Sleep duration, spot urinary 6-Sulfatoxymelatonin levels and risk of breast cancer among Chinese women in Singapore
International Journal of Cancer, 06/08/2012
Wu AH et al. – The authors conclude that sleep duration is not significantly associated with breast cancer risk reduction. Melatonin levels derived from randomly–timed spot urine is unrelated to breast cancer. Randomly–timed, spot urine derived melatonin levels are non–informative as surrogates of nocturnal melatonin production.