Measures
Questionnaire items covered personal details: age and civil service
employment grade; self reported morbidity: self rated health
over the last year from the SF368 (fair or poor versus good, very
good or excellent), presence of longstanding illness, and minor
psychiatric morbidity, which was assessed using the 30-item
General Health Questionnaire9 and comprised GHQ score and
depression, measured using a 4-item depression subscale of
the GHQ, derived by factor analysis; and health related
behaviours: alcohol consumption over the recommended limits
(15 or more units/week for women and 22 or more units/week
for men),10 and smoking prevalence.
Negative affect or reporting bias was assessed at Phase 1
using the five negative affect items from Bradburn’s Affect
Balance Scale.11 Job insecurity was derived from a four
category single item asked of those in civil service employment
at Phase 4 and of all participants in employment at
Phase 5 (How secure do you feel in your present job?). For the
purpose of analysis, those whose job was insecure or very
insecure were compared with participants whose job was
secure or very secure.
Physiological measures
At the Phase 1 and Phase 5 screening examinations, blood
pressure in millimetres of mercury (mm Hg) was measured
twice with the participant seated after a five minute rest, using
a Hawksley random-zero sphygmomanometer. Blood was
taken and serum cholesterol concentration in millimoles/litre
(mmol/l) measured using the cholesterol oxidase/peroxidase
colorimetric method (BCL kit).Weight (wt) in kilograms and
height (ht) in metres were recorded. Body mass index (BMI)
was calculated from these two measures as wt/ht2. Further
details of these measures have been reported previously.