Department of Kinesiology

Iowa law enforcement officers mortality rate study findings

• W.D. Franke, D.F. Anderson, S.A. Collins, D.P. Schultz, D.F. Cox* and P.N. Hinz*
  Departments of Health and Human Performance and *Statistics
  Iowa State University, Ames, IA
  

Considerable evidence suggests that law enforcement officers (LEO) have a higher mortality rate than the "general population." Why?

A number of studies have seen higher death rates in LEO due to the following: higher suicide rates, higher rates of some cancers, higher rates of liver and digestive diseases, higher rates of homicide, and higher rates of cardiovascular disease-related deaths.

However, not all studies have found an excessive CVD mortality in LEO. Why not?

In the last 15 yrs, the national death rate due to CVD has declined 24%, yet the number of hospital discharges related to CVD has remained stable. Therefore, CVD-related mortality may have declined in LEO even though the incidence (or morbidity) may have increased. Thus, only studying mortality data may result in erroneous conclusions about the relationship between LEO and CVD.

Do LEO have a higher incidence (or morbidity) of CVD than other people?

YES. We compared the prevalence of CVD in 232 retirees of the Iowa Dept. of Public Safety to 817 similarly-aged Iowans. The incidence of CVD in the LEO was ~1.7 times that of the Iowans (31.5% vs 18.4%; P<0.001). (Franke et al., JOEM, 40:441-444, 1998)

Is this due to conventional CVD risk factors?

NO. After controlling for the effects of these risk factors via multiple logistic regression, this relationship remained. Moreover, the LEO profession was as strong a risk factor as other more common risk factors (see Table 1). Thus, LEO have an increased risk for CVD that is not due to common risk factors and appears to be due to either risk factors that were not accounted for or unique aspects of the population. Based on feedback from the surveyed officers, we hypothesize that contributing factors may be the stress of the job, poor eating habits and rotating shiftwork. (Franke et al., JOEM, 40:441-444, 1998)

* significant contributor to CVD (P<0.05)

Researchers have found LEO to have a high number of CVD risk factors.

They have suggested that these risk factors are resulting in higher CVD rates. However, the U.S. population has a high prevalence of CVD risk factors, so it is uncertain if the high rates seen in LEO are 1) higher than the U.S. averages and 2) related to their profession or simply a reflection of the U.S. population. Do LEO have more CVD risk factors and, if so, is this why they have a higher CVD morbidity? NO. We compared the number and severity of several common risk factors in 388 LEO to similarly-aged subjects in the Framingham Heart Study cohort. Based on these risk factors, the 10-year risk of developing CVD in the LEO did not differ significantly from the control group (8.9 vs 7.9%; P>0.3). Consequently, the higher CVD-related morbidity seen in LEO is not due to a higher prevalence of CVD risk factors. (Franke et al., Am J Ind Med, 31:733-737, 1997)

Researchers have found LEO to have a below average risk of CVD early in their careers but an above average risk late in their careers.

Because of rigorous pre-employment screening, LEO are usually in above average health and lower-than-average risk for CVD at the start of their careers. However, researchers have suggested that, over the course of their careers, officers develop CVD risk factors at a faster rate than others. Thus, it has been postulated that the higher CVD rates seen in LEO may be due to older officers having a relatively higher risk for CVD than similarly-aged non-LEO. This difference is presumed to be due to their profession.

Over time, do LEO develop CVD risk factors more rapidly than the average person?

NO. We compared the age-associated increase in CVD risk seen over a 13 year period between 246 LEO and similarly-aged members of the Framingham Heart Study cohort. The increase in CVD risk did not differ significantly between the two groups (0.63 vs 0.60% per year; P>0.4) nor did the associated regression equations relating age to CVD risk. (Franke et al., Am J Ind Med, 31:733-737, 1997)

Does physical activity reduce the risk for CVD in LEO?

YES. We compared the 10-year risk for developing CVD (based on risk factors) in active and inactive LEO. While active officers were more fit than their inactive counterparts (Figure 1; P<0.001), physical activity indirectly reduced CVD risk by reducing risk factors on CVD only in officers >48 yrs old. Of course, in all the active officers, activity reduced CVD risk in a direct manner that we could not quantify. Thus, physical activity is associated with both direct and indirect reductions in CVD in LEO but the latter has the largest impact on older LEO. (Franke and Anderson, JOM, 36:1127-1132, 1994)

Acknowledgements

The authors thank the Iowa Department of Public safety for funding, in part, this research and the dozens of graduate and undergraduate students who have assisted in the data collection process since this project began in 1992.