Very high correlations between fresh weight and lipid-adjusted PCB-153 serum concentrations: Irrespective of fasting status, age, body mass index, gender, or exposure distributions Lars Rylander a,⇑ , Carl-Magnus Björkdahl a , Anna Axmon a , Aleksander Giwercman b , Bo A.G. Jönsson a , Christian Lindh a , Anna Rignell-Hydbom a a Division of Occupational and Environmental Medicine, Lund University, SE-221 85 Lund, Sweden b Reproductive Medicine Centre, Malmö University Hospital, Lund University, SE-205 02 Malmö, Sweden article info Article history: Received 4 October 2011 Received in revised form 15 March 2012 Accepted 31 March 2012 Available online 28 April 2012 Keywords: Pcb Epidemiology Biobank Lipid Serum abstract Background and aim: Persistent organochlorine pollutants (POPs) have in epidemiological studies been associated with health hazards. The exposure window might be crucial and it is, accordingly, important to analyze exposure concentrations in samples collected at the window of interest. This makes the use of stored blood samples extremely interesting. However, small blood volumes from stored samples in bio- banks means that the researchers in epidemiological studies most often have to select a limited number of biomarkers representing the POP exposure and abstain from analyses of lipid concentrations. This raises the question of the necessity of lipid adjustment. The aim of the present study was to evaluate the correlation between fresh weight and lipid adjusted concentrations. Methods: We included data from studies were we have used the PCB congener 2,2 0 ,4,4 0 ,5,5 0 -hexachloro- biphenyl (PCB-153) as a biomarker for POP exposure and where fresh weight as well as lipid adjusted PCB-153 concentrations are known (n = 1628). The variety of the cohort members in the different studies gave us the possibility to better understand how well these measures correlate. Results: When all individuals were included in the analyses a correlation coefficient of 0.95 between fresh weight and lipid adjusted serum concentrations was obtained. Restricting the analyses to specific sub- groups (based on gender, fasting status, age and BMI) gave correlation coefficients between 0.85 and 0.97. Conclusions: This study does strongly support the use of samples from biobanks in epidemiological stud- ies for analyzing PCBs, at least regarding PCB-153, even though it is not possible to lipid adjust the results. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane (DDT) and dioxins, are lipophilic pollutants accumulated in the food chain (Gallian et al., 2004). Human exposure to these compounds have been associated with a number of health hazards, not only de- tected among highly exposed populations (see e.g. Eskenazi et al., 2002; Guo et al., 2004; Mocarelli et al., 2011; Yang et al., 2011), but also among populations with lower exposure levels (see e.g. Rylander et al., 1998, 2005; Rignell-Hydbom et al., 2009; Turyk et al., 2009; Ward et al., 2009). The exposure win- dow might be crucial and it is, accordingly, important to analyze exposure concentrations in samples collected at the window of interest (Grandjean et al., 2008). This makes the use of stored blood samples extremely interesting. If, for instance, the fetal exposure is supposed to be of importance it is crucial to find a biobank where the samples are collected during pregnancy or at delivery. However, the blood volumes available from stored sam- ples in biobanks are often less than 0.2 mL, which means that the researchers in epidemiological studies have to select a limited number of biomarkers representing the POP exposure and abstain from analyses of lipid concentrations. This raises the question of the necessity of lipid adjustment and the implications for inter- pretation of health effects. In other words, how well is the corre- lation between fresh weight and lipid adjusted concentrations? Our research group has, in collaboration with other research groups, performed a number of epidemiological studies were we have used the PCB congener 2,2 0 ,4,4 0 ,5,5 0 -hexachlorobiphenyl (PCB-153) as a biomarker for POP exposure (Axmon et al., 2004, 2006; Richthoff et al., 2003; Rignell-Hydbom et al., 2004; Wallin et al., 2005). These studies have frequently been performed among members of fishermen’s families from Sweden, but we have also 0045-6535/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2012.03.089 ⇑ Corresponding author. Address: Division of Occupational and Environmental Medicine, Lund University, Lund University Hospital, SE-221 85 Lund, Sweden. Tel.: +46 46 17 72 87; fax: +46 46 17 36 69. E-mail address: lars.rylander@med.lu.se (L. Rylander). Chemosphere 88 (2012) 828–831 Contents lists available at SciVerse ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere