[Twenty four hours circadian cortisol profile in shift work nurses]

It is well established that adrenal hormone cortisol has long been used in human psychobiological studies as a biological marker of circadian rhythm, stress, and anxiety. There is little information, however, about the anxiety. There is little information, however, about the interrelationships of night work, plasma cortisol levels in females' nurses of the developing countries. The aim of the present study was to compare circadian cortisol profile between two groups of nurses with shift and permanent work in a hospital affiliated to Shiraz University of Medical Sciences, Iran, between January 2006 to September 2008. In this experimental study, we examined the reproducibility of plasma cortisol levels during one month period in 34 shift work nurses and 10 permanent day shift works. We evaluated potential associations between night work and hormone levels, using current and shift work information for the health care shift workers. The results clearly revealed that shift work significantly increased nighttime cortisol levels [34.93 micro g/dl] during night shift and decreased the peak levels of cortisol in the morning [39.03 microg/dl]. During the work shift the plasma cortisol presented a decreased concentration in the morning and increasing levels [44.93 micro g/dl] by the end of the evening. In contrast, the permanent day work nurses, who had never worked at night shits, showed a lowest secretion of cortisol during the first half of night time sleep [10.02 micro g/dl], and a peak value of the cortisol after awakening at 07:00h [59.75 micro g/ml]. We also observed a significant association between night work and increased levels of cortisol over the remaining of the day. It can be concluded that nurses with night shift work have an abnormal cortisol secretion profile. Shift work nurses on rotating night shifts seem to experience changes in hormones levels that may be associated with increased of circadian disorders risk observed among night -shift workers

[Twenty four- hour circadian melatonin profile among women shift work nurses]

According to previous studies shift work could desynchronize the natural circadian rhythm of the body. Although some of the internal physiologic processes become active for adaptation of the body with this desynchronization. One of these physiologic processes is endocrine system and melatonin release. This hormone is one of the most important variants which represent the circadian rhythm in human. Since the pattern of secretion of this hormone in first ours of morning and during the day in Iranian workers in particular in shift workers is unknown, therefore we aimed to determine the 24 hours profile of melatonin in shift work and permanent day shift nurses. This experimental study was carried out on forty four female nurses of the Shiraz university hospital, during 2006-2008. Thirty four people in study group had a cyclic shift work and 10 persons in control group had permanent day shift work. The serum samples with 3 hours intervals during 24 hours were taken from each person. The plasma concentration of melatonin was measured by ELISA. Our study was carried out under realistic conditions. The data were analyzed using one -way ANOVA. The age range was between 22 to 50 years with a mean work history of 5.5 years. The highest and the lowest melatonin levels was found in shift work nurses at 04:00 pm [14.91 pg/mL], and 04:00 am [131.49 pg/mL]. These values for permanent day work nurses in the same times was 1.02 pg/mL and 177.40 pg/mL respectively. There was a significant difference between circadian melatonin profile at different time points [P= 0.000]. The results of this study revealed that night work induces a consistent change in melatonin circadian profile with a progressive reduction at early morning [04:00 am] and awaking time [07:00 am]. These changes will also disturb sleep cycle and level of consciousness during the night and activities during the day