Thiamine deficiency in Cambodian infants with and without beriberi

Abstract

Objectives: To test the hypothesis that heavy metal toxicity and consumption of thiaminase-containing foods predispose to symptomatic thiamine deficiency.

Study design: In a case-control study, thiamine diphosphate (TDP) blood concentrations were measured in 27 infants diagnosed with beriberi at a rural clinic, as well as their mothers and healthy Cambodian and American controls. Blood and urine levels of lead, arsenic, cadmium, mercury, and thallium were measured. Local food samples were analyzed for thiaminase activity.

Results: Mean TDP level among cases and Cambodian controls was 48 and 56 nmol/L, respectively (P = .08) and was 132 nmol/L in American controls (P < .0001 compared with both Cambodian groups). Mean TDP level of mothers of cases and Cambodian controls was 57 and 57 nmol/L (P = .92), and was 126 nmol/L in American mothers (P < .0001 compared with both Cambodian groups). Cases (but not controls) had lower blood TDP levels than their mothers (P = .02). Infant TDP level decreased with infant age and was positively associated with maternal TDP level. Specific diagnostic criteria for beriberi did not correlate with TDP level. There was no correlation between heavy metal levels and either TDP level or case/control status. No thiaminase activity was observed in food samples.

Conclusions: Thiamine deficiency is endemic among infants and nursing mothers in rural southeastern Cambodia and is often clinically inapparent. Neither heavy metal toxicity nor consumption of thiaminase-containing foods account for thiamine deficiency in this region.

Figure 1

Whole blood TDP concentrations in Cambodian and American subjects (nmol/L). Boxes IQR; the lines inside the boxes indicate median values. Whiskers represent the range of non-outlier values outside of the IQR, with outliers indicated by open circles. There were no significant differences between Cambodian cases and controls; P < .0001 for 3-way ANOVA for both infants and mothers.

Figure 2

Relationship between infant whole blood TDP concentration and infant age. P values are for the slope in each of 3 separate linear regressions.

Figure 3

Relationship between infant whole blood TDP concentration and maternal whole blood TDP concentration. P values are for the slope in each of 3 separate linear regressions. The null hypothesis of slope = 1 corresponds to the same rate of increase for infants and mothers.