[Association between social jetlag and presenteeism in Japanese industry: A cross-sectional study].

OBJECTIVES: Research suggests that misalignment of the biological clock and social time, referred to as social jetlag (SJL), can induce physical and mental disorders. SJL may also be associated with presenteeism (i.e., a state in which workers are unable to perform sufficiently due to mental and physical health problems, even though they are going to work). However, the association between SJL and presenteeism among workers in Japan remains unclear. This study aimed to verify the following hypotheses in a sample of workers in an industrial setting in Japan: "Workers exhibiting SJL have a high degree of work functioning impairment due to presenteeism" and "An association between SJL and presenteeism exists, even when taking work style and sleep-related factor into consideration." METHODS: A self-administered questionnaire survey was conducted with 1,573 workers in the manufacturing industry. Of these, 1,501 participants responded (response rate: 95.4%). Individuals who provided invalid answers or used alarm clocks to wake on work-free days were excluded, according to the Munich Chronotype Questionnaire (MCTQ) guidelines. The final sample comprised 980 participants (80.7% male; average age: 44.4 [SD 11.3] years). SJL was assessed using the MCTQ. Presenteeism was measured using the work functioning impairment scale. Using presenteeism as the dependent variable, we conducted hierarchical multiple regression analyses to compare the explanatory power of the different models. Independent variables were SJL, daily rest period between workdays, weekday sleep duration, and subjective insomnia. Models 2 and 3 were adjusted for age, sex, employment position, occupation, employment status, and working regulations. RESULTS: Multiple regression analyses indicated that SJL was significantly and individually associated with presenteeism (ß = .066, p = .038). After adjusting for work- and sleep-related variables (Models 2 and 3), SJL no longer contributed significantly to presenteeism. In the final model, daily rest periods (ß = .076, p = .017) and subjective insomnia (ß = .470, p < .001) remained significantly associated with presenteeism (adjusted R2 = .239). CONCLUSIONS: The hypothesis "Workers experiencing SJL have a high degree of work functioning impairment due to presenteeism" was supported in our univariate analysis. However, after considering the influence of subjective insomnia and daily rest periods, the association disappeared. Therefore, a direct relationship between SJL and presenteeism is not supported. Thus, the risk of presenteeism should be considered in two stages, first confirming the perception of insomnia among workers who experience SJL, and then considering the possibility of presenteeism occurring.

Health-related behaviors associated with subjective sleep insufficiency in Japanese workers: A cross-sectional study.

OBJECTIVES: Sleep disturbances are related to somatic and mental disorders, industrial accidents, absenteeism, and retirement because of disability. We aimed to identify health-related behaviors associated with subjective sleep insufficiency in Japanese workers. METHODS: This cross-sectional study included 5,297 employees (mean age: 43.6±11.3 years; 4,039 men). Multiple logistic regression analysis was used to identify health-related behaviors associated with subjective sleep insufficiency. RESULTS: Overall, 28.2% of participants experienced subjective sleep insufficiency. There was a significant difference between the genders in the proportion of participants with subjective sleep insufficiency (male: 26.4%; female: 34.3%; p<0.001). Multiple logistic regression analysis revealed that being a female or ≥40 years, experiencing a weight change of ≥3 kg during the preceding year, not exercising regularly, not walking quickly, and eating a late-evening or fourth meal were associated with subjective sleep insufficiency. After stratifying by gender, age ≥40 years, not exercising regularly, and eating a late-evening or fourth meal were significantly associated with subjective sleep insufficiency in both genders. Not walking quickly, experiencing a weight change, and eating quickly were positively associated with subjective sleep insufficiency only for males. Females who did not engage in physical activity were more likely to have experienced subjective sleep insufficiency, but this relationship was not observed in males. CONCLUSIONS: The results indicated that certain health-related behaviors, specifically not exercising regularly and nocturnal eating habits, were associated with subjective sleep insufficiency in a group of Japanese workers.

[Educational effectiveness of a group health education program in the workplace and an examination of educational methods to promote behavior modification].

BACKGROUND: It is well-known that health education programs carried out in the work place are useful for employees' health promotion. However, the effectiveness of group health education programs for workers as a population approach is unclear. OBJECTIVE: The purpose of this study was to examine the effectiveness of a group health education program in the workplace, and to investigate educational methods which support workers modifying their health behaviors. METHODS: A total of 289 workers who received a group health education program in the manufacturing industry (mean age, 42.1 ± 11.3 years old; 175 males and 114 females) were enrolled in this study. The group health education program was carried out to educate the subjects about periodontitis, oral health actions and lifestyle behaviors to prevent oral diseases. Participants were required to fill out a self-administered questionnaire which included information about oral health knowledge, oral health actions, lifestyle behaviors and symptoms of periodontitis before, immediately after and one month after the education. We used McNemar's test for the paired comparison of questionnaire responses. The relation between acquiring knowledge about periodontitis and subjects' modification of oral health action, behavior modification and symptoms of periodontitis were examined using the chi-squared test. The relationships of knowledge retention about periodontitis, the modification of the oral health actions and lifestyle behaviors (i.e., cigarette smoking, alcohol drinking and eating between meals), were examined with participants' characteristics (i.e., age, gender and occupational category) using Fisher's exact test. RESULTS: Knowledge about periodontitis significantly improved immediately after receiving the health education, and this effect of education was evident one month later. However, not all of the knowledge was sufficiently retained one month after the education session. The proportion of participants undertaking desirable oral health actions significantly increased one month after the education, whereas lifestyle behaviors did not alter. The modification of oral health actions improved periodontitis-related symptoms, however, no relationship was found between knowledge acquisition and behavior modification. The characteristics of the participants did not influence knowledge retention about periodontitis or modification of oral health actions. CONCLUSIONS: Our group health education program was appropriate and effective at providing knowledge about periodontitis and at modifying oral health actions. We should identify factors that obstruct workers behavior modification, and eliminate them to improve health behaviors.

Ocular defense mechanisms with special reference to the demonstration and functional morphology of the conjunctiva-associated lymphoid tissue in Japanese monkeys.

In order to define the histological components of ocular defense, the conjunctiva in Japanese monkeys was studied using a whole mount method, light microscopy, and electron microscopy. We investigated the distribution of the conjunctiva-associated lymphoid tissue (CALT) using stereoscopic observations of the conjunctiva immunostained with human leukocyte antigen (HLA)-DR antibody and /or stained with alcian-blue. The outer surface of the conjunctival fornix was lined by sheets of mucus secreting goblet cells, with small epithelial patches without goblet cells, scattered among them. The patches, termed CALT, consisted of flattened epithelial cells, intraepithelial lymphocytes and dendritic cells, and lymphoid follicles with a germinal center. The CALT in Japanese monkeys was fundamentally similar in structure to those found in other animal species. CALT patches ranged in size ranging from 200 microm to 300 microm in diameter. The number of patches varied from 20 to 40 in the superior eyelid and 10 to 20 in the inferior eyelid. Latex microspheres administrated as eye drops were selectively taken up first by flattened associated epithelial cells covering the surfaces of CALT patches and then by intraepithelial dendritic cells of the CALT. These morphological findings show that CALT patches in the eyelids of primates are focal sites for particulate uptake and contact with lymphoid constituents, indicating that they are inductive sites for the common mucosal immune system as well as important components in ocular defense.