The Work Site Blood Pressure Study (WSBPS) in New York City
recently completed its fourth wave (1996-2001) of data collection.
It is the only long-term (up to 10 yrs) prospective study of job
strain and blood pressure (BP) employing ambulatory BP (AmBP)
monitoring. Analyses of these data allow us to estimate the effect
of job strain, and changes in job strain, on AmBP.
The sample consists of employed individuals in New York City,
30-60 years of age: 308 were enrolled from 8 work sites between
1985-88 (Time 1), 34 from a 9th site plus 27 women from 2 of the
original work sites between 1988-91 (Time 2), and 103 from a 10th
work site at the end of Time 3 (1991-96), for a total of 472 participants
(37% women, 33% non-Caucasian). Of the baseline sample, 94% were
successfully followed, 77% completing a full re-evaluation.
Prior cross-sectional findings from the WSBPS provide some evidence
for the effect of cumulative exposure. Relative to men without
job strain at either Time 1 or Time 2, those with exposure at
both times, i.e., "chronic exposure", had substantially
higher systolic (11-12 mm Hg) and diastolic (6-9 mm Hg) AmBP at
both Time 1 and Time 2, an effect that was greater than the cross-sectional
effects at either Time (6-7 mm Hg systolic and 2-5 mm Hg diastolic).
Prospective analyses, however, do not indicate a cumulative exposure
effect as there was no change in AmBP over 3 years in the chronic
exposure group (n=15).
There is also evidence that changes in job strain are associated
with changes in AmBP. Men reporting job strain at Time 1 but not
at Time 2 (n=25) exhibited a 3-year decrease in AmBP of 5.3/3.2
mm Hg at work and 4.7/3.3 mm Hg at home (p<.05). On the other
hand, there was no significant change of BP in the group whose
exposure changed from no job strain at Time 1 to job strain at
Time 2.
At this conference we will present the first analyses using all
four waves of data to re-evaluate 1) the cross-sectional effects
of current job strain at each assessment, 2) the cross-sectional
effects of cumulative job strain, and 3) the longitudinal association
between changes in job strain and changes in AmBP. These results
will provide a test of the generalizability of the prior findings
from the first two waves of the study.
CORRESPONDING AUTHOR: Joseph E. Schwartz, Department of Psychiatry and Behavioral Science, 139 Putnam Hall, SUNY - Stony Brook, Stony Brook, NY 11794