Francis Sartor

Determinants of serum zinc in a random population sample of four Belgian towns with different degrees of environmental exposure to cadmium

This report investigated the distribution of serum zinc and the factors determining serum zinc concentration in a large random population sample. The 1977 participants (959 men and 1018 women), 20–80 years old, constituted a stratified random sample of the population of four Belgian districts, representing two areas with low and two with high environmental exposure to cadmium. For each exposure level, a rural and an urban area were selected. The serum concentration of zinc, frequently used as an index for zinc status in human subjects, was higher in men (13.1 μmole/L, range 6.5–23.0 μmole/L) than in women (12.6 μmole/L, range 6.3–23.2 μmole/L). In men, 20% of the variance of serum zinc was explained by age (linear and squared term, R = 0.29), diurnal variation (r = 0.29), and total cholesterol (r = 0.16). After adjustment for these covariates, a negative relationship was observed between serum zinc and both blood (r = −0.10) and urinary cadmium (r = −0.14). In women, 11% of the variance could be explained by age (linear and squared term, R = 0.15), diurnal variation in serum zinc (r = 0.27), creatinine clearance (r = −0.11), log γ-glutamyltranspeptidase (r = 0.08), cholesterol (r = 0.07), contraceptive pill intake (r = −0.07), and log serum ferritin (r = 0.06). Before and after adjustment for significant covariates, serum zinc was, on average, lowest in the two districts where the body burden of cadmium, as assessed by urinary cadmium excretion, was highest. These results were not altered when subjects exposed to heavy metals at work were excluded from analysis.

Transfer of cadmium from a sandy acidic soil to man : a population study

This population study included 230 subjects (age range 20-83 years) who consumed vegetables grown in kitchen gardens on a sandy acidic soil (mean pH approximately 6.3). The study investigated the association between the Cd (cadmium) levels in blood and urine and the Cd concentration in the soil (range 0.2-44 ppm). Seventy-six subjects were current smokers and 122 participants lived in a district with known Cd pollution. Urinary Cd in the 230 subjects averaged 8.7 nmole/24 hr, (range 1.3 to 47 nmole/24 hr) after age adjustment positively correlated with the Cd level in the soil; a twofold increase of the Cd concentration in the soil was accompanied by a 7% rise in urinary Cd in men (R2 = 0.05; P = 0.04) and by a 4% rise in women (R2 = 0.02; P = 0.05). Blood Cd averaged 11.5 nmole/liter (range 1.8-41 nmole/liter) and was negatively associated with the Cd level in the soil. After adjustment for significant covariates (smoking and serum gamma-glutamyl transpeptidase in both sexes, and age and serum ferritin in women), a twofold increase in the Cd concentration in the soil was accompanied by a 6% decrease in blood Cd in men (R2 = 0.03; P = 0.09) and by a 10% decrease in women (R2 = 0.06; P less than 0.01). In conclusion, in a rural population, consuming vegetables grown on a sandy acidic soil, 2 to 4% of the variance of urinary Cd was directly related to the Cd level in the soil. The negative correlation with blood Cd, a measure of more recent exposure, was biased by the implementation of preventive measures in the polluted district.

Decrease in Blood Cadmium Levels over Time in Belgium

During the time period from 1984 to 1988, blood cadmium concentration decreased by 56% in 31 males who were not occupationally exposed to cadmium and who lived in a Belgian urban area where there existed nonferrous industries. A 40% decrease in blood cadmium concentration was also observed in an independent cross-sectional survey conducted in 1985 and 1988 among 412 subjects who lived in a rural area. This latter decrease persisted when the main determinants of blood cadmium concentration--gender, age, and tobacco--were allowed for. The results presented are consistent with a decrease in environmental cadmium exposure in Belgium.

Aminolevulinate dehydratase and blood lead levels in urban male adults

SummaryThe existence of an association between aminolevulinic acid dehydratase activity in erythrocytes (ALA-d) and blood lead level (Pb-B) has been investigated in a male urban population not occupationally exposed to lead. The data show a decrease of the mean ALA-d activity when Pb-B rises but the association is not statistically ascertained in every case when the data are examined by two different procedures.It appears first that the statistical significance depends on an adequate choice of the distribution function of the ALA-d. Secondly, factors such as interindividual variability of this biological index, lack of precision in the analytical measurements of the Pb-B and the range of the environmental exposure under observation may influence the statistical significance and induce misleading statements. The data aggregation allows the avoidance of some inconsistencies.Furthermore, the estimation of mean ALA-d for the different Pb-B may also be biased by confounding risk factors (such as smoking habits). As such factors are not presently taken into consideration in public health surveys, the no-threshold Pb-B hypothesis, suggested by the observed dose-effect relationship, cannot be strongly supported.