In an article published on January 18, 2016 in the peer-reviewed journal Annals of Global Health international scientists discuss how the contribution of exposure to chemicals during early life can be incorporated in the estimations of global burden of chronic non-communicable diseases (NCDs).
NCDs such as asthma, obesity, diabetes, cardiovascular diseases, neurological disorders, and cancers are on the rise worldwide (FPF reported). Global Burden of Disease (GBD) estimations examine traditional risk factors such as smoking, diet, or drug abuse. In contrast, little consideration is given to exposure to environmental chemicals during early life and its influence on the diseases contracted in adulthood, despite the mounting evidence in support of such an association (FPF reported). As an illustration, it is noted that “although obesity is included as a risk factor, chemical exposures in early life that appear likely to contribute to obesity [FPF reported] are not.”
The authors call for a broader consideration of early-life chemical exposures as a risk factor for later disease outcomes. Consequently, the definition of “environmental diseases” should be expanded to include most NCDs. “Without a true understanding of the contribution of environmental exposures in early life to the risk of NCDs […] there will be little impetus to reduce such exposures,” the authors argue.
Among the challenges to be solved by global environmental epidemiology, the authors identify and discuss “individual susceptibility to chemicals related to genetic variation; particular [windows] of susceptibility to xenobiotics during vulnerable periods of pre- and postnatal development; chronic low-dose exposures to ubiquitous chemicals in the environment; non-monotonic dose-response curves; the long latency between early-life exposure and chronic NCDs; and an incomplete acceptance that common, widespread exposures could play a role in apparently disparate diseases affecting different organ systems.”
As a way ahead, recognizing the financial and logistic difficulties associated with performing longitudinal birth cohort studies, the authors propose that research should focus on discovering and validating biomarkers of exposure associated with proximate outcomes that can be assessed during early life and used to model a long-term disease risk.
Sly, P. et al. (2016). “Health consequences of environmental exposures: Causal thinking in global environmental epidemiology.” Annals of Global Health 82:1-9.