(RxWiki News) Many people have insomnia symptoms from time to time, but who's at risk for persistent insomnia? That's a question researchers recently set out to answer.
These researchers found that poor sleep quality and poor mental health were the strongest risk factors associated with having persistent insomnia.
The researchers discovered that people with insomnia at the beginning of the study were most likely to have experienced it throughout the whole study.
"Tell a doctor if you aren't sleeping well."
This study was conducted by Chol Shin, MD, PhD, FCCP, from Korea University Ansan Medical Center, and colleagues.
The study included 1,247 people who were part of a larger, ongoing study called the Korean Genome and Epidemiology Study that started in 2001.
The participants who took part in the current study were between 45 and 74 years old, with the average age of 54 years old. A total of 41 percent of the participants were men. All participants were from Ansan, South Korea.
The researchers examined the participants at the beginning of their study (baseline) in 2007, and twice thereafter at two-year intervals.
Previous studies have reported very different rates of insomnia and the researchers believe this is due to not using uniform definitions of "poor sleep", insomnia and persistance.
The current study uses the term "insomnia syndrome" when referring to participants who report one or more nighttime symptoms at least three times per week each month and include daytime side effects. The researchers used "insomnia symptoms" to refer to the presence of nighttime symptoms that may or may not be associated with daytime side effects.
The participants were asked to rate the frequency of the following four common insomnia symptoms:
- difficulty falling asleep
- difficulty staying asleep
- waking up in the early morning
- feeling tired and unrefreshed after waking up for the day
The researchers defined "persistent insomnia" as the presence of insomnia syndrome or symptoms at all three data collections.
The participants self-reported smoking status, alcohol consumption and history of psychiatric illness.
Body mass index (BMI), high blood pressure status, diabetes status, severity of depressive symptoms, physical and mental health-related quality of life, sleep quality and frequency of sleep-interfering behaviors were also measured at each examination.
Sleep-interfering behaviors included consuming alcohol before going to bed, consuming caffeinated beverages after dinner, and using medication for sleep, among others.
The findings showed that 931 participants (75 percent) did not have any insomnia symptoms at baseline and 316 (25 percent) reported insomnia symptoms at baseline.
Of all the participants, 44 percent reported insomnia symptoms during at least one data point.
The researchers found that 35 percent of the participants with insomnia at baseline had persistent insomnia symptoms at all three data points.
The findings revealed that persistent insomnia at all three data points was the most common experience of those participants with insomnia at baseline.
Of the participants with insomnia at baseline, 14 percent did not have symptoms at the first follow-up examination but had developed symptoms again by the second one. Another 23 percent still had symptoms at the first follow-up examination but not at the second, and 29 percent did not have any symptoms at both follow-up examinations.
The participants who experienced persistent insomnia symptoms had significantly lower physical and mental health-related quality of life, and significantly more depressive symptoms at baseline and the second follow-up exmaination. compared to the participants who did not experience persistent insomnia symptoms.
The researchers discovered that poor sleep quality, frequent sleep-interfering behaviors and low mental health-related quality of life were the strongest predictors of persistent insomnia symptoms.
The authors mentioned a few limitations of their study. First, the study did not evaluate distress associated with poor sleep. Second, problems with breathing during sleep were not considered. Third, psychiatric illness was not completely assessed. Lastly, the participants self-reported sleep quality and insomnia symptoms.
This study was published in the January edition of Sleep Medicine.
The Korean Center for Disease Control and Prevention, the Korean Ministry for Health and Welfare and the National Research Foundation of Korea provided funding.