The Cornell University cohort study of 'job strain' and ambulatory
blood pressure, begun in 1985, has enrolled 372 initially healthy
full-time employees from a wide variety of job titles, aged 30-60,
most with at least 3 years tenure with their employer. Of the
372 participants, 80 (22%) are women, and 95 (25%) are members
of minority racial/ethnic groups, including 67 Black, 21 Hispanic
and 4 Asian participants. An additional 100 participants, nurses
and nurses aides from a new worksite (almost all are female and
50% members of minority groups), are being recruited in 1995 and
their evaluation will be completed by 11/1/95. Every three years,
participants wear an ambulatory (portable) blood pressure monitor
for 24 hours on a work day. Subjects also receive medical tests
and complete a questionnaire. Every 15 minutes during waking hours
(and during hourly sleep) the monitor inflates and records blood
pressure. During waking hours, the subject is asked to remain
as motionless as possible and then to record his/her activity,
location, position, and mood in a diary. The diary information
(i.e., whether the subjects reported being at work, home or sleep)
has been used to calculate average AmBPs for each location category.
The Cornell study was one of the first work stress studies to use an ambulatory blood pressure monitor. The monitor provides a more reliable measure of blood pressure, since there is no "observer bias" and the number of readings is increased. It also has a more valid (accurate) measure of average blood pressure than causal blood pressure measurements, since blood pressure is measured during a person's normal daily activities. Studies using an ambulatory monitor, including the Cornell study, have generally found positive associations between 'job strain' and blood pressure.