Tippawan Pongcharoen

Only a small proportion of anemia in northeast Thai schoolchildren is associated with iron deficiency

BACKGROUND Iron deficiency is assumed to be the major cause of anemia in northeast Thailand, but other factors may be involved. OBJECTIVE We determined the prevalence of anemia among schoolchildren in northeast Thailand and the role of hemoglobinopathies, selected micronutrient deficiencies, and other factors in hemoglobin status. DESIGN Blood samples were collected from 567 children aged 6-12.9 y attending 10 primary schools for the determination of a complete blood count and hemoglobin type [Hb AA (normal hemoglobin), Hb AE (heterozygous for Hb type E), and Hb EE (homozygous for Hb type E)] and the measurement of serum ferritin, transferrin receptor, retinol, vitamin B-12, and plasma and erythrocyte folate concentrations. Children with a C-reactive protein concentration > or = 10 mg/L (n = 12), which indicated infection, were excluded. RESULTS The prevalence of anemia was 31%. Age, hemoglobin type, and serum retinol were the major predictors of hemoglobin concentration. Hb AA and Hb AE children with anemia had lower (P < 0.01) hematocrit, mean cell volume, and serum retinol values than did their nonanemic counterparts; no significant differences in serum ferritin were found by hemoglobin type. Only 16% (n = 22) of the anemic Hb AA and Hb AE children were iron deficient. Hb AA and Hb AE children with a serum retinol concentration <0.70 micromol/L (n = 14) had a significantly higher geometric mean serum ferritin concentration than did those with a retinol concentration > or = 0.70 micromol/L (P = 0.009); no significant difference in transferrin receptor concentrations was found between these 2 groups. CONCLUSIONS Hemoglobinopathies, suboptimal vitamin A status, and age were the major predictors of hemoglobin concentration. The contribution of iron deficiency to anemia was low, and its detection was complicated by coexisting suboptimal vitamin A status.

Risk of zinc, iodine and other micronutrient deficiencies among school children in North East Thailand.

Introduction:Micronutrient deficiencies during childhood can contribute to impairments in growth, immune competence, and mental and physical development, and the coexistence of several such deficiencies can adversely affect the efficacy of single micronutrient interventions.Objective:To assess the prevalence of zinc and iodine deficiency and their interrelationships with vitamin A deficiency and anemia and associations with socio-economic status, hemoglobin type, and anthropometry in a cross-sectional study.Setting:A total of 10 primary schools in North East Thailand.Methods:Non-fasting venipuncture blood samples and casual urine samples were collected from 567 children aged 6–13 years. Anthropometric measures and serum zinc, albumin, C-reactive protein and urinary iodine, are reported here and integrated with published data on vitamin A, anemia, and socio-economic status.Results:Of the children, 57% had low serum zinc and 83% had urinary iodine levels below the 100 μg/l cutoff. Suboptimal serum zinc and urinary iodine concentrations may result from low intakes of zinc and iodized salt. Significant risk factors for low serum zinc were serum retinol <1.05 μmol/l and being male. Those for urinary iodine <100 μg/l were height-for-age score>median and being female. For serum retinol <1.05 μmol/l, risk factors were low hemoglobin, low serum zinc, and <9 years, and for low hemoglobin indicative of anemia risk factors were <9 years, AE hemoglobinopathy, and serum retinol <1.05 μmol/l. Of the children, 60% were at risk of two or more coexisting micronutrient deficiencies, most commonly suboptimal urinary iodine and low serum zinc.Conclusion:The findings emphasize the need for multimicronutrient interventions in North East Thailand.

Influence of Prenatal and Postnatal Growth on Intellectual Functioning in School-aged Children

OBJECTIVE To assess the relative influence of size at birth, infant growth, and late postnatal growth on intellectual functioning at 9 years of age. DESIGN A follow-up, cross-sectional study. SETTING Three districts in Khon Kaen province, northeast Thailand. PARTICIPANTS A total of 560 children, or 92% of former participants of a trial of iron and/or zinc supplementation during infancy. MAIN EXPOSURES Prenatal (size at birth), early infancy (birth to 4 months), late infancy (4 months to 1 year), and late postnatal (1 to 9 years) growth. Multiple-stage least squares analyses were used to generate uncorrelated residuals of postnatal growth. MAIN OUTCOME MEASURES Intellectual functioning was measured at 9 years using the Wechsler Intelligence Scale for Children and the Ravens Colored Progressive Matrices (Pearson). Analyses included adjustment for maternal, household, and school characteristics. RESULTS Significant relationships were found between growth and IQ (Wechsler Intelligence Scale for children, third edition, Thai version), but only up to 1 year of age; overall, growth was not related to the Ravens Colored Progressive Matrices. The strongest and most consistent relationships were with length (birth, early infancy, and late infancy); for weight, only early infancy gain was consistently related to IQ. Head circumference at birth was not collected routinely; head circumference at 4 months (but not head circumference growth thereafter) was related to IQ. Late postnatal growth was not associated with any outcome. CONCLUSION Physical growth in early infancy (and, to a lesser extent, physical growth in late infancy and at birth) is associated with IQ at 9 years of age. Early infancy may be a critical window for human development.

Does zinc deficiency play a role in stunting among primary school children in NE Thailand

Stunting in school-age years may result in a decrease in adult size, and thus reduced work capacity and adverse reproductive outcomes. We have compared the mean intakes of energy, protein and selected growth-limiting nutrients in fifty-eight stunted children and 172 non-stunted controls drawn from 567 children aged 6-13 years attending ten rural schools in NE Thailand. Control children were selected randomly after stratifying children by age in each school. Dietary data were calculated from 24-h recalls using nutrient values from Thai food composition data and chemical analysis. Inter-relationships between stunting and sociodemographic, anthropometric and biochemical variables were also examined. Biochemical variables investigated were serum albumin, zinc, ferritin, transferrin receptor and retinol, and iodine in casual urine samples. Significantly more males than females were stunted (males, n 38, 65.5% v. females, n 20. 34.5%: P=0.025). Stunted males had lower mean intakes of energy, protein, calcium, phosphorus and zinc, and a lower mean (95% CI) serum zinc (9.19 (8.53, 9.84) v. 9.70 (8.53, 9.29) micromol/1) than non-stunted males; no other biochemical differences were noted. Stunted males also had a lower mean arm muscle area (P= 0.015), after adjusting for age, than non-stunted males. In conclusion, the lower dietary intakes of the stunted males compared to their non-stunted counterparts may be associated with anorexia and hypogeusia induced by zinc deficiency. Hence, zinc deficiency may be a factor limiting linear growth, especially among boys in NE Thailand, but more research is needed to establish whether other factors also play a role.

Long-term effects of iron and zinc supplementation during infancy on cognitive function at 9 y of age in northeast Thai children: a follow-up study

BACKGROUND Iron and zinc are important micronutrients for child growth and development. One would expect that iron and zinc supplementation in infancy would affect long-term cognitive development and school achievement, but this has not been evaluated. OBJECTIVE We investigated the effect of iron or zinc supplementation or both during infancy on cognitive performance 8 y later. DESIGN A follow-up study was performed in 560 children aged 9 y or 92% of those who had participated in a randomized controlled trial involving 4 groups who received daily iron, zinc, iron plus zinc, or a placebo at 4-6 mo of age for 6 mo. Cognitive performance was assessed by using the Wechsler Intelligence Scale for Children-Third Edition (Thai version), the Ravens Colored Progressive Matrices (CPM), and school performance tests. General linear mixed models were used to assess long-term effects. RESULTS No significant differences in any of the outcomes at 9 y of age were observed at follow-up between the 4 groups. Mean intelligence quotients ranged across groups from 92.9 to 93.7 for full scale, 93.9-95.4 for verbal, and 93.1-94.0 for performance. The Ravens CPM score ranged from 21.4 to 22.4. CONCLUSION Supplementation with iron or zinc or both during infancy does not lead to long-term cognitive improvement in 9-y-old children. This trial was registered at clinicaltrials.gov as NCT00824304.

Estimation of the Prevalence of Inadequate and Excessive Iodine Intakes in School-Age Children from the Adjusted Distribution of Urinary Iodine Concentrations from Population Surveys

BACKGROUND The urinary iodine concentration (UIC), a biomarker of iodine intake, is used to assess population iodine status by deriving the median UIC, but this does not quantify the percentage of individuals with habitually deficient or excess iodine intakes. Individuals with a UIC <100 μg/L or ≥300 μg/L are often incorrectly classified as having deficient or excess intakes, but this likely overestimates the true prevalence. OBJECTIVE Our aim was to estimate the prevalence of inadequate and excess iodine intake in children (aged 4-14 y) with the distribution of spot UIC from iodine surveys. METHODS With the use of data from national iodine studies (Kuwait, Oman, Thailand, and Qatar) and a regional study (China) in children (n = 6117) in which a repeat UIC was obtained in a subsample (n = 1060), we calculated daily iodine intake from spot UICs from the relation between body weight and 24-h urine volume and within-person variation by using the repeat UIC. We also estimated pooled external within-person proportion of total variances by region. We used within-person variance proportions to obtain the prevalence of inadequate or excess usual iodine intake by using the Estimated Average Requirement (EAR)/Tolerable Upper Intake Level (UL) cutoff method. RESULTS Median UICs in Kuwait, Oman, China, Thailand, and Qatar were 132, 192, 199, 262, and 333 μg/L, respectively. Internal within-person variance proportions ranged from 25.0% to 80.0%, and pooled regional external estimates ranged from 40.4% to 77.5%. The prevalence of inadequate and excess intakes as defined by the adjusted EAR/UL cutoff method was ∼45-99% lower than those defined by a spot UIC <100 μg/L or ≥300 μg/L (P < 0.01). CONCLUSIONS Applying the EAR/UL cutoff method to iodine intakes from adjusted UIC distributions is a promising approach to estimate the number of individuals with deficient or excess iodine intakes.

Low zinc, iron, and calcium intakes of Northeast Thai school children consuming glutinous rice-based diets are not exacerbated by high phytate

Phytate, a salt of phytic acid (myo-inositol 1,2,3,4,5,6-hexakisphosphate), is found in certain plant-based foods. It strongly chelates minerals, forming insoluble complexes in the small intestine that cannot be digested or absorbed. Information on the phytate content of rice-based diets of children in Northeast Thailand is limited. In this study 1-day weighed duplicate diet composites were collected from 40 Northeast Thai children (age 6–13 years) randomly selected from participants (n=567) of an efficacy trial in Ubon Ratchathani province. Diet composites were analyzed for zinc, iron, and calcium by atomic absorption spectrophotometry, and for phytate (as inositol penta-phosphate and hexa-phosphate) by high-performance liquid chromatography; the accuracy and precision were established using a certified reference material for the minerals and an inter-laboratory comparison for phytate. The median (1st, 3rd quartiles) zinc, iron, and calcium contents of the diet composites were 4.3 (3.7, 6.1), 4.3 (3.2, 6.5) and 130 (82, 216) mg/day, respectively. The inositol penta-phosphate and hexa-phosphate levels were so low they were below the detection limit, attributed in part to leaching of water-soluble potassium and magnesium phytate from glutinous rice after soaking overnight before cooking. Clearly, phytate will not compromise mineral absorption from these diets. Instead, low zinc intakes are probably primarily responsible for the low zinc status of these children. In contrast, although intakes of dietary iron appear low, the prevalence of biochemical iron deficiency was also low, suggesting that iron absorption may have been higher than previously assumed. Whether the low calcium intakes compromise optimal bone health in these growing Northeast Thai school children is unknown.

Pre-pregnancy body mass index and gestational weight gain in Thai pregnant women as risks for low birth weight and macrosomia.

BACKGROUND AND OBJECTIVES Maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) have been reported to be associated with pregnancy outcomes. Due to the nutrition transition in Thailand, the double burden of malnutrition is increasing and this may have negative consequences on birth outcomes. This study aimed to investigate the relationship between pre-pregnancy BMI and GWG with the risks of low birth weight and macrosomia. METHODS AND STUDY DESIGN We performed a secondary analysis of data obtained from an iodine supplementation trial in mildly iodine-deficient Thai pregnant women. Pre-pregnancy BMI was classified using the WHO classification. GWG was categorized using the IOM recommendation. Binary and multinomial logistic regressions were performed. RESULTS Among 378 pregnant women, the prevalence of pre-pregnancy underweight (BMI<18.5 kg/m2) and overweight (BMI>=25 kg/m2) were 17.2% and 14.3%, respectively. Normal weight women had the highest median GWG [15.0 (12.0, 19.0) kg] when compared to overweight women [13.2 (9.0, 16.3) kg]. Forty-one percent of women had excessive GWG, while 23% of women gained weight inadequately. Women with a high pre-pregnancy BMI had a 7-fold higher risk of having a macrosomic infant. Women who had excessive GWG were 8 times more likely to deliver a newborn with macrosomia. CONCLUSIONS Both high pre-pregnancy maternal weight and excessive weight gain during pregnancy increase risk of infant macrosomia. Therefore, maintaining normal body weight before and throughout pregnancy should be recommended in order to reduce the risk of excessive infant birth weight and its associated complications.

Vitamin D Status among Thai School Children and the Association with 1,25-Dihydroxyvitamin D and Parathyroid Hormone Levels

In several low latitude countries, vitamin D deficiency is emerging as a public health issue. Adequate vitamin D is essential for bone health in rapidly growing children. In the Thai population, little is known about serum 25-hydroxyvitamin D [25(OH)D] status of infants and children. Moreover, the association between 25(OH)D and the biological active form of 1,25-dihydroxyvitamin D [1,25(OH)]2D is not clear. The specific aims of this study were to characterize circulating serum 25(OH)D, 1,25(OH)2D and their determinants including parathyroid hormone (PTH), age, sex, height and body mass index (BMI) in 529 school-aged Thai children aged 6–14 y. Adjusted linear regression analysis was performed to examine the impact of age and BMI, and its interaction with sex, on serum 25(OH)D concentrations and 1,25(OH)2D concentrations. Serum 25(OH)D, 1,25(OH)2D and PTH concentrations (geometric mean ± geometric SD) were 72.7±1.2 nmol/L, 199.1±1.3 pmol/L and 35.0±1.5 ng/L, respectively. Only 4% (21 of 529) participants had a serum 25(OH)D level below 50 nmol/L. There was statistically significant evidence for an interaction between sex and age with regard to 25(OH)D concentrations. Specifically, 25(OH)D concentrations were 19% higher in males. Moreover, females experienced a statistically significant 4% decline in serum 25(OH)D levels for each increasing year of age (P = 0.001); no decline was seen in male participants with increasing age (P = 0.93). When BMI, age, sex, height and serum 25(OH)D were individually regressed on 1,25(OH)2D, height and sex were associated with 1,25(OH)2D with females exhibiting statistically significantly higher serum 1,25(OH)2D levels compared with males (P<0.001). Serum 1,25(OH)2D among our sample of children exhibiting fairly sufficient vitamin D status were higher than previous reports suggesting an adaptive mechanism to maximize calcium absorption.

Body mass index is associated with fat mass in normal, overweight/obese, and stunted preschool children in central Thailand

BACKGROUND AND OBJECTIVES Body mass index (BMI) is widely used as a surrogate measure of adiposity. The relationship between BMI and body fatness varies by race, sex, and age and more variations have been found among children. This study investigated the relationship between BMI and fat mass among 3-5 year old children having different nutritional status. METHODS AND STUDY DESIGN A cross-sectional study was conducted in 15 daycare centers in central Thailand. 137 healthy preschool children were recruited according to their nutritional status: thin [BMI for age Z scores, (BAZ) <-2 SD], normal BMI (-2 SD<= BAZ <=+2 SD), overweight/obese (BAZ >+2 SD), and stunted [height for age Z scores < -2 SD]. Fat-free mass was determined by deuterium dilution technique. Fat mass (FM) in kilograms (TFM) and in percentage (FM%), and fat mass index (FMI, FM/height2) were calculated. RESULTS FM and FMI were the highest in the overweight/obese groups. In the thin group, girls had higher FMI compared to boys (3.2 vs 2.8 kg/m2, p<0.05). The relationship between BMI with FMI and FM differed by nutritional status. BMI was more strongly associated with FMI, TFM, and FM% in the overweight/ obese (r=0.97, 0.95, 0.80, p<0.05) and the normal (r=0.88, 0.84, 0.68, p<0.05) groups but not in the stunted group, and inconsistent in the thin group. CONCLUSIONS The inconsistency in the relationship between BMI and body fatness suggests that BMI is appropriate for reflecting adiposity in normal and overweight/obese children, but not undernourished preschool children.