Nutritional support and growth in thalassaemia major.

Twelve thalassaemic children under 3 years of age received intensive nutritional support for one month and were discharged on a prescribed diet of locally available foods. Anthropometry, bioelectrical impedance analysis and dietary intake were longitudinally assessed. Mean energy intake was 20% greater than the recommended daily allowance during nutritional supplementation as compared with below the recommended daily allowance before and after the period of nutritional support. Weight, but not height, significantly increased during the support period and was due to increases in both fat free mass and fat mass. Body weight, fat free mass and fat mass declined in line with the reduced intake upon return home; however, height velocity accelerated and exceeded normal through the fourth month before resuming a below normal rate. It can be concluded that (1) nutritional stunting as the result of reduced nutrient intake is an important cause of growth failure in young children with thalassaemia and is responsive to nutritional support, (2) the deficit in height velocity was due to retarded truncal height growth, and (3) the bioelectrical impedance analysis method is suitable for body composition analysis of thalassaemic children.

Iron deficiency and anaemia in children with a high prevalence of haemoglobinopathies: implications for screening.

BACKGROUND: Haemoglobin (Hb) concentration is used as a sole test for iron deficiency anaemia (IDA) in most developing countries since most anaemia is believed to be due to iron deficiency and confirmatory testing is generally unavailable. Yet the validity of this approach in regions where haemoglobinopathies are endemic has not been documented. METHODS: Haemoglobin and serum ferritin (SF) were measured in 559 Northern Thai children aged 6 months to 13 years of age. The sensitivity of SF to identify iron deficiency was also assessed in a subsample of children with low or low-normal Hb and normal SF by testing the Hb response to a trial of oral iron. RESULTS: While anaemia was common (27%), IDA constituted 19% and none of all anaemia in preschool and school age children, respectively (P < 0.002). Iron depletion was similarly more prevalent in younger children (P < 0.002). Children with IDA were younger (P < 0.001) and the anaemia more severe (P < 0.0001) compared to those with non-IDA. Of anaemic children with normal SF values who received a therapeutic trial of iron, only 6% responded with an increase in Hb of > or = 1 g/dl. CONCLUSIONS: For populations such as ours most anaemia is not due to iron deficiency and a single Hb determination is therefore not acceptable for a presumptive diagnosis of IDA.

Hepatitis B immunization: a potential incentive to HIV vaccine trial participation in Thailand?

To assess the effectiveness of hepatitis B immunization as an incentive to retention in HIV seroincidence studies and future HIV vaccine trials in northern Thailand, subjects enrolled in three HIV seroincidence cohorts were screened for hepatitis B markers and seronegatives were offered free hepatitis B immunization. Cohorts studied included female commercial sex workers (CSWs), male sexually transmitted disease (STD) patients, and recently discharged military conscripts. Subjects who agreed to the immunization program were compared with those not enrolled to determine the utility of immunization as an incentive to cohort retention. Full immunization was achieved for 273 (89.5%) of 305 vaccinees; only 323 (60.6%) of 533 subjects not immunized completed the same follow-up visits (OR = 1.49, 95% and CI = 1.27, 1.75). Hepatitis B vaccination was a significant incentive for completion of the follow-up program. The vaccination program had the greatest effect on the CSWs; a similar effect was seen for male STD patients, but not for discharged conscripts. Despite the immunization program, follow-up rates at 12 months were similar in the immunized and nonimmunized groups.

Nutritional factors and thalassaemia major.

Abnormal growth is a common feature of thalassaemia major in children. In an attempt to determine whether it has a nutritional cause, 12 children aged 1 to 3 years with thalassaemia major were studied under metabolic ward conditions. Nutritional status was assessed by anthropometry and biochemistry before and after an intensive nutrition regimen. Five children had wasting or stunting on admission. As a result of the nutrition intervention, mean weight for height improved significantly. The mean height increase of 0.4 cm after one month was not significant. Plasma zinc, depressed in half the children on admission, improved, as did alpha tocopherol, while copper decreased. Plasma insulin-like growth factor-I also increased commensurate with improved growth. Fat absorption was normal in all children. Undernutrition is an important cause of associated growth disturbances in children with thalassaemia major. Malnutrition was primarily caused by inadequate nutrient intake, as indicated by the capacity to gain weight appropriately when provided with nutrition support, and by the absence of intestinal malabsorption. While long term studies are required to determine if nutritional support will prevent stunting, these results underscore its central role in preventing nutritional deficiencies and in promoting normal growth in thalassaemic children.

Effects of iron on lipid peroxidation.

To elucidate the effects of iron on lipid peroxidation, three kinds of assays were done. (i) The effects of intravenous injection of single doses of iron dextran (100 mg iron) on lipid peroxidation in various tissues and the blood plasma of rats were examined by the thiobarbituric acid reaction. Malondialdehyde concentrations were significantly elevated in the spleen, heart, and plasma 3 h after injection, whereas significant increases were observed in the liver and adipose tissue at 24 and 48 h, respectively. In the liver and spleen, the elevated malondialdehyde concentrations persisted until Day 28. In contrast, levels were reduced in the heart and adipose tissue within 4 weeks after iron injection. Plasma malondialdehyde concentrations were 70-times that of controls at 24 h after iron injection. The level subsequently decreased sharply by Day 6. In red blood cells, lipid peroxidation was not affected by iron. Malondialdehyde levels were correlated with the iron contents of the liver, spleen, heart, adipose tissue, and plasma (r value range 0.39-0.88, p less than 0.05). Furthermore, there was a strong correlation in the liver and spleen at iron levels below 2,000 micrograms/g (r = 0.94, p less than 0.0001; r = 0.94, p less than 0.0001, respectively). (ii) In vitro experiments demonstrated that the addition of iron as ferric chloride, iron dextran, ferritin, and hemosiderin to normal liver homogenate accelerated malondialdehyde production. However, such increases were less than 10% of those caused by equivalent iron in the liver homogenate of iron treated rats. (iii) Compared to controls, spleens from eight thalassemia patients showed a high level of malondialdehyde and iron.

Oral contraceptives: effect of long-term use on liver vitamin A storage assessed by the relative dose response test.

Vitamin A status measured by the relative dose response (RDR) test was determined among groups of Northern Thai women who had used estrogen-containing oral contraceptives (OCs) with or without multivitamin supplements through 13 cycles. Mean serum vitamin A values were elevated approximately 40% above those of control subjects (intrauterine contraceptive device (IUCD) users) during OC usage. Daily (one capsule) or periodic (two capsules 7 d/mo) multivitamin supplementation that included 1700 micrograms vitamin A per capsule did not significantly influence vitamin A serum values. The RDR test after 13 cycles was elevated in one individual who had taken OCs and the periodic multivitamin supplement. It reverted to normal after supplementation with vitamin A. A single high-dose vitamin A supplement (68,000 micrograms) did not change circulating levels of the vitamin. Among this population there is little evidence that use of estrogen-containing OCs for greater than 1 y resulted in a physiologically significant deterioration of vitamin A status.

PIP: Vitamin A status measured by the relative dose response (RDR) test was determined among groups of Northern Thai women who had used estrogen- containing oral contraceptives (OCs) with or without multivitamin supplements through 13 cycles. Mean serum vitamin A values were elevated approximately 40% above those of control subjects (IUD users) during OC usage. Daily (1 capsule) or periodic (2 capsules 7 days/month) multivitamin supplementation that included 1700 mcg vitamin A/capsule did not significantly influence vitamin A serum values. The RDR test after 13 cycles was elevated in 1 individual who had taken OCs and the periodic multivitamin supplement. It reverted to normal after supplementation with vitamin A. A single high-dose vitamin A supplement (68,000 mcg) did not change circulating levels of the vitamin. Among this population there is little evidence that use of estrogen-containing OCs for more than 1 year resulted in a physiologically significant deterioration of vitamin A status.

Iron status and the effect of iron supplementation in Thai male blood donors in northern Thailand.

The iron status of voluntary and professional male donor groups was investigated. The study indicated that serum ferritin level was lower significantly in those who donated three times per year compared to the first time donors (p less than 0.05) in voluntary donor group. Similar results were observed among the professional donors. Whereas haemoglobin, haematocrit and transferrin saturation were not altered by donating blood in both groups. It also showed that, in general, the body iron stores of professional donors were lower to those of voluntary donors. Supplementation with iron over a period of three months produced a rise in serum ferritin levels and the percentage prevalence of iron depleted subjects decreased from 23.6% to 6.4%. Haemoglobin, haematocrit and transferrin saturation levels also improved.

An evaluation of monoclonal antibodies for serum ferritin measurements.

Serum ferritin measurements have become an important laboratory parameter of iron status in prevalence surveys. Because the use of monoclonal antibodies may reduce variability and facilitate standardization, the present study was undertaken to determine whether their performance is comparable to conventional immunological reagents in an immunoradiometric assay for serum ferritin. When evaluated as the capture antibody for the solid phase, no differences in dose response curves were observed between monoclonal reagent and whole antiserum. When monoclonal reagent was used as the radiolabeled indicator antibody, the dose response curves were also similar to those obtained with affinity-purified polyclonal reagent although between-assay variability was somewhat higher with monoclonal antibody. In measurements of serum ferritin in patients with a wide range of iron status, no consistent differences were observed in the results from assays using monoclonal antibody and those of the conventional reagent. These preliminary studies indicate that the performance of monoclonal antibodies in a conventional ferritin assay is comparable to conventional immunological reagents.

Iron deficiency in a Northern Thai population: the effects of iron supplements studied by means of plasma ferritin estimations.

Iron deficiency is a common problem, particularly in developing countries, but traditional laboratory methods of detecting this condition are unreliable. The prevalence of iron deficiency in a Northern Thai population (pre-school, school children, adult women) has been assessed by means of plasma ferritin concentrations. The results were compared with prevalences based on blood haemoglobin concentrations. Estimations of prevalences based on plasma ferritin values were 10-24% in non-vegetarian and 49-71% in vegetarian groups, whilst those based on blood haemoglobin were 11-21% (non-vegetarian) and 24-50% (vegetarian). Dietary supplementation with iron produced dramatic rises in plasma ferritin in all of the groups studied. The effects on blood haemoglobin concentration and haematocrit were less marked. These results highlight the extent of iron deficiency in a Thai population and demonstrate the sensitivity of plasma ferritin as a test for detecting this condition and assessing the response to dietary supplementation.

Sensitive sandwich enzyme immunoassay for serum ferritin on microtitre plates.

A solid-phase sandwich enzyme immunoassay for serum ferritin is described. The assay procedure was simple, showed good precision, and was suitable for the routine determination of serum ferritin concentration in a clinical laboratory. The assay compared well with a conventional radioimmunoassay for ferritin. The assay was extremely sensitive and had a detection limit of 2.2pg.