Carolyn Noonan

Chronic Pain, Overweight, and Obesity: Findings from a Community-Based Twin Registry

UNLABELLED Chronic pain and obesity, and their associated impairments, are major health concerns. We estimated the association of overweight and obesity with 5 distinct pain conditions and 3 pain symptoms, and examined whether familial influences explained these relationships. We used data collected from 3,471 twins in the community-based University of Washington Twin Registry. Twins reported sociodemographic data, current height and weight, chronic pain diagnoses and symptoms, and lifetime depression. Overweight and obese were defined as body mass index of 25.0 to 29.9 kg/m(2) and >or= 30.0 kg/m(2), respectively. Generalized estimating equation regression models, adjusted for age, gender, depression, and familial/genetic factors, were used to examine the relationship between chronic pain, and overweight and obesity. Overall, overweight and obese twins were more likely to report low back pain, tension-type or migraine headache, fibromyalgia, abdominal pain, and chronic widespread pain than normal-weight twins after adjustment for age, gender, and depression. After further adjusting for familial influences, these associations were diminished. The mechanisms underlying these relationships are likely diverse and multifactorial, yet this study demonstrates that the associations can be partially explained by familial and sociodemographic factors, and depression. Future longitudinal research can help to determine causality and underlying mechanisms. PERSPECTIVE This article reports on the familial contribution and the role of psychological factors in the relationship between chronic pain, and overweight and obesity. These findings can increase our understanding of the mechanisms underlying these 2 commonly comorbid sets of conditions.

Neurologic Signs and Symptoms in Fibromyalgia

OBJECTIVE To determine the type and frequency of neurologic signs and symptoms in individuals with fibromyalgia (FM). METHODS Persons with FM (n = 166) and pain-free controls (n = 66) underwent systematic neurologic examination by a neurologist blinded to disease status. Neurologic symptoms lasting at least 3 months were assessed with a standard questionnaire. We used logistic regression to evaluate the association of neurologic symptoms and examination findings with FM status. Within the FM group we examined the correlation between self-reported symptoms and physical examination findings. RESULTS Age- and sex-adjusted estimates revealed that compared with the control group, the FM group had significantly more neurologic abnormalities in multiple categories, including greater dysfunction in cranial nerves IX and X (42% versus 8%) and more sensory (65% versus 25%), motor (33% versus 3%), and gait (28% versus 7%) abnormalities. Similarly, the FM group had significantly more neurologic symptoms than the control group in 27 of 29 categories, with the greatest differences observed for photophobia (70% versus 6%), poor balance (63% versus 4%), and weakness (58% versus 2%) and tingling (54% versus 4%) in the arms or legs. Poor balance or coordination, tingling or weakness in the arms or legs, and numbness in any part of the body correlated with appropriate neurologic examination findings in the FM group. CONCLUSION This blinded, controlled study demonstrated neurologic physical examination findings in persons with FM. The FM group had more neurologic symptoms than did the controls, with moderate correlation between symptoms and signs. These findings have implications for the medical evaluation of patients with FM.

A twin study of depression and migraine: evidence for a shared genetic vulnerability.

Objective.— To determine if shared genetic or environmental vulnerabilities could underlie depression and migraine.

The relationship between post-traumatic stress disorder, depression and cardiovascular disease in an American Indian tribe

BACKGROUND Empirical findings suggest that psychiatric illness is associated with cardiovascular disease (CVD). The purpose of this study was to compare the strength of the association of lifetime post-traumatic stress disorder (PTSD) and lifetime major depression on CVD among Northern Plains American Indians. METHOD A total of 1414 participants aged 18-57 years completed a structured interview that assessed psychiatric diagnoses, alcohol abuse/dependence, self-reported CVD, and traditional CVD risk factors including age, sex, education, diabetes, high blood pressure, and smoking. Logistic regression analyses compared the odds ratios of CVD in participants with and without diagnosed PTSD or major depression. RESULTS The rates of lifetime PTSD and major depression were 15% and 8% respectively. CVD was more commonly reported by participants with PTSD than by those without PTSD (12% v. 5%, p<or=0.01). Likewise, more participants with major depression reported CVD than did their non-depressed counterparts (14% v. 6%, p<or=0.05). PTSD was significantly associated with CVD even after controlling for traditional CVD risk factors and major depression (odds ratio 2.0, confidence interval 1.1-3.8). In contrast, the association of major depression with CVD was not significant after accounting for both traditional risk factors and PTSD. CONCLUSIONS Rates of PTSD are high in American Indian communities. Rising CVD rates in this population may be better understood if PTSD is considered along with other traditional risk factors. Future research should examine the association and mechanisms of PTSD and CVD prospectively. Such data could lead to more effective CVD prevention efforts for American Indians.

Unique Environmental Effects on Physical Activity Participation: A Twin Study

Background The health benefits of regular physical activity are well established. However, the relative contribution of heritable and environmental factors to physical activity participation remains controversial. Using a cut-point of 60 minutes of total activity per week, data from the GenomEUtwin project revealed consistent genetic influence on physical activity participation in 37,051 twin pairs from seven countries. We hypothesized that the heritability of physical activity participation would be attenuated using the CDC/ACSM recommended minimum threshold of 150 minutes of moderate intensity activity per week. Methods Data were obtained from 1,389 twin pairs from the community-based University of Washington Twin Registry. Twin similarity in physical activity participation using both cut-points was analyzed using tetrachoric correlations and structural equation modeling in all same-sex pairs. Results Correlations were higher in monozygotic (rMZ = 0.43, 95% CI = 0.33–0.54) than dizygotic pairs (rDZ = 0.30, 95% CI = 0.12–0.47) using the 60 minute cut-point. However, differences were attenuated using the 150 minute standard (rMZ = 0.30, 95% CI = 0.20–0.40; rDZ = 0.25, 95% CI = 0.07–0.42). Using the lower cut-point, the best fitting model of twin resemblance only included additive genetics and unique environment, with a heritability of 45%. In contrast, using the higher threshold, the best fitting model included the common and unique environment, with the unique environment contributing 72% of the variance. Conclusion Unique environment factors provide the strongest influence on physical activity participation at levels recommended for health benefits.

A twin study of cognitive function in chronic fatigue syndrome: the effects of sudden illness onset.

Variable reports of neuropsychological deficits in individuals with chronic fatigue syndrome (CFS) may, in part, be attributable to methodological limitations. In this study, these limitations were addressed by controlling for genetic and environmental influences and by assessing the effects of comorbid depression and mode of illness onset. Specifically, the researchers conducted a co-twin control study of 22 pairs of monozygotic twins, in which 1 twin met strict criteria for CFS and the co-twin was healthy. Twins underwent a structured psychiatric interview and comprehensive neuropsychological assessment evaluating 6 cognitive domains. Results indicated that twin groups had similar intellectual and visual memory functioning, but fatigued twins exhibited decreases in motor functions (p = .05), speed of information processing (p = .02), verbal memory (p = .02), and executive functioning (p = .01). Major depression did not affect neuropsychological functioning among fatigued twins, although twins with sudden illness onset demonstrated slowed information processing compared with those with gradual onset (p = .01). Sudden onset CFS was associated with reduced speed of information processing. If confirmed, these findings suggest the need to distinguish illness onset in future CFS studies and may have implications for treatment, cognitive rehabilitation, and disability determination.

Salivary cortisol among American Indians with and without posttraumatic stress disorder (PTSD): Gender and alcohol influences

Disruptions in hypothalamic-pituitary-adrenal regulation and immunity have been associated with posttraumatic stress disorder (PTSD). We examined the association of PTSD with diurnal rhythms in salivary cortisol in a convenience sample from a population-based study of male and female American Indians. Subjects with and without PTSD were identified from American Indians living on/near a Northern Plains reservation as part of a larger study. Over two days diurnal saliva samples were collected by staff at the University of Colorado Denver Clinical Research Center at waking, 30min after waking, before lunch, and before dinner. Generalized estimating equations linear regression models investigated the influence of PTSD on cortisol over time. The association of a lifetime diagnosis of PTSD with salivary cortisol level was assessed in subjects with complete data (PTSD: n=27; no PTSD n=32) for age, gender, and alcohol consumption in the past month. Subject mean age was 44 years, and 71% were women. When stratified by gender, women with a lifetime diagnosis of PTSD had significantly higher mean cortisol levels throughout the day than women without PTSD (p=0.01); but there was no significant association between PTSD and cortisol levels in men (p=0.36). The cortisol awakening response - the difference in cortisol levels from waking to 30min after waking - was not associated with PTSD in men or women. A lifetime diagnosis of PTSD may influence diurnal cortisol among American Indian women. These effects were independent of influences of current alcohol use/abuse. The unexpected elevation in cortisol in American Indian women with a lifetime diagnosis of PTSD may reflect acute anxiety associated with experiencing a number of novel tests in a strange location (e.g., cardiac imaging, medical, dental exams, etc.), or concurrent depression.

Sensation-seeking predicts initiation of daily smoking behavior among American Indian high school students

PURPOSE American Indian (AI) youth have a high risk of smoking initiation. Sensation-seeking, defined as the tendency to seek novel and thrilling experiences, has been associated with smoking initiation in other groups but has never been examined in AI youth. METHODS Data were from the Voices of Indian Teens Project (VOICES), a longitudinal study of AI youth from seven high schools in four AI communities in the western United States. Participants completed annual surveys in school over a three-year period. Our sample comprised 764 students who were non-smokers at baseline. Smoking initiation was defined as endorsement of daily smoking after baseline. We used binary logistic regression to evaluate the association of baseline sensation-seeking with odds of daily smoking initiation, stratified by gender. RESULTS Participants were 353 males and 411 females aged 13 to 21years at baseline. After adjusting for covariates, baseline sensation-seeking correlated with smoking initiation differently in males and females. Sensation-seeking did not predict daily smoking in males. Among females, however, higher sensation-seeking scores at baseline predicted daily smoking in both the unadjusted (odds ratio=1.4; 95% CI=1.1-1.8; p=0.005) and covariate-adjusted (odds ratio=1.3; 95% CI=1.0-1.6; p=0.04) models. CONCLUSION Gender-specific prevention programs may be warranted in addressing different risk-factor profiles in this high-risk population.

C-Reactive Protein and Pain Sensitivity: Findings from Female Twins

BackgroundSystemic inflammation and pain sensitivity may contribute to the development and maintenance of chronic pain conditions.PurposeWe examined the relationship between systemic inflammation as measured by C-reactive protein (CRP) and cold pain sensitivity in 198 female twins from the University of Washington Twin Registry. We also explored the potential role of familial factors in this relationship.MethodsLinear regression modeling with generalized estimating equations examined the overall and within-pair associations.ResultsHigher levels of CRP were associated with higher pain sensitivity ratings at pain threshold (p = 0.02) and tolerance (p = 0.03) after adjusting for age, body mass index, time to reach pain threshold or tolerance, and clinical pain status. The magnitude of the associations remained the same in within-pair analyses controlling for familial factors.ConclusionsThe link between CRP and pain sensitivity may be due to non-shared environmental factors. CRP and pain sensitivity can be examined as potential biomarkers for chronic pain and other inflammatory conditions.

Genetic and environmental influences on restrained eating behavior

OBJECTIVE We examined the relative contributions of genetic and environmental influences to restrained eating. METHOD Restrained eating was assessed by the Restraint Scale in a survey mailed to all twins enrolled in the University of Washington Twin Registry. We used structural equation modeling to estimate genetic and nongenetic contributions to restrained eating. RESULTS 1,196 monozygotic (MZ), 456 same-sex dizygotic (DZ) twins, and 447 opposite-sex twins were included in analyses. Restraint Scale scores were more closely correlated in MZ twins (r(male) = .55, r(female) = .55) than in same-sex DZ twins (r(male) = .31, r(female) = .19). Based on structural equation modeling, the estimated heritability for restrained eating, adjusted for body mass index (BMI) and sex, was 43% (95% confidence interval 35-50%). There was little evidence for common environmental effects. DISCUSSION These results indicate an inherited component to restrained eating. Genes could influence restrained eating directly or through inherited mediators such as personality factors or tendencies to gain weight.