Detection of vitamin A deficiency in Brazilian preschool children using the serum 30-day dose-response test.

BACKGROUND: Vitamin A deficiency (VAD) is endemic in Brazil and health professionals have difficulty in recognizing its subclinical form. In addition, serum retinol concentrations do not always represent vitamin A status in the organism. OBJECTIVE: To identify VAD in preschool children by the serum 30-day dose-response test (+S30DR) and to examine its potential as a tool for the assessment of vitamin A status in the community. DESIGN: A prospective transverse study in which blood samples were obtained from 188 preschool children for the determination of serum retinol concentrations and the children were submitted to ocular inspection and anthropometric measurements. Information about the presence of diarrhea and/or fever during the 15 days preceding the study was also obtained. The children received an oral dose of 200,000 IU vitamin A immediately after the first blood collection. A second blood sample was obtained 30-45 days after supplementation in order to determine the +S30DR. RESULTS: In all, 74.5% (140/188; 95% confidence interval: 68.3-80.7%) of the children presented +S30DR values indicative of low hepatic reserves. The mean serum retinol concentration was significantly lower before supplementation (0.92 and 1.65 micromol/l, respectively; P < 0.0001). No child presented xerophthalmia; 3.7% (7/188) of the children were malnourished. The presence of fever and/or diarrhea during the 15 days preceding the first blood collection did not affect the +S30DR value. CONCLUSIONS: The prevalence of VAD in the study group was elevated. +S30DR proved to be a good indicator of subclinical VAD in children from an underdeveloped country.

Impact of maternal vitamin A supplementation on the mother-infant pair in Brazil.

BACKGROUND/OBJECTIVES: Vitamin A deficiency (VAD) is a major public health problem. The supplementation of lactating women could be an effective strategy to combat it. The objective of this study was to assess the impact of maternal vitamin A supplementation on the mother-infant pair. SUBJECTS/METHODS: This was a double blind, placebo-controlled randomized clinical assay in which 33 women received 200 000 IU of vitamin A and 33 women received soy oil between 20th and 30th postpartum days. Maternal blood and milk samples were collected immediately before supplementation and 3 months after delivery, when blood was also collected from the babies. Retinol concentrations 0.70 µmol/l in serum and 1.05 µmol/l in milk were considered to indicate VAD. RESULTS: Increase in serum retinol level was observed in the supplemented group compared with the pre-supplementation levels (1.05 and 1.17 µmol/l, respectively; P=0.026) and to the post-supplementation levels of the control group (1.02 µmol/l; P=0.032). Reduction in breast milk retinol was observed in the control group compared with the pre-supplementation levels (1.93 and 1.34 µmol/l, respectively; P<0.0001) and to the post-supplementation levels of the supplemented group (1.56 µmol/l; P=0.0003). There was significant difference in the prevalence of VAD in breast milk after supplementation, 55.6% (15/27) in the control group and 16.1% (5/31) in the supplemented group (P=0.002). VAD was present in 66.1% (39/59) of infants, with mean serum retinol levels of 0.64±0.30 µmol/l in the control group and of 0.69±0.26 µmol/l in the supplemented group. CONCLUSIONS: Supplementation had a positive impact on maternal vitamin A status. No effect on infant status was detectable 2 months after supplementation with a single dose.

Vitamin A deficiency among Brazilian school-aged children in a healthy child service.

BACKGROUND/OBJECTIVES: Vitamin A deficiency (VAD) is a world public health problem contributing to the increase in childhood morbidity and mortality in developing countries and severe deficiency of vitamin A may lead to xerophthalmia and blindness. The objective of this study was to determine the prevalence of VAD among Brazilian school-aged children attended at a primary health unit and to verify if some considered risk factor was associated with VAD in this group. SUBJECTS/METHODS: A descriptive prospective transverse study was conducted on 103 randomly selected children. A total of 54 boys and 49 girls aged 5.5-11 years had the relative dose-response (RDR) test performed on. Possible ocular alterations related to vitamin A and the status of anemia, serum zinc, some acute-phase proteins, and anthropometric situation were determinate by an analytic design. RESULTS: No child presented xerophthalmia. Serum retinol values lower than 1.05 and 0.7 micromol l(-1), respectively were found in 26.2 and 5.8% of the children. The prevalence of hypovitaminosis detected by RDR test was 20.4%. The following variables and their relationship with VAD were evaluated: sex (P=0.33; 95% confidence interval 0.61-4.34), weight and height (P> or =0.5), hemoglobin (P=0.15), C-reactive protein (P=0.56; 95% confidence interval 0.75-18.26), alpha-1-acid-glycoprotein (P=0.56; 95% confidence interval 0.15-15.42) and serum zinc (P=0.31). None of these variables was related to VAD. CONCLUSIONS: In this population, the prevalence of VAD detected could be considered a public health problem. School-aged children can be considered at risk for VAD mainly of a subclinical level, even without some associated risk factors.