K.P. Dawson, P. Hughes, D. Mpofu and M. Patel
Abstract: Forty-six mothers and children from the United Arab Emirates participated in a pilot study to determine possible micronutrient deficiencies in the country. Thirty-five per cent (35 %) of the children and 21 % of the mothers had low serum ferritin levels, while 30 % of the mothers had low serum 25-hydroxyvitamin D with 28 % of mothers having a low serum folate status. These deficiencies are widespread in the nationals of the United Arab Emirates. In view of the increasing importance of intrauterine and early infant nutrition, further investigation and a national study seem warranted.
Introduction
The United Arab Emirates Annual Health Report in 1992 stressed the need for a detailed assessment of nutrition in the country [1]. The report emphasized the lack of reliable information on possible micronutrient deficiencies in the United Arab Emirates. Data from a 1981 United Arab Emirates study suggested that 45% of United Arab Emirates schoolchildren have a haemoglobin level of below 11 g/dl [2]. Recent work from our group revealed that levels of anaemia were, in fact, increasing, and 20% of national mothers delivering their babies in Tawam Hospital, Al Ain, had haemoglobin levels of less than 10 g/dl in contrast to a figure of 7% in Saudi Arabia and 1.1% in Australia [3]. However, a survey showed that the United Arab Emirates fell into the moderately severe iodine-deficient regions and the presence of goitre in young children was as high as 40.4% (Ministry of Health/WHO, unpublished data, 1994).
The aim of the present study was to conduct a community-based pilot assessment of the iron and micronutrient status of United Arab Emirates mothers and their children under two years of age.
Methods
A sample of mothers and children presenting to a primary health care clinic or a maternal and child health clinic formed the study group. Women who had delivered a child within the past two years were approached to be included in the study. No selection was made other than seeking volunteers at random.
A brief history of previous illnesses, data regarding the number of pregnancies and the most recent child's age and health details were recorded from the mothers. A venous sample of blood was drawn from the mother and the child after the parents' informed consent. To this end an Arabic language explanatory leaflet was produced. The study had the permission of the Research Ethics Committee of the United Arab Emirates Medical Faculty. Blood samples were collected in lithium heparinized and plain tubes. They were brought directly to the laboratory and centrifuged at 2000 rpm; the plasma and serum samples were protected from direct sunlight and fluorescent light and were kept frozen at -20 ºC until analysed.
Estimations of vitamins A and E, vitamin D and ferritin, folic acid and thyroid-stimulating hormone (TSH) were carried out by the methods described.
Vitamins A and E
The analyses of retinol (vitamin A) and a-tocopherol (vitamin E) were performed according to Shearer [4] and Bieri et al. [5].
The plasma retinol and a-tocopherol were extracted with n-hexane. The hexane upper layer was isolated carefully and evaporated to dryness under nitrogen, and the residue redissolved in an appropriate solvent prior to injection on the HPLC column.
A 40 ml volume was injected onto a reverse-phase column (Whatman Partisil 5 ODS-3, 25 cm ´ 4.6 mm, for retinol, and Supelcosil 5 LC18, 25 cm ´ 4.6 mm, for a-tocopherol) and eluted with 100% methanol at a flow rate of 1.0 ml/min. Retinol and a-tocopherol were monitored by UV absorbance at 325 nm and 290 nm respectively.
Vitamin D
25-OHD (25-hydroxyvitamin D), the major circulating metabolite of vitamin D, was measured in serum by competitive protein-binding (CPB) assay and radioimmunoassay kit (Nichols, San Juan Capistrano, California).
Ferritin, folic acid and TSH
Ferritin, folic acid and TSH were measured in serum by immunoradiometric assay (IRMA), charcoal boil and double antibody assay kit (DPC, Los Angeles, California), respectively.
Results
Forty-six mothers and children participated in the study. The mothers had a mean age of 30 years (range 24-37 years). Their mean number of pregnancies was five (range 1-11 children). Hypertension during pregnancy was reported by two mothers, the remainder were stated to be in good health.
The children were equally divided between males and females and their mean age was 18 months. No illnesses were reported in any of the children.
Table 1 lists the vitamin assay results while Table 2 gives the ferritin and TSH results for the mothers and the children.
Discussion
The mothers and children recruited for this community-based study were apparently well and were attending a doctor for immunization or routine health advice. No mothers (or infants) known to have had significant antenatal or postnatal disorders were included.
The major findings of the study are not unexpected, but do support previous work in that iron deficiency in both children and mothers, together with 25-hydroxyvitamin D and folic acid deficiencies in mothers have been identified. This is a cause for some concern.
Thirty-five per cent (35%) of children and 21% of mothers in this sample had serum ferritin levels less than 10 ng/ml which is well below the reference range limits for our laboratory and the reported results elsewhere using the immunoradiometric assay method. These findings are in keeping with the prior observations that half of United Arab Emirates schoolchildren and 20% of mothers are anaemic and implicate iron deficiency as the cause [2]. However, there was no correlation between maternal ferritin levels and those of their respective children.
Thirty per cent (30%) of mothers had vitamin D levels below 10 ng/ml. This, again, is in keeping with other findings that, despite adequate sunshine, there are low serum 25hydroxyvitamin D levels in Arab women [6],[7]. Dawodu et al. (unpublished data) have shown significant differences between United Arab Emirates national women and Caucasian women resident in the United Arab Emirates. Two infants with suboptimal vitamin D levels had mothers with low vitamin D levels also. In addition, 28% of the mothers had low serum folic acid levels (below 3 ng/ml), but only one child had a similar finding. This child's mother had low folic levels also.
Three children showed low vitamin E and three showed low vitamin A status, but none of the mothers had levels which were below those expected for young women [8]. Interestingly, the infants who had low vitamin E levels tended to have marginal low vitamin A levels, but the converse was not true.
While results such as these from a small pilot study can at best be considered indicative, it is now clearly an area of importance and concern for the future health of United Arab Emirates mothers and their children. The role of folates in nucleotide synthesis and amino-acid interconversions is well documented together with the efficacy of folate supplementation in the prevention of recurrence of neural tube defects. The role in primary prevention is less clear [9]. However, a steady stream of data is now establishing links between the intrauterine and first year of life "environment" and later adult disease. Maternal anaemia in pregnancy is associated with a large placental weight and placental weight to birth weight ratio, both predictors of adult blood pressure [10]. Such an association between maternal anaemia and raised blood pressure at age 10 to 12 years has also been shown in other ethnic groups [11]. Dietary supplementation per se is not, however, an appropriate response. Excess intake of some nutrients (vitamins A, D) is known to result in birth defects, and other possibilities exist [12].
No elevation of TSH levels in the study group was demonstrated. It must be remembered that the children's mean age was 18 months, and previous work has indicated that the "at risk" group were the 9-13 years age range (Ministry of Health/WHO, unpublished data, 1994).
Overall, this small pilot study on micronutrient deficiencies confirms earlier concerns about anaemia and possible iron deficiency in the United Arab Emirates. In addition, folic acid deficiency as judged by serum folate levels was frequently found in the sample. These findings should prompt much closer scrutiny of dietary micronutrients in the United Arab Emirates and the need for a national nutritional study, especially in rural women and children where traditional lifestyles are still practised. They may also reflect that multiparity is an important factor in the nutritional inadequacies found when consideration is taken of the fact that the mean number of pregnancies in the United Arab Emirates group of mothers was five, a familiar pattern in the United Arab Emirates.
Acknowledgement
This study was supported by a grant from the United Arab Emirates University.
References
- United Arab Emirates Ministry of Health. Annual report 1992. Abu Dhabi, 1992, 132-43.
- The state of child health in the Eastern Mediterranean Region. Alexandria, World Health Organization, Regional Office for the Eastern Mediterranean, 1995, 173-8.
- Hughes PF, Morrison J. Pregnancy outcome data in a UAE population: what can they tell us? Asia-Oceania journal of obstetrics and gynaecology, 1994, 20:183-90.
- Shearer MJ. Vitamins. In: Lim CK, ed. HPLC of small molecules—a practical approach. Oxford, IRL Press, 1986:157-218.
- Bieri JG, Tolliver TJ, Catignani GL. Simultaneous determination of alpha tocopherol and retinol in plasma or red cells by high performance liquid chromatography. American journal of clinical nutrition, 1979, 32(10):2143-9.
- Sedrani SH, El-Idrissy ATH, El-Arabi KM. Sunlight and vitamin D status in normal Saudi subjects. American journal of clinical nutrition, 1983, 38:129-32.
- Taha SA, Dost SM, Sedrani SH. 25-hydroxyvitamin D and total calcium; extraordinarily low plasma concentration in Saudi mothers and their neonates. Pediatric research, 1984, 18:739-41.
- Vahlquist A et al. The concentrations of retinol-binding protein, pre-albumin and transferrin in the sera of newly delivered mothers and children of various ages. Scandinavian journal of clinical laboratory investigations, 1975, 35:569-75.
- Hibbard BM. Folates and fetal development. British journal of obstetrics and gynaecology, 1993, 100:307-9.
- Barker DJP, ed. Fetal and infant origins of adult disease. British Medical Journal, London, 1992.
- Godfrey KM et al. Maternal nutritional status in pregnancy and blood pressure in childhood. International journal of gynecology and obstetrics, 1994, 101:398-403.
- ACOG Technical Bulletin. Nutrition during pregnancy. International journal of gynecology and obstetrics, 1993, 43:67-74.
