Plasma and urinary aluminum concentrations in severely anemic geophagous pregnant women in the Bas Maroni region of French Guiana: a case-control study

Abstract

The clays consumed by geophagous individuals contain large quantities of aluminum, a known neurological and hematological toxin. This is the first study to evaluate the risk of aluminum poisoning in geophagous individuals. Blind determinations of plasma and urinary aluminum concentrations were carried out in 98 anemic geophagous pregnant women and 85 non-anemic non-geophagous pregnant women. Aluminum concentrations were significantly higher (P < 0.0001) in the geophagous anemic women than in the controls, with odds ratios of 6.83 (95% confidence interval [CI] = 2.72-19.31) for plasma concentrations (13.92 ± 14.09 μg/L versus 4.95 ± 7.11 μg/L) and 5.44 (95% CI = 2.17-14.8) for urinary concentrations (92.83 ± 251.21 μg/L versus 12.11 ± 23 μg/L). The ingested clay is the most likely source of this overexposure to aluminum. If confirmed, the clinical consequences of this absorption for pregnant women and their offspring should be explored.

Figure 1.

Box plot showing differences in aluminemia (left graph) and aluminuria (right graph) between the control and geophagy groups. The horizontal line within the boxes, the limits of the boxes, and the whiskers extending beyond the boxes represent the median, quartiles, and values below the first quartile and above the fourth quartile, respectively, excluding outliers.

Figure 2.

Distribution of plasma aluminum concentration as a function of hemoglobin concentration in the control (left) and geophagy (right) groups