For example, we could not account for differences in chemical exposure between different types
of fish and between fish captured from wild fisheries selleck or harvested in fish farms. In addition, only current dietary habits were assessed, which could differ from dietary habits in the past that would also have contributed to the body burden at time of study. Due to these limitations, we may not have been able to detect endocrine disrupting effects of dietary sources of persistent chemical exposures. We also assessed associations between the DR CALUX® measurements and other potential determinants for internal exposure to persistent endocrine disrupting chemicals, including age, BMI, weight loss, and living within a city centre, but the effect estimates were inconclusive (Supplemental Table 2). We did, however, identify a positive association between plasma androgenic activity and the internal dioxin TEQ values over a small range (Table 5). An inverse association between CALUX® TEQs and total and free testosterone in male serum has been reported (Dhooge et al., 2006), as well as between CALUX® TEQs and AEQs in fetal plasma after MTBE extraction (R = − 0.7)
(Pedersen et al., 2010). Selleckchem Alectinib Pliskova and colleagues measured a reduced estrogenic activity in male serum extracts containing high levels of PCBs, which seemed to be associated with a decline in endogenous estradiol (Pliskova et al., 2005). In our study, plasma TEQs were not associated with reduced estrogenic activity in total plasma, but this could also be due to the lower exposure levels. Estrogenic and/or androgenic plasma activities seemed to be increased in men occupationally exposed to disinfectants, Sucrase pesticides, welding or soldering, and vehicle exhaust fumes. These exposures occurred in very diverse occupational settings and often involved mixtures of different substances. As co-exposure to other chemical groups was very common, it was difficult to attribute differences in estrogenic or androgenic activities to specific exposures. In general, multivariable analyses with adjustment for co-exposures did not drastically change the effect estimates. However, reliable estimation of the independent effects of disinfectants, pesticides,
welding or soldering, exhaust fumes, and other occupational exposures, requires a larger population size that allows more specific exposure classification. We interpret the present findings as indications that various occupational exposures can alter estrogenic or androgenic activities and are therefore potentially relevant sources of endocrine disruptors. As pointed out, further research is needed to elucidate the effects of different sources of endocrine disruptors on the estrogenic and androgenic plasma activities in men. Including internal measurements of certain groups of chemicals such as dioxins in future research, could clarify their specific role in the estrogenic and androgenic activities found, especially if these chemicals have long half-lives of excretion.