Study: Irregular Sleep Increases Risks of All Types of Mortality
Sleeping is essential for good health. When people sleep too much or too little, the risks of various diseases increase. Research in Japan revealed that sleeping for more than eight hours or sleep irregularity might increase the risks of all types of mortality. The Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Japan, conducted a massive study that began in 2005 and lasted for nine years. The results showed that sleeping too much or sleep irregularity increased the risks of all-cause mortality by 15 to 30 percent. The results were published in the British journal ScienceDirect on Oct. 10, 2022. To study the association between sleep irregularity and the risks of mortality, lecturer Teruhide Koyama and his colleagues used data from the Japan Multi-Institutional Collaborative Cohort Study (J-MICC). J-MICC is a prospective cohort study and aims to understand the association between the Japanese lifestyle and disease. The study followed 736,319 person-years (mean of 9.01 years) from 2005 to 2014, and 3,376 deaths were recorded. The mortality rate per 1,000 people was 4.59. The research team divided the entire group into six subgroups according to sleep duration and sleep regularity and compared the mortality rate among the groups. The mortality rate of the group of participants who slept more than eight hours was 15 percent higher than those who slept six to eight hours. The mortality rate of participants who slept irregularly was 30 percent higher than those who slept regularly. Then the research team divided all the participants into six groups according to sleep duration and sleep regularity: groups who slept less than six hours, six to eight hours, and eight hours or above. And each group was further divided into those who slept regularly and slept irregularly. The research team used the group who slept regularly for six to eight hours as the control group and compared the risks of mortality of other groups, taking the consideration of other factors which might affect the mortality rate (age, gender, BMI, drinking habits, smoking habits, exercise habits, educational backgrounds, ischemic heart disease, stroke, cancer history, and locations of the research). The results showed that the risk of mortality increased by 14 percent in the group of those who slept regularly for more than eight hours. When participants slept irregularly, regardless of their sleep duration, the risks of all types of mortality were significantly increased, by 21 percent for those who slept less than six hours, by 23 percent for those who slept six to eight hours, and by 52 percent for those who slept more than eight hours. The study shows an association between sleep irregularity and all-cause mortality in a large Japanese population, providing further confirmation of the need to consider not only sleep duration but also the regularity aspect of sleep schedules.
Udumbara
Sleeping is essential for good health. When people sleep too much or too little, the risks of various diseases increase. Research in Japan revealed that sleeping for more than eight hours or sleep irregularity might increase the risks of all types of mortality.
The Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Japan, conducted a massive study that began in 2005 and lasted for nine years.
The results showed that sleeping too much or sleep irregularity increased the risks of all-cause mortality by 15 to 30 percent. The results were published in the British journal ScienceDirect on Oct. 10, 2022.
To study the association between sleep irregularity and the risks of mortality, lecturer Teruhide Koyama and his colleagues used data from the Japan Multi-Institutional Collaborative Cohort Study (J-MICC).
J-MICC is a prospective cohort study and aims to understand the association between the Japanese lifestyle and disease. The study followed 736,319 person-years (mean of 9.01 years) from 2005 to 2014, and 3,376 deaths were recorded. The mortality rate per 1,000 people was 4.59.
The research team divided the entire group into six subgroups according to sleep duration and sleep regularity and compared the mortality rate among the groups.
The mortality rate of the group of participants who slept more than eight hours was 15 percent higher than those who slept six to eight hours. The mortality rate of participants who slept irregularly was 30 percent higher than those who slept regularly.
Then the research team divided all the participants into six groups according to sleep duration and sleep regularity: groups who slept less than six hours, six to eight hours, and eight hours or above. And each group was further divided into those who slept regularly and slept irregularly.
The research team used the group who slept regularly for six to eight hours as the control group and compared the risks of mortality of other groups, taking the consideration of other factors which might affect the mortality rate (age, gender, BMI, drinking habits, smoking habits, exercise habits, educational backgrounds, ischemic heart disease, stroke, cancer history, and locations of the research).
The results showed that the risk of mortality increased by 14 percent in the group of those who slept regularly for more than eight hours.
When participants slept irregularly, regardless of their sleep duration, the risks of all types of mortality were significantly increased, by 21 percent for those who slept less than six hours, by 23 percent for those who slept six to eight hours, and by 52 percent for those who slept more than eight hours.
The study shows an association between sleep irregularity and all-cause mortality in a large Japanese population, providing further confirmation of the need to consider not only sleep duration but also the regularity aspect of sleep schedules.
