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Objective: To clarify whether somatic complaints in healthy normotensive men are associated with differential 24-hour blood pressure and heart rate measures., Method: Twenty-four-hour ambulatory systolic and diastolic blood pressure was monitored in 114 healthy normotensive men, aged 28 to 63 years, engaged in similar physical work. Means were calculated for each hour, for the whole 24-hour period, and for daytime, nighttime, and work time. Subjects were interviewed about somatic complaints, demographic data, and health habits, and body mass index was measured., Results: After controlling for possible confounders, a positive association was found between the somatic complaint score and 24-hour, diurnal, and work-time systolic blood pressure (p = .014, p = .007, and p = .008, respectively). The association with casual systolic blood pressure was of borderline significance (p = .089). There was a positive trend, which did not reach statistical significance, in the relationship between somatic complaint score and all measures of diastolic blood pressure. Diurnal, 24-hour, and work-time heart rates were highest in the subjects with the highest somatic scores (p < .01 for all trends)., Conclusions: In healthy normotensive men, somatic complaints are associated with an increased cardiovascular load. The effects of this increase on long-term cardiovascular morbidity and mortality are uncertain and warrant additional study.

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 beta= -0.2704, P=.0051). A similar trend of borderline significance was found for the association between calcitriol and diastolic blood pressure (standardized beta= -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 mmHg, P=.007, and difference=4 mmHg, 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.

In general, blood pressure is higher in winter than in summer, and this factor may be partly responsible for the higher mortality from cardiovascular disease in winter. Cigarette smoking causes an acute pressor response that may interact with this cardiovascular response to cold exposure. We sought to determine whether the seasonal variation in blood pressure and heart rate differs between cigarette smokers and nonsmokers. We evaluated 24-hour ambulatory systolic blood pressure (SBP), ambulatory diastolic blood pressure (DBP), and ambulatory heart rate of 97 healthy men (73 nonsmokers and 24 smokers), 28 to 63 years of age, during the summer and winter, taking indoor temperatures into consideration. Smokers and nonsmokers both had higher daytime ambulatory SBPs and DBPs in winter than in summer (after adjustment for potential confounders). However, the winter increase seen in the smokers was significantly higher for mean daytime SBP (7.3 versus 2.7 mm Hg, P<.01), for mean daytime DBP (4.4 versus 3.1 mm Hg, P=.051), and for ambulatory heart rate (3.9 versus -1.7 beats/min, P<.001). The double product increased from summer to winter (daytime) by 10.53 for smokers and by only 0.11 for nonsmokers (P<.01). There was an independent interaction between season and smoking status that affected SBP (standardized beta=0.66, P<.0001) and DBP (standardized beta=0.32, P<.0001). Smokers have a greater seasonal variation in blood pressure and heart rate than nonsmokers and show a larger increase in the cardiovascular load in winter. Smoking apparently potentiates the cardiovascular response to various climatic conditions. Season should be taken into account in studies of blood pressure and in the diagnosis and treatment of hypertension, particularly among cigarette smokers.

Background: Many persons exhibit an elevation in blood pressure (BP) when examined in a medical setting. We examined whether individuals exhibiting an exaggerated pressure response (high responders) to BP determination would have an elevated baseline BP on follow-up, independent of the initial BP level., Methods and Results: A total of 1217 employed men not on hypertensive medication, aged 20-64 years were examined over 2-4 years (mean 2.6 years) following the baseline measurements at entry. Pressure response was assessed at entry and defined as the difference between the first and fourth values in successive readings. Such a response was apparent for systolic BP (SBP) but was negligible for diastolic BP (DBP) and the former was negatively related to the baseline BP value. High responders were defined as persons showing a pressure response greater than the average for the respective subgroup with an initially similar baseline BP value. Logistic regression results indicated that those with high SBP responsivity had a 2.7 times greater chance of having an elevated SBP (> or = 140 mm Hg) on follow-up (95% CI 1.8-4.1, P < 0.001), independently of initial SBP, age, or body mass index. Other significant predictors were the initial baseline SBP value and age. In those with an initial SBP of 130-139 mm Hg, the baseline SBP was not predictive of future readings whereas high responders had a four times higher risk of having an elevated SBP on follow-up (OR = 4.0, 95% CI 2.0-8.0, P < 0.001)., Conclusions: These findings suggest that SBP hyperresponsivity, to BP determination at the clinic independently predicts elevated SBP 2.6 years later. Further studies are warranted to determine the predictive value over a longer follow-up period.

Seasonal changes in blood pressure may be partially explained in thermoregulatory terms. We hypothesized that the seasonal variation in blood pressure is related to body mass index, due to the increased thermoregulatory requirements of leaner individuals. Ambulatory systolic and diastolic blood pressure were monitored once each in summer and winter in 101 healthy normotensive men aged 28 to 63 years. Environmental conditions and body mass index were measured. The population was divided according to quartiles of body mass index. The percentage of subjects with systolic blood pressure increases of more than 10 mm Hg from summer to winter was highest among subjects in the lowest body mass index category, and lowest among those in the highest body mass index category (35% and 8%, respectively, P < .0001). After adjusting for possible confounders, the change in mean systolic blood pressure from summer to winter was inversely associated with body mass index (beta = -0.26, P = .0149). There was no association between diastolic blood pressure change and body mass index. The increase in systolic blood pressure from summer to winter is inversely and independently associated with body mass index. Hypertension research and epidemiological blood pressure studies should take into account the interaction between season, body mass index, and blood pressure. It may also be important to assess hypertension and response to antihypertensive treatment in relation to season, particularly in lean hypertensives.

The effect of lead exposure on blood pressure in the modern industrial setting is controversial. In this study, we followed 67 workers in a lead-battery plant for 6-10 y, and blood pressure and blood lead levels were measured every 6 mo. Weight, height, alcohol intake, cigarette smoking, and age were recorded. Partial correlation coefficients showed that initial systolic blood pressure, age, and body mass index (i.e., weight/height squared) accounted for 25%, 30.9%, and 20.2%, respectively, of the variance in systolic blood pressure (p < .001 in all cases). Conversely, average blood lead levels (13 +/- 3 tests/worker) accounted for only 0.4% of the variance (not significant). Repeated-measures analysis of variance showed a small--but significant--association between blood lead levels and systolic blood pressure. There was a negative correlation between blood lead levels and diastolic blood pressure. There were 18 men with average blood lead levels that were less than 30 micrograms/dl (average = 25 +/- 3 micrograms/dl), and 32 men had levels of 40 micrograms/dl or more (average = 47 +/- 6 micrograms/dl). The mean final systolic blood pressure, adjusted for age, and initial systolic blood pressure were 117 +/- 13 mm Hg and 114 +/- 11 mm Hg, respectively. We concluded that blood lead levels had no clinically significant effect on blood pressure in lead-battery workers. The main predictors of the follow-up systolic blood pressure were age, body mass index, and initial systolic blood-pressure measurements.

Objective: The effect of indoor temperature control on summer and winter ambulatory blood pressure levels at work was studied., Method: Ambulatory systolic blood pressure (SBP) and diastolic blood pressure (DBP) were monitored once in summer and once in winter in 101 healthy normotensive subjects aged 28-63 years, engaged in similar physical work, from two plants with and three without air conditioning. Subjects were interviewed about health related habits, and measurements of environmental and occupational conditions were obtained., Results: After controlling for possible confounders, mean SBP and DBP during work were significantly higher in winter than in summer (delta SBP = 3.4 mm Hg, P = 0.035; delta DBP = 3.3 mm Hg, P < 0.003). The seasonal change in SBP and DBP showed an independent association with the presence or absence of air conditioning of the industrial plants (SBP: beta = 0.194, P < 0.0001; DBP: beta = 0.054, P = 0.038). The percentage of subjects with increases of more than 10 mm Hg from summer to winter was higher in plants without than with air conditioning., Conclusions: (1) In normotensive subjects ambulatory working BP varies by season, with higher values in winter. If validated for hypertensive subjects, it may be necessary to tailor drug treatment to these variations. (2) The findings make it clear that drawing valid conclusions from comparisons of BPs between groups requires controlling for several factors, particularly season of the year. (3) Climatic conditions in the industrial plant influence the magnitude of seasonal variations in BP. Work in plants without air conditioning places a considerable added load on the employee's cardiovascular system.

The effects of industrial noise on resting heart rate and blood pressure were studied in 3,105 blue-collar workers. Heart rate and blood pressure were measured in different workers at various times during the workday. After controlling for several possible confounders, we found that resting heart rate in females was associated positively with noise intensity (p = .036) and with time of day (p = .054). In males, resting heart rate was associated with noise intensity; however, such association was related to time of day (p = .046). No such associations were found for blood pressure in either sex. We plotted the mean resting heart rate by time of day for workers exposed to high [ > or = 80 db(A)] and low noise, and no difference was evident with respect to morning heart rate in either sex. After 4 h of noise exposure for males (and less time for females), individuals who were exposed to high noise had higher heart rates; however, in females this was not observed at the end of the workday. Thus, recurrent daily exposure to high noise at work has an acute, though not residual, effect on resting heart rate.

Research interest in the relationship between dietary calcium and blood pressure stemmed from observations that in some cases hypertension occurs concomitant with calcium abnormalities, and from the search for nonpharmacological ways to prevent or control hypertension. A possible association between dietary calcium and blood pressure has been the subject of more than 50 epidemiological studies in the last 15 years. This review encompasses a brief description of the sources of dietary calcium, the distribution of calcium in body compartments, and its physiological role in the regulation of blood pressure. The literature on calcium abnormalities in hypertensive patients, cross-sectional and prospective epidemiological studies, and clinical trials on dietary calcium and blood pressure is reviewed. Possible mechanisms of the hypotensive action of dietary calcium are evaluated. While cross-sectional studies provided considerable evidence of an inverse association between levels of dietary calcium and blood pressure, results of clinical trials and of the small number of prospective studies are inconsistent. However, it appears that calcium supplementation can reduce blood pressure in both subpopulations of normotensives and some hypertensives. Before any recommendation is made to increase dietary calcium to prevent hypertension, further investigations are needed to better define characteristics of those subgroups which may respond to such intervention.