Relationship Between Work Engagement and the Onset of Long-term Sickness Absence Due to Mental Disorders: A 4-year Retrospective Cohort Study.

The aim of the present study was to investigate the association between work engagement and long-term sickness absence due to mental disorders such as mood disorders and anxiety, and whether the relationship differs between men and women, during a 4-year follow-up period. Data were obtained from 21,293 workers at four pharmaceutical companies belonging to the Collabo-Health Study Group in 2014. The baseline data were collected by self-administered questionnaires. We obtained information about long-term sickness absence from the personnel records of the surveyed companies from the baseline survey in 2014 until March 2018. Hazard ratios (HRs) and 95% confidence intervals (CIs) using the low work engagement group as a reference were calculated by Cox proportional hazards analysis as the outcome, defined as the period leading to mental health-related sick leave. A total of 12,025 participants had complete data for analysis, and 123 exhibited long-term sickness absence during a 4-year follow-up period. The high work engagement group for men had a significantly lower HR (0.52, 95% CI: 0.31-0.88, P = 0.015) compared with the low work engagement group. Conversely, among women, the moderate work engagement group had a significantly higher HR (2.44, 95% CI: 1.03-5.84, P = 0.043) compared with the low work engagement group. Work engagement in men may predict the occurrence of long-term sickness absence due to mental disorders in the subsequent four years, but this relationship was different in women. Further research is needed to clarify this issue.

Stretching versus transitory icing: which is the more effective treatment for attenuating muscle fatigue after repeated manual labor?

PURPOSE: Effective recovery from muscle fatigue, especially during rest intervals between periods of high-intensity activity, is important to ensure optimal subsequent performance. Stretching and icing are two types of treatment used for muscle recovery in such situations. However, their effectiveness remains unclear because of a lack of adequate evidence and/or discrepant results of previous studies. We performed a study to elucidate the effects of stretching and icing on muscle fatigue in subjects performing alternating muscle contraction and rest. METHODS: Sixteen healthy male subjects aged 21-27 years were evaluated. Each subject performed repeated isometric muscle contraction exercises that involved lifting and holding a dumbbell to induce muscle fatigue. Four treatments were performed during the rest periods between isometric muscle contraction: static stretching, ballistic stretching, no stretching, or icing. Electromyography and relative muscle oxygen saturation measurements were performed during the exercises. Muscle fatigue was indirectly estimated by the decline in the median frequency of the electromyographic signal. RESULTS: Stretching between alternate isometric muscle contraction exercises resulted in a significantly lower median frequency of the electromyographic signal than did no stretching. There was no significant difference in the change in the median frequency between static and ballistic stretching. Conversely, icing between alternate exercises did not decrease the median frequency. CONCLUSIONS: Stretching, whether static or ballistic, is not beneficial for recovery from muscle fatigue and may actually inhibit recovery. Icing may more effectively induce such recovery and thus may be a better choice between the two treatment techniques.

Age-related effects of fasting on ketone body production during lipolysis in rats.

OBJECTIVE: The age-related effects of fasting on lipolysis, the production of ketone bodies, and plasma insulin levels were studied in male 3-, 8-, and 32-week-old Sprague-Dawley rats. METHODS: The rats were divided into fasting and control groups. The 3-, 8- and 32-week-old rats tolerated fasting for 2, 5, and 12 days, respectively. RESULTS: Fasting markedly reduced the weights of perirenal and periepididymal white adipose tissues in rats in the three age groups. The mean rates of reduction in both these adipose tissue weights during fasting periods were higher in the order of 3 > 8 > 32-week-old rats. Fasting transiently increased plasma free fatty acid (FFA), total ketone body, ß-hydroxybutyrate, and acetoacetate concentrations in the rats in the three age groups. However, plasma FFA, total ketone body, ß-hydroxybutyrate, and acetoacetate concentrations in the 3-week-old rats reached maximal peak within 2 days after the onset of fasting, although these concentrations in the 8- and 32-week-old rats took more than 2 days to reach the maximal peak. By contrast, the augmentation of plasma FFA, total ketone body, ß-hydroxybutyrate, and acetoacetate concentrations in the rats in the three age groups had declined at the end of each experimental period. Thus, the capacity for fat mobilization was associated with tolerance to fasting. Plasma insulin concentrations in the rats in the three age groups were dramatically reduced during fasting periods, although basal levels of insulin were higher in the order of 32 > 8 > 3 week-old rats. CONCLUSION: These results suggest that differences in fat metabolism patterns among rats in the three age groups during prolonged fasting were partly reflected the metabolic turnover rates, plasma insulin levels, and amounts of fat storage.

Dietary zinc-deficiency and its recovery responses in the thermogenesis of rats.

The aim of this study was to elucidate whether dietary zinc-deficiency and its recovery play a role in controlling autonomic thermoregulation. We investigated the effects of dietary zinc-deficiency and its recovery on autonomic thermoregulation by measuring the rectal temperature, an index of deep body temperature. The weaned male Sprague Dawley rats were randomly divided into the dietary zinc-deficient diet (0.6 mg zinc/kg diet) group and the control diet (35.2 mg zinc/kg diet) group, and were fed for 4 weeks. In the recovery period, the rats of two groups were fed with the control diet for 3 weeks. The rectal temperature was significantly decreased throughout the period of zinc-deficiency and the hypothermic responses during the experimental period were recovered to the control group levels at least within 1 week in the recovery process from dietary zinc-deficiency. These results suggest that the deep temperature in rats was clearly associated with the dietary zinc intake levels.

Dietary zinc-deficiency and its recovery responses in rat liver cytosolic alcohol dehydrogenase activities.

The purpose of the present study was to elucidate the effects of dietary zinc-deficient feeding and its recovery on liver cytosolic alcohol dehydrogenase (ADH; alcohol: NAD(+) oxidoreductase, EC1.1.1.1) activities and plasma zinc levels in rats. The weaned male Sprague Dawley rats were randomly divided into the zinc-deficient diet (ZDF: 1.9 mg zinc/kg diet) group and the control diet (53.5 mg zinc/kg diet) group, and were fed for 4 weeks. In the recovery periods, the rats of two groups were fed with the control diet for 3 weeks. Liver cytosolic protein content per body weight in the zinc-deficiency and its recovery period showed no significant changes between both groups. However, zinc-deficiency decreased significantly liver cytosolic ADH specific activity, total liver cytosolic ADH activity and total liver cytosolic ADH activity/body weight by 50%, 76% and 53%, respectively, as compared with the control diet group. Zinc-deficiency also decreased significantly plasma zinc concentration by 84%, as compared with the control diet group. On the contrary, no significant changes in liver cytosolic ADH specific activity, total liver cytosolic ADH activity and total liver cytosolic ADH activity/body weight in the recovery period were observed between both groups. Plasma zinc concentration in the recovery period was almost recovered to the control level. These results suggest that rat liver cytosolic ADH activity was clearly related to dietary zinc intake levels.

Tea catechins enhance the mRNA expression of uncoupling protein 1 in rat brown adipose tissue.

The aim of the present study was to determine whether the antiobesity effects of tea catechins (TCs) are associated with the expression of uncoupling protein 1 (UCP1) in brown adipose tissue (BAT). Male Sprague-Dawley rats were fed a high-fat (HF; 35% fat) diet for 5 weeks, then divided into four groups and fed an HF, HF with 0.5% TC (HFTC), normal-fat (NF; 5% fat) or NF with 0.5% TC (NFTC) diet for 8 weeks. At the end of the experimental period, perirenal and epididymal white adipose tissues (WATs) and interscapular BAT were isolated. The NFTC group had significantly lower perirenal WAT weights than the NF group (NF: 12.7+/-0.53 g; NFTC: 10.2+/-0.43 g; P<.01), but the HF and HFTC groups did not differ significantly. TC intake had no effects on epididymal WAT weights. The NFTC and HFTC groups had significantly lower BAT weights than the NF and HF groups, respectively. The NFTC group had significantly higher UCP1 mRNA levels in BAT than the NF group (NF: 0.35+/-0.02; NFTC: 0.60+/-0.11; P<.05), but the HF and HFTC groups did not differ significantly. Thus, TC intake in the context of the NF diet reduced perirenal WAT weight and up-regulated UCP1 mRNA expression in BAT. These results suggest that the suppressive effect of TC on body fat accumulation is associated with UCP1 expression in BAT.