Prevention paradox between stroke and multiple potential risk factors using data from a population-based cohort study.

Previous studies have found the prevention paradox in the association between stroke events and a single specific risk factor, indicating that a population-based strategy may be more effective than a high-risk-based strategy for prevention. We tested the hypothesis that the prevention paradox does not apply when focusing on multiple potential risk factors simultaneously. The study cohort included 9051 individuals from Japan aged 40-89 years. The time-dependent Cox proportional-hazards models were used to identify the primary risk factor associated with stroke onset. We classified participants based on risk factors in two distinct ways: 1) classifying the high-risk group participants according to a single specific risk factor that had a large association with stroke in both sexes and all ages and 2) classifying the high-risk group participants according to 1-3 risk factor(s) including hypertension, hyperglycemia, and/or dyslipidemia. Then, we compared the proportions of the total number of participants who developed stroke in both groups to assess the prevention paradox. We found that hypertension was a primary risk factor for stroke incidence, regardless of sex and age. The percentage of patients with a single specific risk of and developed stroke was 46%-63%, while the percentage of patients with 1-3 risk factor(s) was 71-83%. This finding leads to the conclusion that the prevention paradox does not hold when multiple stroke risk factors were associated, suggesting that a high-risk-based strategy that focuses on patients with multiple risk factors may be more effective in preventing strokes.

A Nationwide Survey of Obstetric Care Status on Japan's Islands, with Special Reference to Maternal Transport to the Mainland.

Safe obstetric care is a worldwide requirement. In Japan, a reduced number of obstetricians has prompted the centralization of obstetric facilities, and Japan's islands are expected to experience problems in handling deliveries. Although many pregnant women "move" to the mainland at later gestational weeks, "transport" from the island to the mainland may be occasionally needed when disorders manifest before the "move." Other women plan within-island deliveries; however, transport is required when complications arise. Managing delivery- or pregnancy-related problems may differ in transport by the population size of islands. We investigated the following issues in relation to the population size of Japan's islands: 1) How were deliveries handled on islands? 2) How many pregnant women were transported to the mainland? 3) What was the reason for and what affected transport? A total of 142 municipalities were selected to participate in a questionnaire survey, and 108 institutions from 106 municipalities responded. A comparative analysis by island size was performed using 2014 data: small-sized (population < 1,000), mid-sized (1,000 to 5,000), and large-sized (≥ 5,000). The percentage of women transported to the mainland from small-sized islands was significantly higher than that from large-sized islands (6.8 vs. 2.6% of all births in a year, respectively, P < 0.01). Transport was mainly in response to threatened preterm labor. Adverse weather was the most frequent factor affecting transport reliability. Our findings may contribute to a more detailed understanding of the state of obstetric care on Japan's islands.

Perceptions of Residents among Rural Communities with Medical Group Practice in Japan.

Elucidating the perceptions of residents regarding medical group practice (GP) among rural communities (GP-R) in Japan will be useful for establishing this system in such communities. A survey by questionnaire, as made by experts in rural health, was conducted in 2017. The self-administered questionnaire inquired about the perceptions of residents for accepting the GP-R into the community's healthcare using seven major elements of GP-R. The questionnaire was randomly distributed to 400 adult residents who lived in rural communities with a recently launched GP and had access to clinics within the communities. Among the 321 respondents, comparisons were made between younger (≤sixties) and older (≥seventies) residents, and a stepwise multiple regression analysis was performed to extract the factors influencing acceptance of the GP-R system. The results showed that older residents had a greater disapprove of being treated by different physicians daily or weekly in clinics (p < 0.001) and the use of telemedicine (p < 0.001) compared with younger residents. Younger residents showed a greater disapproval of clinics closing on weekdays than older residents (p = 0.007). Among all respondents, regardless of age groups, over half of residents approved of the involvement of nurse practitioners in the GP-R. Living with family and children was also extracted as an independent factor influencing a positive perception of the GP-R. These data suggest that the promotion of GP-R should consider generation gaps in the approach to medical practice as well as the family structures of residents. The involvement of nurse practitioners can also encourage the acceptance of GP-R in Japan.

[Self-reported obituary columns in a local daily newspaper].

Objectives　To reveal the features of death and subsequent funeral services, we analyzed self-reported obituaries in The Shimotsuke, a local daily newspaper in Tochigi, Japan. In addition, the usefulness and disadvantages of such a database of deaths based on the obituaries were discussed.Method　For a 5-year period, from January 2011 through December 2015, all the obituary columns in The Shimotsuke were computerized as a database and analyzed. Some results were compared with the vital statistics data in the corresponding period of time. Data analyzed were: dead persons' address (municipalities), name, sex, cause of death, age at death, date of death and funeral services, the chief mourner (Moshu), and so on.Results　During the observed 5-year period, 69,793 deaths appeared in the columns, which were 67.6% of the all deaths in the vital statistics. No difference was observed in the proportions between the sexes in the published deaths in comparison with the vital statistics. In both sexes, the proportion was low in 0-9 years old, then high among 10-19 years, decreasing in 20s, and after then the proportion increased according to the age. The proportion was low in city areas, such as Utsunomiya and Oyama, and high in some cities and towns in the northern or eastern parts of Tochigi prefecture. The highest was in Motegi Town (88.0%), and the lowest was Nogi Town (38.0%), which is located in the southern-most part of the prefecture and is closest to the Tokyo metropolitan area. Almost all the funeral services were conducted within a week of the death, and no delays were observed to have been caused by the short supply of cremation services, which exists in large cities in Japan. In case where the chief mourner was a child, a parent, or a spouse of a child, the male sex was dominant. Analyses of death from senile decay, suicide, and homicide indicated that the accuracy of the published cause of death was low. The date of the funeral services was strongly influenced by superstitions in this country.Conclusions　Observations of the self-reported obituaries in a local daily newspaper over five years revealed the situations of the deaths in the area that could not be observed using vital statistics. Despite limitations, the information was partially useful as a database.

Epidemiological observations of Kawasaki disease in Japan, 2013-2014.

BACKGROUND: The etiology of Kawasaki disease (KD) is unknown. In Japan, the number of patients and incidence rate of KD has increased continuously since its discovery. The aim of this report was to analyze the latest nationwide epidemiological survey of KD in Japan. METHODS: The 23rd nationwide survey of KD was conducted in 2015. To report on all patients diagnosed with KD in 2013 and 2014, a questionnaire was sent to hospitals with ≥100 beds containing pediatric departments, as well as specialized pediatric hospitals. RESULTS: The number of KD patients reported was 15 696 in 2013 and 15 979 in 2014, resulting in an annual incidence rate of 302.5 and 308.0 per 100 000 population aged 0-4 years, respectively. The number of patients and incidence rate of KD in 2014 were the highest ever recorded in Japan. The number of patients diagnosed per month peaked in January, and a gradual increase in summer was also observed. Eight patients died of KD in 2013 and 2014. CONCLUSIONS: The number of patients and incidence rate of KD in Japan continue to increase. Continued surveillance of epidemiological trends of KD is therefore required.

An 18-Year Follow-up Survey of Dioxin Levels in Human Milk in Japan.

BACKGROUND: Globally, few published studies have tracked the temporal trend of dioxin levels in the human body since 2000. This study describes the annual trend of dioxin levels in human breast milk in Japanese mothers from 1998 through 2015. METHODS: An observational study was conducted from 1998 through 2015. Participants were 1,194 healthy mothers following their first delivery who were recruited annually in Japan. Breast milk samples obtained from participants were analyzed using gas chromatography and mass spectrometry for dioxins, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs). RESULTS: Mean age was 29.5 years, and 53% of participants were 20-25 years old. A declining trend in total dioxin levels was found, from a peak of 20.8 pg toxic equivalence (TEQ)/g fat in 1998 to 7.2 pg TEQ/g fat in 2014. Data from the last 5 years of the study indicated a plateau at minimal levels. In contrast, an increasing trend was found in the mean age of participants during the last 5 years. Although significantly higher dioxin levels were observed in samples from older participants, an upward trend in dioxin levels was not observed, indicating that dietary and environmental exposure to dioxins had greatly diminished in recent years. CONCLUSIONS: Dioxin levels in human breast milk may be approaching a minimum in recent years in Japan. The findings may contribute to global reference levels for environmental pollution of dioxins, which remains a problem for many developing countries.

Cumulative incidence of Kawasaki disease in Japan.

BACKGROUND: Although the incidence rates of Kawasaki disease (KD) in Japan have been determined in nationwide surveys, the cumulative incidence, that is, the proportion of those with a history of KD in the general population of 10-year-olds, is currently unknown. The aim of this study was therefore to assess the cumulative incidence of KD in Japan. METHODS: Using the age- and sex-specific incidence rate of KD in Japan from the results of the nationwide surveys, incidence probabilities, that is, the age-specific number of KD patients divided by the population used in the vital statistics, and cumulative proportions of those not affected by KD up to the end of 9 years of age, were calculated. The cumulative incidence was then defined as 1 minus the cumulative proportion. The observed age classes were 0, 1, 2, 3, 4, and 5-9 years. All data were calculated by sex. RESULTS: The cumulative incidence was 0.004833 for boys and 0.003474 for girls in 1991, but was 0.015284 and 0.012145 in 2014, respectively. According to these figures, 15.284 per 1,000 boys and 12.145 per 1,000 girls have been affected by KD by the age of 10 years. The birth-cohort cumulative incidences had similar trends. CONCLUSIONS: More than 10 persons in 1,000 have a history of KD at age 10 years in Japan.

Does Scale of Public Hospitals Affect Bargaining Power? Evidence From Japan.

BACKGROUND: Many of public hospitals in Japan have had a deficit for a long time. Japanese local governments have been encouraging public hospitals to use group purchasing of drugs to benefit from the economies of scale, and increase their bargaining power for obtaining discounts in drug purchasing, thus improving their financial situation. In this study, we empirically investigate whether or not the scale of public hospitals actually affects their bargaining power. METHODS: Using micro-level panel data on public hospitals, we examine the effect of the scale of public hospitals (in terms of the number of occupancy beds) on drug purchasing efficiency (DPE) (the average discount rate in purchasing drugs) as a proxy variable of the bargaining power. Additionally, we evaluate the effect of the presence or absence of management responsibility in public hospital for economic efficiency as the proxy variable of an economic incentive and its interaction with the hospital scales on the bargaining power. In the estimations, we use the fixed effects model to control the heterogeneity of each hospital in order to estimate reliable parameters. RESULTS: The scale of public hospitals does not positively correlate with bargaining power, whereas the management responsibility for economic efficiency does. Additionally, scale does not interact with management responsibility. CONCLUSION: Giving management responsibility for economic efficiency to public hospitals is a more reliable way of gaining bargaining power in drug purchasing, rather than promoting the increase in scale of these public hospitals.

Differentials in variables associated with past history of artificial abortion and current contraception by age: Results of a randomized national survey in Japan.

AIM: This study analyzes differentials in the variables associated with the experience of artificial abortion (abortion) and use of contraception by age among women in Japan. METHODS: The 2010 National Lifestyle and Attitudes Towards Sexual Behavior Survey was distributed to 2693 men and women aged 16-49 selected from the Japanese population using a two-stage random sampling procedure. From the 1540 respondents, we selected 700 women who reported having had sexual intercourse at least once. We used logistic regression to analyze how social and demographic factors were associated with the experience of abortion and contraceptive use. RESULTS: The abortion rate according to the survey was 19.3%. Of the 700 women in the sample, 6.9% had experienced two or more abortions. Logistic regression revealed that, although significant variables depended on age, a high level of education and discussions about contraceptive use with partners were negatively associated with the experience of abortion. Self-injury, approval of abortion and first sexual intercourse between the age of 10 and 19 were positively associated with the experience of abortion. Marriage, smoking and first sexual intercourse between the age of 10 and 19 were negatively associated with contraceptive use. Higher education and discussion of contraception with partners were positively associated with contraceptive use. CONCLUSIONS: To prevent unwanted pregnancy and abortion, social support and sexual education should be age-appropriate. It is vital to educate young people of the importance of discussing contraceptive use with their partners.

Differences in caregiver daily impression by sex, education and career length.

AIM: We previously proposed the concept of caregiver daily impression (CDI) as a practical tool for emergency triage. We herein assessed how CDI varies by sex, education and career length by determining CDI scores as quantitative outcome measures. METHODS: We carried out a cross-sectional study using a self-reported questionnaire among caregivers in 20 long-term care facilities in Hyogo, Japan. A total of 10 CDI variables measured participants' previous experience of emergency transfers using a scale from 0-10. The resulting total was defined as the CDI score. We hypothetically considered that higher scores indicated greater caregiver focus. The CDI scores were compared by sex, education and career length using analysis of covariance. RESULTS: A total of 601 personal caregivers were evaluated (mean age 36.7 years; 36% men). The mean career length was 6.9 years, with the following groupings: 1-4 years (38%), 5-9 years (37%) and >10 years (24%). After adjustment for sex and education, the CDI scores for the variable, "poor eye contact," significantly differed between caregivers with ≥10 and <5 years of experience (scores of 5.0 ± 3.1 and 4.0 ± 2.7, respectively). The CDI scores for variables related to eyes tended to increase with experience, whereas other CDI scores decreased. Male caregivers focused on residents' eyes significantly more than did female caregivers. CONCLUSIONS: We found that the CDI variable, "poor eye contact," is influenced by career length. Caregivers with more experience attach more importance to their impression of residents' eyes than do those with less experience. Sex-related differences in CDI might also exist. Geriatr Gerontol Int 2016; 17: 410-415.

Time course of cardiac lesions due to Kawasaki disease in Japan: 22nd nationwide survey (2011-2012).

BACKGROUND: Although Kawasaki disease (KD) cardiac lesions can be treated with i.v. immunoglobulin (IVIG) and are associated with age and sex, the time course of cardiac lesions remains unclear on the large scale. METHODS: We used the data of the 22nd nationwide survey of KD in Japan (2011-2012). We divided the time course of cardiac lesions into eight groups according to the combination of timing (first visit to hospital, acute phase, and sequelae) and presence of cardiac lesions (E, existence of cardiac lesions; N, non-existence of cardiac lesions): EEE, EEN, ENE, NEE, ENN, NEN, NNE, and NNN. For example, EEN shows that cardiac lesions existed at first visit to hospital and in the acute phase, but did not exist as sequelae. A total of 24 952 patients were analyzed. RESULTS: The majority (90.6%) of patients belonged to the NNN group, followed by the EEN (3.21%) and NEN (3.33%) groups. Male sex and ages ≤5 months and ≥5 years tended to be more prevalent. Non-response to initial IVIG therapy was the most prevalent in all groups other than NNN. CONCLUSIONS: The time course of cardiac lesions and the relationship with sex, age, and IVIG therapy have been described. KD patients who are male, aged ≤5 months or ≥5 years, and non-responders to initial IVIG tend to have cardiac lesions at some point in the time course of KD.

Temporal and geographical clustering of Kawasaki disease in Japan: 2007-2012.

BACKGROUND: Since 1987, no study has reported the municipal-level geographical clustering of Kawasaki disease (KD) in Japan. Therefore, the aim of the present study was to identify the temporal and municipal-level geographical clustering of KD. METHODS: The annual incidence rates of KD for each municipality were calculated using nationwide data from 73 758 patients with KD (2007-2012). To determine whether temporal and municipal-level clustering existed, we calculated the correlations of the annual incidence rates for each municipality during the study years, and compared these rates with those of the adjacent municipalities. Spatial scanning analysis was used to identify the geographical clusters for each year, and the incidence rates in those clusters were compared with the rates in the surrounding region. RESULTS: The annual national incidence rate of KD, adjusted for the prefecture-specific response rate, was 322.45 patients per 100 000 children aged 0-4 years. The correlation between the annual incidence rates during 2 consecutive years was significantly positive (coefficients, 0.149-0.428). On spatial scanning analysis, the most likely clusters were in the Tokyo metropolitan area during 2007-2010 and 2012, and in Kumamoto prefecture during 2011. CONCLUSION: Kawasaki disease exhibits temporal and municipal-level clustering.

Caregiver daily impression could reflect illness latency and severity in frail elderly residents in long-term care facilities: A pilot study.

AIMS: To propose a caregiver daily impression (CDI) rating instrument for personal caregivers of residents living in long-term care facilities (LTCF) to comprehensively evaluate residents' daily health condition, and to investigate whether the CDI reflects illness latency and severity in residents transferred emergently. METHODS: We carried out a retrospective review of facility care records from 20 LTCF in Hyogo, Japan. The participants were 169 LTCF residents with episodes of transfer to emergency hospitalization facilities during a 3-month period. We determined specific CDI variables by interviewing experienced LTCF caregivers, and then carried out a principal component analysis to determine the major parameter set. The generated components were incorporated into a regression model to investigate the association with hospitalization. RESULTS: The mean age was 87.9 ± 6.5 years, 68% were women and 28% of transfers resulted in hospitalization. The interview procedure identified 12 specific CDI variables, and the principal component analysis generated five distinct components: "change in feeding," "change in emotion," "disengaged or listless gaze," "decrease in eye reactivity" and "change in movement." By multivariate logistic regression, hospitalization was associated with "decrease in eye reactivity" (adjusted OR 1.78, 95% CI 1.07-2.97) and poor vital signs (adjusted OR 2.84, 95% CI 1.15-6.98), but not with body temperature (adjusted OR 1.29, 95% CI 0.52-3.21). CONCLUSIONS: The CDI might reflect underlying illness severity beyond quantitative physical findings. Once the CDI can be appropriately validated, quantified and linked to physical findings, it could be used by caregivers for daily resident assessments and as a practical triage tool in emergency situations. Geriatr Gerontol Int 2016; 16: 612-617.

Descriptive epidemiology of Kawasaki disease in Japan, 2011-2012: from the results of the 22nd nationwide survey.

BACKGROUND: The number of patients and incidence rate of Kawasaki disease (KD) are increasing in Japan. We have therefore characterized the latest epidemiological information on KD. METHODS: The 22nd nationwide survey of KD, which targeted patients diagnosed with KD in 2011 and 2012, was conducted in 2013 and included a total of 1983 departments and hospitals. In order to report on all patients with KD during the 2 survey years, we targeted hospitals of 100 beds or more with pediatric departments, or specialized pediatric hospitals. RESULTS: From a total of 1420 hospitals and departments (71.6% response rate), 26,691 KD patients were reported (12,774 in 2011 and 13,917 in 2012; 15,442 males and 11,249 females). The annual incidence rates were 243.1 per 100,000 population aged 0 to 4 years in 2011 and 264.8 in 2012. The number of cases of KD recorded in 2012 was the highest ever reported in Japan. The incidence rate of complete cases was also the highest ever reported in Japan and contributed to the increase in the rate of total cases in recent years. The number of patients diagnosed per month peaked in January, and additional peaks were noted during summer months, although these peaks were lower than those seen in winter. Age-specific incidence rate showed a monomodal distribution with a peak in the latter half of the year in which patients were born. CONCLUSIONS: The number of patients and the incidence rate of KD in Japan continue to increase. A similar trend has also been seen for patients with complete KD.

Selection bias of Internet panel surveys: a comparison with a paper-based survey and national governmental statistics in Japan.

PURPOSE: To investigate the selection bias of an Internet panel survey organized by a commercial company. METHODS: A descriptive study was conducted. The authors compared the characteristics of the Internet panel survey with a national paper-based survey and with national governmental statistics in Japan. RESULTS: The participants in the Internet panel survey were composed of more women, were older, and resided in large cities. Regardless of age and sex, the prevalence of highly educated people in the Internet panel survey was higher than in the paper-based survey and the national statistics. In men, the prevalence of heavy drinkers among the 30- to 49-year-old population and of habitual smokers among the 20- to 49-year-old population in the Internet panel survey was lower than what was found in the national statistics. CONCLUSIONS: The estimated characteristics of commercial Internet panel surveys were quite different from the national statistical data. In a commercial Internet panel survey, selection bias should not be underestimated.

Prevalence and demographic distribution of adult survivors of child abuse in Japan.

A cross-sectional study was conducted with a national epidemiological survey to investigate the prevalence and demographic distribution of adult survivors of child abuse in Japan. A self-administered questionnaire was used to measure the history of child abuse and the demographic characteristics. The participants reported the following 4 types of child abuse: physical abuse (3%), sexual abuse (0.6%), neglect (0.8%), and psychological abuse (4%). Significant unequal distribution of child abuse was found to be associated with sex, living region, marital status, job status, and educational status. We determined the prevalence of adult survivors of child abuse in Japan and found that their demographic characteristics were unequally distributed. Policy makers and public health providers should take these demographic disparities into account in considering effective public health interventions for survivors of child abuse.

[Satisfaction with hospital care among diabetic outpatients and its associated factors. Secondary use of official statistics].

OBJECTIVES: Generalizable data on current satisfaction levels are required to establish a scientific basis for the political advancement of measures to improve satisfaction with hospital care among patients with diabetes. The present study made secondary use of existing official statistics in order to demonstrate the range of satisfaction levels with hospital care among diabetic outpatients and to closely examine related factors. METHODS: Data sets that consolidated the Patient Survey, the Survey of Medical Care Institutions, and the Patient Behavior Survey (all from 2008) were created. Shared medical institution survey reference numbers were used to consolidate the data from the Patient Survey and the Survey of Medical Care Institutions, and in addition, sex and date of birth were used to consolidate the Patient Behavior Survey data. The range of satisfaction levels with hospital care among diabetic outpatients was investigated along with any relationship with the following potentially related factors: visitation status (first or repeat examination); waiting time until examination; examination duration; care-seeking status (any use of other medical facilities, etc.); diabetic complications; other complications; coverage under the Public Assistance Act; smoking cessation outpatient services; hospitals that specialized in treating diabetes (metabolic medicine); medical care on Saturday, Sunday, and public holidays; and provision of health checkups. RESULTS: Overall, 62.3% of diabetic outpatients were either fairly or extremely satisfied with their hospital care, whereas 5.6% expressed dissatisfaction. Satisfaction levels with hospital care were found to be significantly related to visitation status, waiting time until examination, examination duration, care-seeking status, and Saturday medical care. Multivariate analysis with the factors demonstrated to be significantly related to satisfaction revealed significant relationships between high satisfaction levels and repeat examinations, short waiting times, no use of any other medical facilities, and long examinations. CONCLUSION: Consolidating official statistics from multiple sources indicated the range of satisfaction levels with hospital care among diabetic outpatients and facilitated the clarification of factors affecting satisfaction. Reducing waiting times and ensuring sufficient time spent on examinations are important for increasing satisfaction levels with hospital care among patients with diabetes. It is hoped that official statistics can be further applied to many future public health policy studies.

Mortality among Japanese with a history of Kawasaki disease: results at the end of 2009.

BACKGROUND: The long-term outcomes of Kawasaki disease (KD) are unknown. METHODS: Fifty-two collaborating hospitals collected data on all patients who had received a new definite diagnosis of KD between July 1982 and December 1992. Patients were followed until December 31, 2009 or death. Standardized mortality ratios (SMRs) were calculated based on Japanese vital statistics data. RESULTS: Of the 6576 patients enrolled, 46 (35 males and 11 females) died (SMR: 1.00; 95% CI: 0.73-1.34). Among persons without cardiac sequelae, SMRs were not high after the acute phase of KD (SMR: 0.65; 95% CI: 0.41-0.96). Among persons with cardiac sequelae, 13 males and 1 female died during the observation period (SMR: 1.86; 95% CI: 1.02-3.13). CONCLUSIONS: In this cohort, the mortality rate among Japanese with cardiac sequelae due to KD was significantly higher than that of the general population. In contrast, the rates for males and females without sequelae were not elevated.

[Self-injury in Japan: epidemiological features from the nationwide survey data of 2010].

OBJECTIVES: The purpose of this study was to examine the epidemiological features of self-injury in Japan, and to investigate the factors associated with a history of self-injury, using nationwide random sample data on Japan in 2010. METHODS: Questionnaires were distributed to 2,693 subjects, aged 16-49 years, randomly selected from the all over Japan using 2-stage stratified random sampling; the answers regarding self-injury were analyzed. Potential risk factors were compared between those who answered that they had a history of self-injury (self-injury group) and those who answered that they did not (non-self-injury group). RESULTS: Responses were obtained from 1,540 participants (response rate, 57.2%). Lifetime prevalence of having 1 or more self-injury events was 7.1% overall (3.9% for men; 9.5% for women) and approximately half of them reported a repetitive history of self-injury. Lifetime prevalence of self-injury was highest in those aged 16-29 years (9.9%, 16-29 years; 5.6%, 30-39 years; 5.7%, 40-49 years). Lifetime prevalence among women (16-29 years, 30-39 years, and 40-49 years) decreased with age (15.7%, 7.5%, and 5.8%, respectively), however, that among men increased with age (3.0%, 3.4%, and 5.5%, respectively). Compared with the non-self-injury group, those in the self-injury group were significantly more likely to have a history of cigarette smoking (self-injury group, 47.5%; non-self-injury group, 28.2%; adjusted odds ratio [95% confidence interval]: 2.18 [1.32-3.58]), childhood abuse (23.6% and 3.7%, respectively, 4.24 [2.18-8.25]), induced abortion (30.3% and 12.7%, respectively, 1.93[1.13-3.30]); moreover, they were significantly less likely to answer that they had a happy life when they were junior high school students (41.1% and 78.6%, respectively, 0.45 [0.25-0.79]). In addition, those in the self-injury group were more likely to report a history of parental divorce, that they did not have good communication with their parents, and that they did not have respect and appreciation for their parents; however, these factors were not significant after adjustment. CONCLUSION: These results are consistent with those of previous research reports in which the lifetime prevalence of self-injury was high among women aged 16-29 years, and in which self-injury was more likely to occur among individuals who had a history of cigarette smoking and childhood abuse. Such individuals should be provided care to prevent self-injury. In addition, from a social point of view, research examining family environments including these factors is required.