). In order to make comparisons between groups with different severities of sleep-disordered breathing, we classified the patients in four groups using the apnea-hypopnea index (AHI): Group 1, AHI 5 Ͻ 15 (n ϭ 10); Group 2, AHI 15 Ͻ 30 (n ϭ 10); Group 3, AHI 30 Ͻ 65 (n ϭ 14); Group 4, AHI Ն 65 (n ϭ 17). Results:A wide range of sleep-disordered breathing, ranging from AHI of 2.5 to 128.9 was found. Ninety-eight percent of the sample (n ϭ 51) had an AHI Ն 5 (mean ϭ 51 Ϯ 37), and 33% had severe sleep apnea with AHI Ն 65 with a mean nocturnal desaturation time of Ͻ65% over 135 minutes. Electrocardiographic abnormalities were present in 31% of the patients. Cardiac rhythm alterations showed an association with the level of sleep-disordered breathing and oxygen desaturation. Discussion: We conclude that there is a high prevalence of sleep apnea in morbidly obese patients and that the risk for cardiac arrhythmias increases in this population in the presence of a severe sleep apnea (AHI Ն 65) with severe oxygen desaturation (SaO 2 Յ 65%).

There is an enhanced presence of sleep disorders in patients with SLE. The most frequent primary sleep disorders are respiratory and movement disorders.

Bariatric surgery effectively reduces respiratory disturbances during sleep and improves pulmonary hypertension. Electro cardiographic abnormalities change after surgery. Daytime sleepiness appeared not to be related to respiratory disturbances during sleep.

SUMMARY Evidence in support for the concept of the so-called 'siesta culture' is not well developed and has, to date, relied largely on qualitative anthropological data. Presumably such cultures are characterized by a strong tendency for daytime naps and daytime sleepiness, phenomena which may partially represent the effects of geographic, climatic or light conditions and/or cultural influences. In this study we surveyed the nocturnal sleep habits and daytime sleep tendencies of 577 Mexican college students residing in Mexico City (19°N latitude). Results indicated a number of parallels between the reported sleep habits of these students and those reported from other cultures at latitudes far to the north (North America, Europe), such as longer sleep at the weekends, an association between snoring and daytime sleepiness and a lack of relationship between nocturnal sleep duration and the reported tendency to nap. There was some suggestion that these Mexican students may actually nap less when compared to other college student populations. Taken together, these results call into question what is meant by the concept of a 'siesta culture', at least in this urban, educated, upper social economic scale (SES) population, and suggest that future studies in equatorial regions be undertaken to further appreciate the role of climate, photoperiod and/or culture in the tendency for humans to nap during the day.

In total, 189 consecutive women diagnosed with SLE were evaluated using the ACR 1990 criteria for fibromyalgia. Patients were classified into three subgroups. The fibromyalgia group (FM) included patients experiencing pain on palpation in at least 11 of the 18 tender points examined, as well as having a history of widespread pain for at least three months. Patients who were noted to have pain in fewer than four quadrants with less than 11 of 18 tender points were considered to have regional pain (RP). All patients who did not meet criteria for either FM or RP were classified as having no pain (NP). Measurement of SLE disease activity, sleep complaints, depression, fatigue severity and health status were performed. Only 18 of the SLE patients (9.5%) (95% CI 5.3-14%) fulfilled the ACR criteria for the classification of FM. Of the patients, 106 (56.1%) fulfilled criteria for RP and had a number of tender points of 5.4 +/- 3.4, and the rest of the patients (34.4%) had no tenderness at specific tender point sites. Age, body mass index, educational level and disease duration were comparable between the groups. FM and RP groups had different patterns of symptoms prevalence, with dysmenorrhea being more distinctive for FM. Sleep disturbances were more severe in the FM than in the RP group. Daytime complaints such as sleepiness, fatigue and depression were similar for RP and FM groups, but patients with FM reported more disability. Fibromyalgia is not common in Mexican patients with SLE and has a different pattern of symptoms in RP and NP patients. These data add evidence that ethnicity can play an important role in FM manifestations.