Ikuharu Morioka

Exercise BP response in subjects with high-normal BP: exaggerated blood pressure response to exercise and risk of future hypertension in subjects with high-normal blood pressure.

OBJECTIVES This study was designed to assess the clinical usefulness of an exaggerated blood pressure (BP) response to exercise (EBPR) in predicting the development of hypertension from a high-normal state. BACKGROUND Exaggerated BP response during both dynamic and isometric exercises are associated with increased risk of future hypertension, while the significance of these responses concerning the identification of individuals with high-normal BP who are prone to develop hypertension is unknown. METHODS The study population comprised a sample of 239 men with high-normal BP (aged 42.3 +/- 5.9 years) who underwent a symptom-limited bicycle ergometer exercise testing at baseline and then were followed for 5.1 years. RESULTS The Kaplan-Meier survival analysis showed that the subjects in the upper quartile of BP response to exercise had a significantly higher cumulative incidence of hypertension on follow-up than those in the middle two and lower quartiles (log-rank test, p < 0.05). Multivariate analysis using the Cox proportional hazards survival model showed that the EBPR was significantly and independently associated with the risk of developing hypertension after adjustment for some traditional risk factors for hypertension (RR = 2.31, 95% confidence interval = 1.45 to 6.25). CONCLUSIONS These findings suggest that an EBPR is an important risk factor for new-onset hypertension from a high-normal state and, thus, exercise testing can provide valid information that may help identify individuals with high-normal BP at a greater risk of future hypertension.

Symptoms of contruction workers exposed to whole body vibration and local vibration

SummaryTo study the effects of construction machinery operation on subjective symptoms, a questionnaire survey was caried out among construction machinery operators by a self-reporting method. Subjects were 184 power shovel operators, 127 bulldozer operators, 44 forklift operators as operator groups, and 44 office workers as a control. Their ages were in a range of 30–49 years. The questionnaire contained 20 symptoms referring to fatigue, digestive problems, and upper or lower limbs or back problems. The prevalence rate and symptom characteristics were examined. The dominant symptoms of the operator groups were stiff shoulder, low back pain, and stomack symptoms. The prevalence rate of low back pain was significantly different between forklift operators and controls. No significant differences were found in the symptoms of upper limbs and fingers between operator groups and controls. The prevalence of Raynauds phenomenon was 0.5%–2.3% in the operator groups and 2.3% in the control group.

Monitoring of workers exposed to a mixture of toluene, styrene and methanol vapours by means of diffusive air sampling, blood analysis and urinalysis

SummaryExposure of 34 male workers to combined toluene, styrene and methanol was monitored by personal diffusive sampling of solvent vapours in breathing zone air, analysis of shift-end blood for the 3 solvents and analysis of shift-end urine for hippuric, mandelic and phenylglyoxylic acids and methanol. The exposure of most of the workers was below current occupational exposure limits. Regression analysis showed that a linear correlation exists for each of the 3 solvents between any pairs of the concentrations in air, blood and urine. Namely, toluene, styrene and methanol concentrations in blood obtained at the end of a shift are linearly related to the time-weighted average intensity of exposure to corresponding solvents, and also hippuric, mandelic and phenylglyoxylic acids as well as methanol in shift-end urine. The concentrations of hippuric, mandelic and phenylglyoxylic acids as well as methanol in urine correlated with the respiratory exposure intensity. Comparison of the present results with the exposure — excretion relationship after occupational exposure to the individual solvent showed that no modification in metabolism is induced by the combined exposure when exposure is low, as in the present case.

Evaluation of organic solvent ototoxicity by the upper limit of hearing.

To clarify the effects of organic solvents on hearing, we measured the upper limit of hearing in 93 male workers exposed to organic solvents in 7 factories that produced plastic buttons or baths. Medical examinations, environmental monitoring (i.e., concentration in breathing-zone air), and biological monitoring (i.e., concentration in urine) of the organic solvents were also done. Although the organic solvent concentrations in the environmental monitoring were lower than the occupational exposure limit, the upper limit of hearing was reduced in workers who were exposed for 5 y or more. This reduction was dose-dependent and was related to styrene concentrations in breathing-zone air and mandelic acid concentrations in urine. Even individuals who had normal medical examinations showed a reduced upper limit of hearing. The upper limit of hearing may serve as an early detection indicator of health effects in workers constantly exposed to styrene.

The influence of obesity and metabolic risk variables on brachial-ankle pulse wave velocity in healthy adolescents.

Measurement of brachial-ankle pulse wave velocity (baPWV) is recognized as a simple and practical method for assessing arterial stiffness. We determined whether the baPWV of adolescents is affected by obesity and its associated metabolic risk variables. A cross-sectional sample of 754 apparently healthy adolescents (383 men and 371 women), aged 15–17 years, was recruited for this study. baPWV was measured by a simple automatic oscillometric technique. Adiposity measures, blood pressure, serum lipoproteins, fasting glucose and insulin were evaluated. The baPWV of the adolescents was significantly higher in men than in women and increased with age in both genders. After being statistically adjusted for age and gender, baPWV was significantly correlated with body mass index, percent body fat, waist-to-height ratio, systolic and diastolic blood pressures, mean arterial pressure, triglycerides, high-density lipoprotein cholesterol (HDL-C), atherogenic index, glucose, insulin, and homoeostasis model assessment of insulin resistance (HOMA-IR). In the multivariate regression analysis, mean arterial pressure, atherogenic index, HOMA-IR, systolic blood pressure and age were found to be significant determinants of baPWV (P<0.001). An increasing number of clustered risk variables, including high values (>gender-specific top quartiles) of waist-to-height ratio, mean arterial pressure, atherogenic index and HOMA-IR showed a graded association with baPWV (P<0.001 for trend). These results suggest that obesity and its associated metabolic abnormalities are important factors in the increased baPWV of adolescents and that baPWV may be useful in investigating early arterial wall changes in this population.

Hearing impairment among young Chinese in a rural area

To evaluate hearing levels in Chinese young people, audiometry was carried out at a rural village in Shandong Prefecture. The subjects were 282 healthy school children and students ranging in age from 7-17 y. All subjects were asked to complete a brief questionnaire on otological symptoms, personal histories and use of noisy playthings. Audiometric threshold testing was performed at the audiometric frequencies of 0.5, 1, 2, 4 and 8 kHz. Cluster analysis was used to estimate the associations between questions in the questionnaire and hearing impairment. Fifty-six subjects (20% subjects) were excluded from the normal groups. Twenty-two ears of the excluded subjects showed 4 kHz-dip and 38 ears showed high frequency hearing loss. An increased prevalence of hearing impairment was found when compared with young Japanese (1% from the nationwide school health survey) and with young Chinese in Shandong Prefecture (0.5%). In the questionnaire, 4 questions on dizziness, head trauma, aminoglycoside administration, and suspicion of Menieres syndrome, were included in the cluster of hearing impairment. The cause of this hearing impairment was proposed to be the potentiating effects of aminoglycoside antibiotics and exposure to noise.

Increased mean arterial pressure response to dynamic exercise in normotensive subjects with multiple metabolic risk factors.

Metabolic syndrome (MS) may influence vascular reactivity and might cause an excessive increase in blood pressure (BP) during dynamic exercise. We examined this hypothesis in 698 normotensive men (mean age: 43 years) free of cardiovascular disease, diabetes mellitus and renal disease. The response of BP to exercise was assessed by the mean arterial pressure (MAP) during bicycle ergometry. The MAP values were expressed as z-scores normalized to the relative increases in heart rate. High-normal BP, dyslipidemia and hyperglycemia were diagnosed according to the Japan-specific MS criteria. The z-score of MAP was significantly higher in subjects with high-normal BP (+0.57, P<0.001), dyslipidemia (+0.18, P<0.001) and hyperglycemia (+0.24, P<0.001) than in those without MS component (−0.38). In the high-normal BP subjects, the addition of dyslipidemia and/or hyperglycemia was associated with a progressive increase in the z-score of exercise MAP, whereas no such association was observed in the normal-BP subjects (P=0.033, two-way ANOVA). Multivariate regression analysis revealed that a greater number of MS components (β=0.102, P=0.010) was an independent determinant of increased MAP z-score after adjustment for potential confounders, including age (β=0.123, P<0.001), body mass index (β=0.145, P<0.001) and high-normal BP (β=0.410, P<0.001). These results suggest that accumulation of MS components may alter vascular structure and function and lead to the significant elevation of MAP during dynamic exercise even before clinical manifestation of arterial hypertension.

The Standardized Nordic Questionnaire Applied to Workers Exposed to Hand-Arm Vibration.

The Standardized Nordic Questionnaire Applied to Workers Exposed to Hand‐Arm Vibration: Orawan Kaewboonchoo, et al. Department of Hygiene, School of Medicine, Wakayama Medical University—The standardized Nordic questionnaire (SNQ) is not yet widely used in Japan. This paper describes the possibility whether the SNQ, translated into Japanese, can be applied to workers exposed to hand‐arm vibration. The musculoskeletal symptoms of 40 chain saw operators (CS) in private forests and 40 age‐matched bush cleaner operators (BC) in the public service sector were assessed by the SNQ and the Japanese questionnaire (JQ). Both the SNQ and the JQ showed that CS had a higher prevalence of symptoms than BC. By the SNQ, there were significant differences in the prevalence of musculoskeletal symptom in the elbows, upper back and knees. By the JQ, CS had significantly higher prevalence of pain in the shoulders and elbows than BC. These results show the SNQ also fits the musculoskeletal symptoms and clearly differentiates between the prevalences in the two groups. The SNQ enables us to identify the severity, the duration, the treatment and the disability, but does not include items related to finger numbness and finger blanching. For that reason some JQ items should be applied to workers exposed to hand‐arm vibration.

Development of new instrument for evaluating leg motions using acceleration sensors

ObjectiveThe purpose of this study was to investigate the characteristics of the average acceleration of elderly people during walking.MethodThe subject cohort comprised nine men and 21 women aged ≥63 years. Subjects walked a 10-m straight course (walk test) which required stepping over six obstacles (hurdle walk test). The average acceleration was calculated from the accelerograms. Functional reach test scores and the Tokyo Metropolitan Institute of Gerontology (TMIG) index of competence, fall risk assessment, fall experience within the last year, and carelessness were used as standard indices to estimate the dynamic postural movement and fall risk.ResultsThe average acceleration during the walk test was not significantly correlated with the standard indices. The average accelerations at the lumbar and knee positions clustered with fall experience and carelessness, while those at the ankle and toe positions clustered with the hurdle walk test, TMIG index of competence, and fall risk assessment. Between the high- and low-risk groups classified by the conventional indices, there was a significant difference in the average acceleration at some measurement positions. The receiver operating characteristic analysis showed the possibility to discriminate the high-risk group according to the standard indices with average acceleration.ConclusionsThe average acceleration during walking may be a composite index that encompasses standard indices and discriminate the high-risk group. As such, it may be a useful tool to estimate the dynamic postural movement and fall risk at all measurement positions.

Evaluation of noise-induced hearing loss by reference to the upper limit of hearing.

We have defined the upper limit of hearing as the maximum audible frequency measured with fixed intensity and changing frequency. We have previously established the standard upper limit ageing curves from the normal age variation in the upper limit of hearing. In the present study, we sought to clarify the effects of occupational noise on the upper limit of hearing. We measured the upper limit of hearing in 239 healthy male workers (478 ears) exposed to intensive occupational noise. Their age variation in the upper limit of hearing was compared with the standard upper limit ageing curves in males. There were statistically significant deteriorations. Even if the ears that had normal hearing levels (35 dB or less) were selected, deterioration in the upper limit of hearing was noticeable. The upper limit of hearing may serve as clinically useful information on the hearing impairment that precedes noticeable hearing impairment in conventional audiometry for workers exposed to intensive occupational noise.