2.5: Evidence Will Evolve
As we try to solve health problems with evidence-based practice, we must also consider the time it may take to establish evidence through research, and the risks involved with waiting for an abundance of evidence to be established before we take action. Certainly our understanding of the determinants of health is far better now than it was in the last century. Advances in technology and research methods continue to elucidate the drivers of health outcomes. As Sir Austin Bradford Hill (one of the researchers who first established the link between cigarette smoking and lung cancer) stated:
All scientific work is incomplete - whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have, or to postpone the action that it appears to demand at a given time. (Hill, 1965, p. 300)
Pivotal research like the British Doctors Study conducted by Hill and Doll provided the foundation for the surgeon general’s warning about cigarette smoking causing lung disease. Since then, decades of research has supported this causal relationship, and been the practical basis for cigarette advertising bans, lawsuits against tobacco companies, warning labels on cigarettes, smoke-free policies in public spaces, and public health messaging campaigns to reduce smoking. While efforts to reduce smoking have been successful over the decades, newer, similar threats have emerged - in the form of e-cigarettes and nicotine vape products. While smoking rates have declined from 20.9% of adults in 2005, to 11.5% in 2021 (CDC, 2023), e-cigarette sales have skyrocketed - increasing by over 46% between 2020 to 2023 (CDC, 2024).