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.

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.

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.