ences on health behavior and outcome, and the epidemiological model, which describes a triad of epidemiologic factors to model the complex and interrelated factors contributing to the increasing rate of obesity in the United States and other countries. One of the triad components describes an “obesogenic” environment as “the sum of influences that the surroundings, opportunities, or conditions of life have on promoting obesity in individuals or populations” (Swinburn and Egger, 2002). This obesogenic environment includes physical, economic, policy, and sociocultural factors that can influence eating and physical activity behaviors.
Collectively, these models place emphasis on how the health of individuals is influenced by not only physiological functioning and genetic predisposition, but by a complex interplay of these biological determinants with social and familial relationships, environmental influences, and broader social and economic contexts over the life course. They further suggest that intervention efforts to change health behavior or outcome, such as GWG, should address not only “downstream” individual-level phenomena (e.g., physiologic pathways to disease, individual and lifestyle factors) and “mainstream” factors (e.g., population-based interventions), but also “upstream,” societal-level phenomena (e.g., public policies) (IOM, 2000).
Another model, the life-course perspective (Kuh and Ben-Shlomo, 1997), perceives life not in disconnected stages, but as an integrated continuum; it recognizes that each stage of life is influenced by the life stages that precede it, and it, in turn, influences the life stages that follow (see Chapter 6 for detailed discussion).
Some of the most significant determinants of GWG at multiple levels (social/institutional, environmental, neighborhood/community, interpersonal/family, and individual levels) occur across the life course (Figure 4-1). The following discussion begins with a review of the evidence for a direct relationship between a given determinant (identified in Figure 1-1) and GWG. Where data are lacking, rationale are provided for why the committee thinks that it is potentially an important determinant that merits further research. The committee’s review of evidence (tabulated in Appendix D) included both epidemiologic and clinical studies. Inasmuch as this research discipline is focused largely on observational studies the committee recognized the need for proof of causality for determinants and outcomes significantly associated with GWG.
The committee evaluated the evidence of the impact of four societal/institutional determinants on GWG: media, culture and acculturation, health services (e.g., the type of advice that pregnant women receive about GWG), and policy. The committee recognized that understanding how these factors impact GWG, for example how cultural norms and beliefs may