Associations between sleep disturbance and mental health status: a longitudinal study of Japanese junior high school students.

BACKGROUND: A limited number of longitudinal studies have addressed the association between sleep disturbance and mental health status among adolescents. To examine whether each of these is a risk factor for the onset of the other, we conducted a prospective longitudinal study of Japanese adolescents. METHODS: In 2004, we performed a baseline study of students attending three private junior high schools in Tokyo, and in 2006, a follow-up study was performed on the same population. The mean age of the subjects was 13 years. The Pittsburgh Sleep Quality Index was used to evaluate sleep disturbance, and the 12-item General Health Questionnaire was used to evaluate mental health status. RESULTS: The subjects were 698 students, of whom 516 were suitable for analysis. The incidence of newly developed poor mental health status during the 2 years leading to the follow-up study was 35.1%. New onset of poor mental health status was significantly associated with new onset of sleep disturbance and lasting sleep disturbance. The incidence of sleep disturbance during the 2 years leading to the follow-up study was 33.3%. New onset of sleep disturbance was significantly associated with new onset of poor mental health status and lasting poor mental health status. CONCLUSIONS: Sleep disturbance and poor mental health status increase each other's onset risk.

Use of alcohol and hypnotic medication as aids to sleep among the Japanese general population.

OBJECTIVE: The present study was conducted to clarify the prevalence of the use of alcohol and hypnotic medication as sleep aids, and associated factors, in the general population in Japan. METHODS: The survey was conducted in June 2000, using self-administered questionnaires, targeting a population that was selected randomly from among 300 communities throughout Japan. A total of 18,205 responses indicating alcohol use and 16,804 responses indicating hypnotic medication use were analyzed. RESULTS: The prevalence of alcohol use as a sleep aid one or more times per week was 48.3% among men and 18.3% among women. The prevalence of the use of hypnotic medication one or more times per week was 4.3% among men and 5.9% among women. The prevalence of alcohol used as a sleep aid increased gradually for men and women up to age 55-59 years and 40-44 years, respectively, and then declined with increasing age thereafter. The prevalence of the use of hypnotic medication among both men and women showed a trend toward a gradual increase with age. The use of alcohol as a sleep aid was associated with "difficulty maintaining sleep," but no such problem was associated with the use of hypnotic medication. CONCLUSIONS: Alcohol is a more popular sleep aid than hypnotic medication. The factors associated with the use of alcohol and of hypnotic medication are different.

Epidemiological study on passive smoking among Japanese infants and smoking behavior of their respective parents: a nationwide cross-sectional survey.

BACKGROUND: Passive smoking is a well-known health hazard for infants. This study was conducted to: (1) estimate the prevalence of passive smoking among Japanese infants and (2) clarify the prevalence of indoor smoking and associating factors among parents having infants. METHODS: Subjects were all 53,575 infants born throughout Japan on January 10-17, 2001 or July 10-17, 2001. When the infants reached 6 months of age, the questionnaires were mailed to the homes. Family members answered questions that included information about the current smoking behavior of the parents. RESULTS: A total of 44,562 questionnaires (83.2%) were analyzed. The prevalence of smoking among the mothers and the fathers were 17.1% and 63.5%. The percentages of mothers and fathers who smoked indoors were 12.1% and 36.2%. The percentage of households where mothers and/or fathers smoked indoors was 37.5%. Multivariate logistic analysis indicated that young age, having a spouse who was a smoker, infants having many siblings, the mother not breast-feeding, and lower annual incomes had significantly higher odds ratios for both the mother's and the father's indoor smoking. CONCLUSIONS: Passive smoking is common among Japanese infants. To protect Japanese infants from passive smoking, further public health measures must be taken.