Volume 146

Shift work and night-shift schedules disrupt circadian rhythms, causing chronic misalignment between internal clocks and environmental cycles—an issue increasingly recognized as a key determinant of population health. This study synthesizes epidemiological studies and mechanistic evidence to explore circadian disruption’s impact on population health and corresponding public health responses. Epidemiological studies consistently correlate shift work with heightened cardiovascular disease, metabolic disorder, malignancy, and mental disorder risk; mechanistic evidence supports correlations as circadian disruption alters endocrine regulation, suppresses glucose metabolism and reduces neurophysiologic clearance with sleep. Risks are concentrated disproportionately, with women, older adults, health care providers, and poor individuals carrying greater burdens as a result of biological and structural determinations. Current responses at the population health level are sparse and require personal (e.g., light exposure), organizational (e.g., schedule planning) and policy (e.g., protective regulation) intervention. Recognition of circadian disruption as an occupational hazard is fundamental for reduction of its global burden of illness and highlights extreme population health significance.

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