Associations between dietary diversity and high sensitive C-reactive protein among Japanese workers: findings of a cross-sectional and longitudinal study

PURPOSE

To clarify the association between dietary diversity and inflammatory status in Japanese workers.

METHODS

Of 1,460 men and women aged 20-64 years in 2010 (baseline), those who were followed-up at least once between 2011 and 2018 were included in this study; 1,433 participants and 745 participants were included in the cross-sectional and longitudinal analyses, respectively. Dietary intake was assessed using a food frequency questionnaire at baseline, and the dietary diversity score was determined using the Quantitative Index for Dietary Diversity (QUANTIDD). High-sensitivity C-reactive protein (hs-CRP) was taken to indicate inflammatory status at the baseline and follow-up surveys. In the cross-sectional analysis using baseline data, a generalized linear model was used to calculate adjusted means and 95% confidence intervals (CIs) for hs-CRP according to the QUANTIDD score. In the longitudinal analysis, generalized estimating equations were used to calculate the adjusted mean (95% CI) for hs-CRP in follow-up according to the QUANTIDD score at baseline.

RESULTS

In the cross-sectional analysis, the hs-CRP concentration in male participants was significantly lower in those who had a high QUANTIDD score (adjusted mean [95% CI]: 0.074 [0.009-0.140] mg/dL in the lower group vs. 0.038 [-0.029-0.105] mg/dL in the higher group, p-value = 0.034). In the longitudinal analysis, the hs-CRP concentration of male participants also tended to be lower in those with higher QUANTIDD scores (p-value = 0.103). In both the cross-sectional and longitudinal analyses in women, there was no significant difference between the lower and higher QUANTIDD score groups.

CONCLUSION

These findings suggest that, in male Japanese workers, higher dietary diversity might be important for maintaining a low inflammatory status.

The impact of negative and positive affectivity on the relationship between work-related psychological factors and work engagement in Japanese workers: a comparison of psychological distress

BACKGROUND

A previous study has shown that Japanese individuals generally exhibit behavior that suppresses the expression of positive emotions, which are strongly affected by affectivity traits. In the present study, to clarify the relationship between affectivity traits and work engagement (WE) or work-related psychosocial factors among Japanese workers, we compared it to the association between psychological distress and these same factors.

METHODS

A total of 1,000 full-time Japanese regular workers responded to an online survey that measured demographic variables, negative and positive affectivity, job demands and resources, WE, and psychological distress. A hierarchical multiple regression analysis was conducted separately, which used WE and psychological distress as dependent variables.

RESULTS

The proportion of variance explained by negative and positive affectivity was lower for WE than for psychological distress. However, the proportion of variance defined by job demands and resources was higher for WE than for psychological distress. The proportion of variance explained by all variables for negative and positive affectivity and job demands and resources, and their interactions was approximately equal for WE and psychological distress.

CONCLUSION

These results emphasize when researchers aim to evaluate the change of psychosocial factors in the workplace, such as improving the workplace environment among Japanese workers, it might be beneficial to measure positive indicators in addition to negative indicators. Furthermore, enriching job resources would be effective in improving WE and alleviating psychological distress.

Presenteeism among workers: health-related factors, work-related factors and health literacy

BACKGROUND

Presenteeism is an important factor in workers' health. However, few studies have examined how variables such as socio-economic status, health status, workplace status and health literacy correlate with and affect presenteeism.

AIMS

To assess the correlates of presenteeism with a focus on health-related factors, work-related factors and health literacy.

METHODS

We conducted a cross-sectional study of 2914 Japanese workers from one company. We used a self-administered questionnaire to assess socio-demographic characteristics, health status, work environment, presenteeism and health literacy.

RESULTS

Forty-one per cent of participants were under 40 years of age and 70% were male. We found that 59% of the participants were at high risk of presenteeism. Presenteeism was associated with sex, age, household income, marital status, health-related factors (i.e. self-rated health status, dietary choices, exercise habits), work-related factors (i.e. workplace support, job demands, job control) and health literacy. Logistic regression analyses indicated that presenteeism was associated with self-rated health status, overtime hours, workplace support, job demands, job control and health literacy after adjusting for sex, age and income.

CONCLUSIONS

Health-related factors, work-related factors and health literacy are all associated with presenteeism. Improving the workplace environment, especially factors such as overtime working hours, workplace support, job demands and job control, and increasing health literacy may reduce presenteeism among general office workers.

Five-year cumulative incidence of overweight and obesity, and longitudinal change in body mass index in Japanese workers: The Japan Epidemiology Collaboration on Occupational Health Study

OBJECTIVE

The present study aimed to estimate cumulative incidence of overweight and obesity and describe 5-year longitudinal changes in body mass index (BMI) in a large occupational cohort in Japan.

METHODS

Participants were 55 229 Japanese employees, who were aged 20-59 years and attended at all subsequent annual health check-ups between 2009 and 2014. Mixed model analysis was performed to examine the effects of age and cohort by gender on BMI change, with age as a random variable. Cumulative incidence of overweight (23.0≤ BMI <27.5 kg/m2 ) and obesity (BMI ≥27.5 kg/m2 ) was calculated. Logistic regression analysis was used to estimate odds ratios for the incidence of overweight and obesity according to age group.

RESULTS

The incidence of overweight and obesity was approximately double in men (28.3% and 6.7%, respectively) compared to women (14.3% and 3.9%, respectively).The incidence of obesity decreased with age in men, but did not differ according to age in women (P for trend: .02 and .89, respectively). Among overweight participants, the incidence of obesity was higher in women (18.9%) than men (14.5%) and decreased with advancing age (P for trend: <.001 in men and .003 in women). Mean BMI was higher in men than women in all age groups throughout the period. Younger cohorts tended to have a higher BMI change compared with older cohorts.

CONCLUSIONS

In this Japanese occupational cohort, transition from overweight to obesity is higher in women than men, and the more recent cohorts had a higher change in mean BMI than the older cohorts.

Serum brain-derived neurotrophic factor levels are associated with dyssomnia in females, but not males, among Japanese workers

STUDY OBJECTIVES

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors that promote the growth and survival of neurons. Recent evidence suggests that BDNF is a sleep regulatory substance that contributes to sleep behavior. However, no studies have examined the association between the serum BDNF levels and dyssomnia. The present study was conducted to clarify the association between the serum BDNF levels and dyssomnia.

METHODS

A total of 344 workers (age: 40.1 ± 10.5 years, male: 204, female: 140) were included in the study. The serum BDNF levels were categorized into tertiles according to sex.

RESULTS

The prevalence of dyssomnia was 35.1% in males and 30.0% in females. In the females, the BDNF levels were found to be negatively associated with dyssomnia after adjusting for age, body mass index, hypertension, dyslipidemia, hyperglycemia, depression, smoking, alcohol intake, and regular exercise. Compared with the females in the high BDNF group, the multivariate odds ratio (95% CI) of dyssomnia was 2.08 (0.62-6.98) in females in the moderate BDNF group and 8.41 (2.05-27.14) in females in the low BDNF group. No such relationships were found in the males.

CONCLUSIONS

The serum BDNF levels are associated with dyssomnia in Japanese female, but not male, workers.

Association of gene polymorphism of the fat mass and obesity associated gene with metabolic syndrome: a retrospective cohort study in Japanese workers

To investigate whether gene polymorphism of the fat mass and obesity associated gene (FTO) is associated with metabolic syndrome (MS), we used two MS criteria, the National Cholesterol Education Program-Adult Treatment panel III (NCEP-ATPIII) definition in 2003 and the Japanese definition in 2005. Subjects were respectively 859 and 865 Japanese workers at a company in Shimane Prefecture, Japan. They were non-MS individuals in 1998 and had regular health checkups between 1998 and 2006. The Cox proportional hazard regression was used to predict MS. Three SNPs in the FTO, rs9939609, rs1121980 and rs1558902, were genotyped by the TaqMan PCR assay and a retrospective study was performed. The three SNPs in the FTO were significantly associated with body mass index, and rs1121980 and rs1558902 were associated with fasting plasma glucose. MS defined by the NCEP-ATPIII definition was significantly associated with additive and dominant models of rs9939609 and rs1121980, and the dominant model of rs1558902, even after adjusting for confounding factors such as age, sex and lifestyle. MS defined by the Japanese definition was significantly associated with the additive model of rs1121980 and additive and dominant models of rs1558902 in multivariate analysis. These results suggested that FTO gene polymorphisms, rs9939609, rs1121980 and rs1558902, were associated with an increased risk of MS among Japanese workers.