NRS 428 social determinants and the disease chain

Three questions, and the third one depends on having got the second right. Social determinants of health are the conditions in which people are born, grow, live, work and age — economic stability, education access and quality, healthcare access and quality, neighbourhood and built environment, and social and community context. They contribute to disease through identifiable pathways rather than vaguely: housing density and ventilation affect transmission of respiratory infection, food insecurity affects nutritional status and therefore immune function, employment conditions determine whether someone can isolate when symptomatic, and access to care determines whether an infection is detected early or only once it has already spread. Naming the pathway is what separates a strong answer from a definition, because the question asks how determinants contribute to the development of disease rather than what they are. Two or three worked pathways are worth more than a longer list of domains.

The chain of infection model has six links — infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host — and the fundamental idea it represents is that transmission requires every link to be intact, so interrupting any one of them stops it. That is the whole point of the model: it turns prevention into a menu of intervention points rather than a single strategy, which is why it survives as a teaching tool. The example question then asks for steps a nurse can take to break a link, so name the link explicitly before naming the action — hand hygiene and environmental cleaning interrupt the mode of transmission, immunisation reduces host susceptibility, isolation controls the portal of exit, and treating a case addresses the reservoir. Connecting that back to the determinants makes the post coherent rather than three separate answers — overcrowded housing, for instance, acts directly on the mode of transmission link.