[Low exposure to lead and reproductive health: a cohort study of female workers in the ceramic industry of Emilia-Romagna (Northern Italy)].

AIMS

to assess the effects of low levels of lead exposure on reproductive health (miscarriage, fertility, multiple births, sex ratio at birth, incidence of some diseases during pregnancy), following a cohort of female workers exposed to lead in the ceramic tile industry in the Municipalities of Scandiano (RE) and Sassuolo (MO), Northern Italy.

DESIGN

a cohort of 2,067 female workers was considered. These workers repeatedly underwent blood lead levels testing at the Toxicology Laboratory of Scandiano (RE) in the period 1998-2004. Follow-up was performed for each subject for the 12 months following any blood lead testing. Data on miscarriages and live births were obtained through a linkage with hospital discharge records. Results were compared with the frequency of events in the general female population in the Emilia-Romagna Region (Northern Italy). The frequency of multiple births was also examined, as well as the ratio of male-to-female infants and maternal diseases during pregnancy. An internal analysis within the cohort was conducted to evaluate the associations with increasing lead levels.

RESULTS

the women under study accumulated 5,722 person-years of observation. The age distribution of study subjects was not different from the one observed in the Region. Thirty-one miscarriages and 212 live births were recorded. The miscarriage rate (5.42‰) among the study subjects was not different from the regional reference, while the fertility rate (37.05‰) was lower (RR: 0.72; 95%CI 0.63-0.83). The frequency of multiple births (1.9%) was similar to the regional rate (1.2%). Eighty-six females (40.57%) and 126 males (59.43%) were born, compared to regional percentages of 49% females and 51% males. Of all the indicators examined, only miscarriage showed a positive trend among women exposed to lead. In addition, women exposed to lead had a higher frequency of hypertension during pregnancy (RR: 1.34; 95%CI 1.07-1.68), problems with the amniotic cavity (RR: 1.16; 95%CI 1.02-1.33), and prolonged pregnancy (RR: 1.37; 95%CI 1.09-1.73).

CONCLUSIONS

the cohort of female subjects under study showed rate of miscarriage similar to the general population and a lower fertility rate. There were a higher percentage of male births and an increase of some conditions during pregnancy possibly related to lead exposure.