To investigate the association between psychological distress and obesity among law enforcement officers (LEOs) in the United States.
Self-reported data on psychological distress based on six key questions were obtained from LEOs who participated in the National Health Interview Survey (2004-2010). We used Prochaska's cut-point of a Kessler 6 score ≥ 5 for moderate/high mental distress in our analysis. Mean levels of body mass index (BMI) were compared across three levels of psychological distress.
The average age of LEOs (n = 929) was 39.3 years; 25% were female. Overall, 8.1% of LEOs had moderate or high psychological distress; 37.5% were obese (BMI ≥ 30). Mean BMI increased with increasing psychological distress (no distress, BMI = 27.2 kg/m2; mild distress, 27.6 kg/m2; and moderate/high distress, 33.1 kg/m2; p = 0.016) after adjustment for age, race, income, and education level among female officers only. Physical activity modified the association between psychological distress and BMI but only among male LEOs (interaction p = 0.002). Among male LEOs reporting low physical activity, psychological distress was positively associated with BMI (30.3 kg/m2 for no distress, 30.7 for mild distress, 31.8 for moderate/high distress; p = 0.179) after adjustment, but not significantly. This association was not significant among males reporting high physical activity.
Mean BMI significantly increased as psychological distress increased among female LEOs. A longitudinal study design may reveal the directionality of this association as well as the potential role that physical activity might play in this association.
The law enforcement profession is a highly stressful occupation. Law enforcement officers (LEOs) include police officers, detectives and criminal investigators, correctional officers, bailiffs, fish and game wardens, and parking enforcement workers. Police officers are required to be constantly on alert because they are likely to experience unexpected situations at any moment such as confrontation by criminals. In addition, they commonly work overtime and various shift schedules, and they experience administrative and organizational pressure and demands. These stressors could adversely affect their health and their lifestyle resulting in conditions such as posttraumatic stress disorder (PTSD) [
Protective service workers, police officers and firefighters, had the second highest obesity prevalence (29.8%) among 41 occupational categories, and the annual change in obesity prevalence (2.1% ± 0.8) was two times higher than that for the United States population (0.95% ± 0.11) in the period from 1997 to 2002 [
Several studies have reported that psychological distress is associated with obesity. Psychological distress elevated body mass index (BMI) [
Psychological factors like depression, anxiety, fatigue, and psychological trauma might be risk factors for obesity. The objective of this paper is to investigate the association between psychological distress and obesity among a cross-section of LEOs who responded over a seven-year period in the United States.
The National Health Interview Survey (NHIS), developed and administered by National Center for Health Statistics in the Centers for Disease Control and Prevention, is a nationwide survey on the health of the civilian non-institutionalized United States population [
In the Sample Adults questionnaire, participants were asked their height in inches ("How tall are you without shoes?") and their weight in pounds ("How much do you weigh without shoes?"). BMI was used to assess obesity, and was calculated as weight in kilograms divided by height in meters squared. We used BMI as both a continuous variable and a categorical variable (BMI < 25 kg/m2 for underweight/normal, 25 to < 30 kg/m2 for overweight, and ≥ 30 kg/m2 for obese).
There were six psychological distress questions for assessing the presence of a possible mental health condition that were designed for the United States NHIS, which are referred to as Kessler 6 (K6) [
The NHIS Sample Adult module collected socio-demographic information including age (≥ 18 years), gender, race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, non-Hispanic all other race groups), marital status (single/never married, married, separated/divorced/widowed), highest level of education completed (from never attended/kindergarten to doctoral degree), income earned last year (11 levels from USD 0 to USD 75,000 or more), having more than one job (yes, no), and number of years in the law enforcement profession. Lifestyle information included smoking status (never, former, current), alcohol status (never/former, current [≤ 3 drinks/week], current [> 3 drinks/week]), hours of sleep per day, and leisure-time physical activity (hours per week). To assess leisure-time physical activity, participants were asked to summarize their usual physical activity both in terms of frequency and duration while engaging in aerobic physical activity or muscle-strengthening activity. Hours of leisure-time physical activity per week was calculated based on the frequency and duration. The term "physical activity" in our study refers to leisure-time physical activity. After we assessed effect modification by physical activity and found that it was significant, we examined the association between psychological distress and obesity while stratifying on physical activity which was dichotomized at the median.
In order to more accurately represent the population of the United States, all analyses were performed using a weighting variable, which was divided by seven to take into consideration the seven survey years 2004-2010. Statistical comparisons of cross-tabulated prevalence and mean estimates were analyzed using chi-square tests or the Student's t-tests, respectively. We also investigated whether characteristics of the LEOs varied by survey year. After performing bivariate analysis, regression analyses were used to determine if psychological distress was associated with obesity. We assessed effect modification by gender due to the fact that women and men may process psychological distress in different ways and also tend to have different levels of BMI. We also assessed effect modification by physical activity because physical activity may influence both psychological distress and obesity. Since age, race, annual income, and education level were strongly associated with both psychological distress and BMI, we included them in the multivariate analysis as confounders. We also included age as confounder because it has been strongly related to psychological distress and BMI in previous studies [
The association between selected characteristics and psychological distress is presented in
Physical activity was a significant effect modifier in the relationship between the psychological distress and obesity among male LEOs (interaction p-value = 0.002) but not among female LEOs (interaction p-value = 0.860).
This study shows that psychological distress was positively associated with BMI in female LEOs. There are few published studies that have investigated the association between psychological distress and obesity among LEOs. However, many more studies have been identified that have investigated the association between work-related stress and obesity. Findings regarding the association between high work distress and obesity among workers show mixed results. One study found no significant association between work stress and obesity [
The current study found that the prevalence of serious psychological distress (K6 ≥ 13) among all LEOs was much lower (0.91%) compared to the average prevalence of United States working adults (1.57%). This result may suggest that LEOs are mentally healthy because good mental and physical health are pre-requisites for acceptance into the profession. Our study showed that female LEOs had more than triple the prevalence of serious psychological distress (i.e., K6 > 13) than male LEOs (2.03% vs. 0.56%, respectively) although overall prevalence was low. It is possible that female LEOs may experience greater occupational stress in the male-dominated profession of law enforcement [
Some individuals may use food as a means of coping with distress. Those with high levels of distress may change their food choices from healthy foods (e.g., low fat) to unhealthy foods (e.g., high hydrogenated fat) and may also increase their food consumption [
Some officers may drink alcohol to cope with the strains and pressures of their work or in socialization with coworkers. Davey et al. [
A recent study conducted on a sample of the United States police officers reported significant inverse associations between perceived stress and sleep duration [
One biological mechanism through which psychological stress may be associated with obesity is through increased cortisol production. Cortisol, a hormone which is secreted by the adrenal glands and is responsible for maintaining homeostasis, may be a physiological measure of stress. Chronic psychological stress prolongs high levels of cortisol, which have negative health effects such as hyperglycemia [
There are several limitations in this study. First, information bias may be present regarding BMI values due to the fact that height and weight were self-reported. Under-reporting weight and over-reporting height in the survey may have caused BMI to be underestimated, especially among obese women [
There are also strengths to this study. To our knowledge, this study is the first to investigate the association between psychological distress and obesity in current LEOs. The sample size allowed for adequate power even after stratification by gender and physical activity. Another major strength of this study is that it was conducted in a nationally representative sample of the United States population.
In summary, our study showed that psychological distress was positively associated with BMI in female LEOs. In the highly stressful work environment of law enforcement, it is quite possible that LEOs may be experiencing chronic stress. Identifying interventions to control stress or decrease its effect on overweight and obesity may be critical in female LEOs. A longitudinal study design may reveal the directionality of the association between psychological distress and BMI as well as the potential role that physical activity might play in this association.
No potential conflict of interest relevant to this article was reported. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.
Mean psychological distress scores in law enforcement officers by gender. "I" bar indicates the standard error.
Descriptive statistics for demographic and other characteristics of law enforcement officers by gender; NHIS (2004-2010)
Values are presented as percentage (standard error) or mean ± standard error.
Sample number/estimated population: all, 929/1,180,440; male, 698/950,237; female, 231/237,203; US workers, 105,862/131,822,554.
*p-values are for differences between women and men from Student's t-tests or χ2 tests for independence.
NHIS: National Health Interview Survey, GED: General Educational Development Test, BMI: body mass index; K6: Kessler 6.
Associations between psychological distress and selected characteristics in law enforcement officers: NHIS (2004-2010)
Values are presented as percentage (standard error) or mean ± standard error.
NHIS: National Health Interview Survey, K6: Kessler 6, GED: General Educational Development Test.
*For nominal variables (gender, race, marital status, smoke status, alcohol status, second job), the p-values were obtained from Cochran-Mantel-Haenszel analysis of variance-type test (SUDAAN 10 Example Manual, 2008). For continuous or ordinal variables (age, education, income, years of service, sleep duration, physical activity), the p-values were obtained from linear association.
Mean BMI by psychological distress and gender; NHIS (2004-2010)
Values are presented as mean ± standard error.
Model 1: unadjusted; Model 2: adjusted for age, race/ethnicity; Model 3: adjusted for age, race/ethnicity, annual income, and education.
*The p-values are from linear regression.
Interaction p-value = 0.192 for psychological distress*gender.
BMI: body mass index, NHIS: National Health Interview Survey, K6: Kessler 6.
Unadjusted and adjusted mean BMI across psychological distress categories stratified by physical activity among male law enforcement officers, NHIS (2004-2010)
Values are presented as number or mean ± standard error.
Model 1: unadjusted; Model 2: adjusted for age, race/ethnicity; Model 3: adjusted for age, race/ethnicity, annual income, and education.
*The p-values are from linear regression models.
Interaction p-value <0.002 for psychological distress*physical activity among male law enforcement officers.
BMI: body mass index, NHIS: National Health Interview Survey, K6: Kessler 6, PA: Physical Activity.