Wakabayashi C, Hayashi K, Nagai K, Sakamoto N, Iwasaki Y: Effect of stamped reply envelopes and timing of newsletter delivery on response rates of mail survey: A randomised controlled trial in a prospective cohort study. BMJ Open 2(5):1-7(e001181), 2012.
Hosokawa M, Imazeki S, Mizunuma H, Kubota T, Hayashi K: Secular trends in age at menarche and time to establish regular menstrual cycling in Japanese women born between 1930 and 1985. BMC Women’s Health 12: 19 (1-10), 2012.
Yasui T, Hayashi K, Mizunuma H, Kubota T, Aso T, Matsumura Y, Lee JS, Suzuki S. Factors associated with premature ovarian failure, early menopause and earlier onset of menopause in Japanese Women. Maturitas 72(3): 249-55, 2012.
Kato C, Shimada J, Hayashi K: Sleepiness during shift work in Japanese nurses: A comparison study using JESS, SSS, and actigraphy. Sleep and Biological Rhythms 10(2): 109-17, 2012.