Hisataka Sakakibara

Relationship of obesity to job stress and eating behavior in male Japanese workers

Objective:To examine a possible relationship between obesity, job stress, and eating behavior in male Japanese workers.Method:A questionnaire on life style, job stress, and eating behavior was conducted with 208 male workers aged 19–60 years (33.7±12.3 years) in a manufacturing industry in Japan. Height and weight were measured in an annual health examination. The relation between obesity, job stress, and eating behavior were analyzed between 141 nonobese subjects (BMI ⩽24.9 kg/m2) and 67 obese subjects (BMI ⩾25.0 kg/m2).Results:Obesity was associated with psychological stress responses of tension/anxiety, especially tension. Tension/anxiety was also related to job demands positively and job latitudes negatively. The eating behaviors of subjects with tension/anxiety resembled those of the obese subjects.Conclusions:The present study suggests that obese male Japanese workers tend to be in a stressful state from high job demands and low job latitudes in the workplace. Such stressful conditions may affect eating behaviors to eat much and contribute to obesity. Stress management might be necessary in the workplace for the prevention of obesity among male Japanese workers.

Eating behavior related to obesity and job stress in male Japanese workers.

OBJECTIVE We examined a possible relation among obesity, eating behavior, and job stress in male Japanese workers. METHODS A questionnaire survey on lifestyle, eating behavior, and job stress was conducted with 595 male daytime workers (19-60 y of age, mean +/- SD 41.8 +/- 12.6 y of age) in a synthetic-fiber manufacturing plant. The 431 non-obese men (body mass index <25.0 k/m(2), mean age 41.7 +/- 12.9 y) and 164 obese men (body mass index > or = 25.0 k/m(2), mean age 42.0 +/- 11.9 y) were examined in relation to obesity, eating behavior, and job stress. Body mass index was calculated from height and weight measured in an annual health check. RESULTS Obesity was associated with eating behaviors such as eating to satiety, eating fast, and substitution eating from irritability. These eating behaviors were related to high job demands of quantitative workload. The eating behaviors were also correlated with psychological stress responses of fatigue, tension/anxiety, and depression, which were associated with quantitative workload. CONCLUSION The present study suggests that high job demands of quantitative workload may be a factor related to eating behavior to eat a lot among male Japanese workers. Increased workplace stress from job strain may affect the workers through eating behaviors to eat a lot that contribute to obesity.

The ototoxic interaction of styrene and noise.

The interaction between noise and inhaled styrene on the structure and function of the auditory organ of the male Wistar rat was studied. The animals were exposed either to 600 ppm, 300 ppm or 100 ppm styrene (12 h/day, 5 days/week, for 4 weeks) alone or in combination with a simultaneous 100-105 dB industrial noise stimulant. Auditory sensitivity was tested by auditory brainstem audiometry at 1.0, 2.0, 4.0 and 8.0 kHz frequencies. Inner ear changes were studied by light microscopy. Exposure to 600 ppm styrene alone caused a 3 dB hearing loss only at the highest test frequency (8 kHz). Quantitative morphological analysis of cochlear hair cells (cytocochleograms) showed a severe outer hair cell (OHC) loss particularly in the third OHC row of the upper basal and lower middle coil. Exposure to noise alone caused only a mild hearing loss (2-9 dB), and only an occasional loss of OHCs (<1% missing). Exposure to the combination of noise and 600 ppm styrene caused a moderate flat hearing loss of 23-27 dB. The cytocochleograms showed a more severe damage of the OHCs than after exposure to 600 ppm styrene alone. The inner hair cells were found to be destroyed in some animals in the upper basal turn only after the combination exposure. Only in combination with noise exposure, the lower styrene concentrations (100 and 300 ppm) induced a hearing loss which was equivalent to that seen after exposure to noise alone. We conclude that: (1) There is an ototoxic interaction between styrene and noise. (2) Synergism is manifested only if styrene is applied in concentrations above the critical level (between 300 and 600 ppm in this study).

Secondary Prevention of New Vascular Events with Lifestyle Intervention in Patients with Noncardioembolic Mild Ischemic Stroke: A Single-Center Randomized Controlled Trial

Background: Lifestyle modification is associated with a substantially decreased risk of cardiovascular events. However, the role of lifestyle intervention for secondary prevention in patients with noncardioembolic ischemic stroke is inadequately defined. We assessed the hypothesis that lifestyle intervention can reduce the onset of new vascular events in patients with noncardioembolic mild ischemic stroke. Methods: We conducted an observer-blind randomized controlled trial that enrolled 70 patients (48 men, mean age 63.5 years) with acute noncardioembolic mild ischemic stroke. The patients were allocated in equal numbers to a lifestyle intervention group or a control group. We performed lifestyle interventions, which comprised exercise training, salt restriction and nutrition advice for 24 weeks. Then all patients were prospectively followed up for occurrence of the primary endpoints, including hospitalization due to stroke recurrence and the onset of other vascular events. We also evaluated systolic blood pressure (SBP) at the clinic and at home, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), hemoglobin A1c (HbA1c) and high-sensitivity C-reactive protein (hs-CRP) to compare the efficacy of the lifestyle interventions. Results: This trial was terminated earlier than expected because of the prespecified early stopping rule for efficacy. After the 24-week intervention period, the intervention group showed a significant increase in daily physical activity and a significant decrease in salt intake (physical activity, p = 0.012; salt intake, p < 0.001), with a significant difference between the randomized groups (physical activity, p < 0.001; salt intake, p = 0.018). Similarly, blood pressure was decreased and the HDL-C levels were increased in the intervention group (SBP, p < 0.001; HDL-C, p = 0.018), with significant differences between the randomized groups (SBP, p < 0.001; HDL-C, p = 0.022). In contrast, LDL-C, HbA1c and hs-CRP tended to decrease in the intervention group, but this decrease did not achieve significance. After a median follow-up period of 2.9 years, 12 patients allocated to the control group and 1 patient in the lifestyle intervention group experienced at least 1 vascular event. A sequential plans analysis indicated the superiority of the lifestyle intervention in interim analysis. Kaplan-Meier survival curves after the log-rank test showed a significant prognostic difference between the randomized groups (p = 0.005). Conclusions: Lifestyle intervention with appropriate medication is beneficial for reducing the incidence of new vascular events and improving vascular risk factors in patients with noncardioembolic mild ischemic stroke.

Hand Arm Vibration Syndrome among Quarry Workers in Vietnam

Hand Arm Vibration Syndrome among Quarry Workers in Vietnam: Makoto Futatsuka, et al. Department of Public Health, Graduate School of Medical Sciences, Kumamoto University—Few studies have focused on the health effects of vibrating tools on workers in the tropical area. Work conditions and health effects related to rock drill operation were studied in 102 quarry workers, including 73 rock drill operators in Vietnam. We aimed to clarify (1) risk of vibration exposure, (2) occurrence of vibration‐induced white finger (VWF), and (3) characteristics of handarm vibration syndrome (HAVS). Total weighted r.m.s. acceleration of the Chinese ‐or Russian‐made rock drills, was 45–55 m/s2. According to work observation studies, daily exposure time to vibration was 160–210 min. ISO5349 predicted that this exposure level would be associated with a high risk of HAVS in workers. We found no clear evidence of VWF. There may be several reasons why no worker exhibited VWF: (1) warmer work conditions, (2) younger and less experienced workers, (3) seasonal changes in work operations, and (4) healthy worker effect. On the other hand, 5–10% of rock drill operators might be suffering from moderate HAVS which was sensori‐neural type dominant. There may be some characteristic features of HAVS among quarry workers in the tropical area.

Effect of vibration frequency on finger blood flow

SummaryA total of 18 healthy subjects (9 men and 9 women) 20–35 years of age were used to study the effect of vibration frequency on finger blood flow. Seven vibration frequencies of 16, 31.5, 63, 125, 250, 500 and 1,000 Hz, at vibrational accelerations of 10 m/s2 (rms: root mean square) or 50 m/s2 (rms), with the exception of 16 Hz, which was measured at only 10 m/s2 (rms), were randomly applied to the palm of the right hand for 1 min at intervals of about 3 min. Finger blood flow was measured simultaneously in both the right and the left middle fingers with a blood flowmeter using a thermal diffusion method and in the left middle finger with a laser Doppler flowmeter. The experiments were performed in an artificial climate chamber set at 23°C air temperature and 50% humidity. Relatively great responses were observed at frequencies of 31.5–63 and 250–500 Hz on the exposed and unexposed sides, respectively, as measured with a blood flowmeter using a thermal diffusion method and at 31.5–63 as well as 500 Hz on the unexposed side with a laser Doppler flowmeter. These results may be related to Meissners and pacinian corpuscles.

Skin sympathetic activity in the tibial nerve triggered by vibration applied to the hand

SummaryThe effect of vibration applied to the hand on skin sympathetic activity (SSA) in the lower limbs was studied in five healthy subjects. SSA from the right tibial nerve at the popliteal fossa, plethysmogram from the right index toe and perspiration from the sole of the rigth foot were measured when vibration of 100m/s2 at 60 Hz was applied to the left palm for 1 min. The SSA response to vibration exposure differed among subjects, but every subject showed an increase in SSA from the tibial nerve when vibration was applied to the hand. Decrease in amplitude of plethysmogram from the toe was also found in all subjects. One subject displayed a remarkable increase in perspiration on the sole of the foot together with a great increase in SSA. The present findings indicated that even vibration exposure of the hand triggers sympathetic activity in the tibial nerve innervating the foot, and causes vasoconstriction of the toe and perspiration on the sole of the foot.

Correlation between vibration-induced white finger and symptoms of upper and lower extremities in vibration syndrome

SummaryThe correlation was investigated between the frequency of attacks of vibration-induced white finger (VWF) and numbness or coldness of the fingers and legs in patients with vibration syndrome. Some 1687 patients with vibration syndrome were examined and of these 342 chain-saw operators and 277 rock-drill operators had no disease other than vibration snydrome. Then subjects were matched by age and period of treatment within three years. In the last analysis, 20 in the VWF “almost everyday” group or in the “never” group, and 40 in the “occasionally” group were selected from the chain-saw operators, and from the rock-drill operators 32 in the VWF “everyday” or the “never” group and 64 in the “occasionally” group. The present study showed that, with the frequency of VWF attacks, patients had a higher prevalence of coldness not only in the fingers but also in the legs. These findings suggest a correlation between the severity of circulatory disturbances of the upper extremities and that of the lower ones in patients with vibration syndrome. Further studies on circulatory disturbances in the leg are required.

Relation between overhead work and complaints of pear and apple orchard workers

The relation between working posture in overhead work and the complaints of farmers cultivating pears and apples were investigated by comparing pear work with apple work. The same 20 male and 28 female orchard workers were questioned about complaints associated with thinning out pears and bagging them, and bagging apples. The angle of forward flexion in the shoulder and neck extension was also measured in each job. The prevalence of tiredness, stiffness and pain in the neck, shoulders and arms was significantly higher in thinning out pears and bagging them than in bagging apples. Dizziness and tinnitus among female workers was more frequent in thinning pears. The posture of raising arms and bending the head backwards was higher in thinning and bagging pears. These results suggest that the working postures of elevated arms and backward head bending can cause symptoms in the neck, shoulders and arms. In some cases, they may also lead to symptoms of vertebral artery insufficiency.

Intramuscular adipose tissue determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids.

PURPOSE The purpose of this study was to assess relationships between intramuscular adipose tissue (IntraMAT) content determined by MRI and intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) determined by (1)H magnetic resonance spectroscopy ((1)H MRS) or echo intensity determined by B-mode ultrasonography of human skeletal muscles. METHODS Thirty young and elderly men and women were included. T1-weighted MRI was taken from the right mid-thigh to measure IntraMAT content of the vastus lateralis (VL) and biceps femoris (BF) using a histogram shape-based thresholding technique. IMCL and EMCL were measured from the VL and BF at the right mid-thigh using (1)H MRS. Ultrasonographic images were taken from the VL and BF of the right mid-thigh to measure echo intensity based on gray-scale level for quantitative analysis. RESULTS There was a significant correlation between IntraMAT content by MRI and EMCL of the VL and BF (VL, r=0.506, P<0.01; BF, r=0.591, P<0.001) and between echo intensity and EMCL of the VL and BF (VL, r=0.485, P<0.05; BF, r=0.648, P<0.01). IntraMAT content was also significantly correlated with echo intensity of the VL and BF (VL, r=0.404, P<0.05; BF, r=0.493, P<0.01). CONCLUSION Our study suggests that IntraMAT content determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids, not intramyocellular lipids, in human skeletal muscles.