Doctors commonly view excessive daytime sleepiness as a cardinal sign of disturbed or inadequate sleep. But a new study suggests it could also signal depression or even diabetes, regardless of whether an individual doesn't sleep well. 

    Among a random sample of 16,500 men and women ranging in age from 20 to 100 years old from central Pennsylvania, 8.7 percent had excessive daytime sleepiness. 

    Researchers, who considered a wide range of possible reasons for why these individuals were excessively sleepy during the daytime, found that excessive daytime sleepiness was more strongly associated with depression and obesity or metabolic factors than with sleep-disordered breathing or sleep disruption. 

    Depression was by far the most significant risk factor for excessive daytime sleepiness, they report in the Journal of Clinical Endocrinology and Metabolism. 

    The likelihood of being excessively sleepy during the daytime was more than three times higher in those who reported they were being treated for depression. 

    The investigators also observed strong ties between excessive daytime sleepiness and diabetes. Individuals reporting treatment for diabetes were close to two times more likely to report excessive daytime sleepiness than those who were not being treated for diabetes. 

    Being overweight also increased the likelihood of excessive daytime sleepiness. 

    Excessive daytime sleepiness was more common in people younger than age 30, a finding that hints at the presence of unmet sleep needs and depression, and in the over-75 crowd, suggesting increasing medical illness and health problems, they explain. 

    Smoking also emerged as a risk factor for excessive daytime sleepiness, a link that hasn't been shown before. It could be that smokers use the stimulant effect of nicotine to self-treat their daytime drowsiness, the authors suggest. 

    Sleep apnea -- brief episodes when breathing stops during sleep -- was not a significant player in excessive daytime sleepiness. This is consistent with prior studies that have reported only weak associations between sleep apnea and excessive daytime sleepiness. 

    The authors conclude that adults plagued by excessive daytime sleepiness should be thoroughly evaluated for depression and diabetes, regardless of whether or not sleep-disordered breathing is present. 

    醫生們通常認為白天極度嗜睡是夜晚睡眠時間不足或睡眠紊亂造成的。但美國一項最新的研究結果則顯示，白天極度嗜睡可能是出現糖尿病或抑郁癥的征兆。 

    據路透社9月5日報道，美國研究人員在賓夕法尼亞州中部地區隨機調查了1.65萬名年齡在20歲至100歲的男女，其中8.7％的被調查者曾有過日間極度嗜睡的情況。 

    研究人員在考慮到很多能引起人們日間極度嗜睡的原因后發現，與睡眠呼吸紊亂或睡眠中斷相比，日間極度嗜睡和抑郁癥、肥胖或新陳代謝等因素具有更為緊密的聯系。 

    研究人員發現，到目前為止，精神抑郁是導致人們日間極度嗜睡最為重要的危險因素。在那些患有抑郁癥的被調查者中，出現日間極度嗜睡的可能性要比其他人高3倍還多。另外，糖尿病也和日間極度嗜睡具有非常緊密的聯系。在那些患有糖尿病的被調查者中，他們出現日間極度嗜睡的可能性是其他人的近2倍。研究人員還發現，體型肥胖也能增加人們出現日間極度嗜睡的可能性。 

    研究人員同時發現，日間極度嗜睡癥狀在30歲以下的年輕人和75歲以上的老年人中更為常見。研究人員對此解釋說，年輕人出現這種癥狀暗示著他們常常睡眠不足或精神抑郁；而老年人則是由于逐漸增多的各種疾病和健康問題所致。 

    值得一提的是，睡眠呼吸暫停癥在日間極度嗜睡中扮演的角色卻并不那么重要。這與先前一個研究結果相一致，該研究認為，睡眠呼吸暫停癥和日間極度嗜睡兩者之間具有的聯系非常微弱。

    另外，研究人員還首次發現日間極度嗜睡和吸煙之間存在著某種聯系。研究人員稱，一些吸煙者就是利用尼古丁的刺激作用來驅散自己在白天的睡意。