Recovery from impaired dark adaptation in nightblind pregnant Nepali women who receive small daily doses of vitamin A as amaranth leaves, carrots, goat liver, vitamin A-fortified rice, or retinyl palmitate (original) (raw)
Related papers
The American journal of clinical nutrition, 2007
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. 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. 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. Women who were iron deficient at baseline (n=38...
The Journal of nutrition, 2004
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...
The American journal of clinical nutrition, 2001
Zinc deficiency may result in abnormal dark adaptation or night blindness, a symptom primarily of vitamin A deficiency. During a placebo-controlled trial in Nepal, weekly vitamin A supplementation of women reduced but failed to eliminate the incidence of night blindness during pregnancy, suggesting a role for zinc. The study examined the efficacy of daily zinc supplementation in restoring night vision of pregnant women who developed night blindness while routinely receiving either vitamin A, beta-carotene, or placebo in a field trial. Women (n = 202) who reported to be night blind during pregnancy were randomly assigned in a double-blind manner, stratified on vitamin A, beta-carotene, or placebo receipt, to receive 25 mg Zn or placebo daily for 3 wk. Thus, the 6 groups studied were as follows: beta-carotene + zinc, beta-carotene alone, vitamin A + zinc, vitamin A alone (vitamin A + placebo), zinc alone (zinc + placebo), and placebo (2 placebos: one for the vitamin A or beta-carotene...
Diagnosis of night blindness and serum vitamin A level: a population-based study
American Journal of Ophthalmology, 1996
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 conditions 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 pg/dl; 95% confidence interval (Cl), 13.9-18.7) and highest among those identified as not night blind by both their parents and the investigators (23.6 pg/dl; 95% Cl, 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.
Night blindness of pregnancy in rural Nepal--nutritional and health risks
International Journal of Epidemiology, 1998
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.
European Journal of Clinical Nutrition, 2002
Background: As a result of lack of precise guidelines, nutritional surveys on adults and high-risk groups are using diverse reference values as a dividing line between normal and deficient vitamin A status. Objective: To investigate whether pregnant women at marginally normal serum retinol status exhibit functional alteration that are characteristic of a deficiency state. Setting: Antenatal clinic, Gondar teaching hospital. Subjects: Ninety-six healthy pregnant women were recruited for the study at the antenatal clinic. Intervention: The dark adaptation time was tested in 48 pregnant women with marginal serum retinol level. The time lapse to see successive light stimuli of diminishing luminescence grade and change in retinal sensitivity pattern was measured using dark adaptometer. Results were compared with the results of a control group of women of similar age, parity and gestational period but with serum retinol values above 35 mg=dl. Results: The mean serum retinol levels of cases and controls were 23.35 mg=dl and 40.47 mg=dl respectively (P < 0.008). Cases have a lower dark adaptation than their controls, shown by their remarkably reduced sensitivity to light. For instance at mean final light threshold was 72.20 AE 0.11 log cd=m 2 in cases as compared to 72.88 AE 0.1 log cd=m 2 in the normal group (P < 0.001). Conclusion: During pregnancy, dark adaptation was strongly associated with serum retinol concentration and women with marginal vitamin A concentration had lower dark adaptation. Hence marginally normal serum retinol levels should be categorized as a deficiency state, at least in pregnant women.
Ethiopian Journal of Health Sciences, 2014
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.
European Journal of Clinical Nutrition, 2004
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 ¼ 0.501) and median serum retinol concentrations (0.95 vs 0.93 mmol/l, P ¼ 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% (Po0.001), 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.