Simultaneous zinc and vitamin A supplementation in Bangladeshi children: randomised double blind controlled trial.

OBJECTIVE: To evaluate the effect of simultaneous zinc and vitamin A supplementation on diarrhoea and acute lower respiratory infections in children. STUDY DESIGN: Randomised double blind placebo controlled trial. SETTING: Urban slums of Dhaka, Bangladesh. PARTICIPANTS AND METHODS: 800 children aged 12-35 months were randomly assigned to one of four intervention groups: 20 mg zinc once daily for 14 days; 200 000 IU vitamin A, single dose on day 14; both zinc and vitamin A; placebo. The children were followed up once a week for six months, and morbidity information was collected. RESULTS: The incidence and prevalence of diarrhoea were lower in the zinc and vitamin A groups than in the placebo group. Zinc and vitamin A interaction had a rate ratio (95% confidence interval) of 0.79 (0.66 to 0.94) for the prevalence of persistent diarrhoea and 0.80 (0.67 to 0.95) for dysentery. Incidence (1.62; 1.16 to 2.25) and prevalence (2.07; 1.76 to 2.44) of acute lower respiratory infection were significantly higher in the zinc group than in the placebo group. The interaction term had rate ratios of 0.75 (0.46 to 1.20) for incidence and 0.58 (0.46 to 0.73) for prevalence of acute lower respiratory infection. CONCLUSIONS: Combined zinc and vitamin A synergistically reduced the prevalence of persistent diarrhoea and dysentery. Zinc was associated with a significant increase in acute lower respiratory infection, but this adverse effect was reduced by the interaction between zinc and vitamin A.

Simultaneous vitamin A administration at routine immunization contact enhances antibody response to diphtheria vaccine in infants younger than six months.

A randomized, double-blind, placebo-controlled trial was conducted to evaluate the effect of simultaneous vitamin A supplementation and diphtheria, pertussis and tetanus (DPT) vaccination on the antibody levels. Infants aged 6-17 wk (n = 56) were randomly given 15 mg oral vitamin A or placebo at the time of their DPT immunization. Three such doses were given at monthly intervals. Immunoglobulin (Ig) G antibodies to diphtheria, pertussis and tetanus were assayed on enrollment and 1 mo after the third dose. Baseline antibody concentrations to diphtheria, pertussis and tetanus did not differ between the vitamin A-supplemented and placebo-treated groups. The postdose antibody to diphtheria level was significantly greater in the vitamin A than in the placebo-treated group. The geometric mean +/- SEM antibody levels (mg/L) were 22.9 +/- 1.2 and 11.0 +/- 1.3 in the vitamin A and placebo groups, respectively (P = 0.029). The postsupplementation concentrations of antibodies to pertussis and tetanus did not differ between the two groups. These results suggest that antibody response to diphtheria vaccination was potentiated by simultaneous vitamin A administration and DPT immunization.

Predictors of serum retinol in children with shigellosis.

BACKGROUND: Low serum retinol can be useful as an indicator of depleted liver vitamin A stores, particularly in population-based studies. However, serum retinol concentrations decrease transiently during infection, independent of any changes in liver stores. The magnitude of the decrease in serum retinol is often proportional to indicators of disease severity. OBJECTIVE: We examined the relation of serum retinol in children with culture-positive shigellosis with severity of illness, anthropometric indicators of nutritional status, urinary retinol excretion, and serum concentrations of C-reactive protein, alpha1-acid glycoprotein, retinol binding protein, and transthyretin. DESIGN: This was a prospective study assessing the clinical and laboratory measurements at admission and recovery of 90 children with dysentery (66 with shigellosis) hospitalized in Bangladesh. RESULTS: Serum retinol concentrations were low at admission but were significantly greater at discharge even though no vitamin A supplements were given during the illness (0.36 +/- 0.22 compared with 1.15 +/- 0.50 micromol/L, P < 0.001). Serum retinol concentrations were lower in children with Shigella dysenteriae type 1 infection than in children with shigellosis due to less virulent strains of Shigella. Low serum retinol was independently associated with S. dysenteriae type 1, high serum C-reactive protein concentrations, and low weight-forage in multiple regression analysis. CONCLUSIONS: This study showed that shigellosis was associated with a significant, transient decrease in serum retinol concentrations of approximately 0.8 micromol/L, and that this change was significantly associated with severity of disease and poor underlying nutritional status, particularly low weight-for-age.

Urinary retinol excretion and kidney function in children with shigellosis.

BACKGROUND: Acute infections, including diarrhea, are associated with an increased risk of vitamin A deficiency. Urinary retinol excretion during such infections may contribute to this risk. The mechanism accounting for urinary retinol loss has not been clearly defined. OBJECTIVE: This study attempted to determine whether urinary retinol loss in children with acute infection is associated with impaired kidney function, particularly impaired tubular protein reabsorption. DESIGN: Urinary retinol excretion and kidney function were examined in 66 hospitalized children 5 mo to 5 y of age with acute Shigella dysentery. RESULTS: Urinary retinol loss occurred in 59% of children and was substantial (>0.1 micromol/d) in 8% of them. Children with more severe disease excreted higher concentrations of urinary retinol; those with a body temperature > or =40 degrees C excreted a mean of 0.10 +/- 0.18 micromol/d compared with 0.005 +/- 0.008 micromol/d for other children (P < 0.0001). Children with more severe disease also had impaired tubular reabsorption of low-molecular-weight proteins beta2-microglobulin and retinol binding protein (RBP)], although other measures of tubular and glomerular function were not similarly impaired. In multiple regression analysis, severity of disease indicators were the best predictors of tubular reabsorption of beta2-microglobulin (R2 = 0.53) whereas tubular reabsorption of beta2-microglobulin and RBP were found to be the best predictors of urinary retinol loss (R2 = 0.69). CONCLUSIONS: A significant amount of retinol was excreted in the urine in children with shigellosis: 8% excreted >0.10 micromol/d (15% of the daily metabolic requirement). Impaired tubular reabsorption of low-molecular-weight proteins, such as RBP transporting retinol, appeared to be the cause of this urinary retinol loss.

Helicobacter pylori colonization in infants and young children is not necessarily associated with diarrhoea.

A cohort of 151 infants and young children aged 1-23 months from a poor peri-urban community of Bangladesh was studied to determine the relationship between Helicobacter pylori colonization and morbidity due to diarrhoea. A 13C urea breath test was performed to detect the presence of H. pylori. Children were followed up at home every alternate day for 6 months and diarrhoeal morbidity data were collected. Diarrhoeal morbidity was compared between H. pylori-positive and H. pylori-negative children. Sixty-eight (45 per cent) children were H. pylori positive and 83 (55 per cent) were H. pylori negative. During the first 1-month period following the breath test, three (4.4 per cent) H. pylori-positive and four (4.8 per cent) H. pylori-negative children had diarrhoea. Thirty-two (47 per cent) of the children in the positive group and 43 (52 per cent) in the negative group had one or more episodes of diarrhoea during the 6-month follow-up period. Median number of diarrhoeal episodes was 1.0 (range 1.0-4.0) in the H. pylori-positive children and 2.0 (range 1.0-5.0) in the H. pylori-negative children (p = 0.19). No significant difference was observed in the cumulative days with diarrhoea. The results of this study suggest that H. pylori colonization is not associated with diarrhoeal morbidity in infants and young children.

Serum retinol and HIV-1 RNA viral load in rapid and slow progressors.

Few studies have addressed the relation between serum vitamin A levels and HIV disease progression. Thirty HIV-infected women in Rwanda were studied over a time span of 26 to 99 months. Fourteen subjects seroconverted and died of HIV-related disease at a mean of 44 months (range, 26-69 months) after their first HIV-positive test and were termed "rapid progressors," (RPs). A comparison group of 16 "slow progressors" (SPs) were HIV-positive at the time of their first HIV serology and had asymptomatic HIV infections at a mean of 96 months (range, 93-99 months) after their first HIV serology. Baseline mean serum retinol values were the same in RPs and SPs: 0.65 + 0.08 micromol/L versus 0.67 + 0.09 micromol/L (p = .7). Lower serum retinol levels were observed in RPs compared with SPs for the second and third measurements, obtained at a median of 12 and 24 months past baseline: 0.51 + 0.07 micromol/L versus 0.76 + 0.14 micromol/L (p = .3) and 0.44 + 0.09 micromol/L versus 0.64 + 0.08 micromol/L (p = .08), respectively. Median retinol levels for the third sample measurement were similar in RPs with lower viral load (LVL) and SPs (0.49 micromol/L and 0.52 micromol/L, respectively) compared with only 0.19 micromol/L in RPs with higher viral load (HVL; p = .02). A trend toward decreasing serum retinol levels and increasing HIV-1 RNA viral load was observed at the third sample measurement (p = .04). Subjects with LVL, higher serum retinol levels (> or =0.70 micromol/L), or both had more favorable rates of survival than subjects with HVL, low serum retinol levels (<0.70 micromol/L), or both. Although sample size does not permit definitive conclusions, this study demonstrates an association of high HIV load, rapid progression, and low serum retinol late but not early in disease progression.

Adverse effects of high-dose vitamin A supplements in children hospitalized with pneumonia.

OBJECTIVE: To test the hypothesis that high-dose vitamin A supplements will enhance recovery of children hospitalized for the treatment of community-acquired pneumonia. DESIGN: We conducted a randomized, double-blind, placebo-controlled clinical trial of high-dose vitamin A supplements among children 3 months to 10 years of age (N = 95) admitted to hospital with community-acquired pneumonia in Lima, Peru. Children 1 year of age received 200 000 IU on admission and 100 000 IU the next day. RESULTS: Children receiving vitamin A (n = 48) had lower blood oxygen saturation (the mean difference on day 3 in hospital was 1.1%), higher prevalence rates of retractions (37% in the vitamin A group vs 15% in the placebo group on day 3), auscultatory evidence of consolidation (28% in the vitamin A group vs 17% in the placebo group on day 3), and were more likely to require supplemental oxygen (21% in the vitamin A group vs 8% in the placebo group on day 3) than children in the placebo group (n = 47). Adjustment for baseline severity of disease and nutritional status did not alter the association of vitamin A with increased clinical severity, although the difference in blood oxygen saturation was no longer statistically significant. No differences were seen in duration of hospitalization or in chest x-ray changes 14 days after admission. No deaths occurred, and toxicity of vitamin A was not seen. CONCLUSIONS: This study indicates that high-dose vitamin A supplements cause modest adverse effects in children recovering from pneumonia and should not be used therapeutically in such patients unless there is clinical evidence of vitamin A deficiency or concurrent measles infection.

Serum retinol and HIV-1 RNA viral load in rapid and slow progressors.

Few studies have addressed the relation between serum vitamin A level and HIV disease progression. Thirty HIV-infected women in Rwanda were studied over a time span of 26 to 99 months. Fourteen subjects seroconverted and died of HIV-related disease at a mean of 44 months (range, 26-69 months) after their first HIV-positive test and were termed "rapid progressors," (RPs). A comparison group of 16 "slow progressors" (SPs) were HIV-positive at the time of their first HIV serology and had asymptomatic HIV infections at a mean of 96 months (range, 93-99 months) after their first HIV serology. Baseline mean serum retinol values were the same in RPs and SPs: 0.65 + 0.08 mmol/L versus 0.67 + 0.09 micromol/L (p = .7). Lower serum retinol levels were observed in RPs compared with SPs for the second and third measurements, obtained at a median of 12 and 24 months past baseline: 0.51 + 0.07 mmol/L versus 0.76 + 0.14 mmol/L (p = .3) and 0.44 + 0.09 mmol/L versus 0.64 + 0.08 mmol/L (p = .08), respectively. Median retinol levels for the third sample measurement were similar in RPs with lower viral load (LVL) and SPs (0.49 mmol/L and 0.52 mmol/L, respectively) compared with only 0.19 mmol/L in RPs with higher viral load (HVL; p = .02). A trend toward decreasing serum retinol levels and increasing HIV-1 RNA viral load was observed at the third sample measurement (p = .04). Subjects with LVL, higher serum retinol levels (> or =0.70 mmol/L), or both had more favorable rates of survival than subjects with HVL, low serum retinol levels (<0.70 mmol/L), or both. Although sample size does not permit definitive conclusions, this study demonstrates an association of high HIV load, rapid progression, and low serum retinol late but not early in disease progression.

Intra- and extracellular water dynamics on rehydration in cholera and noncholera patients.

To estimate the intra- and extracellular body water compartments during rehydration of patients with cholera and noncholera diarrhea by bioimpedance analyzer, we studied 30 patients with acute watery diarrhea. Total body water (TBW), intracellular water (ICW), and extracellular water (ECW) of severely dehydrated adult patients were measured with a dual frequency bioimpedance analyzer at different phases of rehydration. Fluid compartments between cholera and noncholera patients were compared. Cholera patients gained more TBW than noncholera patients during recovery. Unlike patients with noncholera diarrhea, the gain in cholera patients was mainly contributed by the ICW (1.5 +/- 1.6 vs 3.0 +/- 1.2 liters, respectively, P < 0.01). It was also observed that the recovery of the ICW compartment in cholera patients occurred rapidly within the first 2 hr after infusion. Differential dynamics of body water compartments in cholera compared to noncholera patients as observed in this study may contribute further to understanding the mechanism of dehydration in diarrheal disease, which might help in improving case management.

Body composition, resting metabolic rate, and energy requirements of short- and normal-stature, low-income Guatemalan children.

We examined body composition using bioelectrical impedance analysis and isotope dilution (18O and 2H), resting metabolic rate (RMR) by indirect calorimetry, and total energy expenditure (TEE) by doubly labeled water in 15 short-stature (height-for-age < or = -1.5 SD) and 15 normal-stature (height-for-age > -1.5 SD) Guatemalan children aged 4-6 y. Although, in absolute terms significant group differences were found in fat-free mass (FFM), fat mass, and total body water (TBW), there were no significant differences in fat mass and TBW after adjustment for FFM. RMR of the short-stature children (3791 +/- 376 kJ/d) was not significantly different from that of normal-stature children (4038 +/- 531 kJ/d), and the regression between RMR and FFM was also not significantly different between groups. TEE was not significantly different in short-stature (4753 +/- 761 kJ/d) compared with normal-stature children (5304 +/- 1020 kJ/d); the regression between TEE and FFM was not significantly different between the two groups. There were no significant group differences in RMR and TEE after adjustment for FFM. FFM was the strongest predictor of TEE, but could only explain 29% of the variance. We conclude that 1) the lower TBW and fat mass in the short-stature group is proportional to their lower FFM, 2) there is no significant difference in either RMR or TEE between short- and normal-stature children, and 3) TEE is highly variable among these children and cannot be explained by differences in body size alone.

Effect of early vitamin A supplementation on cell-mediated immunity in infants younger than 6 mo.

One hundred twenty infants were randomly assigned to receive either 15 mg vitamin A or placebo with each of three DPT/OPV (diphtheria, pertussis, tetanus/oral polio vaccine) immunizations at monthly intervals. Sixty-two received vitamin A and 58 received placebo. One month after the third supplementation dose, the response to the delayed cutaneous hypersensitivity test [multitest cell-mediated immunity (CMI) skin evaluation] for tetanus, diphtheria, and tuberculin (purified protein derivative, PPD) was the same in the vitamin A and placebo infants. The number of anergic infants was 17 (27%) and 19 (33%) in the vitamin A and placebo groups, respectively. The number of positive tests among well-nourished infants was significantly higher than that in malnourished infants irrespective of supplementation (P < 0.001). Among the infants with adequate serum retinol concentrations (> 0.7 mumol/L) after supplementation, the vitamin A-supplemented infants had a significantly higher proportion of positive CMI tests than the placebo infants (chi-square test: 8.99, P = 0.008). Among the infants with low serum retinol concentrations (< 0.7 mumol/L) after supplementation, vitamin A supplementation had no effect on CMI response. These results indicate that CMI in young infants was positively affected by vitamin A supplementation only in those infants whose vitamin A status was adequate (ie, serum retinol > 0.7 mumol/L) at the time of the CMI test. CMI was consistently better in well-nourished infants irrespective of supplementation.

Acute respiratory infections prevent improvement of vitamin A status in young infants supplemented with vitamin A.

At immunization contact, 165 infants 2.5 mo old were randomly assigned to receive either 15 mg vitamin A (retinyl palmitate) or placebo. Three doses were given at monthly intervals with each diphtheria, pertussis, tetanus and oral polio (DPT/OPV) immunization dose. The diarrhea and acute respiratory infection (ARI) morbidity was similar in the vitamin A and placebo groups. However, the duration (days per child-year, mean +/- SD) of ARI was less in the vitamin A group compared with placebo group (27.6 +/- 17.1 vs. 40.8 +/- 22.7; P = 0.005). Fasting retinol concentrations were measured at entry and in 61 infants, the relative dose response (RDR) test was done 1 mo after the third dose of vitamin A. Eighty-five percent of the infants had serum retinol concentration < 0.70 mol/L at entry. After 3 mo the serum retinol levels improved significantly in both groups, and in the vitamin A-supplemented group the serum retinol concentration was significantly better than that in the placebo group (P= 0.02). However, 61% of the infants remained deficient despite vitamin A supplementation. Among vitamin A-supplemented infants only, diarrhea and ARI morbidity during the 3-mo period were compared in children with normal versus children with abnormal RDR at the end of the supplementation period. The ARI episodes were more frequent in the supplemented infants who remained vitamin A deficient at the end of the 3 mo (P = 0.027). Also, the cumulative duration (days, mean +/- SD) of fever and cough was 5.0 +/- 2.8 in the normal versus 11.2 +/- 6.0 in the deficient group (P = 0.04). The results of this study suggest that a large proportion of infants remain vitamin A deficient even after large dose vitamin A supplementation because of frequent respiratory infections, particularly those accompanied by fever.

Conjunctival impression cytology fails to detect subclinical vitamin A deficiency in young children.

Thirty-four asymptomatic children, ages 5-35 mo, were studied to compare the conjunctival impression cytology technique with the relative dose response test in detection of subclinical vitamin A deficiency. Conjunctival smears were collected from the infero-temporal-bulbar conjunctiva of each eye with a strip of cellulose acetate filter paper and transferred onto a glass slide. Venous blood was drawn at 0 and 5 h after administration of an oral dose of 1000 micrograms of retinol palmitate (relative dose response test). An increase in serum retinol concentration (> or = 20%) in the 5-h value was considered indicative of an inadequate liver store of vitamin A and hence subclinical vitamin A deficiency. Of the 34 children, 26 (76.5%) had moderate to severe protein-energy malnutrition. Only three children (9%) had abnormal conjunctival impression cytology, whereas 23 (68%) had abnormal relative dose response. Even more striking was the finding that only two of the 23 children with abnormal relative dose response had abnormal conjunctival impression cytology. The results suggest that the conjunctival impression cytology test has poor agreement with the relative dose response test results in assessing vitamin A status in young children. If relative dose response is considered an acceptable reference method for assessing vitamin A status, then the conjunctival impression cytology test cannot be considered a valid measure of subclinical vitamin A deficiency in this population.

Comparison of the modified relative dose response (MRDR) and the relative dose response (RDR) in the assessment of vitamin A status in malnourished children.

The modified-relative-dose-response (MRDR) test and the relative-dose-response (RDR) test were compared in 49 mildly to moderately malnourished Bangladeshi children. The MRDR test had a significantly lower sensitivity, detecting only 71% of children with very low serum retinol (< or = 0.35 mumol/L) and 33% of children with low serum retinol (0.355-0.70 mumol/L) compared with 100% and 80% for the RDR test, respectively. The MRDR test showed a very strong dependency on retinol-binding protein (RBP) saturation (ie, percent saturation of RBP with retinol) compared with the RDR test. Only 3 (23%) of 13 children with RBP saturation > or = 55% but low vitamin A stores were diagnosed as abnormal by the MRDR test. This suggests that when apo-RBP concentration is limiting, as it is in malnourished children, didehydroretinol, the analog used in the MRDR test cannot effectively compete with retinol for binding to apo-RBP. Under these circumstances, the MRDR test is rendered ineffective. The possibility of increasing the sensitivity of the test by using a high dose of didehydroretinol needs to be investigated.

Urinary excretion of retinol in children with acute diarrhea.

Acute infections of childhood are associated with an increased of xerophthalmia, apparently due to depletion of vitamin A stores. The mechanism responsible for this is not known. Recently, it has been reported that severe infections in adult patients (ie, sepsis and pneumonia) result in excretion of large quantities of retinol in the urine. In 44 children hospitalized for treatment of acute diarrhea we found mean urinary excretions of 1.44 mumol retinol/24 h on day 1 of hospitalization, 0.62 mumol retinol/24 h on day 2, and 0.23 mumol/24 h on day 3. Healthy control subjects matched for age did not excrete measurable amounts of retinol in the urine. Retinol excretion was associated strongly with rotavirus diarrhea and presence of fever. Furthermore, serum retinol concentration was negatively associated with duration of diarrhea before hospitalization, suggesting that urinary excretion of retinol may be an important contributor to vitamin A depletion.

Nutrition, tooth development, and dental caries.

Many studies involving small animals have clearly shown that malnutrition affects tooth formation and causes increased dental caries. We have conducted two cross-sectional studies and one longitudinal study among Peruvian children to investigate the effect of early malnutrition on oral health. The cross-sectional studies have shown that in malnourished children the pattern of caries development as a function of age is significantly altered as a result of a delayed eruption and exfoliation of the deciduous teeth. This phenomenon has made difficult the observation by other scientists of a clear effect of nutritional status on total caries experience because the comparison of age-adjusted caries data between populations of children with different nutritional status is inappropriate. The use of peak caries activity has allowed the observation of a strong association between malnutrition and increased dental caries. The longitudinal study has confirmed the results of the cross-sectional studies and has demonstrated that one mild to moderate malnutrition episode occurring during the first year of life is associated with increased caries in both the deciduous and permanent teeth many years later.

Vitamin A is excreted in the urine during acute infection.

Episodes of acute infection are thought to deplete body stores of vitamin A. The mechanism by which this might occur is not known, but increased metabolic requirements are presumed to play a role. We have found, however, that significant amounts of retinol and retinol-binding protein (RBP) were excreted in the urine during serious infections, whereas only trace amounts were found in the urine of healthy control subjects. The geometric mean excretion rate in 29 subjects with pneumonia and sepsis was 0.78 mumol retinol/d. Subjects with fever (temperature > or = 38.3 degrees C) excreted significantly more retinol (geometric mean = 1.67 mumol/d) than did those without fever (0.18 mumol/d; t = 3.53, P < 0.0015). Aminoglycoside administration and low glomerular filtration rates (< 35 mL/min) were also associated with higher rates of urinary retinol excretion. Thirty-four percent of patients excreted > 1.75 mumol retinol/d, equivalent to 50% of the US recommended dietary allowance. These data show that vitamin A requirements are substantially increased during serious infections because of excretion of retinol in the urine, and suggest that these losses are due to pathologic changes associated with the febrile response.

Plasma homocyst(e)ine, folate, and vitamin B-12 concentrations and risk for early-onset coronary artery disease.

High plasma homocyst(e)ine (Hcy) concentrations may be a determinant of coronary artery disease (CAD). Folate and vitamin B-12 are required for the primary metabolic pathway to reduce Hcy concentrations. The interrelationships of Hcy and these two vitamin cofactors were investigated in a case-control study of 101 white males aged 30-50 y with angiographically demonstrated CAD, and 108 white male, similarly aged, control subjects living in the same community as the patients. The odds ratio (OR) of CAD per quartile increase of plasma Hcy concentration based on control values was 1.6 (95% CI: 1.3, 2.1). After age, HDL and LDL cholesterol, body mass index, smoking, hypertension, and diabetes were controlled for, Hcy remained an independent risk factor (OR: 1.4; 95% CI: 1.0, 2.0). The OR change per quartile increase of folate concentration was 0.8 (95% CI: 0.6, 1.0). This difference was reduced (OR: 0.9; 95% CI: 0.7, 1.2) after Hcy adjustment. No difference in the geometric mean of vitamin B-12 concentration was found between patients and control subjects, both 5.8 nmol/L. However, after Hcy and the other CAD risk factors were controlled for, the OR per quartile increase in vitamin B-12 concentration was 1.5 (95% CI: 1.0, 1.8). Reduction in plasma Hcy by interventions to increase plasma folate concentration may decrease CAD risk.