Tanno Sakurako, Ikeda Ai, Maruyama Koutatsu, Saito Isao, Tomooka Kiyohide, Tanigawa Takeshi
Department of Public Health, Juntendo University Graduate School of Medicine, 2-2-5 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, Japan.
Sleep Breath. 2024 Dec 5;29(1):50. doi: 10.1007/s11325-024-03214-x.
Brain iron deficiency is known to cause dopaminergic dysfunction in people with restless legs syndrome. Considering the role that dopamine plays in the wake-promoting system, we speculated that iron deficiency may contribute to the development of excessive daytime sleepiness (EDS). Therefore, we conducted the present study to examine the association between iron intake and EDS in the general population.
We collected data from the participants of the Toon Health Study from 2009 to 2017 (N = 2405) and conducted a cross-sectional analysis. EDS was defined as an Epworth Sleepiness Scale score ≥ 11. Participants were divided into four groups according to quartiles of estimated iron intake from their responses to the Food Frequency Questionnaire. We used sex, age, body mass index, and sleep duration as adjustment variables.
The mean age of the participants was 57.9 years, and 64.2% were women. Compared to the highest quartile of iron intake, the multivariable-adjusted odds ratio for EDS of the lowest quartile was 1.38 (95% confidence interval [CI]: 1.04-1.83, p for trend = 0.03). When the analysis was restricted to participants with a Pittsburgh Sleep Quality Index (PSQI) score < 6, the odds ratio was 1.57 (95% CI: 1.06-2.31, p for trend = 0.04).
Significant inverse associations were observed between iron intake and EDS. This tendency was also observed in participants without substantial subjective sleep disturbance (i.e., PSQI score < 6), suggesting that iron deficiency may play a role in the wake-promoting system independently of sleep disturbances.
已知脑铁缺乏会导致不安腿综合征患者出现多巴胺能功能障碍。考虑到多巴胺在促觉醒系统中的作用，我们推测铁缺乏可能导致日间过度嗜睡（EDS）的发生。因此，我们开展了本研究以检验普通人群中铁摄入量与EDS之间的关联。
我们收集了2009年至2017年香椿健康研究参与者的数据（N = 2405）并进行了横断面分析。EDS定义为爱泼沃斯嗜睡量表评分≥11。根据参与者对食物频率问卷的回答所估算的铁摄入量四分位数，将其分为四组。我们将性别、年龄、体重指数和睡眠时间作为调整变量。
参与者的平均年龄为57.9岁，64.2%为女性。与铁摄入量最高的四分位数相比，最低四分位数的EDS多变量调整优势比为1.38（95%置信区间[CI]：1.04 - 1.83，趋势p值 = 0.03）。当分析仅限于匹兹堡睡眠质量指数（PSQI）评分<6的参与者时，优势比为1.57（95%CI：1.06 - 2.31，趋势p值 = 0.04）。
观察到铁摄入量与EDS之间存在显著的负相关。在没有明显主观睡眠障碍（即PSQI评分<6）的参与者中也观察到了这种趋势，这表明铁缺乏可能在促觉醒系统中独立于睡眠障碍发挥作用。
