The cortisol response in policemen: Intraindividual variation, not concentration level, predicts truncal obesity

Health Effects Laboratory Division (HELD), Biostatistics and Epidemiology Branch, National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia.
American Journal of Human Biology (Impact Factor: 1.7). 07/2013; 25(4). DOI: 10.1002/ajhb.22397
Source: PubMed


Chronic stress, characteristic of police work, affects the hypothalamic-pituitary-adrenal axis' control of cortisol production. Capacity to vary cortisol may be the appropriate measurement to interpret associations with chronic diseases, including obesity, best measured by variability within a person, not central tendency.

On each of 217 policemen, 18 saliva specimens were obtained for cortisol. Statistical models examined the associations of within-subjects (W-S) cortisol standard deviation (SD) and W-S cortisol mean with waist circumference and four body composition indexes: BMI, and three derived from DEXA: fat-mass, and trunk and extremities lean-mass. Explained variance and the functional nature of associations are reported.

Associations of anthropometrics with W-S cortisol mean were not statistically significant at P < 0.05; all associations with W-S cortisol SD were significant. The association of trunk lean mass index (LMIt ) with W-S cortisol SD dominated all models. Associations of W-S cortisol SD with other indexes vanished when models contained LMIt ; when any other index was included in models predicting LMIt , associations with W-S cortisol SD remained significant. The functional association between LMIt and W-S cortisol SD is progressively "hockey stick," monotonic increasing, and flattens at joint high values.

Results support inferences that LMIt measures visceral adiposity and W-S cortisol variability appears to be an appropriate construct to measure in association with visceral adiposity. The "hockey stick" character of the association is consistent with other investigations suggesting obesity is associated with less W-S cortisol variation; however, the monotonic increase and flattening of association at increasing W-ScortisolSD values suggests a more complex association, potentially interpretable by allostasis models of causation.

Download full-text


Available from: Diane Miller
  • Source
    • "Among the associations between the cortisol response across time and the individual components, abdominal obesity was most strongly associated with the cortisol response in our study. These results agree with a related study of variability in cortisol among these subjects in which visceral adiposity, as measured by lean trunk mass index, was consistently associated with within-subjects cortisol variability, but not with the within-subjects cortisol mean (Sharp et al., 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Policing is considered a high-stress occupation and officers have elevated cardiovascular morbidity and mortality. To investigate a potential connection, we evaluated the association between salivary cortisol response to a high-protein meal challenge and the metabolic syndrome (MetSyn), a subclinical disorder associated with increased cardiovascular risk. Cross-sectional data were from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Study (2004-2009). MetSyn was defined as having ≥3 components: abdominal obesity, hypertension, elevated triglycerides, reduced high-density lipoprotein cholesterol, and glucose intolerance. Officers provided five saliva samples for cortisol analysis, one before challenge (high-protein shake) and four at 15-min intervals thereafter, where the usual response is increase. Regression models were used to examine trends in mean number of MetSyn components across quartiles of area under the curve (AUC) salivary cortisol. Patterns of mean cortisol response were assessed by MetSyn status using repeated-measures analysis of covariance. Prevalence of MetSyn was 25.7% among 373 officers (74.0% male). The mean count of MetSyn components decreased (1.89, 1.75, 1.55, 1.37; P < 0.01) across increasing quartiles of AUC salivary cortisol. Mean salivary cortisol decreased from baseline (5.55, 4.58, 4.47, 4.79, 4.75 nmol/l) in officers with MetSyn and increased (5.08, 5.82, 5.92, 5.82, 5.60 nmol/l) in their counterparts. The test for interaction between MetSyn status and time of saliva collection was statistically significant (P < 0.001). Reduced cortisol response to a high-protein meal challenge may be associated with MetSyn. Future longitudinal studies could provide useful evidence for planning intervention studies on cardiovascular risk among police officers. Am. J. Hum. Biol. 00:000-000, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    Full-text · Article · Jun 2015 · American Journal of Human Biology