Essential hypertension represents a major epidemic of the 21st century. It is a socially patterned disease and evidence suggests that the workplace plays an important etiologic role. The empirical data is strongest with respect to exposure to job strain (work characterized by high psychological demands and low decision-making latitude) and elevated ambulatory blood pressure at work. In the clinical setting, however, the widespread application of ambulatory blood pressure (AmBP) monitoring has focused attention upon white coat hypertension (elevated casual clinic BP (CCBP) with normal AmBP), an entity of low predictive value with respect to hypertensive sequelae. Meanwhile, work-related hypertension, which is often characterized by just the opposite pattern (normal CCBP and elevated work AmBP-or occult workplace hypertension), remains under-detected, despite its potential importance.
Initial case-control data are analyzed from the Work Site BP Study. There were 86 men with elevated CCBP and 181 with normal CCBP, all of whom underwent AmBP on a working day. A total of 27 men had white coat hypertension, while 36 had occult workplace hypertension. These figures suggest that among working populations the problem of occult workplace hypertension could be of even greater magnitude than that of white coat hypertension.
We performed stratified analysis of this sample, based upon self-reported exposure to job strain, with the aim of improving diagnostic accuracy. This appears to have been achieved with respect to the positive predictive value of CCBP. Among the 59 men who were exposed to job strain, there were only three cases of white coat hypertension. Thus, for those exposed to job strain, the positive predictive value of CCBP was high (87%) with respect to elevated AmBP at work. In contrast, among the 208 men classified as unexposed to job strain, twenty-four had white coat hypertension and the positive predictive value of CCBP was only 61.9%, with respect to increased AmBP at work. Thus, consideration of job strain status helped defined the group in whom white coat hypertension could be expected: those without exposure to job strain.
Stratifying by job strain was not as informative with respect to occult workplace hypertension (OWH). There was a relatively high percentage of OWH in both the unexposed and the exposed to job strain strata. This suggests that in addition to exposure to job strain, other job-related factors associated with workplace hypertension need to be taken into consideration.
We develop a preliminary algorithm to help detect work-related hypertension. Therein, AmBP monitoring is judiciously utilized for those cases where it is likely to provide the maximal clinical yield. Elsewhere, more widely applicable screening methods are suggested. The need for a public health approach incorporating workplace surveillance is underscored as the optimal strategy for tackling the epidemic of work-related hypertension.