85, 95% CI 0.82 to 0.87; 15 studies; 77,946 participants; low-quality evidence) and measles (RR 0.50, 95% CI 0.37 to 0.67; 6 studies; 19,566 participants; moderate-quality evidence). However, there was no significant effect on incidence of respiratory disease or hospitalisations due to diarrhoea or pneumonia. There was an increased risk of vomiting within the first 48 hours of VAS (RR 1.97, 95% CI 1.44 to 2.69; 4 studies; 10,541 participants; moderate-quality evidence).

AUTHORS' CONCLUSIONS

Vitamin A supplementation is associated with a clinically meaningful reduction in morbidity and mortality in children. Therefore, we suggest maintaining the policy of universal supplementation for children under five years of age in populations at risk of VAD. Further placebo-controlled trials of VAS in children between six months and five years of age would not change the conclusions of this review, although studies that compare different doses and delivery mechanisms are needed. In populations with documented vitamin A deficiency, it would be unethical to conduct placebo-controlled trials.

Consumption of vitamin A rich foods and dark adaptation threshold of pregnant women at Damot Sore District, Wolayita, Southern Ethiopia

BACKGROUND

More than 7.2 million pregnant women in developing countries suffer from vitamin A deficiency. The objective of this study was to assess dark adaptation threshold of pregnant women and related socio-demographic factors in Damot Sore District, Wolayita Zone, Southern Ethiopia.

METHODS

A cross-sectional study design was employed to collect data from 104 pregnant women selected by a two stage cluster sampling. A Dietary Diversity Score was calculated by counting the number of food groups consumed by the women in 24 hour period prior to the study. Scotopic Sensitivity Tester-1 was used to test participant's pupillary response to graded amounts of light in a dark tent.

RESULTS

Half of the pregnant women in this study had dietary diversity score less than three. The majority of participants (87.5%) had consumed either animal or plant source vitamin A rich foods less than three times a week. For a unit increase in individual dietary diversity score, there was a decrease in dark adaptation measurement by 0.29 log cd/m(2) (p=0.001). For a unit increase in gestational week of pregnancy, there was an increase in dark adaptation measurement by 0.19 log cd/m(2) (P=0.027).

CONCLUSIONS

Results from this study indicated that the pregnant women had low consumption of vitamin A rich foods, and their dark adaptation threshold increases with gestational age indicating that their vitamin A status is getting worse. There is a need to design appropriate intervention and target this group of population.

Risk factors associated with night vision disturbances after phakic intraocular lens implantation

PURPOSE

To investigate the incidence and severity of night vision disturbances after implantable collamer lens surgery and to analyze the risk factors.

DESIGN

Retrospective, noncomparative study.

METHODS

Medical charts from 50 eyes of 25 patients who underwent implantable collamer lens implantation were retrospectively reviewed. The incidence and severity of night vision disturbances were evaluated using questionnaires administered 6 months after surgery. Univariate simple and multiple logistic regression analyses were used to detect risk factors associated with postoperative night vision disturbances. Potential risk factors included in the analysis were keratometric value, anterior chamber depth, postoperative residual refractive error, higher-order aberrations, preoperative and postoperative mesopic pupil size, the difference between preoperative and postoperative mesopic pupil size, the difference between mesopic pupil size and implantable collamer lens optic zone diameter, white-to-white diameter, sulcus-to-sulcus diameter, and postoperative implantable collamer lens vaulting. The power, size, optic zone diameter, and toricity of the implantable collamer lens were also included as variables.

RESULTS

The incidence of night vision disturbances was 34.0% for halos and 26.0% for glare. Halos were found to be significantly related to the difference between mesopic pupil size and implantable collamer lens optic zone diameter (P = .013), white-to-white diameter of the cornea (P = .028), and implantable collamer lens optic zone diameter (P = .030). For glare, toricity of the implantable collamer lens was revealed as a significant risk factor (P = .047).

CONCLUSIONS

Although not severe, the incidence of night vision disturbances after implantable collamer lens implantation was not negligible. Possible risk factors for night vision disturbances include implantable collamer lens optic zone diameter, the difference between mesopic pupil size and implantable collamer lens optic zone diameter, and white-to-white diameter of the cornea for causing halos, and the toricity of the implantable collamer lens for causing glare.

Prevalence of vitamin A deficiency in South Asia: causes, outcomes, and possible remedies

Vitamin A deficiency (VAD) has been recognized as a public-health issue in developing countries. Economic constraints, sociocultural limitations, insufficient dietary intake, and poor absorption leading to depleted vitamin A stores in the body have been regarded as potential determinants of the prevalence of VAD in South Asian developing countries. VAD is exacerbated by lack of education, poor sanitation, absence of new legislation and enforcement of existing food laws, and week monitoring and surveillance system. Several recent estimates confirmed higher morbidly and mortality rate among children and pregnant and non-pregnant women of childbearing age. Xerophthalmia is the leading cause of preventable childhood blindness with its earliest manifestations as night blindness and Bitot's spots, followed by blinding keratomalacia, all of which are the ocular manifestations of VAD. Children need additional vitamin A because they do not consume enough in their normal diet. There are three general ways for improving vitamin A status: supplementation, fortification, and dietary diversification. These approaches have not solved the problem in South Asian countries to the desired extent because of poor governmental support and supervision of vitamin A supplementation twice a year. An extensive review of the extant literature was carried out, and the data under various sections were identified by using a computerized bibliographic search via PubMed, Web of Science, and Google Scholar. All abstracts and full-text articles were examined, and the most relevant articles were selected for screening and inclusion in this review. Conclusively, high prevalence of VAD in South Asian developing countries leads to increased morbidity and mortality among infants, children, and pregnant women. Therefore, stem efforts are needed to address this issue of public-health significance at local and international level in lower- and middle-income countries of South Asia.

Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis

OBJECTIVE

To determine if vitamin A supplementation is associated with reductions in mortality and morbidity in children aged 6 months to 5 years.

DESIGN

Systematic review and meta-analysis. Two reviewers independently assessed studies for inclusion. Data were double extracted; discrepancies were resolved by discussion. Meta-analyses were performed for mortality, illness, vision, and side effects.

DATA SOURCES

Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Medline, Embase, Global Health, Latin American and Caribbean Health Sciences, metaRegister of Controlled Trials, and African Index Medicus. Databases were searched to April 2010 without restriction by language or publication status.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised trials of synthetic oral vitamin A supplements in children aged 6 months to 5 years. Studies of children with current illness (such as diarrhoea, measles, and HIV), studies of children in hospital, and studies of food fortification or β carotene were excluded.

RESULTS

43 trials with about 215,633 children were included. Seventeen trials including 194,483 participants reported a 24% reduction in all cause mortality (rate ratio=0.76, 95% confidence interval 0.69 to 0.83). Seven trials reported a 28% reduction in mortality associated with diarrhoea (0.72, 0.57 to 0.91). Vitamin A supplementation was associated with a reduced incidence of diarrhoea (0.85, 0.82 to 0.87) and measles (0.50, 0.37 to 0.67) and a reduced prevalence of vision problems, including night blindness (0.32, 0.21 to 0.50) and xerophthalmia (0.31, 0.22 to 0.45). Three trials reported an increased risk of vomiting within the first 48 hours of supplementation (2.75, 1.81 to 4.19).

CONCLUSIONS

Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias. Further placebo controlled trials of vitamin A supplementation in children between 6 and 59 months of age are not required. However, there is a need for further studies comparing different doses and delivery mechanisms (for example, fortification). Until other sources are available, vitamin A supplements should be given to all children at risk of deficiency, particularly in low and middle income countries.

Evaluation of status of calcium, magnesium, potassium, and sodium levels in biological samples in children of different age groups with normal vision and night blindness

BACKGROUND

The most common cause of blindness in developing countries is vitamin A deficiency. The World Health Organization (WHO) estimates 13.8 million children have some degree of visual loss related to vitamin A deficiency. The causes of night blindness in children are multifactorial and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological sample composition. Vitamin and mineral deficiency prevents more than two billion people from achieving their full intellectual and physical potential.

METHODS

This study was designed to compare the levels of magnesium (Mg), calcium (Ca), potassium (K), and sodium (Na) in scalp hair, serum, blood, and urine of night blindness children in two age groups, (1-5) and (6-10) years, of both genders comparing them to sex- and age-matched controls. A microwave assisted wet acid digestion procedure was developed as a sample pretreatment for the determination of Mg, Ca, K, and Na in biological samples of children with night blindness. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, serum, blood, and urine. The digests of all biological samples were analysed for Mg, Ca, K, and Na by flame atomic absorption spectrometry (FAAS) using an air/acetylene flame.

RESULTS

The results indicated significantly lower levels of Mg, Ca, and K in the biological samples (blood, serum, and scalp hair) of male and female children with night blindness and higher values of Na compared with control subjects of both genders.

CONCLUSIONS

These data present guidance to clinicians and other professionals investigating deficiency of essential mineral elements in biological samples (scalp hair, serum, and blood) of children with night blindness.

Assessment of vitamin A status of preschool children in a sub-Saharan African setting: comparative advantage of modified relative-dose response test

A nationally-representative sample of 2,696 preschool children living in Congo was examined during Au gust-September 2003 to determine the rates of vitamin A deficiency. Ninety clusters of 30 children, aged six months to six years, were selected, using a randomized two-level cluster-sampling method. Vitamin A deficiency was determined by assessing the prevalence of active xerophthalmia (nightblindness and/or Bitot spots) in the cross-over sample of 2,696 individuals. A semi-quantitative seven-day dietary questionnaire was concurrently applied to the mothers of children enrolled to estimate the latter's consumption of vitamin A-rich food. Vitamin A status was assessed by performing the modified relative dose-response test (MRDR) on dried blood spots (DBS) from a subsample of 207 children aged less than six years and the impression cytology with transfer (ICT) test on a subsample of 1,162 children. Of the children enrolled, 5.2% suffered from nightblindness, 8.0% had Bitot spots, and 2.5% had other vitamin A deficiency sequellae. Fifty-three percent of the ICT tests showed the presence of vitamin A deficiency. The biochemical MRDR test showed that the vitamin A status of 30% of the study children was critical. Twenty-seven of them had retinol levels of < 10 microg/dL [mean +/- standard deviation (SD) 7.02 +/- 2.0 microg/dL], and 50% had retinol levels of 10-20 microg/dL (mean +/- SD 14.2 +/- 2.83 microg/dL). The poor health status and low rates of consumption of vitamin A-rich food are the main factors determining critical status. Vitamin A deficiency, reflecting poor nutrition and health, is a serious public-health issue among children aged less than six years in Congo.

Supplementation with iron and riboflavin enhances dark adaptation response to vitamin A-fortified rice in iron-deficient, pregnant, nightblind Nepali women

BACKGROUND

Nightblindness affects 16-52% of pregnant women in areas of Nepal and in some cases persists after vitamin A treatment. Iron and riboflavin affect vitamin A utilization and photoreceptor function, respectively, and pilot data in the study population showed a high prevalence of iron and riboflavin deficiencies.

OBJECTIVE

The objective was to assess the effect of supplemental iron and riboflavin on pupillary threshold (PT) and plasma retinol in nightblind, pregnant Nepali women given vitamin A-fortified rice.

DESIGN

Nightblind pregnant women were randomly assigned to receive, 6 d/wk under supervision for 6 wk, a vitamin A-fortified rice curry dish providing 850 microg retinal activity equivalents/d with either a 30-mg Fe and 6-mg riboflavin (FeR + VA) capsule or a placebo control (VA only) capsule. Hemoglobin, erythrocyte riboflavin, and plasma ferritin and retinol were measured before and after the intervention. Dark adaptation was assessed by PT score.

RESULTS

Women who were iron deficient at baseline (n=38) had significantly greater improvement in PT score with iron and riboflavin supplementation than without (P=0.05). Iron and riboflavin supplements significantly reduced the prevalences of riboflavin deficiency (from 60% to 6%; P<0.0001), iron deficiency anemia (from 35% to 15%; P<0.007), and abnormal PT (from 87% to 30%; P<0.05) from baseline. Mean increases in erythrocyte riboflavin (P<0.0001) and plasma ferritin (P=0.01) were greater in the FeR + VA group than in the VA only group.

CONCLUSIONS

Iron deficiency may limit the efficacy of vitamin A to normalize dark adaptation in pregnant Nepali women. Further studies are needed to assess the effect of simultaneous delivery of iron and vitamin A for the treatment of nightblindness.

Electrophysiological findings in persons with nyctalopia

INTRODUCTION

Ophthalmologists are occasionally confronted with an individual presenting with nyctalopia (i.e., a relatively greater difficulty seeing at night). When there is no accompanying abnormality seen in the fundus, visual electrophysiology becomes useful as an objective means of assessing rod (scotopic) photoreceptor function or pathway defects.

MATERIALS AND METHODS

A retrospective study was performed on 50 consecutive patients, aged less than 40 years, with seemingly normal fundi and good vision [visual acuity (VA) >6/12] presenting to the Visual Electrodiagnostic Unit, Singapore National Eye Centre, for the investigation of nyctalopia over a 2-year period. Subjective scotopic threshold sensitivity (STS) and objective full-field electroretinogram (ERG) were performed. Persons with abnormal test results were identified.

RESULTS

Normal ERG scotopic responses were obtained in 74% of subjects. There was no significant difference in age, refraction and STS levels between subjects with abnormal and normal ERG. In the group with abnormal scotopic ERG responses, 9 were identified to have nonspecific rod dysfunction, 2 had rod-cone dystrophies and 2 had ERG changes suggestive of congenital stationary night blindness (CSNB).

CONCLUSION

A large number of subjects presenting with nyctalopia had normal ERG findings. We can only assume that in these patients, no significant rod pathway dysfunction exists and that optical (e.g., night or instrument myopia) and psychological aetiologies should be considered. The fact that an abnormal result occurs in 26%, however, suggests that ncytalopia should be evaluated with electrophysiolgoical testing even when the fundi appear normal.

Vitamin A deficiency disorders in children and women

Vitamin A deficiency is an endemic nutrition problem throughout much of the developing world, especially affecting the health and survival of infants, young children, and pregnant and lactating women. These age and life-stage groups represent periods when both nutrition stress is high and diet likely to be chronically deficient in vitamin A. Approximately 127 million preschool-aged children and 7 million pregnant women are vitamin A deficient. Health consequences of vitamin A deficiency include mild to severe systemic effects on innate and acquired mechanisms of host resistance to infection and growth, increased burden of infectious morbidity, mild to severe (blinding) stages of xerophthalmia, and increased risk of mortality. These consequences are defined as vitamin A deficiency disorders (VADD). Globally, 4.4 million preschool children have xerophthalmia and 6 million mothers suffer night blindness during pregnancy. Both conditions are associated with increased risk of morbidity and mortality. While reductions of child mortality of 19-54% following vitamin A treatment have been widely reported, more recent work suggests that dosing newborns with vitamin A may, in some settings, lower infant mortality. Among women, one large trial has so far reported a > or = 40% reduction in mortality related to pregnancy with weekly, low-dose vitamin A supplementation. Epidemiologic data on vitamin A deficiency disorders can be useful in planning, designing, and targeting interventions.

Association between gestational night blindness and serum retinol in mother/newborn pairs in the city of Rio de Janeiro, Brazil

OBJECTIVE

Gestational night blindness (XN) is associated with increased risk of reproductive morbidity and mortality. This study investigated the prevalence of gestational XN among postpartum women treated in a public maternity hospital in the city of Rio de Janeiro, Brazil and evaluated its association with maternal and neonatal (cord blood) serum retinol concentrations.

METHODS

XN was evaluated retrospectively, using an interview according to guidelines of the World Health Organization, in 222 postpartum women (< or = 6 h after delivery) after singleton births who had low obstetric risk. Serum retinol concentrations were measured according to the modified Bessey method, with a cutoff point lower than 1.05 micromol/L for inadequate serum retinol concentration.

RESULTS

Prevalence of gestational XN was 18%, and inadequate maternal and cord blood serum retinol concentrations were found in 24.4% and 45.5% of samples, respectively. The results associated gestational XN with inadequate maternal serum retinol concentration (P = 0.000), and an association was observed between maternal and neonatal serum retinol concentrations (P = 0.000). A poor association was observed between maternal XN and serum levels of retinol in newborn children (P = 0.06).

CONCLUSIONS

The results suggest that prevalence of gestational XN and inadequate serum retinol concentration among postpartum women and newborns is a concern, calling attention to the need for studies in other parts of Brazil. In addition, the risk of inadequate serum retinol in newborns was significantly higher among infants of postpartum women with serum retinol levels below 1.05 micromol/L. Gestational XN was associated with inadequate levels of maternal serum retinol, and the results suggest a poor relation between maternal XN and vitamin A nutritional status of newborns.

Gestational nightblindness among women attending a public maternity hospital in Rio de Janeiro, Brazil

This study evaluated the prevalence of gestational nightblindness among postpartum women seen at the University Maternal Hospital of the Federal University in Rio de Janeiro, Brazil and the association of this symptom with a biochemical indicator (serum retinol levels) and sociodemographic, anthropometric and antenatal care variables. In total, 262 postpartum women, who did not receive vitamin A supplementation during pregnancy, were interviewed. Gestational nightblindness was diagnosed through the standardized interview as proposed by WHO. Serum retinol levels were evaluated by spectrophotometry. Gestational nightblindness relating to low levels of serum retinol (<1.05 micromol/L, p = 0.000) was diagnosed in 17.9% of subjects interviewed. Less than five antenatal care appointments (odds ratio [OR] = 2.179; confidence interval [CI] 95% = 1.078 - 4.402) and a history of one or more miscarriage(s) (OR = 2.306; CI 95% = 1.185 - 4.491) were predictors for gestational nightblindness. These findings justify the need for nutritional counselling, aimed at improving the vitamin A nutritional status, especially among pregnant women with a history of previous miscarriages and poor antenatal care.

Vitamin A deficiency in Afghanistan

PURPOSE

To evaluate children 6 years old and younger, lactating mothers, and women of childbearing age for vitamin A deficiency in the districts of Kabul City, Afghanistan.

METHODS

A set number of patients selected randomly in all 13 districts of the city limits were examined between August and September 2000 for ocular signs of vitamin A deficiency.

RESULTS

Night blindness, Bitot's spot, corneal ulceration, and corneal scars were seen in increased amounts as defined by the World Health Organization among the sampled population.

CONCLUSIONS

Vitamin A deficiency is a moderate to severe public health problem in children and lactating mothers in Kabul City, Afghanistan.

The night vision threshold test is a better predictor of low serum vitamin A concentration than self-reported night blindness in pregnant urban Nepalese women

This study was conducted to validate the night vision threshold test (NVTT) as an indicator of night blindness. A total of 1401 pregnant women from the National Maternity Hospital participated in this study. Women were queried about night blindness and took the NVTT using standardized procedures after 10 min of dark adaptation. Sixteen percent failed the NVTT, but only 6.4% reported having night blindness. Blood samples from women who failed the NVTT (cases) and matched controls indicated the serum vitamin A (SVA) concentration was lower (P < 0.05) in cases (1.19 +/- 0.03 micromol/L) than in controls (1.29 +/- 0.03 micromol/L). The SVA concentrations did not differ between women who reported and did not report night blindness. The SVA concentration was correlated (r = 0.22, P < 0.001) with the NVTT scores. Twenty-five percent of women with an SVA < 0.35 micromol/L reported night blindness while 100% failed the NVTT. Nineteen percent of women with an SVA < 0.70 micromol/L reported night blindness while 73% failed the NVTT. A receiver operating characteristics analysis indicated that the NVTT had greater sensitivity (0.73 vs. 0.19) and less specificity (0.51 vs. 0.87) compared with reported night blindness for women with SVA < 0.70 micromol/L and greater sensitivity (100.0 vs. 0.73) and similar specificity (0.51 vs. 0.50) for women with SVA < 0.35 micromol/L. The NVTT identified women with low SVA and self-reported night blindness was misleading. We provide a preliminary algorithm to predict the population of women with low SVA concentrations.

Validation of night blindness reports among children and women in a vitamin A deficient population in rural Tanzania

OBJECTIVE

This study validates different definitions of reported night blindness (XN) in a vitamin A deficient African population with no local term for XN.

DESIGN

Case-control study with follow-up after treatment.

SETTING

Eight primary schools and health centres in rural Tanzania.

SUBJECTS

A total of 1214 participants were screened for reported XN and other eye signs of xerophthalmia: 461 children aged 24-71 months, 562 primary school-age children and 191 pregnant or breast-feeding women. All 152 cases of reported XN were selected for the validation study and group matched with 321 controls who did not complain of XN. XN reports were validated against serum retinol concentrations and pupillary dark adaptation measurements in cases and controls.

INTERVENTION

All children and women who reported XN or had other signs of active xerophthalmia were treated with vitamin A and followed up 3-4 weeks later. Half of the untreated control group who had their serum retinol examined in the baseline examination were also followed up.

RESULTS

The overall prevalence of reported XN was 12.5%. At baseline, mean pupillary threshold (-1.52 vs -1.55 log cd/m(2), P=0.501) and median serum retinol concentrations (0.95 vs 0.93 micromol/l, P=0.734) were not significantly different in cases and controls either overall or in each population group. More restricted case definitions reduced the prevalence of reported XN to 5.5% (P<0.001), but there was still no significant difference between cases and controls although the results were in the expected direction. After treatment, the median serum retinol concentration improved significantly only in the most deficient group, the young children. Dark adaptation improved in all the subgroups but the difference was only significant for young children and primary school-age children when the restricted case definitions were used.

CONCLUSIONS

XN reports are a poor indicator of vitamin A deficiency in this population.

SPONSORSHIP

Task Force Sight and Life, Basel, Switzerland.

Risk factors for nightblindness among women of childbearing age in Cambodia

OBJECTIVE

To characterize risk factors for nightblindness among nonpregnant women of childbearing age, a group recently recognized to be at high risk of vitamin A deficiency in some developing countries.

DESIGN

Case-control study.

SETTING

The study included >15 000 households in National Micronutrient Survey of Cambodia conducted in 2000.

SUBJECTS

The prevalence of nightblindness among 13 358 nonpregnant women was 2.0%. A total of 328 nonpregnant women with nightblindness were matched by province with 1009 nonpregnant women without nightblindness.

METHODS

Univariate and multivariate logistic regression models were used to estimate odds ratios (ORs) as estimates of the relative risk of factors associated with nightblindness.

RESULTS

In a final model, materials in the wall of the house (OR 1.4, 95% confidence interval (CI) 0.9-2.0), land ownership < or =0.5 hectares (OR 1.4, 95% CI 1.0-1.9), nightblindness in last pregnancy (OR 44.5, 95% CI 29.2-67.8), parity >3 (OR 1.5, 95% CI 1.0-2.1), diarrhea within the last 2 weeks (OR 1.9, 95% CI 1.3-2.8), maternal body mass index <18.5 (OR 1.8, 95% CI 1.2-2.7), and lack of consumption of vitamin A-rich animal foods in the last 24 h (1-60 retinol equivalents (RE) OR 1.1, 95% CI 0.7-1.6; > or =60 RE, OR 0.7, 95% CI 0.4-1.0) were associated with nightblindness among nonpregnant women.

CONCLUSIONS

Women of childbearing age in Cambodia with low socioeconomic status, low consumption of vitamin A-rich animal foods, a history of nightblindness during the previous pregnancy, parity >3, malnutrition, and diarrhea have a higher risk of nightblindness.

SPONSORSHIP

United States Agency for International Development (442-G-00-95-00515-00).

Current status of vitamin A deficiency and the National Vitamin A Control Program in Nepal: results of the 1998 National Micronutrient Status Survey

The overall objective of the Nepal Micronutrient Status Survey (NMSS) was to assess the distribution and severity of micronutrient malnutrition, and to measure the progress achieved by different interventions. Data presented in this paper concern the prevalence of vitamin A deficiency (VAD) and the outreach and coverage of the National Vitamin A Supplementation activity. A multi-stage cluster sample design was employed that provided statistically representative data for each of thirteen eco-development strata (because of low population density, the West Mountains, Mid-west Mountains and Far-west Mountains were combined into a single stratum). The design allowed for aggregate estimates to be made at the national and ecological zone level. The survey showed a significant improvement in the status of clinical vitamin A deficiency in Nepal. The prevalence of both Bitot's spots and night-blindness among preschool children decreased from levels observed in surveys conducted in the previous twenty years. However, the prevalence of night-blindness was found to be 5% among women, and over 1% among school-aged children, which indicates that the entire population is vulnerable to VAD. These observations support findings from other surveys that have noted a high prevalence of maternal night-blindness in Nepal. Biochemical data collected as part of the survey indicated a high prevalence of low serum retinol (< 0.70 mumol/l), particularly among preschool children. Almost one of every three children (32.3%) and one of every six women (16.6%) had low serum retinol values. Low serum retinol among preschool children was associated with young age (6-11 months), rural location, wasting, presence of night-blindness and Bitot's spots, and residence in the Terai or Mountains. Similarly, sub-clinical VAD in women was associated with age (less than 20 years), pregnancy, the presence of night-blindness and residence in the Terai or Mountains. In the 42 districts covered by the National Vitamin A Programme (NVAP), more than 87% of preschool children were reached with vitamin A capsules. In addition to this, the National Immunisation Day (NID) provided oral polio vaccine drops to an estimated 95.7% of children 12-59 months. Awareness of the importance of vitamin A was, however, much higher in the NVAP districts than in non-programme districts. As would be expected, clinical VAD was most prevalent among children who had not received vitamin A during the most recent vitamin A capsule distribution. Indeed, the data show that vitamin A capsule receipt among children conferred a 59% protective effect for night-blindness and a 51% effect for Bitot's spots. These results point to significant progress having been achieved by the NVAP and NID capsule distribution activities.

National immunisation days and vitamin A distribution in Mali: has the vitamin A status of pre-school children improved?

OBJECTIVES

The impact on vitamin A status of the distribution of vitamin A during national immunisation days (NIDs) has not been well established despite strong promotion by international agencies and donors. Using a pre-post design, the change in prevalence of vitamin A deficiency was examined in pre-school children in Mali.

DESIGN

Two cross-sectional surveys were conducted in Mopti region, the first in March 1997 before this strategy was adopted and the second in March 1999, four-and-a-half months after a mass distribution of vitamin A during NIDs.

SUBJECTS AND SETTING

We compared the vitamin A status of children aged 12 to 66 months targeted in 1999 by NIDs with the status of children in the same age group in 1997. Infectious events of the previous two weeks were concurrently recorded. Within the 1999 sample, the status of recipient and non-recipient children was also compared.

RESULTS

In 1997, the prevalence of xerophthalmia (defined by the presence of night blindness and/or Bitot spots) was 6.9% (95% confidence interval (CI) 5.1-9.2) and the modified retinol dose response (MRDR) test proved abnormal in 77.8% of 12-66-month-old children (95% CI 68.27-85.17). In 1999 this picture had improved significantly, both for xerophthalmia prevalence, 3.3% (95% CI 2.1-5.2), and abnormal MRDR test response, 63.1% (95% CI 54.25-71.23). The infectious morbidity rates between 1997 and 1999 tended to decrease. No significant improvement was found among children older than those targeted by NIDs. In 1999, children who received vitamin A had a lower risk for xerophthalmia (3.0% for recipients vs. 8.7% for non-recipients) and experienced fewer infectious events.

CONCLUSIONS

The clinical and biological vitamin A status of pre-school children improved between 1997 and 1999. Mass distribution of vitamin A appears to reduce the occurrence of xerophthalmia and would seem to be associated with a decrease in other related illnesses. Vitamin A supplementation during NIDs should be given a high priority when vitamin A deficiency remains a public health problem.

[Hypovitaminosis A in Brazil: a public health problem]

Vitamin A deficiency is considered one of the most important of the easily preventable public health problems in a number of countries, including Brazil. The objective of this study was to review the scientific literature in the MEDLINE and LILACS databases that was published between 1970 and 2000 concerning vitamin A deficiency, and to assess the occurrence of hypovitaminosis A in Latin America, especially Brazil. Our research showed that until around 1980 the public health concerns focused mainly on the importance of vitamin A in ensuring good vision. In the second half of the 1980s, epidemiological studies suggested that, on a population level, subclinical vitamin A deficiency could also have a negative effect on metabolic functions, with a great impact on childhood morbidity and mortality. Marginal vitamin A deficiency has been reported in all the regions of Brazil for which there are data available, with high prevalences in various age groups. This situation is inexcusable, given the health care technology and resources that are now available. There must be a commitment to reducing vitamin A deficiency in order to ensure the adequate development of future generations.

Prevalence of undernutrition and vitamin A deficiency in the Dogon Region, Mali

OBJECTIVES

A representative sample of 1510 preschool children living in the Bandiagra circle (Mopti Region, Mali) was examined between March and April 1997 to determine the level of vitamin A deficiency.

METHODS

Using a randomized two level cluster sampling, 20 clusters of 75 children aged six months to six years were selected for evaluating xerophthalmia (XN night blindness and/or X1B Bitot spot). Concurrently stature and weight were determined. A semiquantitative seven-day dietary questionnaire was applied to the mothers of 484 infants to assess consumption of vitamin A rich foodstuffs. The prevalence of biochemical deficiency was attested using the Modified Relative Dose Response test (MRDR) on a sub-sample of 192.

RESULTS

Of the studied children, 4.3% (95% Confidence interval [CI]: 3.2-5.3) reported night blindness and 2% (95% CI: 1.3-2.7) had Bitot spots. Prevalence of xerophthalmia attested by at least one of these signs was 5.4% (95% CI: 4.2-6.5). The prevalence reached 10.5% at three years of age. The MRDR test proved abnormal in 77.1% of the subjects (95% CI: 70.3-82.7). Serum retinol was lower than 0.35 micro mol/L in 43.8% (95.6% CI: 36.9-51.3) and less than 0.70 micro mol/L in 92.7% of the children (95% CI: 87.8-95.8). Weekly consumption of vitamin A rich food was rare: 75.8% had not eaten any animal vitamin A rich food, and 22.1% had consumed less than seven times a vitamin A rich food of either vegetable or animal origin.

CONCLUSIONS

These data define vitamin A deficiency as a severe public health problem in the Bandiagara area of Mali.

Recommendations for indicators: night blindness during pregnancy--a simple tool to assess vitamin A deficiency in a population

Night blindness during pregnancy caused by vitamin A deficiency is associated with an increased risk of morbidity and mortality among women. Because a history of maternal night blindness is simple and reliable to use, it is recommended as a population-based indicator of vitamin A deficiency. Furthermore, a maternal night blindness prevalence of >/=5% is recommended as a cut-off at which vitamin A deficiency may be considered to be a problem of public health significance within the community. This paper provides the justification for these recommendations. Night blindness during pregnancy is strongly associated with low serum and breast milk vitamin A concentration, abnormal conjunctival impression cytology and impaired dark adaptation, which suggests that it is a valid indicator of vitamin A deficiency. The prevalence of night blindness during pregnancy tends to be high in countries where the prevalence of xerophthalmia in children is high and in countries where interventions are in place to reduce childhood vitamin A deficiency. Existing data suggest that misclassification of self-reported maternal night blindness may account for a prevalence of up to 3%. The suggested cut-off, 5%, is set higher than this potential level of false-positive prevalence (3%). Illustrative data from India and Cambodia on childhood xerophthalmia and maternal night blindness rates are used to demonstrate the validity of using a 5% prevalence of maternal night blindness as indicative of a community vitamin A deficiency problem. Finally, it is recommended that night blindness history be elicited for a previous pregnancy that ended in a live birth in the past 3 y, using the local term for night blindness whenever possible.

Prevalence of vitamin A deficiency among pre-school and school-aged children in Arssi Zone, Ethiopia

OBJECTIVE

To investigate vitamin A status of pre-school and school aged children in the study area.

DESIGN

Cross-sectional.

SETTING

Arssi, Ethiopia.

SUBJECTS

Four hundred and two children.

RESULTS

Night blindness, Bitots spot, corneal xerosis, corneal ulceration and corneal scar were observed in 7.2%, 2.2 %, 0.2%, 0.5%, and 0.5% of the children respectively. The prevalence of xerophthalmia was higher in school aged children than pre-school children (P< 0.0001). Based on the WHO recommended cut-off level, serum retinol levels were in the "low" range (<20 microl/dl) in 51% of the children.

CONCLUSION

The results indicate that vitamin A deficiency (VAD) is a public health problem in Arssi, with higher prevalence among school aged children than pre-school children.

Vitamin A deficiency disorders in 16 districts of India

A multicentre study to assess vitamin A deficiency disorders (Bitot's spot and corneal scars) in 164,512 children (< 6 years) and night blindness among 113,202 children (24-71 months) from 16 districts of 11 states was carried out during 1997-2000. The prevalence of night blindness among 6,633 pregnant women from 15 districts was also assessed. The sampling methodology followed was a "30 cluster survey". The highest prevalence of Bitot's spot (4.71%), corneal scar (0.5%) and night blindness (5.17%) in children was found in Gaya district whereas the highest prevalence of night blindness (19.62%) among pregnant women was observed in Dibrugarh. No case of Bitot's spot was found in children screened from Mandi, Dehradun and Badaun districts. Similarly prevalance of night blindness was 'nil' among pregnant women of Badaun, Baramulla, Dehradun, Mainpuri, Srinagar, Bikaner and Raigarh.

Evaluation of vitamin A status during pregnancy

Adequate maternal vitamin A nutrition is essential for successful pregnancy outcome and estimation of serum retinol among pregnant women enables a precise and objective assessment of vitamin A status, during pregnancy, even in subclinical state. In order to evaluate vitamin A status during pregnancy, and its relationship with personal and pregnancy related variables of the mother, 300 antenatal clinic attenders were interviewed at RG Kar Medical College and Hospital, Calcutta and tested for serum retinol, using Carr-Price test. Serum retinol values less than 30 microg/dl and 20 microg/dl, in this study, were considered as poor and severe vitamin A deficiency respectively. According to this 14.7% and 4% pregnant women were found to be suffering from poor and severe vitamin A deficiency respectively. Clinical signs of vitamin A deficiency (eg, nightblindness) were reported only among 60% cases of the deficient population. The problems of vitamin A deficiency were associated with low literacy and poor nutritional status of the mother, advanced gestational age of current pregnancy,increased number of pregnancies, shorter interval between births and poor dietary intake of vitamin A rich foods during pregnancy. The study thus raises the question of supplementation of vitamin A, during pregnancy, in Indian context where habitual diets are either inadequate or deficient in vitamin A.

Vitamin A deficiency in children with acute diarrhoea: a community-based study in Bangladesh

The prevalences of nightblindness and xerophthalmia were assessed in 400 children, aged 6-59 months, with acute diarrhoea in a rural community in Bangladesh. The prevalences of nightblindness, conjunctival xerosis, and Bitot's spot were 7.8%, 9.5%, and 2.7% respectively. Fifty-two percent of the children who complained of nightblindness had ocular signs of vitamin A deficiency compared to 9% of those without nightblindness (p < 0.000). The nightblindness was significantly higher among the male children, aged 24-59 months, who were dysenteric and undernourished, did not consume vitamin A-containing foods daily, and were not breastfed. The coverage of periodic administration of vitamin A capsule was inversely related to the prevalence of nightblindness. This finding was determined by logistic regression analysis of data indicating that a combination of male sex, history of dysentery, absence of periodic administration of vitamin A treatment, and daily intake of vitamin A-containing foods gave the best-fitted model with an overall prediction of 92.5% of being nightblind. The findings of the study suggest that mothers should be educated to observe their diarrhoeal children about development of nightblindness and to seek treatment for it. The locally-relevant nutrition education should also be offered to them.

The Night Vision Threshold Test (NVTT): a simple instrument for testing dark adaptation in young children

It is estimated that 41 per cent of the population aged under 5 in the developing world has an inadequate vitamin A dietary intake resulting in increased morbidity and mortality. Half a million children go blind each year as a result of vitamin A deficiency. Thirteen and a half million have night blindness, the first sign of vitamin A deficiency. Unfortunately, there is no simple, sensitive and inexpensive means to identify the child who has marginal levels of vitamin A and thus institute means to prevent their development of severe deficiency. A low cost, simple, easy-to-use instrument designed to detect a young child's ability to adapt to darkness was tested in children admitted to the Mwanamugimu Nutrition Unit at Makerere Medical School in Kampala, Uganda. Despite the severe degree of malnutrition found in these children, Night Vision Threshold Test results and serum retinol levels were related (r = 0.41, p < 0.05). Further efficacy trials for this instrument are planned at community sites in Nepal.

Endemic goiter with iodine sufficiency: a possible role for the consumption of pearl millet in the etiology of endemic goiter

BACKGROUND

Deficiencies of iodine, iron, and vitamin A are the 3 most common micronutrient deficiencies in developing countries, although control programs, when properly implemented, can be effective.

OBJECTIVE

We investigated these deficiencies and their possible interaction in preschool children in the southern Blue Nile area of Sudan.

DESIGN

Goiter, signs of vitamin A deficiency, and biochemical markers of thyroid, vitamin A, and iron status were assessed in 984 children aged 1-6 y.

RESULTS

The goiter rate was 22. 3%. The median urinary iodine concentration was 0.79 micromol/L and 19.3% of the children had a concentration >1.57 micromol/L. Although serum thyroxine and triiodothyronine concentrations were within reference ranges, the median thyrotropin concentration was 3.78 mIU/L and 44% of the children had thyrotropin concentrations above normal. The mean urinary thiocyanate concentration was high (259 +/- 121 micromol/L). The prevalences of Bitot spots and night blindness were 2.94% and 2.64%, respectively, and 32% of the subjects had serum retinol binding protein concentrations <15 mg/L. A significant positive correlation was observed between thyrotropin and retinol binding protein. Whereas 88% of the children had hemoglobin concentrations <1.86 mmol/L, only 13.5% had serum ferritin concentrations below the cutoff of 12 microg/L and 95% had serum transferrin concentrations above the cutoff of 2.50 g/L.

CONCLUSIONS

Our results indicate that goiter is endemic in this region of Sudan despite iodine sufficiency and that both anemia and vitamin A deficiency are health problems in the area. Moreover, consumption of millet, vitamin A deficiency, and protein-energy malnutrition are possible etiologic factors in this endemic area.

Vitamin A or beta-carotene supplementation reduces but does not eliminate maternal night blindness in Nepal

We investigated the effect of supplementing women weekly with 7000 microg retinol equivalents as preformed vitamin A or beta-carotene vs. a placebo, on the incidence of night blindness during pregnancy and the postpartum period in the rural plains of Nepal. Over a period of approximately 3 y, approximately 29,000 women of child-bearing age, living in 171 wards that were randomized to one of the three supplements, contributed 9932 first pregnancies. A prospective, weekly surveillance identified night blindness in pregnant women, verified further by detailed questioning about nighttime vision. After delivery, women were also interviewed at approximately 3 and approximately 6 mo postpartum to elicit a night blindness history over the preceding 3 mo. Vitamin A supplementation reduced the incidence of night blindness during pregnancy from 10.7% among controls to 6.7% (relative risk 0.62, 95% confidence interval: 0.45-0.85). beta-Carotene supplementation had less of an effect (0. 83, 0.63-1.11). Among women who took >95% of their vitamin A supplements during pregnancy, incidence of verified night blindness was reduced by 67%. Incidence (per 100 person-years) of night blindness during the first 3 mo postpartum was 11.3 in the control, 4.3 in the vitamin A and 8.7 in the beta-carotene groups, yielding corresponding relative risks of 0.38 (0.26-0.55) and 0.77 (0.57-1. 04). In the second 3 mo postpartum, both vitamin A and beta-carotene reduced night blindness by approximately 50%. Vitamin A intakes approaching a recommended amount for pregnancy markedly reduced but did not eliminate night blindness in Nepali women. Greater intakes of vitamin A than provided and/or other nutrients may be needed to prevent maternal night blindness in rural South Asia.

Night blindness of pregnancy in rural Nepal--nutritional and health risks

BACKGROUND

Night blindness (XN) is the most common clinical symptom of vitamin A deficiency among children in developing countries. Yet little is known about the aetiology or associated risks of maternal XN. Emerging evidence from South East Asia suggests that it may be more frequent than previously thought in women of reproductive age, especially during pregnancy.

METHODS

A population-based, case-control study was conducted to reveal the epidemiology of XN among pregnant Nepali women. Night blind cases were identified by history through a weekly community surveillance system. Controls were randomly selected from a pool of pregnant women without XN and pair-matched for gestational age of the cases. A home-based assessment was done within a week of selection, at which 7-day food frequency and morbidity histories were collected, anthropometry measured, and capillary blood drawn for serum retinol, beta-carotene and haemoglobin (Hb) estimation.

RESULTS

Cases and controls did not differ by age or number of previous pregnancies. However, cases were more likely to be from the lower castes, be illiterate, live in poorer quality homes, and own no land. The mean serum retinol level of cases was approximately 0.30 mumol/l lower than controls (P < 0.001), indicating a low vitamin A status of night blind pregnant women. Mean Hb level was significantly lower (by 0.7 g/dl, P < 0.004), and the risk of severe anaemia (Hb < 7.0 g/dl) higher among cases than controls (odds ratio = 3.0, 95% CI: 1.25-7.23). Cases were more under-nourished than controls reflected by lower mean weight (-2.6 kg), body mass index (-0.8), arm circumference (-0.9 cm) and triceps skinfold (-0.8 mm). Night blindness was associated with less frequent consumption of preformed vitamin A (milk products, fish and meat) and provitamin A (dark green leafy vegetables and mangoes) foods, especially in summer. Night blind women were 2-3 times more likely to report symptoms of urinary/reproductive tract infections such as lower abdominal pain, painful and burning urination, or vaginal discharge, symptoms of diarrhoea/dysentery, of pre-eclampsia or eclampsia, and of nausea, vomiting or poor appetite throughout pregnancy than controls.

CONCLUSION

Women who experience XN during pregnancy have a low vitamin A status, although several other risk factors appear to cluster among these women as well. Night blind women are also more likely to be anaemic, ill, and acutely under-nourished, and to be consuming a nutritionally poorer diet in pregnancy than non-night blind pregnant women. A simple history of XN can identify women at high risk during pregnancy who may require special nutritional support, antenatal care and counselling.

An ethnographic study of night blindness "ratauni" among women in the Terai of Nepal

Night blindness is the most common ocular condition representing moderate-to-severe vitamin A deficiency in children. Very little, however, is known about maternal night blindness, which has recently been reported to occur frequently during pregnancy in parts of south-east Asia. In Nepal, the prevalence of night blindness is reported to be 16%. We carried out an ethnographic study of night blindness during pregnancy in the south-eastern, rural plains of Nepal as preliminary research for a case-control study of the determinants of this condition. The purpose of the research was to identify local terms and concepts of night blindness and to examine women's perceptions of its causes, symptoms, severity, and consequences during pregnancy. Data collection involved in-depth interviews, case studies, unstructured observations and structured anthropologic methods, such as free listing and quick sort ranking. Women considered night blindness to be an important illness of pregnancy, ranking it second (to vaginal bleeding) in perceived severity from a list of 15 "women's illnesses". Local terms for night blindness were identified in three different languages from the region. Informants described a complex ethnomedical model of night blindness that included causes, symptomatology, and treatment alternatives. However, there was no perceived link between food intake and the occurrence of night blindness. The major causes of night blindness were attributed to pregnancy, weakness, or "hotness". Some women sought treatment for the condition but most women chose not to treat it since they believed that it was a transient condition of pregnancy. Interviews with women who had previously experienced night blindness and home-based observations of women exhibiting concurrent night blindness showed that it adversely affected their activity patterns, especially those related to child care and food preparation. Night blindness increased reliance on family members to perform various domestic chores and was also associated with personal injury and accidents. The findings of this study have relevance for women's reproductive health and nutrition throughout the Indian sub-continent. A simple history of night blindness may be a practical tool to identify women with nutritional and health risks. Maternal night blindness should be more routinely investigated in vitamin A deficient areas of the world, both to define the magnitude of the problem, and to develop programs/interventions that specifically target this population.

Case report of Usher's syndrome in two sisters--first reported case in Singapore

A 28-year-old Chinese woman presented with poor night vision since childhood. Ocular examination showed pigmentary retinopathy and systemic examination revealed sensorineural hearing loss. Family history showed a similar condition in her youngest sister. Ocular and systemic examination of her sister showed similar findings. This is presented as the first case report of Usher's syndrome in Singapore. A general discussion of Usher's syndrome is also presented.

Protein energy malnutrition, vitamin A deficiency and night blindness in Bangladeshi children

The occurrence of night blindness and serum vitamin A concentrations among children in rural Bangladesh were studied in relation to protein energy malnutrition, dietary habits and intake of vitamin A capsules. In 1992, 124 night-blind children were registered in a cross-sectional survey in the northern part of Bangladesh, and age-, sex- and neighbourhood-matched controls were selected. Of these, the first reported night-blind child from a household (n = 105) and their controls were included in the analyses. Our results showed that night blindness was associated with protein energy malnutrition when using the mid-upper arm circumference (MUAC) as a measure of nutritional status. The odds ratio for a confirmed diagnosis of night blindness among children with a MUAC < 80% of the reference versus normal children was 5.4 (CI 1.9-15.5). Low MUAC was associated with low intake of beta-carotene-rich and vitamin A-containing foods as well as with low serum vitamin A in the total series of cases and controls. This may indicate that night blindness is only one aspect of the general protein energy malnutrition problems in this population. We therefore suggest that measures to prevent vitamin A-related morbidity and mortality should include improvement of the general diet with increased consumption of dietary vitamin A.

Serum vitamin A in relation to socio-economic, demographic and dietary characteristics in Bangladeshi children

The purpose of this study was to examine socio-economic conditions, demographic factors, use of vitamin A capsules and dietary practices in relation to the risk of low serum vitamin A. One hundred and twenty four night blind cases were identified by parents in a cross-sectional survey in Bangladesh in 1992. Age-, sex- and neighbourhood-matched controls were selected. Venous blood was collected from 87 cases and 97 controls for the determination of serum vitamin A. Information about socio-economic conditions, demographic factors, use of vitamin A capsules and dietary practices was obtained by interview. The level of serum vitamin A was strongly related to age and consumption of beta-carotene rich foods. The preschool years (2-6 years) are important risk periods for vitamin A deficiency among children. We conclude that long-term prevention of vitamin A deficiency should rely on efforts to improve local diet.

Vitamin A deficiency and protein-energy malnutrition in a sample of pre-school age children in the Kivu Province in Zaire

OBJECTIVE

To assess pre-school age children's vitamin A status in a population where protein-energy malnutrition is endemic and serum retinol binding protein and transtyretin concentrations are low.

DESIGN

A cross-sectional study.

SETTING

Health district of Katana, South-Kivu, Zaire.

SUBJECTS

415 pre-school age children.

METHODS

Three methods were used to assess vitamin A status: ophtalmological examination, retinol serum concentration and Relative Dose Response (RDR) test.

RESULTS

The only ophthalmological signs of vitamin A deficiency appeared in two cases of night blindness, which represents a prevalence of 0.7%. Deficient serum retinol concentration (< 0.35 mumol/l) was found in 19.7% of the whole study population and in 10.4% of non-infected children in good nutritional status. RDR test carried out on a reduced sample of 79 subjects was abnormal for 7.6% of the children but showed a low sensitivity when compared with serum retinol concentration.

CONCLUSION

This survey suggests that in this population of the South-Kivu Province in Zaire, vitamin A deficiency co-exists with protein-energy malnutrition and is a public health problem even with non-malnourished and non-infected children.

Environmental conditions, health behavior, and mortality in siblings as risk indicators of night blindness

The purpose of the study was to estimate the association of environmental factors (water and sanitation), health behavior (breast feeding practice and vaccination), and mortality among siblings with night blindness. A total of 5,420 children were enrolled in a cross-sectional study from 2,101 households in the northern part of Bangladesh, a high risk area for night blindness. One hundred twenty-four children were reported by parents to have night blindness. Our results indicated that environmental factors, health behavior, and the death of siblings were significantly associated with the occurrence of night blindness in crude analyses, as well as in analyses with adjustment for a number of potential confounding variables. The strongest association was noted for sibling death. The findings support the notion that night blindness should not be viewed as an isolated health problem and that approaches aimed at improving vitamin A status should also include interventions directed to environmental and health-associated behavioral factors.

Sustainability of a nutrition education programme to prevent night-blindness in Bangladesh

Cross-sectional surveys were conducted to assess prevalence of night-blindness and dietary habits prior to intervention (in 1986), after 3 years of intervention (in 1989) and 3 years after the termination of active intervention (in 1992), in the northern part of Bangladesh. The prevalence of night-blindness per thousand children decreased from 1986 to 1989 (during intervention) and rose from 1989 to 1992, but remained significantly lower in 1992 than the 1986 prevalence. Household income declined from 1989 to 1992, and lower consumption of beta-carotene rich food, protein items and vitamin A capsules was registered in 1992 despite almost the same level of awareness relating to the prevention of night-blindness in the community during the period 1989-1992. The results indicate that the long-term impact of a health education programme to prevent night-blindness is uncertain. Improvement in socioeconomic conditions, in addition to relevant knowledge, is probably a precondition for maintaining a sustainable impact of health education.

Night blindness is prevalent during pregnancy and lactation in rural Nepal

The prevalence of night blindness during pregnancy and lactation was assessed in a sample of 426 women living in the rural terai of Nepal. These women were also examined for ocular signs of vitamin A deficiency. Among 241 lactating women, 16.2% reported experiencing night blindness at some time during the pregnancy that produced the infant they were now breast-feeding. Among 185 pregnant women, 8.1% reported being night-blind at the time of the interview. The odds of night blindness in the current pregnancy were six times greater for women who reported night blindness in their previous pregnancy. Night-blind women were more likely to come from households with lower socioeconomic status. Teenage women and those over the age of 30 were at highest risk, particularly those of higher parity within these age groups. Vitamin A deficiency, for which night blindness is a marker, seems to be a problem in this population of pregnant and lactating women, with potential health consequences for women and their infants.

[Xerophthalmia. Identification of populations at intermediate risk]

In developing countries, vitamin A deficiency (VAD) is a major contributor to child blindness and is associated with increased mortality. We assessed the vitamin A status of a Sahelien population and evaluated the correlation between the various criteria used to score xerophthalmia. The survey was carried out between June 1992 (the end of the dry season) using a representative sample of 906 children between the ages of 3 and 7 years in the district of Douentza. The population sample was selected by a two stage cluster sampling method (villages and then households). Vitamin A status was evaluated using clinical, histological and nutritional criteria. Clinical examination included testing for night blindness (XN), Bitot's spots (X1B) and corneal scars (XS). The Impression Cytology with Transfer (ICT) test described by Amedee-Manesme was used for histological analysis. Cases of follicular trachoma were recorded because of the possible influence of active trachoma on the findings of the ICT test. Nutritional status was determined by measuring the height for weight ratio according to the National Center for Health Statistics criteria. The prevalence of XN was 2.7% (1.6-3.7), significantly higher than the WHO threshold for a public health problem. The prevalence of X1B was 0.5% (0.1-1.2), and no corneal scars were detected. 31.7% of the children were suffering from malnutrition, but malnutrition did not correlate with any of the ophthalmological indicators of a public health problem. Among the 842 readable ICT tests, 265 were abnormal (31.4% of the total, 28.2-34.5). This incidence of abnormal results was unexpectedly low, in the light of the clinical results, and well below the threshold value of 50% suggested by Carlier.(ABSTRACT TRUNCATED AT 250 WORDS)

Pupillary and visual thresholds in young children as an index of population vitamin A status

A prototype scotopic sensitivity machine was used to evaluate pupillary and visual thresholds for 295 Indonesian children aged 1-5 y, most of whom were initially vitamin A-deficient. Subjects were tested 6 and 9 mo after receiving a high dose of vitamin A. A group of 136 older children was tested at 6 mo after dosing; all subjects underwent testing at 9 mo. After testing at 9 mo, children randomly received either a second high dose of vitamin A or placebo and were tested a final time 2 wk later. Children with abnormal pupillary thresholds had significantly higher relative dose responses (RDRs) (P < 0.01) and significantly lower serum retinol values (P = 0.05) than did normal children. The mean pupillary threshold rose (eg, retinal sensitivity fell) as vitamin A status deteriorated between 6 and 9 mo after initial dosing, and was significantly different from a group of normal American children tested previously (P < 0.001). After placebo-controlled dosing, the decline in pupillary and visual thresholds (rise in retinal sensitivity) was significant for children receiving vitamin A but not for children receiving placebo.

Diagnosis of night blindness and serum vitamin A level: a population-based study

In a cross-sectional survey of 5420 children in northern Bangladesh, 124 were reported to have night blindness by their parents. Of these, 105 cases along with controls matched for age, sex, and neighbourhood had their scotopic vision examined under standard condition using a luxometer, underwent an ophthalmological examination, and had their serum vitamin A level determined. The mean serum vitamin A level was lowest among children identified as night blind by both their parents and the investigators (16.3 micrograms/dl; 95% confidence interval (CI), 13.9-18.7) and highest among those identified as not night blind by both their parents and the investigators (23.6 micrograms/dl; 95% CI, 21.3-25.9). The results show that parents' report of their children's night blindness had low sensitivity compared with diagnosis using standard observations of scotopic vision with a luxometer.

Evaluation of vitamin A deficiency in the Yelimane Circle of Mali, west Africa

Of 207 children (aged 4-7 years) in western Mali examined clinically and by conjunctival impression cytology (CIC), 2% had night blindness, no child had Bitot spots and 78% were found to have abnormal CIC suggesting deficiency in vitamin A. In a cohort of 53 children examined by CIC pre- and post-harvest (June and December), abnormal CIC were seen in 77.4% and 54.7%, respectively (P = 0.04). Subclinical vitamin A deficiency is a problem in this area. A seasonal variation is demonstrated. CIC is a useful method for identifying communities with subclinical vitamin A deficiency. A variety of strategies for dealing with vitamin A deficiency are discussed.

Serum vitamin A levels of preschool children in a Nigerian rural community

A study was carried out to determine the serum vitamin A levels of 250 preschool children in a rural community in eastern Nigeria. The children were aged between 2 months and 5 years and comprised 117 boys and 133 girls. A total of 23 (9.2%) children had 'deficient levels' (< 10 micrograms/dl) and 41 (16.4%) had 'low levels' (< 20 micrograms/dl) according to the Interdepartmental Committee on Nutrition for National Defence criteria for the interpretation of serum vitamin A levels. The sex distribution showed that 14 (11.97%) boys and nine (6.77%) girls had deficiency levels. A history of night blindness was obtained in six (3.7%) of 162 children aged 3-5 years.

Determinants of night blindness in Bangladesh

A cross-sectional study was conducted to evaluate the effect of a community-based health education intervention programme and to study the determinants of night blindness in Bangladesh. The intervention programme was implemented to reduce the morbidity of nutritional blindness (night blindness) in the northern part of Bangladesh (Ranjpure district) during 1986-1989. A baseline study in 1986 covered 2010 households with a total population of 11,600, and the evaluation study in 1989 covered 2011 households with a total population of 10,456. Prevalence of night blindness was studied among children aged < 9 years in these households. The prevalence of night blindness per 1000 children was reduced significantly during the intervention period from 50.7 in 1986 to 26.7 in 1989. However, the post-intervention prevalence varied significantly between areas. Multivariate analyses showed that consumption of fish, meat, milk or eggs, dark green leaf vegetables, yellow fruits and vitamin A capsules were significant predictors of night blindness. In addition, family income, mother's literacy, family size and area of residence exhibited strong and statistically significant associations with night blindness in the 1989 cross-sectional study. The prevalence of night blindness was highest among 4-6 year old girls and 7-8 year old boys. The sex difference was, however, not statistically significant.

Assessment of vitamin A deficiency in the Republic of Djibouti

In a countrywide survey, we assessed the prevalence of vitamin A deficiency by clinical examination and impression cytology with transfer method (ICT) in a randomized sample of 2445 subjects representative of the population of the Republic of Djibouti. A plasma retinol determination was made on a part of this sample. Results lead to believe that serious vitamin A deficiency may periodically occur in Republic of Djibouti when nutritional conditions become poor. Meanwhile a large number of children, mostly in the rural area, have a marginal vitamin A status and are exposed to a high level of risk.