Natto Intake is Inversely Associated with Osteoporotic Fracture Risk in Postmenopausal Japanese Women.

BACKGROUND: The direct association between intake of Japanese fermented soybeans, namely natto, and bone mineral density (BMD) is known. However, the association with osteoporotic fractures has not been studied. OBJECTIVE: This study aimed to investigate whether habitual natto intake is associated with a risk of osteoporotic fractures. METHODS: This prospective cohort study included 1417 postmenopausal Japanese women who were enrolled in the Japanese Population-Based Osteoporosis cohort study in 1996, 1999, 2002, and 2006 and were aged ≥45 y at baseline. The intake of natto, tofu, and other soybean products was surveyed with use of a FFQ at baseline. Fractures were ascertained in follow-up surveys conducted in 1999, 2002, 2006, and 2011/2012. Osteoporotic fracture was the primary outcome and was defined as a clinical fracture occurring without strong external force, diagnosed with radiographs by a medical doctor. HRs with 95% CIs were estimated with Cox proportional hazard models. RESULTS: During the 17,699 person-years of follow-up (median, 15.2 y), 172 women experienced osteoporotic fractures. After adjustment for age and BMD at the total hip, the HRs compared with those of < 1 pack (approximately 40 g)/wk natto intake were 0.72 (95% CI: 0.52, 0.98) and 0.51 (95% CI: 0.30, 0.87) for 1-6 and ≥7 packs/wk, respectively. After further adjustment for BMI, history of osteoporotic fractures, history of myocardial infarction or stroke, diabetes mellitus, current smoking, alcohol intake, frequency of tofu and other soybean product intakes, and dietary calcium intake, the HRs were 0.79 (95% CI: 0.56, 1.10) and 0.56 (95% CI: 0.32, 0.99) for 1-6 and ≥7 packs/wk, respectively. Frequency of tofu or other soybean product intakes had no association with the risk of osteoporotic fractures. CONCLUSIONS: Habitual natto intake may be associated with a reduced risk of osteoporotic fractures independent of confounding factors, including BMD, in Japanese postmenopausal women. This trial was registered at umin.ac.jp as UMIN 000032869.

Does Trabecular Bone Score (TBS) improve the predictive ability of FRAX® for major osteoporotic fractures according to the Japanese Population-Based Osteoporosis (JPOS) cohort study?

This study examined whether bone microarchitecture determined by Trabecular Bone Score (TBS) is associated with the risk of major osteoporotic fractures independent of FRAX® in Japanese women. Participants included 1541 women aged ≥ 40 at baseline. Major osteoporotic fractures during a 10-year follow-up period were documented by the Japanese Population-based Osteoporosis Cohort Study. TBS and areal bone mineral density (aBMD) were calculated for the same spinal regions at baseline. To compare the predictive ability of FRAX® model when used alone versus in combination with TBS, Akaike information criterion (AIC), the area under the receiver operating characteristic curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were calculated. We identified 67 events of major osteoporotic fractures. The skeletal sites of the first fracture event were as follows: hip (11), vertebrae (13), radius (42), and humerus (1). The model incorporating FRAX® [1.35 (95% CI 1.09-1.67) for 1 standard deviation (SD) increase] with TBS [1.46 (95% CI 1.08-1.98) for 1 SD decrease] demonstrated better fit compared to a model consisting of FRAX alone (AIC 528.6 vs 532.7). NRI values for classification accuracy showed significant improvements in the FRAX® and TBS model, as compared to FRAX® alone [0.299 (95% CI 0.056-0.541)]. However, there were no significant differences in AUC or IDI between these models. The TBS score is associated with a risk of major osteoporotic fracture independent of FRAX® score obtained with or without BMD values among Japanese women during a 10-year follow-up period.

Muscle strength is associated with bone health independently of muscle mass in postmenopausal women: the Japanese population-based osteoporosis study.

There are conflicting reports on whether muscle strength is associated with bone mineral density (BMD) independently of muscle mass. Here, we examined the association between muscle strength and BMD in a representative population of Japanese women. Cross-sectional data from 680 postmenopausal women, who were participants in the 15th-year follow-up survey of the Japanese Population-based Osteoporosis cohort study, were analyzed. Areal BMD (aBMD) at the femoral neck and lumbar spine, whole-body bone mineral density, and appendicular skeletal muscle mass (ASM, kg) were measured by dual-energy X-ray absorptiometry. The ASM index (ASMI, kg/m2) was calculated as ASM divided by height squared (m2). Grip strength (kg) was measured as an indicator of muscle strength. Grip strength showed significantly (P < 0.05) positive relationships with aBMDs at several skeletal sites after adjusting for ASMI and age (standardized partial regression coefficient (ß) = 0.102 at femoral neck, ß = 0.126 at lumbar spine). Adjusted means of aBMD at the femoral neck and lumbar spine showed significant increasing trends from the lowest to highest tertile of grip strength. Our findings indicate that muscle strength is associated with aBMD at several sites independently of muscle mass in Japanese postmenopausal women. Thus, postmenopausal women with strong muscle strength tend to have a healthy bone status regardless of muscle size.

Relative Importance of Central and Peripheral Adiposities on Cardiometabolic Variables in Females: A Japanese Population-Based Study.

In epidemiological studies, there is little evidence regarding the relative impact of central adiposity and peripheral adiposity on cardiometabolic risk factors, especially in Asian populations. This study investigated associations between central-to-peripheral fat ratios and cardiometabolic variables using data from a population-based study of Japanese women. The source population was composed of 1800 women aged 50 yr or older at the 15th- to 16th-yr follow-up survey of the Japanese Population-Based Osteoporosis Cohort Study. This study analyzed cross-sectional data from 998 women for whom complete information about body fat variables according to dual-energy X-ray absorptiometry, cardiometabolic variables, and potential confounding factors was available. Both before and after adjusting for potential confounding factors, trunk-to-appendicular fat ratios showed significant (p < 0.05) correlations with brachial-ankle pulse wave velocity, serum lipids, and hemoglobin A1c levels. Relationships between fat ratios and cardiometabolic variables were independent of relationships between fat volumes (in whole body or in trunk) and cardiometabolic variables. Furthermore, relationships between trunk-to-appendicular fat ratios and cardiometabolic variables were observed among women in the lowest tertile of total body fat (brachial-ankle pulse wave velocity, ß = 0.08; high-density lipoprotein cholesterol, ß = -0.32; low-density lipoprotein cholesterol, ß = 0.15; and hemoglobin A1C, ß = 0.16; p < 0.05, respectively). Central adiposity is more related to cardiometabolic variables than peripheral adiposity. Information on central-to-peripheral fat ratios is particularly valuable for the evaluation of relatively thin Japanese women.

Association between the 110-kDa C-terminal agrin fragment and skeletal muscle decline among community-dwelling older women.

BACKGROUND: C-terminal agrin fragment (CAF) is a biomarker for neuromuscular junction degradation. This study aimed to investigate whether 110-kDa CAF (CAF110) was associated with the presence and incidence of low muscle mass and strength. METHODS: This cross-sectional retrospective cohort study comprised women aged ≥65 years. We measured muscle mass using a dual-energy X-ray absorptiometry scanner, hand-grip strength, and blood sampling between 2011 and 2012. A follow-up study with the same measurements was conducted between 2015 and 2017. Low muscle mass and strength were defined as an appendicular skeletal muscle mass index <5.4 kg/m2 and hand-grip strength <18 kg, respectively. The CAF110 level was measured using enzyme-linked immunosorbent assay kits. RESULTS: In total, 515 women (74.3 ± 6.3 years) were included in this cross-sectional analysis. Of these, 101 (19.6%) and 128 (24.9%) women presented with low muscle mass and strength, respectively. For low muscle mass, the odds ratios (ORs) of the middle and highest CAF110 tertile groups, compared with the lowest group, were 1.93 (95% confidence interval: 1.09-3.43; P = 0.024) and 2.15 (1.22-3.80; P = 0.008), respectively. After adjusting for age, the ORs remained significant: 1.98 (1.11-3.52; P = 0.020) and 2.27 (1.28-4.03; P = 0.005), respectively. Low muscle strength ORs of all the CAF110 tertile groups were not significant. In the longitudinal analysis, 292 and 289 women were assessed for incidents of low muscle mass and strength, respectively. Of those, 34 (11.6%) and 20 (6.9%) women exhibited low muscle mass and strength, respectively. For incident low muscle mass, the crude OR of the CAF110 ≥ the median value group was marginally higher than that of the CAF110 < median value group (median [interquartile range]: 1.98 [0.94-4.17] (P = 0.072). After adjusting for age and baseline muscle mass, the OR was 2.22 [0.97-5.06] (P = 0.058). All low muscle strength ORs of the median categories of CAF110 were not significant. CONCLUSIONS: CAF110 was not associated with low muscle strength. However, CAF110 may be a potential marker for the incidence of low muscle mass.

Risk factors for future osteoporosis in perimenopausal Japanese women.

OBJECTIVE: The aims of this study were to investigate trends in bone mineral density (BMD) loss and related factors in early postmenopausal women in Japan, identify risk factors for future osteoporosis, and predict osteoporosis before it occurs. METHODS: The study population consisted of women who were 50 to 54 years old at the time of the survey in 2002 or 2006. The study included a questionnaire and physical measurement findings (BMD, height, body weight [WT], body mass index [BMI], and handgrip strength). One hundred sixty-seven women continued to participate in the study and had BMD measurements at the 9- or 10-year follow-up of the Japanese Population-based Osteoporosis study. Statistical analyses were performed using Pearson correlation to examine each factor of physical measurement and BMD for lumbar spine (LS) and femoral neck (FN). The receiver operating characteristic curve of this data was also predictive of osteoporosis in 2011 for 2002 data; BMD at the age of 50 to 54 years was then used to predict the likelihood of being diagnosed with osteoporosis 9 and 10 years later. RESULTS: At the baseline in 2002 and 2006, WT, BMI, height, and handgrip strength were positively correlated with BMD. The optimal cutoff values for BMD in 2006 to predict osteoporosis in 2016 were LS less than 0.834 g/cm 2 and FN less than 0.702 g/cm 2 . These data were also predictive of osteoporosis in 2011 for 2002 data; applying this to the 2002 data, LS/FN had a sensitivity of 92%/100%, a specificity of 87%/81%, a positive predictive value of 55%/48%, and a negative predictive value of 98%/100%. The larger WT and BMI also resulted in a greater decrease in BMD of FN after 9 or 10 years. CONCLUSIONS: We have identified a cutoff value for BMD to predict future osteoporosis in menopausal women and found a negative correlation between WT and BMI in menopausal women and changes in BMD of the FN over the next 10 years.

Tracking of appendicular bone mineral density for 6 years including the pubertal growth spurt: Japanese Population-based Osteoporosis kids cohort study.

Bone development up to early adulthood plays an important role in determining the risk of osteoporosis later in life. However, bone development in children has not been fully documented by longitudinal studies in Japanese children. The purpose of this study is to determine the degree of tracking of areal bone mineral density (aBMD) from pre-puberty to 6-year follow-up, and to determine the target period to achieve maximal peak aBMD. This study was conducted as the pediatric part of a larger cohort study, the Japanese Population-based Osteoporosis (JPOS) study. Of 448 children aged 9-12 years who completed the baseline survey, 225 participated in the follow-up study 6 years later (follow-up rate: 50.2%). aBMD at the forearm was measured using dual-energy X-ray absorptiometry. aBMD values in pre-pubertal children at baseline showed a significant tracking correlation with aBMD obtained at 6-year follow-up in both genders (boys r = 0.655, girls r = 0.759). Although boys and girls in the lowest quartile of aBMD pre-pubertally had greater annual increases in aBMD from pre-puberty to 6-year follow-up than those in other aBMD quartiles, they still showed the lowest mean aBMD at 6-year follow-up. Children with lower pre-pubertal aBMD showed greater increases in BMD up until 6-year follow-up, but the increase was not great enough to catch up with other children. About 50% of the variance in aBMD at 6-year follow-up was determined by the aBMD achieved during the pre-pubertal period. Activities that increase aBMD are important not only for children during puberty, but also for younger pre-pubertal children.

Smoking among premenopausal women is associated with increased risk of low bone status: the JPOS Study.

The impact of smoking on peak bone density has not been conclusively established. We examined how smoking exposure influences bone mineral density (BMD) or the risk of low bone status in premenopausal women. We conducted a baseline survey with a representative sample of Japanese women in 1996. The effect of current and former smokers (ever-smoker) was investigated with 789 premenopausal women aged 20-40 years. The multiple regression with stepwise method was used to identify significant determinants for BMD or the risk of low bone status (T-score < -1) with age, height, weight, calcium intake, coffee consumption, exercise habits, level of daily activity, parity >or= 1, and smoking as explanatory variables. The smoking effect was determined after adjusting for age, height, weight, and significant variables in the multiple regression with stepwise method. Ever-smoker was significantly associated with decreased lumbar BMD adjusted for age, height, and weight. The odds ratio of an ever-smoker for low bone status at the lumbar spine was 2.03 (95% CI 1.12, 5.82) adjusted for age, height, weight, and parity. The odds ratio for low bone status at the lumbar spine was 1.59 (95% CI 0.65, 3.91) and 2.55 (95% CI 1.12, 5.82) in those with less than 3 pack-years of tobacco use and in those with 3 or more pack-years of tobacco use, respectively. These values were adjusted for age, height, weight, and parity using a never-smoker as a reference. Cumulative smoking exposure may be associated with increased risk of low bone status among premenopausal women.

Decreased bone mineral density and osteoporotic fractures are associated with the development of echogenic plaques in the carotid arteries over a 10-year follow-up period: The Japanese Population-based Osteoporosis (JPOS) Cohort Study.

OBJECTIVES: To investigate whether low bone mineral density (BMD) and history of fracture at baseline are associated with the development of echogenic carotid plaques over a 10-year follow-up period. STUDY DESIGN: A prospective cohort study. MAIN OUTCOME MEASURES: Development of echogenic plaques identified by ultrasonography of the carotid arteries. METHODS: Among 1048 women aged 40 or more who completed the baseline survey of the Japanese Population-based Osteoporosis (JPOS) cohort study, 500 women who completed the first decade of follow-up and 267 women who completed the second decade of follow-up were included. We identified history and incidence of clinical osteoporotic fracture during the follow-up through medical interviews, and determined vertebral fractures by morphometry of absorptiometric images. RESULTS: We identified 67 (13.4%) and 31 (11.6%) women with echogenic plaques at the end of first and second decade of follow-up, respectively. Participants with echogenic plaques were significantly older, exhibited lower spine BMD, and had a higher prevalence of osteoporotic fracture, diabetes, and hypertension. A generalized estimating equation analysis was used to combine the participants from the two follow-up periods into a single cohort, and showed that osteoporotic BMD and osteoporotic fractures were significantly associated with the development of echogenic plaques, after adjusting for atherosclerosis risk factors (odds ratio (OR): 2.15, 95% confidence interval (95% CI): 1.04, 4.44; OR: 1.84, 95% CI: 1.03, 3.28, respectively). CONCLUSION: Osteoporotic BMD and osteoporotic fracture history were significantly, and independently, associated with an increased occurrence of echogenic plaques. Ultrasonographic screening of the carotid artery may benefit patients with osteoporosis.

Lifestyle and overweight among Japanese adolescents: the Toyama Birth Cohort Study.

OBJECTIVE: To investigate the effects of lifestyle factors on overweight among Japanese adolescents. METHODS: We studied 5753 junior high school students (2842 boys and 2911 girls) aged 12 to 13 years. The students were residents of Toyama prefecture, Japan and completed a questionnaire about their height, weight, and lifestyle factors, in June and July 2002. Subjects with a body-mass index (BMI) higher than age- and sex-specific cut-off points were defined as obese. Parental overweight was defined as a BMI of 25 or higher. Logistic regression analysis was used to examine associations between lifestyle factors and overweight. RESULTS: Skipping breakfast, eating quickly, excessive eating, physical inactivity, and long hours of TV watching were positively and significantly associated with overweight in both sexes. There was a negative association between snacking and overweight in girls (P<0.001); no such association was found in boys (P>0.05). Nighttime snacking was negatively associated with overweight in boys and girls (P<0.05). Extended video game playing (>or=2 hours; OR=2.00, P=0.012) and short sleep duration (<7 hours; OR=1.81, P=0.004) were significantly associated with overweight in girls only. The respective risks of overweight that derived from the subjects' fathers and mothers were 2.0 and 2.5 times, respectively, in boys and 1.9 and 3.0 times in girls. CONCLUSIONS: Parental overweight, skipping breakfast, eating quickly, excessive eating, long hours of TV watching, long hours of video game playing, physical inactivity, and short sleep duration were associated with adolescent overweight. Furthermore, there were significant negative associations between adolescent overweight and snacking in girls and nighttime snacking in both sexes.

Relationship between body image and lifestyle factors in Japanese adolescent girls.

BACKGROUND: Body image, defined here as an inaccurate perception of personal bodyweight, plays a significant role in the development of obesity, eating problems and eating disorders. Certain lifestyle factors may influence an individual's body image, but current knowledge is based mainly on studies in Western populations. METHODS: The associations between body image and lifestyle factors were investigated in samples of the Japanese female adolescent population. RESULTS: Respondents who reported that they ate meals slowly (odds ratio [OR] 1.81, P < 0.001) or only consumed small amounts of food (OR 3.17, P < 0.001) were more likely to underestimate their body image, as determined by their body mass index, than eaters who had average behavior for this age group. Individuals who reported eating faster (OR 1.47, P < 0.001) or consuming large amounts (OR 1.67, P < 0.001); those who do not eat breakfast on a daily basis (OR 1.35, P = 0.006); those who go to bed later than the average time for this age group (OR 1.38, P < 0.001) or sleep <7 h (OR 1.40, P < 0.001) and those individuals who rarely exercise (OR 1.27, P = 0.03) were more likely to overestimate their body image, as determined by BMI, compared with those who had average eating, sleeping and exercise behaviors for this age group. CONCLUSIONS: Variation from the norm in eating, sleeping and exercise behaviors showed a relationship with a distorted perception of body image in Japanese adolescent girls. These findings are of potential importance in understanding the underlying mechanisms involved in the development of body image and for exploring interventional approaches.

Association between hand-grip strength and site-specific risks of major osteoporotic fracture: Results from the Japanese Population-based Osteoporosis Cohort Study.

OBJECTIVES: To investigate the association between hand-grip strength and site-specific risks of major osteoporotic fracture. STUDY DESIGN: Prospective cohort study. MAIN OUTCOME: Associations between low hand-grip strength and increased risk of fracture at the distal forearm, vertebrae, and hip. MEASURES: We enrolled 1342 postmenopausal women aged 50 years or more into baseline and follow-up surveys of the Japanese Population-based Osteoporosis Cohort Study in 1996, 1999, 2002, or 2006. Fracture events were ascertained by follow-up surveys until 2011 or 2012. The Cox proportional hazards model was used to estimate hazard ratios (HRs) of hand-grip strength on fracture event. RESULTS: During a median follow-up of 15.2 years, 162 women sustained at least one osteoporotic fracture and 135 of these women sustained at least one major osteoporotic fracture, the larger group including 65, 38, 35, and 8 women with fractures of the distal forearm, vertebrae, hip, and proximal humerus, respectively. In the crude models, the associations between low hand-grip strength and increased risk of fracture at the distal forearm, vertebrae, and hip were significant; the HRs (95% confidence interval) of the lowest tertile of hand-grip strength were 2.02 (1.10-3.71), 11.35 (4.07-31.63), and 4.72 (1.79-12.47), respectively. Age adjustment attenuated the significance of hip fracture risk, and adjusting for bone mineral density attenuated the significance of distal forearm fracture risk. After additional adjustment for body mass index, history of diabetes mellitus, and calcium intake, the HR for vertebral fracture risk was 4.55 (1.56-13.27). When limiting the follow-up period to 5 and 10 years, low hand-grip strength was associated with an increased risk of distal forearm fracture independently of the aforementioned covariates; the HRs were 4.22 (1.12-15.95) and 2.52 (1.03-6.17), respectively. CONCLUSIONS: Low hand-grip strength is specifically associated with the risk of distal forearm fractures within 10 years and clinical vertebral fractures within 15 years or more in Japanese postmenopausal women.

Low bone mineral density is associated with an elevated risk of developing increased arterial stiffness: A 10-year follow-up of Japanese women from the Japanese Population-based Osteoporosis (JPOS) cohort study.

OBJECTIVE: Only a few longitudinal studies have assessed the relationship between bone mineral density (BMD) and arteriosclerosis. This study aimed to determine whether low BMD at baseline is associated with the development of increased arterial stiffness, as evaluated by brachial-ankle pulse wave velocity (baPWV), in Japanese women. METHODS: A baPWV value of ≥1800 cm/s was adopted as the criterion for increased arterial stiffness, i.e., the outcome of the study. Of the 725 women aged ≥50 years who completed the baseline survey, we excluded the 166 who already met this criterion. Of the remaining women, we analyzed data from the 446 who completed at least one of the follow-up surveys conducted 5 or 10 years after baseline. BMD at the lumbar spine (LS) and total hip (TH) was measured by dual-energy X-ray absorptiometry in the baseline survey. baPWV was measured both at baseline and at follow-up. Multivariate logistic regression was used to evaluate the independent effect of BMD at baseline on developing the outcome during 10-year follow-up. RESULTS: We identified 166 women who newly developed increased arterial stiffness. The odds ratios (OR) for a 1 SD decrease in BMD at LS and TH for developing the outcome were 1.20 (95% confidence interval [CI]: 0.91-1.50), and 1.44 (95% CI: 1.14-1.81), respectively, after adjusting for age and systolic blood pressure. After additionally adjusting for baPWV at baseline, the OR for a 1 SD decrease in BMD at TH remained significant (1.33, 95% CI: 1.02-1.72). CONCLUSION: Low BMD at TH was significantly associated with the development of increased arterial stiffness during a 10-year follow-up of Japanese women.

Associations of job strain and working overtime with adverse health behaviors and obesity: evidence from the Whitehall II Study, Helsinki Health Study, and the Japanese Civil Servants Study.

Adverse health behaviors and obesity are key determinants of major chronic diseases. Evidence on work-related determinants of these behavioral risk factors is inconclusive, and comparative studies are especially lacking. We aimed to examine the associations between job strain, working overtime, adverse health behaviors, and obesity among 45-60-year-old white-collar employees of the Whitehall II Study from London (n=3,397), Helsinki Health Study (n=6,070), and the Japanese Civil Servants Study (n=2,213). Comparable data from all three cohorts were pooled, and logistic regression analysis was used, stratified by cohort and sex. Models were adjusted for age, occupational class, and marital status. Outcomes were unhealthy food habits, physical inactivity, heavy drinking, smoking, and obesity. In London, men reporting passive work were more likely to be physically inactive. A similar association was repeated among women in Helsinki. Additionally, high job strain was associated with physical inactivity among men in London and women in Helsinki. In London, women reporting passive work were less likely to be heavy drinkers and smokers. In Japan, men working overtime reported less smoking, whereas those with high job strain were more likely to smoke. Among men in Helsinki the association between working overtime and non-smoking was also suggested, but it reached statistical significance in the age-adjusted model only. Obesity was associated with working overtime among women in London. In conclusion, job strain and working overtime had some, albeit mostly weak and inconsistent, associations with adverse health behaviors and obesity in these middle-aged white-collar employee cohorts from Britain, Finland, and Japan.

Daytime sleepiness and associated factors in Japanese school children.

OBJECTIVE: To examine daytime sleepiness and sleepiness interrelationship with sleep-wake patterns, eating habits, physical activity, and TV/video game time. STUDY DESIGN: A cross-sectional survey with 9,261 school children (mean age of 12.8 years) from 93 junior high schools in Toyama prefecture, Japan. RESULTS: The main outcome measures were daytime sleepiness during schooldays and sleepiness interrelationship with sleep-wake patterns, eating habits, physical activity, and visual media use. A total of 2,328 children (25.2%) reported sleepiness almost always and 4,401 (47.6%) sleepiness often. Regarding sex difference, a higher proportion of girls reported sleepiness in comparison to boys (79% vs 66%, P < .001). Higher body mass index values were associated with the presence of sleepiness. In girls with preferences for daily snack (versus those who reported no snack) sleepiness presented significantly (P < .001) higher values. Reduced sleep time was significantly associated with sleepiness. The prevalence of sleepiness did not significantly differ among groups who had 7.5 hours sleep or more. A dose-response relation was found between sleepiness and sleep disturbances, physical activity, and media use time. CONCLUSIONS: Sleep insufficiency represents a main cause for daytime sleepiness in Japanese junior high school children. Proper sleep habits, high physical activity level, and limited TV viewing time should be promoted among school children.

Association of smoking behavior and socio-demographic factors, work, lifestyle and mental health of Japanese civil servants.

Few studies have examined the individual and social impact of smoking behavior in the Japanese population. The purpose of this study was to clarify the association between smoking behavior and socio-demographic factors, lifestyle, mental health and work characteristics of Japanese civil servants. A self-administered questionnaire survey of 1,439 employees (821 men and 618 women) aged 20-64 yr was conducted in a local government department in 2001. The questionnaire included items on socio-demographic factors, education level, grade of employment, lifestyle, affect balance scale, and work characteristics. Smoking status was divided into current smoker, ex-smoker and never smoked. Multiple logistic regression analysis was performed to evaluate the relationship between smoking and the other items. Men presented a higher smoking prevalence rate than women (53.1% vs. 4.9%). In men, a strong relationship between current smoker and advanced age (40 yr or older), low education level, less physical activity, irregular breakfast and negative affect balance was found. Among men with a low education, the prevalence of smoking cessation was significantly lower in comparison to men with a high education. In women, being young (20-29 yr), unmarried (single or other), having a hobby, and irregular breakfast were associated with smoking behavior. Furthermore, smoking cessation was significantly associated with having a hobby and negative affect balance. The above results suggest that socio-demographic, lifestyle and mental health characteristics are independently associated with current smoking. These factors should be considered in smoking cessation policies as program components.

Work and family characteristics as determinants of socioeconomic and sex inequalities in sleep: The Japanese Civil Servants Study.

STUDY OBJECTIVE: To clarify whether socioeconomic and sex inequalities in poor sleep quality are explained by socioeconomic and sex differences in work and family characteristics. DESIGN: A cross-sectional study. PARTICIPANTS: Three thousand five hundred fifty-six employees (2397 men and 1159 women) aged 20 to 65 years in local government in Japan. MEASUREMENTS: Respondents completed a self-administered questionnaire that asked about sleep quality, as measured by the Pittsburgh Sleep Quality Index; work characteristics, as measured by the job-demand-control-support model, work hours, and shift work; and family characteristics, such as family structure and family-work conflicts. RESULTS: Lower control at work, higher work demands, lower social support, shorter and longer working hours, shift work, being single, higher family-to-work conflict, and higher work-to-family conflict were independently associated with poorer sleep quality in both men and women. In men, the age-adjusted odds ratio (OR) of low-grade employees for poor sleep quality was 1.64 (95% confidence interval: 1.14-2.36) in comparison with high-grade employees. The difference in sleep was attenuated when work and family characteristics were adjusted for (OR=1.25 [0.84-1.86]). Among women, there was no significant grade difference in sleep. Women tended to have poorer sleep quality than men (the age-adjusted OR=1.75 [1.49-2.06]). The sex difference was attenuated and no longer significant when adjustments were made for work and family characteristics (OR=1.04 [0.85-1.27]). CONCLUSIONS: The results of this study suggest that work and family characteristics may be important for reducing socioeconomic and sex inequalities in sleep. Sex differences in the pattern of socioeconomic inequalities in sleep deserve further research.

Gender differences in associations of C-reactive protein with atherosclerotic risk factors and psychosocial characteristics in Japanese civil servants.

OBJECTIVE: Several prospective studies have demonstrated a direct association between high-sensitivity C-reactive protein (hsCRP) and the risks of developing cardiovascular disease. A strong sense of coherence (SOC) has also been associated with a reduced risk of cardiovascular mortality, but the underlying pathophysiologic mechanism remains unclear. We have evaluated the relationship of serum CRP and SOC and assessed the association of atherosclerotic risk factors with CRP in male and female subjects. METHODS: Data were collected in 2003 and 2004 cross-sectionally from the two phases of a longitudinal study. Atherosclerotic risk factors were evaluated along with psychosocial characteristics for 1,339 apparently healthy civil servants (748 women and 591 men) aged 20 to 60 years. The Japanese version of the SOC-13 was used in the study. RESULTS: After controlling for traditional atherosclerotic risk factors, SOC was inversely associated with hsCRP levels only in men. Among the atherosclerotic risk factors, body mass index and high-density lipoprotein cholesterol had the strongest associations with hsCRP in both sexes. Mean arterial pressure and blood glucose were positively correlated with hsCRP in men, and serum triglyceride levels positively correlated with hsCRP in women. CONCLUSION: The findings suggested that a higher SOC might be associated with lower serum CRP levels in men. Also, the association of traditional atherosclerotic risk factors with CRP was not equal in men and women.

Socioeconomic inequalities in physical and mental functioning of Japanese civil servants: explanations from work and family characteristics.

Poor physical and mental functioning is more common among people of low socioeconomic status (SES) and those with disadvantaged work and family characteristics. This study aims to clarify whether the SES inequalities in functioning can be explained by the SES differences in work and family characteristics. The subjects were 3787 male and female civil servants, aged 20-65, working in a local government on the west coast of Japan. Logistic regression analysis was performed to examine (1) whether there were employment-grade (SES) differences in poor physical and mental functioning as measured by the Short Form 36 (SF-36) and (2) whether these SES differences were explained by work and family characteristics. In general, low control at work, high demands, low social support, short and long work hours, shift work, being unmarried, high family-to-work conflict and high work-to-family conflict were independently associated with poor physical and mental functioning in both men and women. In men, the age-adjusted odds ratio (OR) of low-grade employees for poor physical functioning was 1.93 (95% confidence interval: 1.38-2.69) in comparison to high-grade employees. The grade difference was mildly attenuated, when adjusted for work and family characteristics (OR = 1.72)(1.20-2.47). The age-adjusted OR of the low-grade employees for poor mental functioning was 1.88 (1.29-2.74). The grade difference was attenuated and no longer significant when adjusted for work and family characteristics (OR = 1.51)(0.99-2.31). Among women, there were no significant grade-differences in poor physical and mental functioning. Although longitudinal research is necessary to clarify the causal nature of these associations, improvements in SES differences in work and family characteristics may be important for reducing SES inequalities in physical and mental functioning among Japanese men. The different patterns of SES inequalities in health between men and women deserve further research.