Evolution of DOHaD: the impact of environmental health sciences

Abstract

Environmental exposures have a significant influence on the chronic health conditions plaguing children and adults. Although the Developmental Origins of Health and Disease (DOHaD) paradigm historically has focused on nutrition, an expanding body of research specifically communicates the effects of chemical exposures on early-life development and the propagation of non-communicable disease across the lifespan. This paper provides an overview of 20 years of research efforts aimed at identifying critical windows of susceptibility to environmental exposures and the signaling changes and epigenetic influences associated with disease progression. DOHaD grants funded by the National Institute of Environmental Health Sciences (NIEHS) in 1991, 2001 and 2011 are identified by grant-analysis software, and each portfolio is analyzed for exposures, disease endpoints, windows of exposure, study design and impact on the field based on publication data. Results show that the 1991 and 2001 portfolios comprised metals, PCBs and air pollutants; however, by 2011, the portfolio has evolved to include or expand the variety of endocrine disruptors, pesticides/persistent organic pollutants and metals. An assortment of brain-health endpoints is most targeted across the portfolios, whereas reproduction and cancer increase steadily over the same time period, and new endpoints like obesity are introduced by 2011. With mounting evidence connecting early-life exposures to later-life disease, we conclude that it is critical to expand the original DOHaD concept to include environmental chemical exposures, and to continue a research agenda that emphasizes defining sensitive windows of exposure and the mechanisms that cause disease.

Keywords: portfolio analysis.

Fig. 1

Science milestones and events that have impacted the field of DOHaD research as it relates to environmental exposures.

Fig. 2

(a) Overview of the timing of funded disease/organ endpoint studies and relative predominance in each portfolio (1991, 2001 and 2011); (b) overview of the timing of funded toxicity endpoint studies and relative predominance in each portfolio; (c) content analysis of three grant portfolios (1991, 2001 and 2011) for windows of exposure and human subject studies v. model organisms, or both (note: if a grant assessed more than one endpoint, each was counted individually); (d) content analysis of three grant portfolios (1991, 2001 and 2011) – the number of grants; human subject studies v. model organisms or both (note: if a grant assessed more than one endpoint, each was counted individually); and total dollars spent for each portfolio.

Fig. 3

Most studied disease/organ endpoints and associated toxicity endpoints.

Fig. 4

(a) Epigenetics-based DOHaD grants across three grant portfolios (1991, 2001 and 2011) (note: if a grant studied more than one epigenetic process, each was counted individually). Also shown, the evolution of epigenetics research from examining mostly DNA methylation to including chromatin remodeling and regulatory RNAs; (b) The number of publications related to NIEHS DOHaD grants with an epigenetic focus during the years from 2007 to 2011. NIEHS, National Institute of Environmental Health Sciences; DOHaD, Developmental Origins of Health and Disease.