Negative Affect-Related Autonomic Arousal Mediates the Association between Baroreflex Dysfunction and Insulin Resistance in Non-Diabetic Young Adults.

Autonomic dysfunction, in particular under-regulation of heart rate (HR) by the baroreflex, is implicated in development of insulin resistance (IR). According to reactivity hypothesis, sympathetic response to stressors may be more sensitive at predicting IR than baroreceptor sensitivity (BRS), a baseline measure of baroreflex functioning. Using ecological momentary assessment (EMA) of negative affect coupled with minute-to-minute HR and heart-rate variability (HRV) monitoring, we examined whether negative affect (NA)-related autonomic arousal mediates the association of BRS with IR. At baseline, BRS was measured, and fasting serum glucose and insulin levels were collected from 178 young adults (18-39 years old), from which homeostasis model assessment of IR (HOMA-IR) and beta-cell functioning (HOMA %B) were derived. Participants subsequently underwent one day of Holter HR and HRV monitoring while reporting negative affect levels via EMA. Multilevel modeling was used to assess the associations of momentary negative affect with HR and low- (LF) and high-frequency (HF) HRV during the 5-minute intervals following each EMA reading. Structural equation modeling was then used to determine whether individual differences in these associations mediated the association of BRS with IR, measured by HOMA-IR, HOMA %B, and insulin levels. As predicted, BRS was negatively associated with the IR (ß = -.17, p = .024). However, NA-related autonomic arousal mediated their association, accounting for 56% of the covariance between BRS and IR. Not only do these results provide support for reactivity hypothesis, they reveal a potential point of intervention in the treatment of affective dysregulation.

Knowledge Gaps around Smoking and Nicotine among U.S. Military Veterans Who Smoke and Implications for Practice.

The present study describes the knowledge about smoking and nicotine among a sample of current Iraq-/Afghanistan-era veterans who smoke (N = 117). A majority of participants had knowledge regarding general risks of smoking and benefits of nicotine replacement therapy. However, many participants underestimated their personal cardiovascular and cancer risk as a smoker. Many participants also inaccurately believed that nicotine causes cancer and that nicotine medications work by making one physically sick if used while smoking. These beliefs could lead to reluctance to use nicotine replacement therapy. Discussion of findings offers potential solutions in the form of patient education as well as emphasis on training healthcare providers training on best practices for patient education (beyond simple advice to quit). More nuance and detail in patient education may facilitate increased knowledge about smoking and nicotine among U.S. military veterans with the ultimate goal of increasing cessation rates.