Adipose tissue concentrations of arsenic, nickel, lead, tin, and titanium in adults from GraMo cohort in Southern Spain: An exploratory study

Background: Adipose tissue has been acknowledged as a potential target of obesogenic pollutants, including metals. However, the presence of these chemicals in the adipose tissue has been poorly characterized. Assessment of adipose tissue metal content may provide valuable information for the study of metabolic disturbances related to human exposure to metals. Objective: To examine the distributions of adipose tissue concentrations of five toxic metals (i.e., arsenic [As], nickel [Ni], lead [Pb], tin [Sn], and titanium [Ti]) in adults, and potential socio- demographic and lifestyle factors associated with metal concentrations. Methods: The study population consisted of a subsample of 228 subjects from GraMo cohort in Southern Spain (N=387). Adipose tissue samples were intra- operatively collected from adults recruited in 2003-2004 in two public hospitals, and concentrations of metals in adipose tissue were analyzed in 2015 by High-Resolution Inductively Coupled Plasma Mass Spectrometry. Data on socio-demographic and lifestyle factors were obtained by baseline questionnaire completion. Linear and multinomial regression was used to identify factors associated with metal levels. Results: Ni, Pb, Sn, and Ti were detected in all adipose tissue samples, and As in 51%. Ni was the metal showing the highest median concentration (0.56 µg/g), followed by Ti (0.31 µg/g), Pb (0.08 µg/g), Sn (0.06 µg/g), and As (0.003 µg/g). Predictors of As levels included area of residence, social class, and oily fish intake ; for Ni: area of residence and consumption of cheese, meat, eggs, and canned food ; for Pb: vegetables intake and industrial occupation ; for Sn: age, body mass index, and consumption of lean fish, eggs, and milk ; and cheese intake for Ti. Some of these predictors were sex-specific, particularly those regarding dietary intake. Conclusions: This exploratory study provides the first evidence of the wide occurrence of Ni, Pb, Sn, Ti, and As in adipose tissue from adult population, and highlights the potential of this tissue as a biological matrix for studying exposure levels and chronic health effects of toxic metals.