The objective was to determine if a cluster of chronic fatigue
syndrome (CFS)-like illness had occurred among employees in
two large state office buildings in northern California, and
to identify risk factors for and features of fatiguing illness
in this population.
DESIGN: case-control study.
POPULATION AND SETTING: Over 3300 current employees in two
state office buildings and employees in a comparable "control"
building. Information was collected on demographic and occupational
variables, the occurrence of fatiguing illness for at least
one month in the previous year, and the presence of 36
RESULTS: A total of 3312 (82%) of 4035 employees returned
questionnaires. Overall, 618 (18.7%) persons reported fatigue
lasting at least one month; including 382 (11.5%) with fatigue
of at least six months' duration and 75 (2.3%) with symptoms
compatible with a CFS-like illness. Independent risk factors
for fatigue lasting one month or longer were found to be
Native American ethnicity (OR 2.4, CI 1.1,5.3), Hispanic
ethnicity (OR 1.7, CI 1.3,2.3), female sex (OR 1.5, CI
1.2,1.9), gross household incomes of less than $50,000 (OR
1.3, CI 1.1,1.6), and less than a college education (OR 1.3,
CI 1.1,1.6). Similar risks were observed for persons who
reported fatigue lasting six months or longer. Female sex (OR
3.2, CI 1.7, 6.4) was the only independent risk factor found
for those persons classified as having a CFS-like illness.
Case prevalence rates for all three categories of fatigue, as
determined by multivariate analysis, were not significantly
different among buildings. Despite finding a substantial
number of employees with fatiguing illness in the two state
office buildings, the prevalence was not significantly
different than that for a comparable control building.
Previously unidentified risk factors for fatigue of at least
one month and at least six months identified in this
population included Hispanic ethnicity, not having completed
college, and income below $50,000.
MCM: From 1994 AACFS meeting in Ft. Lauderdale