BUFFALO, N.Y. -- A police officer who works the night shift,
typically from 8 p.m. to 4 a.m., already is at a disadvantage when
it comes to getting a good "night's" sleep.
Add frequent overtime to that schedule, and an officer may be
climbing into bed as the sun comes up, setting the stage for short
and unrestful slumber.
A new study published in the current issue of Archives of
Environmental & Occupational Health (vol. 64, No. 3) shows that
this combination of night work, overtime and shortened sleep can
contribute to the development among police officers of the
metabolic syndrome, a combination of unhealthful factors that
increase the risk of cardiovascular disease (CVD), primarily heart
disease and stroke.
John M. Violanti, PhD, research associate professor in UB's
Department of Social and Preventive Medicine in the School of
Public Health and Health Professions, is first author on the paper,
and received significant contributions from biostatisticians in the
CDC's National Institute for Occupational Safety and Health
"These findings reinforce the scientific value of studying the
effects of occupation on cardiovascular risk factors," said
Violanti. "This is especially important in first responders, who
are selected on initial good overall physical and mental health.
Exploring specific job-related associations, such as shift work,
add to the benefit of such investigations."
The research is based on data from the Buffalo Cardio-Metabolic
Occupational Police Stress (BCOPS) study, which has been ongoing
since 2003. Metabolic syndrome is defined as abnormalities in any
three of five important clinical measures: abdominal obesity,
triglycerides, high-density lipoproteins (HDL), blood pressure and
fasting glucose level.
This baseline study involved 98 police officers who were
selected randomly from a total of 934 officers. Clinic personnel in
UB's Center for Preventive Medicine obtained a fasting blood
sample, and measured systolic and diastolic blood pressure and
waist circumference, and participants also completed an extensive
questionnaire on demographics and lifestyles choices.
Researchers obtained day-by-day data on shift-work and overtime
hours from payroll records.
Results showed that overall, 30 percent of officers working the
night shift had metabolic syndrome, compared to 21 percent in the
National Health and Nutritional Examination Survey (NHANES III),
which is based on data collected from the overall general
However, officers in the night shift were younger on average
than those working the day shift -- 36.5 years vs. 42.6 years --
but despite their younger age, the percentage with metabolic
syndrome (30 percent) was higher than the 24-percent average for
the 30-39 age group in the general population.
"This slightly higher prevalence at a younger age coincides with
police mortality cohort studies, which found a higher risk of CVD
among younger officers," said Violanti. "This finding is in
contrast to that in the general population, in which CVD risk
increases with age.
"One potential explanation for this unusual finding is that
midnight-shift officers were most likely to be sleep deprived
because of difficulties associated with day sleeping. Sleep debt
has been shown to have a harmful impact on carbohydrate metabolism
and endocrine function, which could contribute to metabolic
The percentages of several factors related to risk of metabolic
syndrome were higher in night-shift officers than in the general
population, as well as in day and evening-shift officers in the
• 55 percent had elevated waist circumference, compared to
50 percent and 30 percent for women and men
• 50 percent had low HDL cholesterol levels, compared to 38
percent and 35 percent in women and men, respectively.
• Hypertension and glucose intolerance, an indication of
diabetes, were more prevalent in night-shift officers.
In addition, officers who worked midnight shifts and had less
than six hours sleep had a significantly higher average of
metabolic-syndrome components than those who worked day shifts.
"Information from this study could help guide further
investigation into health of first responders," Violanti said, "not
only of police officers, but firefighters, emergency medical
technicians, nurses, physicians, air traffic controllers and the
"Results of this study, and possible future prospective studies,
may add to our existing knowledge of the associations between shift
work and cardiovascular health in high-risk occupations."
The research was supported by a grant to Violanti from
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