Cancer mortality during the 1968-1994 period in a mining area in France.

We performed a geographical analysis of cancer mortality in the communes surrounding an industrial mining complex (Salsigne, France) where suspicious levels of pollution due to arsenic were measured. Compared with that observed in a control area, we showed a significant excess of mortality due to all cancer types (ratio of standard mortality ratios (ratio of SMRs)=1.1), lung cancer (ratio of SMRs=1.8), pharynx cancer (ratio of SMRs=2.1) in the whole population, and due to digestive system cancer (ratio of SMRs=1.3) among women. The results were similar after controlling for the occupation distribution in the populations. Excluding mining complex workers deaths from the deaths in the studied populations did not modify the pattern of our results. We concluded that the excess of cancer deaths could not be exclusively due to potential professional exposures among the workers of the mining complex and are probably explained by environmental contamination.

Gold-mining activities and mercury contamination of native amerindian communities in French Guiana: key role of fish in dietary uptake.

In 1994, the French National Public Health Network reported significant mercury exposure of native Amerindians in French Guiana. In 1997, a study was conducted in the Wayana community to quantify the dietary intake and to identify the fish species contributing the most to the contamination. The study was completed by an impregnation analysis based on Hg determination in hair samples. The methodology used was a detailed familial dietary study associated with Hg measurements in fish and some game. The study was conducted over 7 days in two different seasons in the four most populated Wayana villages on the upper part of the Maroni River (521 people; 70% of the Wayana population in French Guiana). Analysis was based on data on consumption obtained from 165 people in a 1-14 day period (i.e., 940 persons [times] days) and involved 270 fish samples from 48 species. Total Hg and monomethylmercury (MMHg) were also determined in hair samples (235 samples for total Hg). The results confirm mercury exposure of the Wayana population related to a diet rich in fish, which are relatively highly contaminated for certain species (up to 1.62 mg/kg fresh weight or 8.1 mg/kg dry weight in skeletal muscle). Results from hair samples showed that 57% of the Amerindians had Hg levels above the World Health Organization (WHO) safety limit (10 microg/g); all those over 1 year of age had a Hg intake greater than the WHO safety limit (200 microg MMHg/week for a 60-kg male). Hg concentrations in fish muscle were closely linked to the feeding regime and position of fish in the food webs. Overall, 14.5% of the fish collected exceeded the 0.5 mg/kg (fresh weight) safety limit. Four carnivorous species accounted for no less than 72% of the metal ingested by the Wayana families, although these represented only 28% of the consumed fish biomass. In conclusion, this study revealed excessive exposure to mercury in the Wayana population in French Guiana related to the consumption of contaminated fish.

Environmental exposure to cadmium and human birthweight.

Fetal toxicity of cadmium (Cd) is well documented in rodents. However, little information is available regarding the human fetus. To investigate the effect of low levels of Cd on the human placenta and the consequences on birthweight, we conducted a study of 102 mothers and their newborns in an obstetrical care unit. Placental and hair samples were collected at delivery to determine Cd concentrations. The main finding of this study was the relationship between a decrease in birthweight and an increase of newborn hair Cd which varied in the presence of placental calcification. In cases of parenchymal calcifications, placental Cd levels were higher (Wilcoxon test, P < 0.05) and newborn hair Cd levels were lower (Wilcoxon test, P < 0.01) than in the absence of calcification. These relationships remained significant even after taking into account smoking habits and gestational age. In the presence of calcification, an increase in the level of Cd in newborn hair was related to a decrease in birthweight which was independent of placental Cd concentration (rpartial = -0.49, P < 0.01). In the absence of calcification, a decrease in birthweight was observed for the upper values of newborn hair Cd (r = -0.44, P < 0.05 when Cd > or = 0.3 ppm). The difference in birthweight between infants in the first and last quartiles of newborn hair Cd was 472 g in cases of calcifications and 122 g in the absence of calcification. Other placental parameters were not significantly related to placental Cd concentration.

Joint effect of gestational age and maternal lead exposure on psychomotor development of the child at six years.

A prospective study has been carried out to assess the psychomotor deficit resulting from a moderate decrease in gestational age and pre-natal lead exposure. The general cognitive index of the McCarthy psychometric scale (adjusted for confounders) in six-year-old children was related to gestational age. Most of the psychomotor scores showed smoothing variations with gestational age ranging from 37 to 39 weeks, whereas sharp changes occurred between 39 to 40 weeks, with plateau values above such a cut-off for all spheres of development examined. Maternal hair lead content, used as an indicator of lead exposure during pregnancy, was found to be negatively related to general cognitive, verbal, quantitative, and memory subscales (p less than 0.01), whereas its relationship with perceptual and motor subscales was close to 0.05 significance level. Control for gestational age did not change the significance level of the associations. When controlling for maternal hair lead levels, the significance of the association between gestational age and the McCarthy subscales also remained stable, only the general cognitive index and verbal subscale reaching the conventional significance level.

Aryl hydrocarbon hydroxylase activity in human placenta and threatened preterm delivery.

Induction of aryl hydrocarbon hydroxylase (AHH) activity in the placenta has been well documented. This enzyme may be induced by a variety of Polycyclic Aromatic Hydrocarbons (PAHs) and the AHH inducibility is associated with harmful effects of environmental chemicals. Toxic effects of PAHs in tissues such as placenta have been demonstrated to be due to their metabolites, epoxides, which interact with DNA. Thus, environmental PAHs may be related to its alterations in fetal development. Founded on these findings the PAH metabolites could interfere with the normal course of the pregnancy and may be an aborticide, a teratogen or a carcinogen. We hypothesize that low increased activity of placental Aryl Hydrocarbon Hydroxylase (AHH) may be an important determinant of human fetotoxicity. The present investigation was designed to examine the possible implications of PAH exposure at environmental exposure levels on the normal course of the pregnancy using AHH induction as an indicator of PAH exposure. Threatened Preterm Delivery (TPD) was used as an index of problems in the normal course of pregnancy. A group of forty pregnancies at term with TPD was compared with eighty controls for placental AHH induction. Macroscopic placental examination was also performed. A significant increase in prevalence of placental AHH induction with TPD was shown (Odds-Ratio = 2.8; 95% confidence bounds [1.3-6.2]; chi 2 = 6.7 p < 0.01). No such increases were found associated with placental pathology. When taking into account the group of placenta without basal plate calcifications, the significant increase in prevalence of placental AHH induction with TPD above mentioned was greatly increased (Odds-Ratio = 8.9; 95% confidence bounds [2.4-32.9]; chi 2 = 11.1 p < 0.001) controlling for gestational age. The increase in prevalence of placental AHH induction with TPD disappeared when taking into account the subgroup with basal plate or parenchyma calcifications. It is hypothesized that the high estrogen and progesterone at term may explain these associations.

Vitamin B12 among parturients and their newborns and its relationship with birthweight.

Vitamin B12 (Cobalamin) is an essential nutrient in the diet of humans, particularly during pregnancy, nevertheless very few epidemiological studies have been reported, particularly concerning variation factors. The purpose of this study is to assess the role of vitamin B12 on birthweight after taking into account potential confounders, such as obstetrical, socioeconomic, and biological factors which will be identified. This study was conducted on 188 single births occurring during a 5-month period in an obstetrical care unit in Paris. Vitamin B12 plasma levels and folate plasma levels of mothers and cords along with haematological parameters were measured. Social and obstetrical features of the mothers as well as their tobacco exposure and alcohol consumption were recorded. Cord blood vitamin B12 levels were highly correlated with maternal levels (r = 0.63, P less than 0.001) and were 2-3-fold higher. Three variation factors of vitamin B12 were identified: maternal age, ethnicity and tobacco exposure. Negative correlations between birthweight and vitamin B12 levels were observed only among the smoker group (r mothers = -0.46, P less than 0.05 and r cords = -0.42, P less than 0.05). After adjustment for ethnicity and parity, birthweight remained negatively linked to vitamin B12 in smokers. This relationship could suggest that the availability of vitamin B12 for fetal development depends on certain biological factors present only in mothers who smoked. We hypothesized this relationship could be explained, in part, by lipid metabolism, particular to smokers.

Evolution of blood lead levels in urban French population (1979-1995).

BACKGROUND: The aim of the Council Directive of 29 March 1977 of the European Union was to measure non-occupational lead exposure levels in the general adult populations of European countries through biological monitoring. In France, such measurements were carried out during 1979 and 1982 in eight metropolitan areas (having more than 500 000 inhabitants), a period during which the lead content of petrol was decreased. The aim of this study conduct in 1995 was to evaluate the exposure trend to lead. METHODS: In 1995 this measurement was repeated, only in the three largest urban areas (Paris, Marseilles and Lyons). The same sampling method used in the first two campaigns was retained to ensure that the results of 1995 could be compared with those from 1979 and 1982. RESULTS: In these three metropolitan areas, the average blood lead levels decreased by the order of 60 microg/l between the beginning of the 1980's and 1995. This represents a fall of more than 50%. CONCLUSIONS: Certainly car pollution is not the only vector of dissemination of lead in the centre of urban zones, but it is there that the most sustained efforts at eradication have been made. The improvement we have observed is probably due to the policy of eliminating lead from petrol. In conclusion, the blood lead levels in French urban populations seem to have greatly decreased from those of the early 1980s.

Sex ratio of human T-lymphotropic virus type I infection and blood transfusion.

The prevalence of human T-lymphotropic virus type I (HTLV-I) infection is higher for females than for males. Blood transfusion is a potential confounding factor which might contribute to this high female:male ratio. Two studies were performed in Martinique (French West Indies) to clarify this issue: a case-control survey comparing the experience of previous blood transfusion among 62 HTLV-I-seropositive and 88 HTLV-I-seronegative blood donors, and a retrospective study of the sex of recipients of blood. Blood transfusion was strongly associated with HTLV-I infection (odds ratio = 6.4, p less than 0.001). Females were more often given blood transfusions (57.9 percent, p less than 0.001) and received a higher percentage of blood units (53.5 percent, p less than 0.05) than could be expected from their proportion in the general population (51.6 percent). Thus, the high female:male sex ratio of HTLV-I-infected subjects might be due partially to a sex difference for blood transfusion.

HTLV-I infection in French West Indies: a case-control study.

A case-control study was performed in Martinique, French West Indies, comparing 66 anti-p24 antibody carriers to 91 seronegative subjects for HTLV-I, matched for age and place of residence. The aim of our study was to identify factors associated with HTLV-I infection and to observe whether clinical examination and biological measurements would reveal any abnormalities among the seropositive subjects. We observed a predominance of females among seropositive subjects (74% compared to 59%, p less than 0.05), and a greater risk due to earlier blood transfusions (p less than 0.001). This survey revealed important differences between cases and controls regarding socioeconomic factors: cases had fewer luxuries or advantages (i.e. bathroom, toilets, refrigerator, telephone, p less than 0.01), were more corpulent (p less than 0.05), and more often widowed, divorced or separated (p less than 0.01) than the controls. Although the differences were not significant, the seropositive donors seemed to be less educated, and were from a lower socioprofessional class than the seronegative donors. With regard to clinical symptoms (infections, adenopathies, splenomegaly, hepatomegaly) and biological parameters (blood count; T-cell subsets, electrophoresis of protids, immunoglobulins, calcemia, antischistosomal antibody), seropositive subjects appeared to be healthy; no parameters, except for alpha 1 globulin (p less than 0.05) and monocytes (p less than 0.05), were found to be correlated with seropositivity; but these two parameters remained within their normal ranges. This study confirms blood transfusion as a risk factor. It underscored the importance of socioeconomic factors for seropositivity.