Razavi P, et al. - Given the link between night-shift work and melatonin disruption, with mixed evidence about the modulating impact of chronotype (ie, diurnal preference), researchers assessed 6-sulfatoxymelatonin, which is known as the major urinary metabolite of melatonin. This study included 130 active nurses (84 rotating-shift and 46 day-shift workers). Compared with day-shift workers, greater light exposure and lower urinary melatonin levels were evident among rotating-shift workers on night shifts. Both chronotype and rotating-shift work type were decisive factors for melatonin rhythms. Less disrupted melatonin rhythms were generated by better alignment of rotating-shift work and chronotype.