Waist circumference is simpler than body mass index.

in the secretory phase (Fig. 1C). Dysmorphic erythrocytes (morphologically variable) have been reported to be a marker for glomerular bleeding and isomorphic erythrocytes (morphologically uniform) for nonglomerular bleeding (2 ). The present study revealed that most erythrocytes in the menstrual phase are isomorphic but that all erythrocytes detected in the other phases are dysmorphic, suggesting the existence of dysmorphic erythrocytes in urine from healthy women, especially in the proliferative and secretory phases of the menstrual cycle. Little is known about the usual variation in urinary leukocytes among healthy women. In the present study, leukocytes displayed significant size changes and were largest in the menstrual phase, decreasing in size thereafter. Recently reported cyclic changes in granulocyte colony-stimulating factor expression in the human follicle during the normal menstrual cycle (3 ) may be associated with our results, but the underlying mechanisms remain to be elucidated. During the menstrual cycle, estrogen influences the proliferation and maturation of the vaginal epithelial cell layers during the proliferative phase, whereas progesterone is associated with shedding of the superficial epithelial cell layers during the secretory phase (4, 5). The number of small epithelial cells increases after menstruation and peaks in the secretory phase. Physiologic changes in vaginal secretions during the menstrual cycle could explain this. In conclusion, although the number of participants was limited and an investigation of the same individuals during the menstrual phases will provide more appropriate and valid information, our results suggest an important influence of menstrual cycle on the morphology of urine particles.