Characterizing patients issued DNR orders who are ultimately discharged alive: a retrospective observational study in Japan.

BACKGROUND: The present study aimed to characterize factors associated with patients issued DNR orders during hospitalization who are discharged alive without any instruction orders by physicians regarding end-of-life treatment, with a focus on the timing of DNR order issuance. METHODS: In total, 2997 DNR cases from all 61,037 patients aged ≥20 years admitted to a representative general hospital in Tokyo were extracted and divided into two groups by patient hospital release status (discharged alive/deceased). Study items included age, sex, disease type (non-cancer/cancer), hospital department (internal medicine/others), timing of DNR order issuance, implementation (or not) of life-sustaining treatment (LST) or the presence of any restrictions on LST and hospital length of stay. We conducted multiple logistic regression analysis, setting hospital release status as the dependent variable and each above study item as explanatory variables. RESULTS: DNR orders were issued at a rate of 4.9%. The analysis revealed that patients with a DNR who were ultimately discharged alive were statistically more likely to be those for whom DNR orders are issued early after admission (adjusted odds ratio: AOR, 13.7), non-cancer patients (AOR, 3.4), internal medicine department patients (AOR, 1.63), females (AOR, 1.34), and elderly (aged ≥85 years; AOR, 1.02); these patients were also less likely to be receiving LST (AOR, 0.36). CONCLUSIONS: By focusing on those with DNR orders who were ultimately discharged alive, we discovered that these patients were likely to have DNR orders issued early after admission, and that they were more likely to be elderly, female, non-cancer patients, or those in internal medicine departments. Further examination of these data may help to elucidate why these particular DNR-related characteristics (including socio-economic and cultural factors) are evident in patients who end up being discharged alive.

Association between changes in 12 lifestyle behaviors and the development of metabolic syndrome during 1 year among workers in the Tokyo metropolitan area.

BACKGROUND: Practicing healthy lifestyle behaviors is a means to prevent metabolic syndrome (MetS), but the effect of changes of various behaviors over a short period is not fully understood. The purpose of this study was to elucidate the influence of changes in 12 behaviors on the development of MetS during 1 year. METHODS AND RESULTS: Of 10,442 workers who received a periodic health checkup in a health center in Tokyo in 2008, 3,137 workers aged 30-69, without MetS, who received another health checkup in 2009 were analyzed. Smoking, amounts and frequency of alcohol drinking, sleeping, exercise, walking duration and speed, late-night dinners, bedtime snacking, breakfast, eating speed, and weight control were classified into 4 groups according to change from 2008 to 2009. To examine the influence of behavioral changes on developing MetS, multiple logistic analysis was conducted after adjustment for sex, baseline age and MetS components. Changes from healthy to unhealthy behaviors in exercise, walking duration and speed, daily drinking, and weight control were significant in developing MetS compared with maintaining healthy behaviors. Those risks were higher than keeping unhealthy behaviors. Unhealthy to healthy behavior in smoking increased the risk while healthy to unhealthy behavior in eating speed decreased the risk of developing MetS. CONCLUSIONS: To prevent developing MetS during 1 year, healthy behaviors regarding physical activity, drinking, and weight management should be maintained.

Features of perceived neighborhood environment associated with daily walking time or habitual exercise: differences across gender, age, and employment status in a community-dwelling population of Japan.

OBJECTIVE: Perceived neighborhood environment (NE) is considered a determinant of daily physical activity (PA). However, evidence concerning differences among types of PA, gender, and age is limited. The study purpose was to clarify the association between NE and walking time (WT) or habitual exercise (HE) across gender, age, and employment status in a community-dwelling population of Japan. METHODS: A questionnaire mail survey with a stratified random 7,515 sampling was conducted in a northeast city in January 2007. Multiple logistic analysis was conducted to examine the associations between seven NE indices and WT or HE across gender, age, and employment status: 20-39 (young-employed), 40-59 (middle-employed), and 60-79 (old-employed or old-unemployed) after adjustment for age and means of transportation. RESULTS: A total of 3,806 residents (52.4 % females) completed the survey. Traffic and crime safety in old-unemployed males and proximity to service facilities and traffic and crime safety in middle-employed females were significantly associated with a low risk of insufficient WT. Proximity to service facilities in old-employed males, number of service facilities, places for walking, and good view in middle-employed females, and density of dwelling and proximity to service facilities in old-unemployed females were significantly associated with a low risk of non-HE. CONCLUSIONS: The association between NE and WT or HE differed across type of PA, gender, age, and employment status, and was observed mainly in middle- and old-aged females. The middle- and old-aged female residents' PA possibly were more influenced by their NE, and NE would contribute to promote active living.

Disclosure of Spousal Death to Patients with Dementia: Attitude and Actual Behavior of Care Managers.

As the number of dementia patients increases, there is a need to protect patients' right to know. However, in reality, there are cases in Japan where spouses' deaths are concealed from patients. We conducted a questionnaire survey of care managers (CMs) to obtain their attitude and actual behavior regarding the disclosure of a spouse's death to patients with dementia. A self-administered, anonymous questionnaire survey was implemented at academic meetings attended by CMs from March to December 2019, inquiring about experiences with spousal deaths of patients with dementia, disclosure rates, behavioral and psychological symptoms of dementia, and depression. Over 80% had experienced the spousal death of a patient with dementia; the percentage of CMs who had implemented the disclosures varied widely. About 18% had experienced worsening behavioral and psychological symptoms of dementia (BPSD), and 26% had worsening depression as a result of the disclosure. About 83% of respondents were positive about disclosure, but about 44% did so less than 50% of the time. This study is the first to reveal the current state of CMs' policies and behaviors regarding the disclosure of spousal death to patients with dementia in Japan. Family members' wishes and the possibility of BPSD put a relatively large number of caregivers in a dilemma regarding disclosure.

Factors of influenza vaccine inoculation and non-inoculation behavior of community-dwelling residents in Japan: Suggestions for vaccine policy and public health ethics after COVID-19.

The aim of this study is to provide basic information that contributes to vaccine inoculation policy after COVID-19. We used the secondary data of the influenza vaccine inoculation behavior survey for community-dwelling adults conducted in 2011, before the COVID-19 pandemic, but after the 2009 novel influenza A (H1N1) pdm 09 pandemic. All factors such as socio-demographic characteristics, health-related behaviors, family environment, physical and social environment, and area of residence were adjusted, and factors related to vaccine inoculation behavior were analyzed. Those living with pregnant women had a significantly higher odds ratio of inoculation; this was self-evident in that those people considered infection to their family. Regarding the social environment, those aged 20-64 years with a significantly higher adjusted odds ratio of inoculation were those with "at least five people with which they interacted in the neighborhood". This result can be interpreted in two ways relating to altruism in Japan. Finally, we indicated the importance of learning from the past, including the case of 2009.

A Cross-Sectional Study of Attitudes toward Willingness to Use Enhancement Technologies: Implications for Technology Regulation and Ethics.

Neuroenhancement is rapidly re-emerging as a research topic because of the development of minimally invasive brain intervention technologies, including neurofeedback. However, public attitude toward enhancement technologies remains relatively unexplored. To fill this gap in the literature, we conducted an online survey of 1258 people in Japan who were presented with four scenarios depicting minimally and highly invasive enhancement interventions. Approximately 20% of the respondents stated that they were willing to use enhancement technologies, whereas 80% were not. Most respondents were cautious about using enhancement technologies. We used a generalized linear mixed-effects model to study the association between the type of intervention and participants' willingness to use such technologies. Factors related to willingness to use these technologies included interventions' degree of invasiveness, as well as participants' gender, educational attainment, and limit or suppression experiences. We also examined the influence of others' choices and behaviors, and participants' tolerance toward others' use of enhancement technologies. We explored important aspects of policymaking vis à vis enhancement technologies. This study could provide valuable insights for a debate on the ethics and regulation of enhancement technologies.

Facts and Recommendations regarding When Medical Institutions Report Potential Abuse to Child Guidance Centers: A Cross-Sectional Study.

BACKGROUND: Medical institutions are required to report suspected cases of child abuse to administrative agencies, such as child guidance centers in Japan. It is left to the discretion of the medical institutions whether to notify the family of the child or the center. However, it is unclear what kinds of measures are being taken to ensure a robust policy of notification versus non-notification and how notifying the family will affect the child. METHODS: An unregistered questionnaire survey on reporting suspected child abuse cases to child consultation centers and notifying families was conducted by mail across 518 pediatric specialist training facility hospitals designated by the Japanese Pediatric Society. RESULTS: Responses were received from 323 facilities (62.4% response rate), of which 5 facilities were excluded because of incomplete responses. Therefore, in all, 318 facilities were included in the analysis. The results showed that 59.8% of the facilities had a policy of notifying the family, 33.7% said the decision varies from case to case, and 6.6% did not have a policy of notifying the family. The facilities that had a policy of either notifying or not notifying the family were less likely to experience problems than those with a policy of deciding on a case-by-case basis. The proportion of cases in which some problems occurred was higher in the cases where families were notified than in the cases where they were not, with 51.4% of the children experiencing worsening of relationships with family members. In the cases where the families were not notified, the children were twice as likely to experience further abuse than in cases where the families were notified. CONCLUSION: Problems arise in the case of both notification and non-notification. It is necessary to examine background factors and specific methods of notification in the cases where problems arise.

Disclosing a diagnosis of autism spectrum disorder without intellectual disability to pediatric patients in Japan in early diagnostic stages and associated factors: a cross-sectional study.

BACKGROUND: With a recent increase in the prevalence of autism spectrum disorder (ASD), an important issue has emerged in clinical practice regarding when and how patients themselves should be given explanations following a diagnosis of ASD. The clinical guidelines of the UK National Institute for Health and Care Excellence state that children diagnosed with ASD should receive an explanation about what ASD is and how it affects their development and functioning-"if appropriate". However, the guidelines do not provide any specifics regarding what constitutes "appropriate" situations METHODS: We conducted an anonymous self-administered postal questionnaire survey targeting all members of the Japanese Society for Child and Adolescent Psychiatry (n=1,995). The analysis included only physicians who had newly diagnosed pediatric patients with ASD in the past year. We imposed a limit of one year because diagnoses further back than that are difficult to recall; in other words, this would enhance the recall bias RESULTS: The recovery rate was 30.8%, and the rate of diagnosis disclosure to patients themselves without intellectual disability was 15.3%. We asked 361 physicians who responded that "deciding on a case-by-case basis" was the ideal way to disclose an ASD diagnosis about 20 items prioritized by physicians at the time of diagnosis disclosure and extracted three factors through exploratory factor analysis. Multiple logistic regression analysis was performed with physician attributes, awareness of ASD as a disorder or personality, and the three extracted factors as explanatory variables; diagnosis disclosure was the dependent variable. The patient age group and only one of the three factors (i.e., "factor related to readiness to accept diagnosis") showed a significant association with disclosure of the diagnosis to the individual. Items included in the "factor related to readiness to accept diagnosis" were as follows: the degree of parental understanding, relationship of the patient with their parents/physician, agreement in opinion between parents, parental consent, "sufficient" patient understanding, symptom stabilization, and a guarantee of sufficient time required to explain the diagnosis to the patient CONCLUSION: In clinical settings, disclosing an ASD diagnosis with the consideration of patient/parent readiness toward accepting the diagnosis could help to guide physicians in determining an ideal timing for disclosure. Future studies are needed to establish detailed and concrete guidelines regarding disclosure of an ASD diagnosis to patients.

An Exploratory Study on Information Manipulation by Doctors: Awareness, Actual State, and Ethical Tolerance.

(1) Background: To what extent is information manipulation by doctors acceptable? To answer this question, we conducted an exploratory study aimed at obtaining basic data on descriptive ethics for considering this issue. (2) Methods: A self-administered questionnaire survey was conducted on a large sample (n = 3305) of doctors. The participants were queried on (1) whether they consider that information manipulation is necessary (awareness), (2) whether they have actually manipulated information (actual state), and (3) their ethical tolerance. (3) Result: The response rate was 28.7%. Sixty percent of the doctors responded that information manipulation to avoid harm to patients is necessary (awareness), that they have actually manipulated information (actual state), and that information manipulation is ethically acceptable. (4) Conclusion: While the present survey was conducted among doctors in Japan, previous studies have reported similar findings in the United States and Europe. Based on our analysis, we hypothesize that a relationship of trust between patients and medical personnel is crucial and that information manipulation is not needed when such a relationship has been established.

Influence of abdominal obesity and habitual behaviors on incident atrial fibrillation in Japanese.

BACKGROUND: As atrial fibrillation (AF) increases with the aging of the population, it is urgently required to clarify modifiable factors to prevent AF. However, evidence regarding the independent influence of abdominal-obesity and habitual behaviors on incident AF is limited among Japanese. METHODS AND RESULTS: Those aged 40-79 years undergoing periodic health checkups during 2008-2014 were followed-up in 2015 (n=96,841) and the independent risk of incident AF was estimated using multivariate Cox proportional hazards regression models after adjustment for potential covariates. Participants were classified into four groups according to the baseline body mass index (BMI: kg/m2) (normal-BMI or overweight: < or ≥25) and waist circumference (WC: cm) (normal-WC or abdominal-obesity: < or ≥85 for male, ≥90 for female). Baseline habitual behaviors, smoking status, alcohol intake, and physical activity, were also included as modifiable factors. Among 65,984 eligible participants, 349 developed AF over mean follow-up of 5.5±1.6 years. Increase of both BMI and WC significantly elevated the risk of AF. Compared to the normal-BMI and normal-WC group, the normal-BMI but abdominal-obesity and the overweight and abdominal-obesity groups in males and the overweight and abdominal-obesity group in females had significantly elevated risk of AF. Among modifiable behavioral factors including abdominal-obesity, alcohol intake (≥40g/day) and abdominal-obesity significantly elevated the risk of AF in males, and abdominal-obesity was the strongest risk factor in both sexes, but smoking and physical activity were not significant. However, an aggregation of these four behavioral factors increased the risk of AF more than 2.5 times in both sexes. CONCLUSIONS: Abdominal-obesity could be a crucial risk factor in prediction of AF in Japanese, and an aggregation of four behavioral factors increased the risk of AF almost three times. To prevent incident AF, practicing healthy habitual behaviors is recommended.

Effective cut-off values of waist circumference to detect the clustering of cardiovascular risk factors of metabolic syndrome in Japanese men and women.

The purpose of this study was to determine effective cut-off values of waist circumference (WC) to detect the clustering of cardiovascular risk factors (CCRF) in a Japanese population. The subjects were 2,476 men and women who participated in a health examination in Tokyo. The CCRF was defined according to the International Diabetes Federation (IDF) and the Japanese Committee of the Criteria for Metabolic Syndrome (JCCMS). The effective (accurate and sensitive) values were tested using the receiver operating characteristics analysis. The accurate (maximised sensitivity plus specificity) values were 81 cm and 80 cm using the IDF and JCCMS criteria for men, and 82 cm for both criteria for women. From the ROC curve, 85 cm was identified as an effective value for men. Thus, the effective cut-off value of WC for the Japanese should be approximately 85 cm for men and approximately 82 cm for women.

How do health behaviours relate to dietary practice patterns among Japanese adults?

BACKGROUND AND OBJECTIVES: To identify dietary practice patterns for Japanese adults and investigate the links between health behaviours and these patterns. METHODS AND STUDY DESIGN: A random sample, stratified according to area, sex, and age, of 4570 adults aged 20-80 years completed a survey conducted in 2011 in a city, in Yamagata Prefecture, Northeast Japan. RESULTS: Cluster analysis of 16 dietary practice items revealed four patterns labelled as: low fat, sugar, or salt; emphasis on nutrition; regular breakfast and staples; and meals not snacks. Findings from multiple linear regression analyses showed that those not engaged in habitual physical exercise had lower scores on low fat, sugar, or salt (beta coefficient -0.22: 95% confidence intervals -0.30, -0.14); emphasis on nutrition (-0.17: -0.25, -0.09); meals not snacks; (-0.38: -0.46, -0.3) that other participants. Current smokers had lower scores than never smokers on low fat, sugar, or salt (-0.23: -0.32, -0.14); emphasis on nutrition (-0.28: -0.37, -0.19); regular breakfast and staples (-0.42: -0.51, -0.33) patterns. Compared with nondrinkers, those who had reduced their consumption of alcohol had higher scores on low fat, sugar, or salt (0.19: 0.09, 0.29) and emphasis on nutrition (0.17: 0.07, 0.27). These relationships were adjusted for other dietary practice patterns, sociodemographic factors, body mass index, and the presence of major illness or pain. CONCLUSIONS: Findings support an integrated and targeted approach as part of public health policy by considering links between dietary practices and other health behaviours, such as habitual exercise and smoking behaviour that may facilitate changes in dietary practices.

Clustering patterns of obesity-related multiple lifestyle behaviours and their associations with overweight and family environments: a cross-sectional study in Japanese preschool children.

OBJECTIVES: The purpose of this study is (1) to identify obesity-related lifestyle behaviour patterns of diet, physical activity, sedentary and sleep behaviours in preschool children, (2) to examine the association between identified behaviour clusters and overweight/obesity and (3) to investigate differences in children's family environments according to clusters. DESIGN SETTING AND PARTICIPANTS: A cross-sectional study on 2114 preschool children aged 3-6 years who attended childcare facilities (24 nursery schools and 10 kindergartens) in Tsuruoka city, Japan in April 2003 was conducted. MAIN OUTCOME MEASURES: Children's principal caregivers completed a questionnaire on children's lifestyle behaviours (dinner timing, outside playtime, screen time and night-time sleep duration), family environment (family members, maternal employment, mealtime regularity and parents' habitual exercise and screen time) and measurements of weight and height. Cluster analysis was performed using children's 4 lifestyle behaviours based on those non-missing values (n=1545). The χ2 tests and analysis of variance (ANOVA) estimated cluster differences in overweight/obesity and family environments. RESULTS: 6 clusters were identified. Children's overweight/obesity varied across clusters (p=0.007). The cluster with the most screen time, shorter night-time sleep duration, average dinner timing and outside playtime had the highest overweight/obesity prevalence (15.1%), while the cluster with the least screen time, the longest sleep duration, the earliest dinner timing and average outside playtime had the lowest prevalence (4.0%). Family environments regarding mealtime regularity and both parents' screen time also significantly varied across clusters. The cluster having the highest overweight/obesity prevalence had the highest proportion of irregular mealtimes and the most screen time for both parents. CONCLUSIONS: This study suggests that public health approaches to prevent children's overweight/obesity should focus on decreasing screen time and increasing night-time sleep duration. To shape those behaviours, regular mealtimes and decreasing parents' screen time within family environments need to be targeted among family members.

Combined eating behaviors and overweight: Eating quickly, late evening meals, and skipping breakfast.

OBJECTIVE: Various eating behaviors have been linked with body weight management. However, combined effects of major eating behaviors are not fully understood. This study aimed to clarify the association of the combination of eating quickly (EQ), late evening meals (LEM), and skipping breakfast (SB) with being overweight. METHOD: A cross-sectional study with standardized questions for EQ, LEM, and SB was conducted. Stratified random sampling of 5% of residents aged 20 to 80years was surveyed in a city in northeast Japan in 2011, and 4249 (84.9%) residents were analyzed. Association of combinations of eating behaviors on being overweight (BMI (kg/m(2)≥25.0)) was estimated by using logistic analysis, and odds ratio (OR) and 95% confidential interval were calculated after adjustment for potential covariates. RESULTS: LEM, SB, or a combination of LEM and SB was not significantly associated with being overweight. However, the combination of EQ or only EQ was significantly associated with being overweight. As the number of eating behavior practices increased, there was a linear increase in OR for being overweight. The OR of all three combined eating behaviors was higher than that of any combined two behaviors or of each behavior. DISCUSSION: This study result supports the evidence that EQ increases the risk of being overweight whether by itself or in combinations with LEM and/or SB. However, only LEM or only SB did not increase the risk of being overweight.

Identification of a domain conferring nucleotide binding to the N-acetyl-d-glucosamine 2-epimerase (Renin binding protein).

Renin binding protein (RnBP), a cellular renin inhibitor, has been identified as the enzyme N-acetyl-D-glucosamine (GlcNAc) 2-epimerase. Our recent studies demonstrated that rat GlcNAc 2-epimerase has a ten-times higher affinity for ATP, dATP, and ddATP than the human enzyme [Takahashi, S. et al. (2001) J. Biochem. 130, 815-821]. To identify the domain conferring nucleotide binding to GlcNAc 2-epimerase, we constructed a series of chimeric enzymes successively replacing the three domains of the human enzyme (N-terminal, middle, and C-terminal domains) with the corresponding domains of the rat enzyme. Chimeras were expressed in Escherichia coli JM109 cells under the control of the Taq promoter. The purified chimeric enzymes had GlcNAc 2-epimerase activity and inhibited renin activity in a dose-dependent manner. The recombinant human and rat enzymes required catalytic amounts of ATP with apparent K(m) values of 73 and 5.5 microM, respectively. Chimeric enzymes of HHR, RHH, and RHR (H, human type domain; R, rat type domain) had nearly the same nucleotide specificity as the human GlcNAc 2-epimerase. On the other hand, HRR, HRH, and RRH chimeras had the same nucleotide specificity as the rat enzyme. These results indicate that the middle domain of the GlcNAc 2-epimerase molecule participates in the specificity for and binding of nucleotides, and that nucleotides are essential to form the catalytic domain of the enzyme.

The alteration of odor-induced c-Fos immunoreactivity in the rat olfactory bulb after olfactory nerve transection.

We used the rats in which one olfactory nerve had been transected and observed the odor (Propionic acid) -induced c-Fos immunoreactivity in the bulb at different times (2, 4, 8 weeks) after nerve transection. The exposure to odor produced a strong cluster of c-Fos positive cells in the mediodorsal region of the intact bulb. On the other hand, the transected bulb showed much less reactivity 2 weeks after neurectomy; however, a large number of positive cells were observed in the whole of the bulb from 4 weeks after neurectomy. Furthermore, we measured the levels of mRNA for tyrosine hydroxylase (TH), which was the marker of odor-induced olfactory nerve activity in the bulb, by using real-time PCR. The level of TH mRNA decreased on the transected side at 2 weeks but recovered to the level of the contralateral side at 4 weeks after neurectomy. We firstly demonstrated that projection mapping of odor receptors was altered after olfactory nerve transection by using an immunohistochemical method.

Phylogenetic analysis of Lactococcus lactis subspecies based on decoding the sequence of the pepT tripeptidase gene, the pepV dipeptidase gene and 16S rRNA.

Tripeptidase (PepT) and dipeptidase (PepV), the enzymes located in the final stage of the intracellular proteolytic system, were demonstrated to be distributed widely in lactic acid bacteria, especially in lactococci. Both the tripeptidase genes (pepT) and dipeptidase genes (pepV) of 15 lactococcal strains consisting of the type and domestic strains were cloned and sequenced using normal and TAIL PCR methods. Amino acid sequences of these enzymes were highly conserved among strains. Evolutionary distance trees based on the sequence of 1239 nucleotides of pepT and 1416 nucleotide of pepV showed a similar cluster as that obtained from the 1499 fragment of the 16S rRNA. Based on this profile, the species Lactococcus lactis is reasonably divided into three subspecies groups, subsp. lactis, cremoris, and hordniae, as in the current classification. Figure of trees from pepT and pepV were essentially identical to each other and slightly more intricate than that from 16S rRNA. The K nuc values obtained from pepT and pepV genes were approximately ten times as high as that from 16S rRNA. Considering these results, phylogenetic analysis based on pepT and pepV genes may aid in a more precise index of classification of L. lactis subspecies. PepT and PepV seem to have evolved in similar directions in lactococci.

Modulation of T-cell functions by laser surgery in patients with allergic rhinitis.

OBJECTIVE: Potassium-titanyl-phosphate (KTP) laser turbinectomy is an established treatment for hypertrophied inferior turbinates that do not respond to other medical treatments. KTP laser surgery is usually performed with the aim of reducing the size of hypertrophied inferior turbinates. We hypothesized that laser vaporation may also inhibit the allergic reaction in the nasal mucosa of inferior turbinates. MATERIAL AND METHODS: We examined the effect of KTP laser therapy on T-cell responses using peripheral blood mononuclear cells (PBMCs). RESULTS: Levels of T-cell proliferation after stimulation with Staphylococcus enterotoxin B (SEB) were higher in post- than pre-surgery patients. Levels of interferon-gamma and IL-2 produced by PBMCs after stimulation with SEB appeared to be higher in post- than pre-surgery patients. Serum levels of house dust-specific IgE were lower in post- than pre-surgery patients. These results indicate that KTP laser therapy modulates T-cell responses and probably tilts the Th1/Th2 balance towards the Th1-dominant state. CONCLUSION: KTP laser surgery eases or cures allergic rhinitis not only by reducing the volume of the inferior turbinates but also by modulating T-cell functions.

Distinct impact of education and income on habitual exercise: a cross-sectional analysis in a rural city in Japan.

Education and income are important socioeconomic indicators that reflect different aspects of social hierarchy. However, only a few studies have explicitly examined how different the relationship between education and health behaviour is from that between income and health behaviour. According to the human capital theory of health investment, education would reflect knowledge assets that allow an efficient investment in health, while income would relate to the value of healthy days and/or the time cost of health investment. Since time cost and the relative price of health would differ across age strata, we examined the significance of effect modification by age strata to distinguish the effects of education on habitual exercise from the effects of income. A cross-sectional survey was conducted using a self-administered questionnaire in a rural city in northern Japan in January 2007 (n = 3385). Logistic regression analyses were conducted to assess the association of educational attainment and household income with habitual exercise. Interaction terms of these socioeconomic indicators with age strata (<60 years versus ≥60 years) were included to test the distinctive association across age, followed by a stratified analysis. As theoretically predicted, higher income was significantly associated with habitual exercise among those aged 25-59 years, while the association was null or negative among those aged 60 and above. Education was significantly associated with habitual exercise regardless of the age groups. These results suggest that the effects of socioeconomic factors on health behaviours vary according to which socioeconomic indicators are analysed, and which age group is selected. We conclude that studies on the socioeconomic disparity of health behaviours should carefully choose socioeconomic indicators to explain specific health behaviours to reveal underlying mechanisms and provide relevant policy implications, based on explicit behavioural models.