Shift Work Linked to Subtle Shrinkage in Amygdala and Thalamus, Reversible Upon Stopping

An analysis of UK Biobank data found that people who work shifts show a small but detectable volume loss in the left amygdala and right thalamus compared with non-shift workers, with greater loss at higher shift-work frequency. In participants who ceased shift work, the brain-volume decline halted within about 2.4 years and may show slight recovery; additional microstructural changes and lower scores on memory, processing speed, and fluid intelligence were observed. The authors caution that causality cannot be established and the effects are small, noting the UK Biobank sample is healthier and less diverse than the general population.