Proof of concept testing of a positive reference material for in vivo and in vitro sensitization testing of medical devices.

In vivo skin sensitization tests are required to evaluate the biological safety of medical devices in contact with living organisms to provide safe medical care to patients. Negative and positive reference materials have been developed for biological tests of cytotoxicity, implantation, hemolysis, and in vitro skin irritation. However, skin sensitization tests are lacking. In this study, polyurethane sheets containing 1 wt/wt % 2,4-dinitrochlorobenzene (DNCB-PU) were developed and evaluated as a positive reference material for skin sensitization tests. DNCB-PU sheet extracts prepared with sesame oil elicited positive sensitization responses for in vivo sensitization potential in the guinea pig maximization test and the local lymph node assay. Furthermore, DNCB-PU sheet extracts prepared with water and acetonitrile, 10% fetal bovine serum-containing medium, or sesame oil elicited positive sensitization responses as alternatives to animal testing based on the amino acid derivative reactivity assay, human cell line activation test, and epidermal sensitization assay, respectively. These data suggest that the DNCB-PU sheet is an effective extractable positive reference material for in vivo and in vitro skin sensitization testing in medical devices. The formulation of this reference material will lead to the development of safer medical devices that contribute to patient safety.

Clinical and Pathophysiological Features of High-altitude Pulmonary Edema in the Japanese Population: A Review of Studies on High-altitude Pulmonary Edema in Japan.

High-altitude pulmonary edema (HAPE) is a life-threatening, noncardiogenic pulmonary edema that occurs in unacclimatized individuals rapidly ascending to high altitudes above 2,500 m above sea level. Until the entity of HAPE was first identified in a case report published in Japan in 1966, the symptoms of severe dyspnea or coma occurring in climbers of the Japan Alps were incorrectly attributed to pneumonia or congestive heart failure. The Shinshu University Hospital serves as the central facility for rescuing and treating patients with HAPE in the region. Over the past 50 years, a series of studies have been conducted at Shinshu University to gain a better understanding of the characteristics of HAPE. This review summarizes the major achievements of these studies, including their clinical features, management, and pathogenesis of HAPE, particularly in the Japanese population.

Effects of work-family life support program on the work-family interface and mental health among Japanese dual-earner couples with a preschool child: A randomized controlled trial.

OBJECTIVES: This study examined the effectiveness of a newly developed work-family life support program on the work-family interface and mental health indicators among Japanese dual-earner couples with a preschool child(/ren) using a randomized controlled trial with a waitlist. METHODS: Participants who met the inclusion criteria were randomly allocated to the intervention or the control groups (n = 79 and n = 85, respectively). The program comprised two 3-h sessions with a 1-month interval between them and provided comprehensive skills by including self-management, couple management, and parenting management components. The program sessions were conducted on weekends in a community center room with 3-10 participants. Outcomes were assessed at baseline, 1-month, and 3-month follow-ups. Primary outcomes were work-family balance self-efficacy (WFBSE), four types of work-family spillovers (i.e., work-to-family conflict, family-to-work conflict, work-to-family facilitation, and family-to-work facilitation), psychological distress, and work engagement reported by the participants. RESULTS: The program had significantly pooled intervention effects on WFBSE (P = .031) and psychological distress (P = .014). The effect sizes (Cohen's d) were small, with values of 0.22 at the 1-month follow-up and 0.24 at the 3-month follow-up for WFBSE, and -0.36 at the 3-month follow-up for psychological distress. However, the program had nonsignificant pooled effects on four types of work-family spillovers and work engagement. CONCLUSIONS: The program effectively increased WFBSE and decreased psychological distress among Japanese dual-earner couples with a preschool child(/ren).

Retrospective quantitative risk assessment of skin sensitization caused by an antimicrobial agent used in a consumer product: 2,3,5,6-Tetrachloro-4-(methylsulfonyl) pyridine.

BACKGROUND: Serious cases of allergic contact dermatitis (ACD) caused by exposure to 3,5,6-tetrachloro-4-(methylsulfonyl)pyridine (TCMSP; CAS no. 13108-52-6) used as an antimicrobial agent for desk mats have been reported in Japan. OBJECTIVE: A quantitative risk assessment (QRA) of TCMSP contained in desk mats was performed retrospectively. MATERIALS AND METHODS: A local lymph node assay (LLNA): BrdU-ELISA was conducted to determine a reliable EC1.6 value for TCMSP. The acceptable exposure level (AEL) for TCMSP was derived from the EC1.6 value by applying sensitization assessment factors (SAFs). The exposure level was estimated based on the assumption referring to the use conditions of thiabendazole in the same purpose. Then, the estimated exposure level was compared with the AEL to evaluate the skin sensitization risk. RESULTS: The AEL was calculated as 0.00458 µg/cm2 based on the EC1.6 value (0.011%, 2.75 µg/cm2 ) by applying a composite SAF of 600. The estimated TCMSP exposure level from the desk mat was 500 times greater than the AEL, indicating a serious skin sensitization risk. CONCLUSIONS: Assessments of skin sensitization potencies of chemicals to be used in consumer products are strongly recommended, and QRAs should be performed at the pre-marketing stage to avoid the skin sensitization risk in consumers.

Time-course analysis of pulmonary inflammation induced by intratracheal instillation of nanosized crystalline silica particles in F344 rats.

Crystalline silica is an important cause of serious pulmonary diseases, and its toxic potential is known to be associated with its surface electrical properties. However, in vivo data clarifying the relevance of silica's toxic potential, especially its long-term effects, remain insufficient. To investigate the contribution of physico-chemical property including surface potential on the hazard of nanocrystalline silica, we performed single intratracheal instillation testing using five different crystalline silicas in a rat model and assessed time-course changes in pulmonary inflammation, lung burden, and thoracic lymph node loads. Silica-nanoparticles were prepared from two commercial products (Min-U-Sil5 [MS5] and SIO07PB [SPB]) using three different pretreatments: centrifugation (C), grinding (G), and surface dissolving (D). The five types of silica particles-MS5, MS5_C, SPB_C, SPB_G, and SPB_D-were intratracheally instilled into male F344 rats at doses of 0 mg/kg (purified water), 0.22 mg/kg (SPB), and 0.67, 2, or 6 mg/kg (MS5). Bronchoalveolar lavage, a lung burden analysis, and histopathological examination were performed at 3, 28, and 91 days after instillation. Granuloma formation was present in MS5 group at 91 days after instillation, although granuloma formation was suppressed in MS5_C group, which had a smaller particle size. SPB_C induced severe and progressive inflammation and kinetic lung overload, whereas SPB_G and SPB_D induced only slight and transient acute inflammation. Our results support that in vivo toxic potential of nanosilica by intratracheal instillation may involve with surface electrical properties leading to prolonged effect and may not be dependent not only on surface properties but also on other physico-chemical properties.

Development of a Japanese Version of the Index of Sexual Satisfaction for Use in Couples with Young Children.

The occurrence of sexual dysfunction in couples after childbirth is well recognized, yet sexual satisfaction in couples with young children (CYC) has received little research attention. This study sought to enable this construct to be measured by developing and validating a Japanese version of the Index of Sexual Satisfaction (ISS) in CYC. Data were collected using a self-administered questionnaire. Scale construction and validation were conducted using two independent samples drawn from 316 mothers and 272 fathers in Japan who had at least one child aged 6 or younger. Two underlying factors were identified using exploratory factor analysis: sexual satisfaction, measured by eight items, and sexual dissatisfaction, measured by three. Polychoric ordinal alpha coefficients indicated the reliability of the resulting scale (overall: 0.89, factor 1: 0.89, factor 2: 0.78), and confirmatory factor analysis and testing supported its validity, showing good model fit (goodness of fit index: 0.984, root mean square residual: 0.062) and satisfactory composite reliability (scale: 0.93, factor 1: 0.90, factor 2: 0.81) and average variance extracted (all ≥0.5). The Japanese version of the ISS for Couples with Young Children will be useful for investigating sexual satisfaction, which is essential to marital stability.

A New Health Promotion Program That Includes Wadaiko Rhythm Exercise to Maintain the Health of Persons Excluded from Receiving Specific Health Guidance.

This study examined the effectiveness of a new health promotion program, which is a collective intervention program aimed at improving lifestyle habits. It was designed as a one-year prospective cohort study. This program targeted non-obese persons at risk of developing lifestyle-related diseases and participants with hypertension, dyslipidemia, or hyperglycemia who were not included in the specific health guidance system in Japan. The Wadaiko rhythm exercise, which is a traditional performing art, is incorporated into this intervention as an enjoyable routine that can help participants continue the program, preventing them from dropping out. After a one-year follow-up, the effectiveness of the health promotion program was evaluated in 18 participants (2 males, 16 females; mean age 65.2 ± 3.4 years) and 92 controls. The results showed that triglyceride in the intervention group significantly decreased (−24.5 mg/dL; p = 0.02; 95% confidence interval [CI], −44.73 to −4.27) and high-density lipoprotein cholesterol significantly increased (+6.1 mg/dL; p < 0.01; 95% CI, 2.46 to 9.65), although levels in the control group did not change. These results suggest that the health promotion program could contribute to lifestyle habit improvements in those who are excluded from receiving specific health guidance.

Effects of soy protein isolate and soy peptide preload on gastric emptying rate and postprandial glycemic control in healthy humans.

BACKGROUND: This study aims to compare the effects of soy protein isolate (SPI) and soy peptide (PEP) preload 30 min before a 75-g oral glucose tolerance test (OGTT) on the gastric emptying rate, plasma insulin, and blood glucose responses. METHODS: Nine healthy young subjects were evaluated on four occasions. The participants consumed a 200-ml solution containing either 20 g of SPI or PEP in experiment 1. In experiment 2, 30 min after consuming either 20 g of SPI or PEP solutions, an OGTT was performed to evaluate the individual glycemic response. The gastric emptying rate was measured by the 13C-sodium acetate breath test. Blood glucose and plasma insulin were measured before and after consuming either the SPI or PEP solutions and during the OGTT. RESULTS: In experiment 1, plasma insulin levels were higher 30 min after consuming the PEP solution than after the SPI solution. PEP resulted in a faster gastric emptying rate than SPI. In experiment 2, just before performing the OGTT, the plasma insulin response was higher for PEP than for SPI. Fifteen minutes after starting the OGTT, the blood glucose response was lower after consuming PEP than after SPI. The gastric emptying rate tended to be faster after consuming PEP than after SPI (p = 0.08). CONCLUSION: A PEP preload might be slightly more effective for the suppression of postprandial blood glucose excursion compared with SPI; thus, a PEP preload potentially induces an enhanced insulin response just before the OGTT.

Time-course comparison of pulmonary inflammation induced by intratracheal instillation of four different nickel oxide nanoparticles in male Fischer rats.

Occupational exposure to nickel oxide (NiO) is an important cause of respiratory tract cancer. Toxicity is known to be associated with the dissociated component, i.e. nickel (II) ions. To address the relationship between physicochemical properties, including solubility in artificial lysosomal fluid, of NiO and time-course changes in the pulmonary response, we conducted an intratracheal instillation study in male Fischer rats using four different well-characterized NiO products, US3352 (NiO A), NovaWireNi01 (NiO B), I small particle (NiO C), and 637130 (NiO D). The NiOs were suspended in purified water and instilled once intratracheally into male F344 rats (12 weeks old) at 0 (vehicle control), 0.67, 2, and 6 mg/kg body weight. The animals were euthanized on days 3, 28, or 91 after instillation, and blood analysis, bronchoalveolar lavage fluid (BALF) testing, and histopathological examination were performed. The most soluble product, NiO B, caused the most severe systemic toxicity, leading to a high mortality rate, but the response was transient and surviving animals recovered. The second-most-soluble material, NiO D, and the third, NiO A, caused evident pulmonary inflammation, and the responses persisted for at least 91 days with collagen proliferation. In contrast, NiO C induced barely detectable inflammation in the BALF examination, and no marked changes were noted on histopathology. These results indicate that the early phase toxic potential of NiO products, but not the persistence of pulmonary inflammation, is associated with their solubility.

Comparative analysis of sperm motility in liquid and seminal coagulum portions between Bornean orangutan (Pongo pygmaeus) and chimpanzee (Pan troglodytes).

Coagulum in the semen of some primates plays different roles, depending on the species. In the present study, we examined sperm motility in the coagulum and liquid portions of semen collected from captive individuals from two great ape species: two adult Bornean orangutans (Pongo pygmaeus) (n = 27) and three adult chimpanzees (Pan troglodytes) (n = 14). The results revealed that orangutan sperm remained motile for significantly longer in the coagulum than in the liquid portion (> 18 h). By contrast, chimpanzee sperm motility did not differ significantly over time between the two portions of the semen, although motility was slightly higher in the liquid portion than in the coagulum. The evolution of the seminal coagulum is thought to be related to postcopulatory sperm competition; however, functions of seminal coagulum have not been completely elucidated. Our data from the orangutan semen suggest that in this species, seminal coagulum may strengthen own-sperm survival. This report is the first to provide evidence for this distinctive function of the seminal coagulum. This unique property of orangutan seminal coagulum might be attributable to their reproductive traits, e.g., difficulty in predicting ovulation due to a lack of genital swelling during estrus. The orangutan is a Critically Endangered species, and captive breeding, including artificial insemination (AI), is expected. However, worldwide, only one case of orangutan AI has been successful. Our findings may contribute to an understanding of their basic semen characteristics and help improve the AI method.

Development of a relational workplace social capital scale for Japanese nurses.

BACKGROUND: Although nurses' workplace social capital for a healthy work environment has received considerable attention, few scales about nurses' workplace social capital are based on the attributes of clinical settings in Japan. This study aims to develop a Relational Workplace Social Capital Scale for Japanese Nurses (RWSCS-JN), which includes bonding, linking, and bridging social capital and assessing its reliability and validity. METHODS: We assessed its reliability and validity using questionnaire survey data collected from 309 nurses in the first survey and 105 nurses in the second survey in four hospitals in Japan. First, we determined the number of factors and items for the RWSCS-JN through the parallel and factor analyses after conducting the item analysis. Then, we confirmed the omega coefficients and intraclass correlation coefficients (ICC) of the RWSCS-JN. Finally, we examined the Pearson product-moment correlation coefficient between the RWSCS-JN score and other variables, including an existing measurement of workplace social capital, work engagement, and turnover intention. RESULTS: The newly developed RWSCS-JN contained 15 items, comprising three factors as follows: bonding social capital, linking social capital, and bridging social capital. The omega coefficient and the ICC of the RWSCS-JN were 0.90 and 0.85, respectively. The Pearson product-moment correlation coefficient between the RWSCS-JN and the existing scale of the workplace social capital was 0.88 (p < 0.01). Furthermore, the Pearson product-moment correlation coefficient between the RWSCS-JN and work engagement was 0.36 (p < 0.01) and that of the RWSCS-JN and turnover intention was - 0.40 (p < 0.01). CONCLUSIONS: This study suggests that the RWSCS-JN could be sufficiently useful for a healthy work environment in a clinical setting.

Timing of Nutrient Ingestion after Mild to Moderate Cycling Exercise Does Not Affect Gastric Emptying Rate in Humans.

This study examined the effect of carbohydrate drink ingestion timing on gastrointestinal tract blood flow and motility after mild cycling exercise. Eight healthy participants were randomly assigned to ingest a liquid solution with 75 g glucose at either 5 min (PE-5) or 30 min (PE-30) after a single bout of leg cycling exercise according to target heart rate (approximately 120 beats/min). As the control trial (Con), participants ingested the same liquid solution without exercise. Celiac artery blood flow (BF), superior mesenteric artery BF, and gastric emptying rate were assessed by ultrasonography before and for 60 min after ingesting the glucose solution. Blood lactate, glucose, and plasma insulin were also measured at baseline and for 60 min after ingesting the glucose solution. Celiac artery BF significantly decreased from resting baseline immediately after exercise in both the PE-5 and PE-30 trials, and then returned to resting baseline just before the ingestion of glucose solution in the PE-30 trial. After ingesting the glucose solution, changes in celiac artery BF, superior mesenteric artery BF, % gastric emptying rate, blood lactate, blood glucose, and plasma insulin were not significantly different among the three trials. The timing of nutrient ingestion after mild exercise does not seem to impact the subsequent gastrointestinal motility, blood flow, and glycemic responses.

Inter-laboratory comparison of pulmonary lesions induced by intratracheal instillation of NiO nanoparticle in rats: Histopathological examination results.

OBJECTIVE: In this study, in order to investigate the usefulness of intratracheal instillation in assessing the pulmonary toxicity of nanomaterials, intratracheal instillation of nickel oxide-nanoparticles (NiO-NP) was performed. METHODS: In this study, rats were administered test materials by intratracheal instillation at five different research institutions in order to assess the validity of using intratracheal instillation for hazard identification of nanomaterials. Eight-week-old male SD rats were administered NiO-NP dispersed in deionized water by a single intratracheal instillation at doses of 0 (vehicle control), 0.2, 0.67, and 2 mg/kg BW. Three days after instillation, histopathological examination of the lungs was performed. RESULTS: NiO-NP was distributed in the vicinity of hilus of the lung and in the alveoli around the bronchioles. Histopathological changes such as degeneration/necrosis of macrophages, inflammation, and proliferation of type II pneumocyte in the lung were observed, and their severity corresponded with increasing dose. The histopathological observations of pulmonary toxicity were almost similar at each institution. CONCLUSION: The similarity of the histopathological changes observed by five independent groups indicates that intratracheal instillation can be a useful screening method to detect the pulmonary toxicity of nanomaterials.

Applicability of the proposed GHS subcategorization criterion for LLNA:BrdU-ELISA (OECD TG442B) to the CBA/J strain mouse.

The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is a hazard classification and communication system for providing information on the safe handling of chemicals worldwide. In this study, we evaluated the applicability of the newly proposed GHS subcategorization criterion for murine local lymph node assay:2-bromodeoxyuridine enzyme-linked immunosorbent assay (LLNA:BrdU-ELISA), Category 1A:EC1.6 ≤6%, Category 1B:EC1.6 >6%, to data derived from LLNA:BrdU-ELISA performed in the CBA/J strain mouse. Fifteen chemicals categorized in GHS hazard Category 1 sensitizers listed in the LLNA performance standard were tested by LLNA:BrdU-ELISA in the CBA/J strain mouse and were classified according to the new criterion. The results revealed that all of the GHS 1A or 1B category chemicals classified according to the EC3 values derived from radioisotopic LLNA (LLNA-RI) could be correctly assigned into the respective 1A and 1B categories using the newly proposed GHS subclassification criterion. In addition, analysis of the correlation between the reported EC3 values and EC1.6 values derived from the LLNA:BrdU-ELISA performed in the CBA/J strain mouse confirmed the existence of a strong correlation (r = 0.9076, P < .0001). These findings suggest that the newly proposed GHS subcategorization criterion for LLNA:BrdU-ELISA is potentially applicable for practical use in GHS subcategorization.

Predicting Healthy Lifestyle Behaviours Among Patients With Type 2 Diabetes in Rural Bali, Indonesia.

BACKGROUND: Type 2 diabetes is a lifelong metabolic disease closely related to unhealthy lifestyle behaviours. This study aimed to identify factors explaining the healthy lifestyle behaviours of patients with type 2 diabetes in rural Indonesia. The extended health belief model, demographic characteristics, clinical lifestyle factors and diabetes knowledge were investigated to provide a complete description of these behaviours. METHOD: A sample of 203 patients with type 2 diabetes representing a cross-section of the population were recruited from community health centres in the rural areas of Bali province. The data were collected through questionnaires. Descriptive statistics and a hierarchical regression test were employed. RESULTS: This study showed demographic characteristics, clinical and lifestyle factors, diabetes knowledge and the extended health belief model accounted for 71.8% of the variance in healthy lifestyle behaviours of patients with type 2 diabetes in rural Indonesia. The significant demographic factors were age, education level, employment status and traditional beliefs. The significant clinical and lifestyle factors were alcohol use, diabetic medicine and duration of symptoms. Finally, the significant extended health belief model factors were perceived severity, susceptibility, barriers, family support, bonding social capital and chance locus of control. CONCLUSIONS: The extended health belief model forms an adequate model for predicting healthy lifestyle behaviours among patients with diabetes in rural Indonesia. The contribution of this model should be strengthened in developing the diabetes management.

Do multiple personal roles promote working energetically in female nurses? A cross-sectional study of relevant factors promoting work engagement in female nurses.

BACKGROUND: Like most women, female nurses in the workforce experience life events such as marriage, childbirth, and child-rearing, and carry out numerous personal roles. This may result in an increase in various demands for nurses, and coping with these roles may promote work engagement. However, few studies have focused on work engagement or spillover effects, including those in the family domain, in female nurses with multiple roles. In the present study, we aimed to examine work engagement in female nurses and investigate its relationship with factors such as the presence or absence of multiple personal roles. METHODS: The subjects of this study were 1225 female nurses working at three general hospitals, each with at least 200 hospital beds in Fukuoka Prefecture, Japan. The cross-sectional design of the study used anonymous self-administered questionnaires. Responses were received from 650 nurses (response rate 53.1%), of which 612 were valid (valid response rate 50.0%). Multiple regression analysis was performed on the 612 responses regarding associations between work engagement and the presence or absence of multiple roles (role as a wife or mother), spillover effects, coping characteristics, job demands, and job resources. RESULTS: In general, the work engagement of female nurses was low, as is the case with other female workers in Japan, but work engagement was higher among female nurses with multiple roles than among those without. The regression analysis showed that factors associated with better work engagement in female nurses were family-to-work positive spillover, job resources, coping strategies including "changing a point of view," "active solution for problems," "avoidance and suppression," and the presence of multiple roles. CONCLUSIONS: The results indicate that in addition to resources in the work domain, a family-to-work positive spillover effect, which is a variable in the non-work domain, may also promote energetic work among female nurses. Therefore, it is necessary for nurses to receive support at work and use effective coping strategies.

Suppression of sweet sensing with glucose, but not aspartame, delays gastric emptying and glycemic response.

Previously, we reported that oral stimulation with Gymnema sylvestre (GS), a plant that selectively suppresses sweet taste sensation in humans, delayed gastric emptying and glycemic response during and after oral glucose ingestion. It is unclear whether these responses are triggered by sweet taste sensing per se. We tested the hypothesis that the effects of sweet taste sensing involving a low-energy sweetener, aspartame, alters gastric emptying, blood glucose, and plasma insulin responses during and after the prandial phase. Nine participants rinsed their mouths with either 25 mL of water (control) or a 2.5% GS solution, and then ingested 200 g (50 g × four times) of either 0.09% aspartame or 15% glucose solution containing 100 mg of 13C-sodium acetate. Gastric emptying was measured with a 13C breath test. Blood glucose and plasma insulin were measured at baseline as well as during and after ingestion of the sweet solutions. Decreased subjective sweet taste intensity was observed in the GS group for both the aspartame and glucose trials. In the aspartame trial, no measurements showed significant differences between either group. In the glucose trial, gastric emptying was delayed in the GS group compared to controls. In the initial phase, both during and after glucose ingestion in the glucose trial, blood glucose and plasma insulin responses were lower in the GS group than the controls. The presence or absence of sweet taste-sensing involving glucose had a significant effect on gastric emptying and glycemic metabolism, both during and after the prandial phase, as opposed to the effects involving aspartame.

A comparative study of the physiological and psychological effects of forest bathing (Shinrin-yoku) on working age people with and without depressive tendencies.

BACKGROUND: In recent years, many of Japanese workers have complained of fatigue and stress, considering them as risk factors for depression. Studies have found that "forest bathing" (Shinrin-yoku) has positive physiological effects, such as blood pressure reduction, improvement of autonomic and immune functions, as well as psychological effects of alleviating depression and improving mental health. In this study, we investigate the physiological and psychological effects of "forest bathing" on people of a working age with and without depressive tendencies. METHODS: We conducted physiological measurements and psychological surveys before and after forest bathing with subjects who participated in day-long sessions of forest bathing, at a forest therapy base located in Hiroshima Prefecture. After excluding severely depressed individuals, the participants were classified into two groups: those with depressive tendencies (5 ≤ K6 ≤ 12) and those without depressive tendencies (K6 < 5) for comparative study. The evaluation indices measured were systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse rate (PR), autonomic functions, and profile of mood states (POMS). RESULTS: Of the 155 participants, 37% had depressive tendencies, without any differences observed between males and females. All participants showed significant decrease in SBP, DBP, and in negative POMS items after a forest bathing session. Before the session, those with depressive tendencies scored significantly higher on the POMS negative items than those without depressive tendencies. After forest bathing, those with depressive tendencies demonstrated significantly greater improvement in many of POMS items than those without depressive tendencies, and many of them no longer differed between those with and without depressive tendencies. CONCLUSIONS: Examining the physiological and psychological effects of a day-long session of forest bathing on a working age group demonstrated significant positive effects on mental health, especially in those with depressive tendencies. Not applicable; this is not a report of intervention trial.

Factors Associated With Mental Health Status Among Older Primary Caregivers in Japan.

This study aimed to elucidate factors affecting the mental health status of older primary caregivers. Participants comprised 81 pairs of home care recipients aged ≥65 years and primary caregivers aged ≥65 years who were caring for the recipients. We used an individual interview method, which covered basic attributes, activities of daily living by Barthel Index, mental health status by Center for Epidemiologic Studies Depression Scale (CES-D), sense of coherence (SOC), and sense of care burden by Japanese version of the Zarit Burden Interview (J-ZBI). The score for the comprehensibility subscale of the SOC was significantly higher for the old-old caregivers compared with the young-old caregivers (P < .01). A significant positive correlation between the number of years of caregiving and the score for the SOC meaningfulness subscale was seen for the young-old caregivers (P < .05). For the old-old caregivers alone, negative correlations were seen between the CES-D score and the scores for all the SOC items. Multiple linear regression analysis using CES-D as the dependent variable showed a significant positive relationship to J-ZBI in all caregivers (P < .01). In contrast, a significant negative relationship was seen with meaningfulness, an SOC subscale only for the old-old caregivers. Meaningfulness as well as J-ZBI was extracted as a factor affecting the mental health status of the old-old caregivers, suggesting that higher SOC relates to lower stress levels with a remarkable decline in physical condition. Meaningfulness, an SOC subscale, is an important factor for improving the mental health of old-old caregivers.