Masao Ishizaki

Gender differences in the association between anthropometric indices of obesity and blood pressure in Japanese.

To investigate which of four anthropometric variables of obesity has the strongest association with blood pressure (BP), and to investigate whether there are gender differences in these relationships in Asian adults, we evaluated the associations of four anthropometric variables, body mass index (BMI), waist circumference, waist-to-hip ratio and waist-to-height ratio, with BP and the prevalence of hypertension in a cross-sectional study. A total of 4,557 employees of a metal-products factory in Toyama, Japan (2,935 men and 1,622 women, aged 35 to 59 years) were included in the study. Waist circumference in men and BMI in women had the strongest associations with BP. As for the age-adjusted rate ratio (RR) of the prevalence of hypertension for one standard deviation increase in each anthropometric variable, RR was the highest for waist circumference in men (RR, 1.44; 95% confidence interval [CI], 1.31–1.58), and for BMI in women (RR, 1.61; 95% CI, 1.38–1.88). The associations of waist circumference in men and BMI in women remained significant after adjustment for each of the other variables. The associations of waist-to-height ratio with BP and the prevalence of hypertension were a little weaker than those of waist circumference for both men and women. In conclusion, among four anthropometric variables of obesity—i.e., BMI, waist circumference, waist-to-hip ratio, and waist-to-height ratio—waist circumference had the strongest association with BP and the prevalence of hypertension in men and BMI had the strongest association with BP and hypertension in women. Waist circumference in men and BMI in women should be given more importance in the screening of and guidelines on hypertension in Asians.

Progress of renal dysfunction in inhabitants environmentally exposed to cadmium

The reversibility of beta 2-microglobulinuria, glucosuria, and aminoaciduria was examined in 74 inhabitants (32 males and 42 females) over 50 yr of age, who lived in a cadmium-polluted area. The subjects participated in two examinations conducted just after the cessation of cadmium exposure and 5 yr later. All urinary parameters did not show reversible changes. During the 5 yr the geometric mean concentrations of beta 2-microglobulinuria, glucosuria, and aminoaciduria indicated significant increases in excretion. In cases where greater than 1,000 micrograms/g creatinine of beta 2-microglobulinuria was observed (at the time cadmium exposure ended), almost all individuals exposed to cadmium showed deterioration of beta 2-microglobulinuria, whereas in the case of less than 1,000 micrograms/g creatinine of beta 2-microglobulinuria, no significant changes were observed. The present study indicates that cadmium-induced renal dysfunction in individuals environmentally exposed to cadmium is irreversible.

A dose-response analysis of cadmium in the general environment with special reference to total cadmium intake limit

An epidemiological study on the dose-response relationship of cadmium was performed on 1850 Cd-exposed and 294 nonexposed inhabitants of the Kakehashi River basin in Ishikawa Prefecture. beta 2-microglobulinuria was used as an index of the effect of cadmium on health and the average cadmium concentration in locally produced rice was employed as an indicator of cadmium exposure. Cadmium exposure was found to affect health in a dose-related manner when the subjects were classified according to the average cadmium concentration in their village rice and their length of residence in the polluted area. Based on the available data, the total cadmium intake that produced an adverse effect on health was calculated as approximately 2000 mg for both men and women.

Mechanism for bone disease found in inhabitants environmentally exposed to cadmium: decreased serum 1α, 25-dihydroxyvitamin D level

SummaryTo investigate the mechanism for bone disease caused by exposure to cadmium serum samples were collected from 5 itai-itai disease patients, 36 Cd-exposed residents with renal tubular damage and 17 non-exposed individuals and analyzed for 1α,25-dihydroxyvitamin D[1α, 25(OH)2D], parathyroid hormone, β2-microglobulin, calcium and inorganic phosphorus. Measurement of percentage tubular reabsorption of phosphate (%TRP) were performed only on the Cd-exposed subjects. Serum 1α, 25(OH)2D], levels were lower in itai-itai disease patients and cadmium-exposed subjects with renal damage than in non-exposed subjects. Parathyroid hormone and β2-microglobulin concentrations in serum were higher in the Cd-exposed subjects. Decrease in serum 1α,25(OH)2D levels were closely related to serum concentrations of parathyroid hormone, β2-microglobulin and %TRP. This study suggests that cadmium-induced bone effects were mainly due to a disturbance in vitamin D and parathyroid hormone metabolism, which was caused by the cadmium-induced kidney damage.

Impact of obesity on musculoskeletal pain and difficulty of daily movements in Japanese middle-aged women.

OBJECTIVE To investigate the impact of obesity on musculoskeletal pain and disability, which impairs well-being, associations between body mass index (BMI), frequency of musculoskeletal pain and difficulty of daily movements were assessed in middle-aged women. METHODS Subjects were 709 Japanese women in a community, aged 40-69. Measured BMI, current smoking habits, frequency of pain (pain score)(rarely (0), occasionally (1) or frequently (2)) during the last 1 month at shoulders, neck, upper back, lower back and legs, difficulty of three daily movements: walking continually for more than a half hour, climbing stairs and sitting on the floor with ones legs bent beneath one another, (score for each movement) (rarely (0), occasionally (1) or frequently (2)) by a questionnaire. The summed score was defined as the difficulty score of daily movements (DS) (0-6). RESULTS BMI increased significantly with age. Lower back pain (occasionally or frequently) was the most common symptom (40.3%) in the subjects. There was a peak in prevalence of frequent pain of shoulders at age 50. Pain score for legs and DS increased significantly with age. Higher BMI was related to increased prevalence of frequent leg pain and DS (>or=3), but there were no significant associations between age or BMI, and scores of back pain. DS was correlated significantly with pain scores at shoulders, upper back, lower back and legs. After adjustment for age and smoking habit using a logistic regression analysis, odds ratios for frequent pain at legs and DS (>or=3) were 4.02 (CI: 1.83-8.80) and 2.92 (CI: 1.56-5.47), respectively, in the obese women (BMI>or=26.4, n=61), compared with 401 women with normal BMI (20-24). CONCLUSION Obesity tended to impair well-being through musculoskeletal pain at legs and difficulty of daily movements in Japanese middle-aged women.

Urinary cadmium excretion is correlated with calcaneal bone mass in Japanese women living in an urban area.

Nine hundred eight women aged 40-88 years living in a non-Cd-polluted area in Japan were analyzed for urinary cadmium (Cd), N-acetyl-beta-D-glucosaminidase (NAG) activity, beta(2)-microglobulin (B2MG) concentration, and for the stiffness index (STIFF) of calcaneal bone using an ultrasound method. The urinary Cd in the subjects, with a mean and range of 2.87 and 0.25-11.4 microg/g creatinine, respectively, showed a significant correlation with NAG but not with B2MG. STIFF was significantly inversely correlated with urinary Cd, and the association remained significant after adjusting for age, body weight, and menstrual status, suggesting a significant effect of Cd on the bone loss in these subjects without signs of Cd-induced kidney damage. A two-fold increase in urinary Cd was accompanied by a decrease in STIFF corresponding to a 1.7-year rise in age. These results emphasize the need for reassessment of the significance of Cd exposure in the general Japanese population.

Alcohol, high blood pressure, and serum gamma-glutamyl transpeptidase level.

The influence of the level of serum gamma-glutamyl transpeptidase, a biological marker of alcohol consumption, on elevations of blood pressure and on the development of hypertension related to increases in alcohol consumption was determined in a cross-sectional study of 1,492 middle-aged male workers and in a subsequent 5-year follow-up study of 1,393 workers. Blood pressure levels, as well as the prevalence and incidence of hypertension, were higher in the subjects with serum gamma-glutamyl transpeptidase levels above 50 units/l than in those with normal levels. These differences were more marked in drinkers who consumed 30 ml or more of alcohol per day. Thus, elevated serum gamma-glutamyl transpeptidase activity may identify drinkers at higher risk for the development of alcohol-related hypertension.

The association between renal dysfunction and osteopenia in environmental cadmium-exposed subjects.

Two hundred and three cadmium (Cd)-exposed subjects with renal dysfunction and 80 non-exposed subjects were examined to reveal the relationship between Cd-induced renal dysfunction and osteopenia. As biological indicators of renal function, urinary beta 2-microglobulin (beta 2-mg), and serum creatinine, calcium, and phosphorus were selected. Cd in the urine and blood was also measured. The results indicated that significant differences exist between both sexes in Cd-exposed as well as nonexposed subjects. To evaluate the degree of osteopenia, a microdensitometrical (MD) method was used. The relationships between biological parameters and each index of the MD method were analyzed using multivariate analysis. Age, urinary beta 2-mg, and serum creatinine were significantly associated with indices of osteopenia in Cd-exposed men. In contrast, age showed the most significant association with MD indices in women of both groups. However, urinary beta 2-mg was significantly associated with MD indices only in Cd-exposed women. In Cd-exposed subjects, after the number of predictor variables was increased, urinary beta 2-mg was also strongly associated with osteopenia. These results suggest a causal relationship between renal dysfunction and osteopenia in Cd-exposed subjects.

Organizational justice, psychological distress, and work engagement in Japanese workers

PurposeTo investigate the cross-sectional association between organizational justice (i.e., procedural justice and interactional justice) and psychological distress or work engagement, as well as the mediating roles of other job stressors (i.e., job demands and job control, or their combination, effort–reward imbalance [ERI], and worksite support).MethodsA total of 243 workers (185 males and 58 females) from a manufacturing factory in Japan were surveyed using a self-administered questionnaire including the Organizational Justice Questionnaire, Job Content Questionnaire, Effort–Reward Imbalance Questionnaire, K6 scale, Utrecht Work Engagement Scale, and other covariates. Multiple mediation analyses with the bootstrap technique were conducted.ResultsIn the bivariate analysis, procedural justice and interactional justice were significantly and negatively associated with psychological distress; they were significantly and positively associated with work engagement. In the mediation analysis, reward at work (or ERI) significantly mediated between procedural justice or interactional justice and psychological distress; worksite support significantly mediated between procedural justice or interactional justice and work engagement.ConclusionThe effects of organizational justice on psychological distress seem to be mediated by reward at work (or ERI) while those regarding work engagement may be mediated by worksite support to a large extent, at least in Japanese workers.

Evaluation of the effects of shift work on nutrient intake: a cross-sectional study.

Evaluation of the Effects of Shift Work on Nutrient Intake: A Cross‐sectional Study: Yuko Morikawa, et al. Department of Epidemiology and Public Health, Kanazawa Medical University—The aim of this study was to investigate the effects of shift work on nutrient intakes, including macronutrient intake and micronutrient intake, in a large sample size. The study population included 2,254 male manual workers, 20–59 yr of age, employed in a factory. A self‐administered diet history questionnaire was used. The subjects were classified into 3 groups according to their work schedule: (i) fixed day workers; (ii) shift workers without midnight shifts; and (iii) shift workers with midnight shifts. The nutrient intakes of the groups were compared by age group. There was a significant difference in nutrient intakes between subjects aged 20–29 yr and those aged 30 yr and over. Among subjects aged 20–29 yr, the energy density value for saturated fat and the energy adjusted intakes of calcium, potassium, vitamin A, and vitamin B1 were the lowest among shift workers with midnight shifts. Among subjects aged 30 yr and over, the total energy intake was the highest among shift workers with midnight shifts; the difference was significant compared to fixed day workers. Shift workers with midnight shifts had the highest intake of cereals among subjects 30 yr of age and older. In conclusion, there were no significant differences in nutrient intakes between fixed day workers and shift workers without midnight shift. Shift work, particularly midnight shift work, affected nutrient intake. The impact of shift work on nutrient intakes differed by age and the type of shift work.