Failure of Post-Action Stages of the Transtheoretical Model to Predict Change in Regular Physical Activity: A Multiethnic Cohort Study

Background: Predicting variation in meeting recommended levels of physical activity is important for public health evaluation. Purpose: The purpose of this study is to determine the predictive value of stages of the Transtheoretical Model (TTM) for classifying people who meet the US Healthy People 2010 guideline for regular physical activity. Methods: A cohort (N = 497) from a random, multiethnic sample of 700 adults living in Hawaii was assessed at 6-month intervals three or more times for 2 years. Latent transition analysis was used to classify people according to TTM stages and separately according to whether they met the guideline. The predictive value of pre- vs. post-action stages was then tested. Results: Stages were more likely to falsely classify people as meeting the guideline than to falsely classify them as not meeting it. Probabilities of predicting 6-month transitions were about 50% for the stable class of meeting the guideline each time and just 25% for transitions between meeting and not meeting the guideline. Conclusion: The TTM post-action stages had limited usefulness in this cohort. Further longitudinal study is needed to determine whether TTM stages can accurately classify transitions from physical inactivity to physical activity below recommended levels

Posttraumatic Stress Disorder and Incidence of Coronary Heart Disease: A Twin Study

OBJECTIVES: To determine whether posttraumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. BACKGROUND: It has long been hypothesized that PTSD increases the risk of CHD but empirical evidence using objective measures is limited. METHODS: We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [N13] positron emission tomography, including a stress total severity score (STSS) and coronary flow reserve (CFR). RESULTS: A total of 562 twins (281 pairs) were included with mean age of 42.6 yrs at baseline. The incidence of CHD was more than double in twins with PTSD (22.6%) than those without PTSD (8.9%; p<0.001). The association remained robust after adjusting for lifestyle factors, other CHD risk factors and major depression (OR=2.2, 95% confidence interval, 1.2-4.1). STSS was significantly higher (+ 95%, p=0.001) and CFR lower (−0.21, p=0.02) in twins with PTSD than those without, denoting worse myocardial perfusion. Associations were only mildly attenuated within 117 twin pairs discordant for PTSD. CONCLUSIONS: Among Vietnam era veterans, PTSD is a risk factor for CHD

Early trauma and inflammation: role of familial factors in a study of twins.

OBJECTIVE: Although early trauma (trauma in childhood) has been linked to adult inflammation and adult disease of inflammatory origin, it remains unknown whether this relationship is due to long-term consequences of early life stress or other familial factors. METHODS: We examined 482 male middle aged twins (241 pairs) born between 1946 and 1956 from the Vietnam Era Twin Registry. Childhood traumatic experiences, before age 18, were measured retrospectively with the Early Trauma Inventory (ETI) and included physical, sexual, emotional abuse, and general trauma. Lifetime major depressive disorder and posttraumatic stress disorder were assessed with the Structured Clinical Interview for DSM IV. Traditional risk factors for cardiovascular disease were also assessed. Plasma C-reactive protein (CRP) and interleukin-6 (IL-6) were measured to determine levels of inflammation. Mixed-effect regression models with a random intercept for pair were used to separate between and within twin pair effects. RESULTS: When twins were analyzed as individuals, increasing levels of early trauma were positively related to CRP (p=0.03) but not IL-6 (p=0.12). When estimating within and between pair effects, only the between pair association of early trauma with the inflammatory markers remained significant. CONCLUSION: The link between early trauma and inflammation is largely explained by familial factors shared by the twins, because levels of inflammation were highest when both twins were exposed to trauma. Exposure to early trauma may be a marker for an unhealthy familial environment. Clarification of familial factors associated with early stress and adult inflammation will be important to uncover correlates of stress and disease

Abstract 14272: Posttraumatic Stress Disorder, Major Depression and Incidence of Coronary Heart Disease

Background. Posttraumatic stress disorder (PTSD) is an emerging risk factor for CHD, but is comorbid with major depressive disorder (MDD), an established CHD risk factor. We sought to determine the..

Effects of smoking on coronary microcirculatory function: A twin study

BACKGROUND: In asymptomatic smokers, coronary microcirculatory dysfunction, assessed by coronary flow reserve (CFR), is an early indicator of cardiovascular risk. Inflammation and oxidative stress may be the mechanisms through which smoking affects the microvasculature. OBJECTIVES: The purpose of this study was to determine the relationship between smoking and CFR, taking into account potential shared genetic effects. METHODS: We examined 360 male middle aged twins (288 non-smokers and 72 smokers), including 46 twin pairs discordant for current smoking. Coronary flow reserve (CFR) in response to adenosine was measured with positron emission tomography [N(13)] ammonia and quantitation of coronary blood flow at rest and after adenosine stress. Inflammation was assessed by measuring interleukin-6 and C-reactive protein, and oxidative stress was determined by measuring plasma hydroperoxides, glutathione (GSH), the oxidized form of GSH, GSSG, and the ratio of GSH to GSSG. RESULTS: CFR was significantly lower in smokers compared to nonsmokers (2.25 vs. 2.75, p<0.01). This relationship persisted after accounting for known cardiovascular disease risk factors, and was marginally affected by adjusting for inflammatory and oxidative stress biomarkers. In addition, in smoking-discordant twin pairs, CFR in the smoking twin was significantly lower than in the non-smoking co-twin (2.25 vs. 2.67, p = 0.03) even after adjustment for cardiovascular risk factors. CONCLUSIONS: Our results demonstrate the adverse effects of smoking in the early phases of cardiovascular disease. Mechanisms other than peripherally-measured inflammation and oxidative stress are involved