Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.1999.2002AhmadinejadZahra ZiaeeVahid RezaeeMakan YarmohammadiLeila ShaikhHengameh BozorgiFatemeh YousefiReza BehjatiardekaniJavad 102006910Ramadan is the holiest month in the Islamic calendar and Muslims fast during this month. We designed this study to evaluate the effect of Ramadan fasting on thyroid hormone profile. This cohort study was performed during Ramadan of 1423 (Dec. 2002). Subjects were 81 students of Tehran University of Medical Sciences. We evaluated weight, Body Mass Index (BMI), Thyroxin (T4), triiodothyronine (T3) and Thyrotropin-stimulating Hormone (TSH) before and after Ramadan. Eighty one healthy volunteers were included in the study. T4 decreased significantly during fasting in Ramadan in both genders, TSH increased significantly in male subjects, although TSH and T4 levels were within the normal range. There was a positive correlation between T4 changes and number of days of fasting in women. There were no significant changes in T3 after Ramadan fasting. Short fasting is not probably accompanied by significant changes in thyroid hormone, but the repetitiveness of this in Ramadan fasting decrease T4 and increase TSH. The reason of this finding is not well understood.]]>Azizi, F.,197827935945Azizi, F. and H. Amir Rasouli,19866957A57AAzizi, F., M. Nafarabadi and M. Amini,199412140143Bensouda, J.D, W. Ouazzani, A. Lachkar, A. Harniani and J. Belkhadir,19911991Bogdan, A., B. Bouchareb and Y. Touitou,20016816071615Chan, J.L., K. Heist, A.M. DePaoli J.D. Veldhuis and C.S. Mantzoros,200311114091421Coiro, V., R. Volpi, L. Capretti, G. Caffarri, R. Colla and P. Chiodera,199947227231Fedail, S.S., D. Murphy, S.Y. Salih, C.H. Bolton and R.F. Harvey,198236350353Haouari-Ourerro, F., M. Haouari, A. Aouidet, A. Sfaxi, A. Hedhili and K. Nagati,19991999Iraki, L., A. Bogdan, F. Hakkou, N. Amrani, A. Abkari and Y. Touitou,19978212611273Kmiec, Z., G. Kotlarz, B. Smiechowska and A. Mysliwski,199826161175LoPresti, J.S., D. Gray and J.T. Nicoloff,199172130136Reyns, G.E., K.A. Janssens, J. Buyse, E.R. Kuhn and V.M. Darras,2002132239245Romijn, J.A., R. Adriaanse, G. Brabant, K. Prank, E. Endert and W.M. Wiersinga,19907016311636Sajid, K.M., M. Akhtar and G.O. Malik,199141213216Spaulding, S.W., I.J. Chopra, R.S. Sherwin and S.S. Lyall,1976297200Spencer, C.A., S.M. Lum, J.F. Wilber, E.M. Kapten and J.T. Nicoloff,198356883888Suleiman, R.A.,19888549552Van der Geyten, S., E. Van Rompaey, J.P. Saders, T.J. Visser, E.R. Kuhn and V.M. Darras,1999116272280