No association of 6-sulfatoxymelatonin with in-bed 60-Hz magnetic field exposure or illumination level among older adults.

We examined the association of 6-sulfatoxymelatonin (aMT6s) excretion with in-bed 60-Hz magnetic field (MF) exposure and other potential regulators. Adults aged 50-81 years (n=242 years, mean 67.6+/-5.7 years) were monitored for 1 week in their home environments. Mean and maximum MF exposure were assessed with EMDEX Lite instruments. Illumination mesor, amplitude, and acrophase (peak time) were determined from 24-h Actillume wrist monitors. Other regulators of aMT6s assessed were age, usage of melatonin-altering medications, and day length. During two 24-h intervals, all urine voidings were collected. The mesor, amplitude, and acrophase of aMT6s excretion were determined. Multiple regression analyses revealed no association between MF and aMT6s. Medication usage was associated with significantly lower aMT6s mesor and amplitude. Illumination acrophase and amplitude were significantly associated with aMT6s acrophase. These data suggest no influence of nocturnal environmental MF exposure on aMT6s excretion in older adults.