3.1.4—Environmental factors

Environmental explanations focus on conditions around a person—stressors, resources, pollution, social support, discrimination, routines and learned opportunities—that can alter health behaviour or physiology.

Environment is not a single variable. A causal account must identify the exposure, pathway, timing and comparison, while considering selection and reverse causation. The same setting can protect one person and burden another.

A noisy housing area may reduce sleep through repeated disturbance, which can affect concentration and stress. Measuring noise, sleep and baseline health is stronger than attributing every difference to ‘the environment’.

Environmental does not mean non-biological: exposures can change biological processes. Identify the exposure, its timing and dose, the pathway to symptoms, and competing explanations before drawing a causal conclusion.