The purpose of this study was to clarify the possible associations between the serum 1,25-dihydroxyvitamin D (calcitriol) level and blood pressure. Cross-sectional analysis of data was performed. Data collected included levels of serum calcitriol, parathyroid hormone, serum calcium, and blood lead; blood pressure; dietary history; and demographic and anthropometric variables. One hundred normotensive male industrial employees made up the study population. Systolic blood pressure and diastolic blood pressure were main outcome measures. After possible confounders were controlled for, multivariate analyses yielded an inverse, independent, and statistically significant association between calcitriol level and systolic blood pressure (standardized β=−0.2704, P =.0051). A similar trend of borderline significance was found for the association between calcitriol and diastolic blood pressure (standardized β=−0.1814, P =.0611). Parathyroid hormone, serum calcium, and blood lead levels were not associated with blood pressure. When subjects were divided into four groups by calcitriol level, those in the lowest quartile showed significantly higher systolic and diastolic blood pressures than those in the upper quartile (difference=11 mm Hg, P =.007, and difference=4 mm Hg, P =.071, respectively). There is an inverse association between serum calcitriol level and blood pressure. This suggests that in addition to its role in calcium homeostasis, the active metabolite of vitamin D may play a role in determining blood pressure. The differences in both systolic and diastolic blood pressures between the upper and lower quartiles of serum calcitriol were substantial and may be of clinical significance.

Kristal-Boneh E, Raifel M, Froom P, Ribak J. Heart rate variability in health and disease. Scand J Work Environ Heal th 199521 :85-95.Beat-to-beat fluctuations in heart rate (HR) or instantaneous HR is mainly determined by activity of the cardiac sympathetic and parasympathetic systems. Despite the need for standardization in methodology to facilitate the interpretation and coinparison of results, the data presented in this review clearly show that there are individual differences in heart rate variability (HRV) and that these differences partly reflect differences in the degree of parasympathetic and sympathetic stimulation of the heart. HRV and its spectral components can be easily and noninvasively assessed and call provide valuable information to the occupational physician. Measurements of HRV and the quantification of its spectral components are powerful predictors of cardiovascular morbidity and mortality. Therefore it may help assess the return to work of patients with ischemic heart disease. Studies in the workplace can also indicate the effects of various stresses of the work environment on such patients and even on asymptomatic workers. Key words occupation, review.For a long time the study of heart rate variability (HRV) was confined to the laboratory. However, thanks to recent advances in microprocessor technology, the analysis of beat-to-beat variation has become possible also to the clinician. The increasing number of HRV investigations in the clinical and physiological literature emphasizes the value of HRV measures as a prognostic tool for the rapid and noninvasive assessment of the autonomic nervous function of the heart. Provided herein is an update of the current knowledge on HRV, in health and disease. Hearf rate variability -definifion and causesHRV is defined as spontaneous fluctuations in sinus rate due to internal and external body processes. It is usually measured as the standard (or average) deviation from the mean R-R intervals of all cardiac cycle lengths (R-R intervals for normal sinus beats) over a given period, most commonly 5 min. Beat-to-beat fluctuations in heart rate are mainly determined by the activity of the cardiac sympathetic and parasympathetic systems. Physiological experiments have demonstrated a correlation between cardiac nervous activity and immediate R-R interval changes (1-4). These studies form the basis for the examination of autonomic cardiac activity by HRV. The rate and variation of heart beats are the result of a complex interaction between sympathetic and parasympathetic efferent impulse activity in addition to the influence of sinus node pacemaker properties (5-7). The sinoatrial (S-A) node is directly and richly innervated by both sympathetic and parasympathetic (vagus) nerve fibers, which are continually active; the atrioventricular (A-V) node is less affected. Parasympathetic stimulation hyperpolarizes the S-A node, decreasing the rate of spontaneous firing and the cardiac rate. Sympathetic nerve endings, on the other hand, release norepinephrine, and th...

Workplace-specific interventions to reduce WRMD in PTs should be developed and tested in future studies.

Formaldehyde (FA) is a widely produced industrial chemical. Sufficient evidence exists to consider FA as an animal carcinogen. In humans the evidence is not conclusive. DNA-protein crosslinks (DPC) may be one of the early lesions in the carcinogenesis process in cells following exposures to carcinogens. It has been shown in in vitro tests that FA can form DPC. We examined the amount of DPC formation in human white blood cells exposed to FA in vitro and in white blood cells taken from 12 workers exposed to FA and eight controls. We found a significant difference (P = 0.03) in the amount of DPC among exposed (mean +/- SD 28 +/- 5%, minimum 21%, maximum 38%) than among the unexposed controls (mean +/- SD 22 +/- 6%, minimum 16%, maximum 32%). Of the 12 exposed workers, four (33%) showed crosslink values above the upper range of controls. We also found a linear relationship between years of exposure and the amount of DPC. We conclude that our data indicate a possible mechanism of FA carcinogenicity in humans and that DPC can be used as a method for biological monitoring of exposure to FA.

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The present study examined the usefulness of personal variables: noise annoyance, and components of the protection motivation theory (R. W. Rogers, 1983) along with social-organizational factors in explaining hearing protection device (HPD) use among Israeli manufacturing workers. Participants were 281 men exposed to harmful noise levels for which routine HPD use is required by regulation. In practice, 3 HPD user groups were identified: nonusers (n = 38), occasional users (n = 125), and regular users (n = 118). HPD use was objectively verified. HPD use was primarily related to the personal variables but not to management pressure, coworker pressure, or family support. The most powerful predictors of HPD use were perceived self-efficacy (for long-term HPD use), perceived susceptibility (to hearing loss), and noise annoyance, together explaining 48% of the outcome variance. These findings have implications for interventions aimed at motivating workers to use HPDs regularly.

This study was designed to test whether the total objective adverse work and environmental conditions, expressed as the ergonomic stress level (ESL), would predict occupational injuries over a 2-year period. The study population consisted of 4,096 men from 21 factories in six industrial sectors who were studied as part of the Israeli Cardiovascular Occupational Risk Factors Determination in Israel (CORDIS) Study, 1985-1987. The ESL (assigned four levels, 1-4) was based on an ergonomic assessment which covered 17 risk factors pertaining to safety hazards, overcrowding, cognitive and physical demands, and environmental stressors. The ESL was found to be a highly reliable measure and stable over a period of 2-4 years. The incidence of injuries among workers in low ESL conditions (level 1) was 10.3%. It increased with higher ESL's: 11.7% in level 2 (relative risk (RR) = 1.13, 95% confidence interval (CI) 0.86-1.50); 21.6% in level 3 (RR = 2.09, 95% CI 1.68-2.62); and 23.8% in level 4 (RR = 2.31, 95% CI 1.85-2.88). After adjustment for age, job experience, educational level, managerial status, and occupational status (white/blue collar), injury occurrence was significantly elevated for those at level 3 (adjusted odds ratio (OR) = 1.46, 95% CI 1.12-1.91) and level 4 (adjusted OR = 1.81, 95% CI 1.39-2.37) but not for level 2 (adjusted OR = 0.87, 95% CI 0.65-1.18). The authors conclude that adverse work and environmental conditions, objectively assessed, can predict occurrence of occupational injuries.