The questionnaire was first translated into Farsi, i.e. the language of the study population, and then converted into English. Score 1 was allocated to each question if the answer was yes, scores between 0 and 3 denoted sleeping well (first group), scores between

3 and 6 indicated sleeping quite well (second group), scores between 6 and 9 signified sleeping quite badly (third group), and scores between 9 and 12 stood Inhibitors,research,lifescience,medical for sleeping badly (fourth group). Regarding the reliability and validity of the questionnaire, after completing the first 35 questionnaires, based on SPSS, Cronbach’s alpha coefficient was reported to be 0.7526 (>0.7). Accordingly, the questionnaire had reasonable validity and reliability in

this study. Table 1 Authors’ revised sleep history questionnaire Inhibitors,research,lifescience,medical (adopted from tenth edition of Kaplan & Sadock synopsis of psychiatry) This study was approved by the Ethics Committee of Birjand University of Medical Sciences. All the patients and controls were fully informed about the study protocol, and a signed informed consent was obtained from each of them. The data were then analyzed with SPSS software (version 13). Age and sleep requirement between the two groups were compared using Inhibitors,research,lifescience,medical the t test. Also, the Kruskal–Wallis test was used to compare the mean level of 24-hour urine 6-sulfatoxymelatonin (in hours) in each group, and the Mann-Whitney test was employed to compare the mean level of 24-hour urine 6-sulfatoxymelatonin between the two groups. Additionally, the chi-squared test was utilized to compare sleep distribution

from the point of quality and quantity between the two groups. A p value Inhibitors,research,lifescience,medical less than 0.05 was considered statistically significant. Results The study population comprised 140 Selleck BAY 87-2243 individuals, divided into two equally numbered groups: a case group at a mean age of 54.8±12.2 and a control group at a mean age of 54.4±12.1 years. Age and sex between the two groups were comparable (table 2). Table 2 Demographic data and melation in level Inhibitors,research,lifescience,medical of the patients compared with the controls There was no significant difference between the case and control groups regarding sun and light exposure duration (P=0.9). The mean level of 24-hour urine 6-sulfatoxymelatonin in the case group was 15.9±8.1, while it was 47.0±23.6 in the control group. no This was in accordance with the duration (quantity) and sleep quality in the two groups inasmuch as the control group slept more and better than did the case group generally (P=0.005) (table 3). Table 3 Sleep quantity and sleep quality of the patients compared with the controls Discussion The results of the present study demonstrated that the case group had a lower level of 24-hour urinary 6-sulfatoxymelatonin, which may be interpreted that lower levels of melatonin are correlated with a rise in the risk of SCC and BCC.