Sachi Nakagome

Nationwide epidemiological study of insomnia in Japan

BACKGROUND This study was a nationwide epidemiological study of insomnia in Japan. It was conducted because very few studies on this topic have previously been performed for the general Japanese population. METHODS An interview survey on symptoms of insomnia (difficulty initiating sleep, difficulty maintaining sleep with difficulty resuming sleep, and early morning awakening with difficulty resuming sleep) and daytime dysfunction was conducted on the general nationwide population in the winter (February) and summer (August) of 2008. Data from 2614 participants who provided valid responses (age range 20-95 years, valid response rate 54.2%) were analyzed. RESULTS The prevalence of difficulty initiating sleep, difficulty maintaining sleep with difficulty resuming sleep, and early morning awakening with difficulty resuming sleep was 8.3%, 5.8%, and 5.8%, respectively, in men, and 11.0%, 8.1%, and 7.4%, respectively, in women. The prevalence of insomnia was 12.2% in men and 14.6% in women, and the prevalence of insomnia with daytime dysfunction was 3.2% in men and 4.2% in women. The results of logistic regression analyses indicated that the factors aggravating insomnia for men were unemployment and having mental health issues, and for women they were being aged ≥70 years, completing fewer years of schooling, and having mental health issues. Seasonality and regionality in association with insomnia were also examined, but no significant associations were found. CONCLUSION In the present survey, insomnia was defined by using criteria that were closer to the clinical diagnostic criteria (eg, coexistence of both difficulty resuming sleep and daytime dysfunction was considered). Therefore, it is believed that the results of this study were representative of the clinical actuality of insomnia in Japan.

Association Between Smoking and Problematic Internet Use Among Japanese Adolescents: Large-Scale Nationwide Epidemiological Study

The aim of this study was to clarify the association between smoking and problematic Internet use (PIU), such as Internet addiction (IA) and excessive Internet use (EIU), among Japanese adolescents. A self-administered questionnaire was administered to students enrolled in randomly selected junior and senior high schools throughout Japan. Responses were obtained from 100,050 students (0.94:1 ratio of boys to girls). The prevalence of IA (as indicated by a Young Diagnostic Questionnaire for Internet Addiction score ≥5) in all participants, boys, and girls was 8.1%, 6.4%, and 9.9%, respectively. The prevalence of EIU (≥5 hours/day) in all participants, boys, and girls was 12.6%, 12.3%, and 13.0%, respectively. The results of multiple logistic regression analyses indicated that the adjusted odds ratios (AORs) for IA and EIU were significantly higher among students who smoked (including those who previously smoked) than among those who never smoked (p < 0.01 for all comparisons). In addition, the AORs were the highest for students who smoked ≥21 cigarettes per day. The prevalence and AORs of IA and EIU tended to increase with smoking frequency and number of cigarettes smoked per day, indicating a dose-dependent relationship. Thus, IA and EIU have strong associations with smoking. This study revealed that adolescents who routinely smoked or those who smoked more cigarettes per day had a higher risk of PIU than adolescents who did not. These findings suggest that there is a close association between smoking and PIU among Japanese adolescents.

The association between alcohol use and problematic internet use: A large-scale nationwide cross-sectional study of adolescents in Japan.

Background This study aimed to clarify the associations between the frequency and amount of alcohol consumption and problematic Internet use, such as Internet addiction and excessive Internet use. Methods A self-administered questionnaire survey was administered to students enrolled in randomly selected junior and senior high schools throughout Japan, and responses from 100,050 students (51,587 males and 48,463 females) were obtained. Multiple logistic regression analyses were performed in order to examine the associations between alcohol use and problematic Internet, use such as Internet addiction (Young Diagnostic Questionnaire for Internet Addiction ≥5) and excessive Internet use (≥5 h/day). Results The results of multiple logistic regression analyses indicated that the adjusted odds ratios for Internet addiction (YDQ ≥5) and excessive Internet use (≥5 h/day) became higher as the number of days in which alcohol had been consumed during the previous 30 days increased. In addition, the adjusted odds ratio for excessive Internet use (≥5 h/day) indicated a dose-dependent association with the amount of alcohol consumed per session. Conclusions This study revealed that adolescents showing problematic Internet use consumed alcohol more frequently and consumed a greater amount of alcohol than those without problematic Internet use. These findings suggest a close association between drinking and problematic Internet use among Japanese adolescents.

Anger and Impulsivity Among Japanese Adolescents: A Nationwide Representative Survey

OBJECTIVE This study aimed to clarify the prevalence of anger and impulsivity and its associated factors through a nationwide survey of junior and senior high school adolescent students in Japan. METHODS A self-administered questionnaire covering (1) personal data, (2) lifestyle, (3) mental health status, and (4) feelings of anger and impulsivity was distributed to junior and senior high school students in Japan. Among the total of 10,955 junior high schools and 5,115 senior high schools nationwide, 130 and 110 were randomly selected, respectively. Of those, 92 junior and 80 senior high schools participated in the survey. The survey period was from December 2008 to the end of January 2009. A total of 95,680 questionnaires were collected. After excluding invalid responses, the remaining 94,777 responses (response rate: 62.3%) were analyzed. RESULTS From the questions regarding anger and impulsivity, 8.7% (95% CI, 8.5%-8.9%) and 7.5% (95% CI, 7.3%-7.7%) of the participants were considered to have experienced intense anger and impulsivity, respectively. Logistic regression analysis indicated that the odds ratios for experiencing intense feelings of anger were significantly higher (all P values < .05) among students who smoked, consumed alcohol, skipped breakfast, did not wish to go to university, had short sleep duration, had decreased positive feelings, had increased depressive feelings, or used mobile phones for longer hours. The odds ratios for experiencing intense impulsivity were significantly higher among students who smoked, consumed alcohol, skipped breakfast, did not participate in club activities, had short sleep duration, had decreased positive feelings, had increased depressive feelings, or used mobile phones for longer hours. CONCLUSIONS The results suggest that healthy lifestyle habits, good sleep habits, and improved mental health are important for preventing intense feelings of anger and impulsivity among adolescents.

Factors Related to Alcohol Consumption Among Japanese Physicians

This study aimed to investigate the drinking habits of Japanese physicians, and clarify their causal factors. A self-administered questionnaire was sent to 6000 male and 1500 female physicians, selected from among members of the Japan Medical Association. We analyzed the correlation of drinking habits with age, medical department, smoking and exercise status, work environment, sleep problems, and mental health. The response rate was 79.4%. Physicians with a heavy drinking habit were most frequently men in their 60s and women in their 20s to 50s. Drinking or heavy drinking tendencies decreased with increasing age. Smoking status was correlated with heavy drinking. Exercise status was correlated with drinking among men, and drinking/heavy drinking among women. Mental health was not correlated with drinking habit. However, sleep problems were correlated with a heavy drinking habit. These results suggest that countermeasures need to be taken to decrease the rate of heavy drinking among physicians.