Serum levels of ochratoxin A in healthy adults in Tuscany: Correlation with individual characteristics and between repeat measurements

Ochratoxin A (OTA), a mycotoxin widely contaminating staple foods and bever ages, has been classified as a "possible human carcinogen (Group 2B)" by th e IARC, Serum levels of OTA were measured in a group of 138 healthy adults (age, 35-65 years) living in the area surrounding Florence (Tuscany, centra l Italy) and detected in all but four samples (97%), After the exclusion of one subject with a peak value of 57.2 ng/ml, OTA levels ranged between 0.1 2 and 2.84 ng/ml, with mean and median values of 0.56 and 0.48 ng/ml, respe ctively. OTA levels were significantly higher in men than in women (0.64 ve rsus 0.50) and correlated positively with height, A strong association was found with the season in which blood samples were obtained, with summer val ues higher than autumn values. On the other hand, OTA levels tended to be n egatively associated with blood pressure, either systolic or diastolic; no association was evident with age, weight, body mass index, and smoking hist ory. The associations with height and season persisted in a multivariate re gression analysis, A subgroup of subjects provided a repeat blood sample approximately 1 year later. The Spearman correlation coefficient between 68 pairs of original an d repeat measurements was practically null (r = 0.05). Only two subjects (2 .9%) had OTA levels of >1 ng/ml on both occasions. These results suggest that OTA contamination is widespread in foods consume d by this population, in agreement with previous reports from Italy and oth er countries, A strong seasonal variation, which possibly differs from year to year, was observed. OTA serum levels are a short-term biomarker with a high within-subject variability; therefore they have limited use at the ind ividual level but can be used to characterize populations or subgroups of s ubjects. Additional analyses are needed to explore the dietary determinants of OTA levels in this population.