Levels and determinants of adipose tissue cadmium concentrations in an adult cohort from Southern Spain

This study was conceived as a first step to evaluate the suitability of adipose tissue cadmium (Cd) concentrations as a biomarker for the assessment of long-term exposure. Specifically, the aim of this work was to explore the socio-demographic, dietary, and lifestyle determinants of adipose tissue Cd concentrations. The study population is a subsample of GraMo cohort. Adipose tissue samples were intraoperatively collected from 226 adult volunteers recruited in two public hospitals from Granada, Spain. Cd concentrations in adipose tissue were analyzed by High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Data on socio-demographic characteristics, lifestyle, diet and health status were collected by face-to-face interviews. Predictors of Cd concentrations were assessed by multivariable linear regression with a stepwise variable selection. We found detectable levels of Cd in the adipose tissue of all the study participants, with a mean concentration (±standard deviation) of 12.66 ± 18.91 μg/kg. Smoking habit at recruitment was associated with increased adipose tissue Cd concentrations (β for smokers = 0.669 p 0.001; β for former smokers = 0.502, p 0.001; reference = non-smokers). Age was positively associated with Cd concentrations (β = 0.014, p 0.001), and men showed lower concentrations than women (β = -0.424, p 0.001). Obesity, measured as Body Mass Index (BMI), showed an inverse association with Cd concentrations (β = -0.038, p 0.001). Egg consumption ≥2 portions/week (β = 0.241, p = 0.025) was positively associated with Cd concentrations. Perceived exposure to paints was also positively associated with Cd concentrations. The observed associations with age, smoking habit, BMI, and egg and meat consumption did not substantially change after sex/gender stratification. Our results are consistent with currently-known Cd sources and suggest other potential pathways, which might be population-specific. As a whole, our findings underline the potential relevance of adipose tissue as a biological matrix for exposure characterization to Cd, as well as for the assessment of long-term clinical implications of the exposure, particularly in obesity-related diseases.