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Background: Polychlorinated biphenyls (PCBs) may interact with several thyroid functions. Severe environmental pollution by PCBs has been observed in Brescia, Italy, due to the presence of a factory that produced these compounds until 1984., Objectives: We aimed to investigate the correlation between serum levels of total PCBs and PCB 153 and thyroid hormone serum levels in adults in a cross-sectional population-based study., Methods: A total of 527 subjects were enrolled; they were face-to-face interviewed about their history of thyroid disease and provided a blood sample under fasting conditions. The serum levels of free and total triiodothyronine (FT3 and TT3), thyroxine (FT4 and TT4) and thyroid-stimulating hormone (TSH), anti-thyroperoxidase (anti-TPO) and anti-thyroglobulin (anti-TGA), and lipid-adjusted total PCBs and PCB 153 were determined., Results: There was no statistically significant difference in total PCB and PCB 153 concentrations in subjects with and without thyroid disease. Inverse, weak, statistically significant correlations were found between total PCBs and FT3 (Spearman's r=-0.09) and between total PCBs and PCB 153 and TSH (Spearman's r=-0.16 and -0.12, respectively). However, multiple regression analysis with FT3 and TSH serum levels as dependent variables and total PCBs and PCB 153 serum levels as predictors, including age, gender and BMI, showed a positive, rather than negative, association of PCBs and PCB 153 with FT3 and no association with TSH., Conclusions: This study does not support the hypothesis that relatively high PCB environmental exposure can determine substantial alterations in thyroid function among adult people.

Introduction: A chemical factory located in Brescia, an industrialized town in North Italy, produced polychlorinated biphenyls (PCBs) since the 1930s to the 1980s, determining a relevant pollution of soil, food and people. Since 2001, following a survey carried out in the general population living in the town, the individuals with PCB serum levels higher than the reference entered a follow-up study.Methods: We performed a prospective cohort study including subjects with at least three PCB measures during the period 2003-2015. We evaluated the temporal trends of total PCB serum levels, the most common PCB congeners (PCB 138,153, 170, 180, 194 and 209), and toxic equivalency of dioxin-like PCBs using univariate and multivariate mixed models with and without a cubic-spline term for time.Results: A total of 128 subjects were enrolled (46.1% males, mean age at enrolment 57.7 years). The geometric mean of PCBs decreased from 35.4ng/ml at 0-3 years to 29.3ng/ml at 4-8 years and to 23.0ng/ml at 9-12 years. A 3.8% reduction of total PCB serum levels per year was estimated using both univariate and multivariate mixed models adjusted for age; a similar reduction was found for the most common PCB congeners and for toxic equivalency. Total PCB serum levels decreased over time for each age group: -3.9%, -4.0% and -3.4% for subjects aged ≤55 years, 56-65 and ≥66 years, respectively.Conclusion: A significant decrease of serum concentrations of PCBs was observed in subjects with high serum levels of these chemicals at enrolment over a twelve year period. The decrease was evident for each PCB congener and age group. [ABSTRACT FROM AUTHOR]

Introduction Polychlorinated biphenyls (PCBs) are persistent pollutants classified among endocrine disruptors and human carcinogens. In an urban area in Northern Italy (Brescia), a chemical factory producing PCBs from 1938 to 1984 caused soil and food pollution. Since the discovering of the environmental pollution in the area in 2001, various public health interventions have been implemented to avoid human contamination. Methods Two independent surveys were carried out in 2003 and 2013 using the same study design and methods. A random sample of the adult general population living in four areas of the town with different soil contamination level was enrolled in both surveys. Investigation included serum levels of 24 PCB congeners and of other common clinical-chemical parameters and questions about residential and occupational history as well as current and past diet and consumption of locally produced food. 537 subjects were tested in the 2003 and 488 in the 2013 survey. Results Total PCB serum levels showed a strong correlation with age (Spearman r = 0.71 in 2003 and r = 0.80 in 2013), but not with gender. Consumers of food produced in the most polluted area had higher total PCB serum levels (median 15.6 and 4.7 ng/ml in 2003 and 2013, respectively) than non-consumers (4.1 and 2.3 ng/ml) and consumers of food produced in non-polluted areas (6.5 and 1.9 ng/ml), with increasing trend of PCB serum levels with cumulative local food intake. PCB serum levels from 2003 to 2013 survey declined by around half in all age groups, especially among the youngest people. The total PCB reduction was found to be due to a combination of a birth cohort effect (− 41% every 10 years) and survey period effect (− 18% in 2013 versus 2003), with medium chlorinated CB congeners showing the most relevant reduction (− 30%) between the two surveys. High chlorinated CBs were more strongly associated with birth cohort (− 46% every 10 years): in the 2013 survey they represented 58% of total PCBs in 60–79 years old while they were 37% among the under 40s with a median value 20 times higher in the oldest than in the youngest (3.1 versus 0.16 ng/ml). Conclusions PCBs serum levels declined from the 2003 to 2013 survey though they are still high in the elderly mainly because of past intake of locally produced contaminated food. Present findings suggest that PCBs food chain contamination and human absorption have been interrupted successfully in the area since discovery of the pollution in 2001. [ABSTRACT FROM AUTHOR]