Zinc and multivitamin supplementation have contrasting effects on infant iron status: a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

Zinc supplementation adversely affects iron status in animal and adult human studies but few, trials have included young infants.

OBJECTIVE

To determine the effects of zinc and multivitamin supplementation on infant hematologic and iron status.

METHODS

In a double-blind RCT, Tanzanian infants were randomized to daily, oral zinc (Zn), multivitamins (MV), Zn and MV, or placebo treatment arms at age 6 wk. Hemoglobin concentration (Hb) and red blood cell indices were measured at baseline and at 6, 12, and 18 mo of age. Plasma samples from 589 infants were examined for iron deficiency (ID) at 6 mo.

RESULTS

In logistic regression models, Zn treatment was associated with greater odds of ID (OR 1.8 [95% CI 1.0–3.3]), and MV treatment was associated with lower odds (OR 0.49 [95% CI 0.3–0.9]). In Cox models, MV were associated with a 28% reduction in risk of severe anemia (HR=0.72 [95% Cl 0.56–0.94]) and a 26% reduction in risk of severe microcytic anemia (HR=0.74 [0.56–0.96]) through 18 months. No effects of Zn on risk of anemia were seen. Infants treated with MV alone had higher mean Hb (9.9 g/dL [95% CI 9.7–10.1]) than those given placebo (9.6 g/dL [9.4–9.8]) or Zn alone (9.6 g/dL [9.4–9.7]).

CONCLUSIONS

MV treatment improved iron status in infancy, whereas Zn worsened iron status but without an associated increase in risk for anemia. Infants in long-term zinc supplementation programs at risk for ID may benefit from screening and/or the addition of a multivitamin supplement.

Detection of congenital malaria by polymerase-chain-reaction methodology in Dar es Salaam, Tanzania

The examination of congenital malaria was performed by Giemsa staining and polymerase-chain-reaction (PCR) methodology. We randomly selected 298 neonates who had been admitted to Muhimbili Medical Center (MMC) at Dar es Salaam, Tanzania. One baby among all the enrolled neonates was recognized as having a congenital malaria infection, which gave a prevalence of 0.33%. The present result was 5-fold the clinically recognized prevalence of congenital infection with malaria in the ward. The PCR method identified two cases, one of which was negative as determined by the Giemsa-staining method. Therefore, the PCR method was useful for the detection of scant amounts of malarial parasites in numerous blood samples. The screening of malaria by a sensitive PCR method contributes to reduce the mortality of asymptotic neonates in particular.

A high prevalence of metabolic bone disease in exclusively breastfed very low birthweight infants in Dar-es-Salaam, Tanzania

Metabolic bone disease (MBD), or rickets, is common in very low birthweight infants. A descriptive, cross-sectional, hospital-based study was carried out at Muhimbili Medical Centre, Dar-es-Salaam from 15 April to 30 June, 1995 to discover the magnitude, contributory factors, morbidity and suitable biochemical diagnostic tests for MBD. One hundred infants with a postnatal age of 6-12 weeks, whose birthweights were 1500 g or less were studied. Thirty-three of 100 (33%) infants, 16 boys and 17 girls, were radiographically diagnosed as having metabolic bone disease. The mean (SD) gestational age of those infants was 30.4 (2.7) weeks, while that of the infants without metabolic bone disease was 32.4 (3) weeks (p = 0.003). There was no significant difference in birthweight, serum calcium and serum phosphate levels between those infants with MBD and those without. The mean (SD) serum alkaline phosphatase in infants with MBD was 1052.9 (493.3) U/l and 766.8 (301.7) in those without MBD (p = 0.006). Thus, metabolic bone disease is common in very low birthweight infants. Wrist radiography and serum alkaline phosphatase levels remain important diagnostic tools. MBD should be considered seriously in very low birthweight infants.

Cryptosporidium, enterocytozoon, and cyclospora infections in pediatric and adult patients with diarrhea in Tanzania

Cryptosporidiosis, microsporidiosis, and cyclosporiasis were studied in four groups of Tanzanian inpatients: adults with AIDS-associated diarrhea, children with chronic diarrhea (of whom 23 of 59 were positive [+] for human immunodeficiency virus [HIV]), children with acute diarrhea (of whom 15 of 55 were HIV+), and HIV control children without diarrhea. Cryptosporidium was identified in specimens from 6/86 adults, 5/59 children with chronic diarrhea (3/5, HIV+), 7/55 children with acute diarrhea (0/7, HIV+), and 0/20 control children. Among children with acute diarrhea, 7/7 with cryptosporidiosis were malnourished, compared with 10/48 without cryptosporidiosis (P < .01). Enterocytozoon was identified in specimens from 3/86 adults, 2/59 children with chronic diarrhea (1 HIV+), 0/55 children with acute diarrhea, and 4/20 control children. All four controls were underweight (P < .01). Cyclospora was identified in specimens from one adult and one child with acute diarrhea (HIV-). Thus, Cryptosporidium was the most frequent and Cyclospora the least frequent pathogen identified. Cryptosporidium and Enterocytozoon were associated with malnutrition. Asymptomatic fecal shedding of Enterocytozoon in otherwise healthy, HIV children has not been described previously.

Cerebral metabolism within 18 hours of birth asphyxia: a proton magnetic resonance spectroscopy study

Proton magnetic resonance spectroscopy (1H MRS) was performed within 18 h of birth (median 13, range 4-18 h) on 16 term infants with clinical features of birth asphyxia. Ten infants with no evidence of birth asphyxia were studied as controls at 5-18 (median 8) h after birth. To detect delayed impairments in cerebral energy metabolism, 15 infants suspected of asphyxia underwent 31P MRS at 33-106 (median 62) h of age. Choline, creatine, and N-acetylaspartate (NAA) were detected in spectra located to the basal ganglia in all infants. Lactate was detected in 15 of the 16 infants suspected of asphyxia, but in only 4 of the 10 controls (p < 0.05, chi 2). Glutamine and glutamate (Glx) was detected in 11 infants suspected of asphyxia and in three controls, but this difference was not significant at the 5% level. The spectra revealed no other significant differences between asphyxiated infants and controls. In the asphyxiated infants, there was a negative correlation between the ratio of lactate to creatine in the first 18 h of life and phosphocreatine/inorganic phosphate (PCr/ P(i)) at 33-106 h (p < 0.001). Five severely asphyxiated infants had PCr/P(i) < 0.75 (median 0.53, range 0.14-0.65), indicating a poor neurodevelopmental prognosis, and a further infant died before PCr/Pi could be measured. Ten infants had PCr/P(i) > 0.75 (1.03, 0.76-1.49). Median lactate/creatine was 1.47 (range 0.67-3.81) in the six severely affected subjects, 0.38 (0-1.51) in the latter group, and 0 (0-0.6) in controls (p < 0.0005, Kruskall-Wallis). These results suggest that, after birth asphyxia, cerebral energy metabolism is abnormal during the period when 31P MRS characteristically gives normal results. 1H MRS might be of value in predicting which infants are likely to suffer a decline in cerebral high energy phosphate concentrations and subsequent neurodevelopmental impairment.