4 Comparison of two alternative methodologies to estimate the weekly intake of cadmium in an italian population

Abstract

Background/aim Cadmium (Cd) is a human carcinogen. In non-smoking and non-occupationally exposed subjects diet is the main source of exposure. The Tolerable Weekly Intake-TWI of 2.5 µg/kg body weight has been recently set by the European Food and Safety Authority in order to guarantee a high protection to general population. In this study, we aimed to compare two different methods to estimate its weekly intake. Methods In a random sample of the adult general population of Modena, Northern Italy, we collected information about personal characteristics and life styles and dietary habits using the European Prospective Investigation into Cancer and Nutrition-EPIC semi-quantitative self-administered food frequency questionnaire. Then we measured Cd levels in a fasting serum sample using inductively coupled plasma mass spectrometry (ICP-MS). Two methods assessing Cd intake were implemented, the first one through dietary questionnaire and the second one from levels of biomarker. To do that, we considered the ratio between total and circulating Cd, the percentage of absorption of Cd ingested with foods and the contribution of tobacco smoke. Results We recruited 51 subjects (male/female: 26/25) with mean age of 50 years (range: 35–71). Median (interquartile range-IQR) of dietary Cd intake was 13.4 µg/day (IQR: 10.4–16.8) estimated with the EPIC questionnaire. Serum median level of Cd was 0.041 µg/L (IQR: 0.030–0.054). The weekly intake (WI) of Cd was 1.34 µg/kg body weight (IQR: 0.85–1.70, range: 0.26–3.18) and 0.78 µg/kg body weight (IQR: 0.62–1.09, range: 0.27–2.47) based on dietary questionnaire and biomarker data, respectively. In this Italian population, we found higher WI of Cd using the dietary questionnaire than using serum sample. This difference in Cd WI highlights the importance in evaluating the relation between dietary intake and levels of biomarker when assessing the individual exposure. Conclusion Dietary assessment methods based on FFQ might therefore overestimate Cd WI, or alternatively a higher ratio between dietary and serum Cd has to be considered compared to what predicted by literature data. Finally, possible health concerns could be highlight for some subjects of the study population with Cd WI higher than level recommended by the European Food and Safety Authority.