Maria M. Llabre

Validation of the insulin sensitivity index (ISI0,120): comparison with other measures ☆

The purpose of this study was to explore possible calculations using oral glucose tolerance test (OGTT) values in order to develop a simple measure of insulin sensitivity. We devised a formula for an insulin sensitivity index, ISI(0,120), that uses the fasting (0 min) and 120 min post-oral glucose (OGTT) insulin and glucose concentrations. It appears to be generalizable across a spectrum of glucose tolerance and obesity. Most importantly, our data show that ISI(0,120) correlates well, when applied prospectively in comparative studies, with the insulin sensitivity index obtained from the euglycemic hyperinsulinemic clamp (r = 0.63, P < 0.001). This correlation was demonstrably superior to other indices of insulin sensitivity such as the HOMA formula presented by Matthews, and performed comparably to the computerized HOMA index. Measurement of insulin sensitivity has traditionally been possible only in research settings because of the invasiveness and expense of the methods used. Clinical investigators have therefore sought more practical methods to obtain an index of insulin sensitivity. Such an index should approximate insulin sensitivity as measured by the euglycemic hyperinsulinemic clamp (M). We present ISI(0,120), a simple yet sensitive measure of insulin sensitivity which is adaptable for use in clinical settings as well as large epidemiologic studies.

Cognitive impairments associated with early Parkinson's disease

We administered a battery of cognitive tests to 41 recently diagnosed Parkinson patients and 41 controls to assess the early neuropsychological changes associated with Parkinsons disease (PD). Parkinson subjects did as well as controls on tasks assessing attention and select language and visuospatial measures. However, PD subjects did significantly worse on embedded figures, facial recognition, proverbs, and verbal and figural memory measures, and made more perseverative responses on a set shifting task. A discriminant function of measures of proverbs, embedded figures, and memory accounted for 22% of the variance between groups. These data suggest that the cognitive changes in early PD are more pervasive than originally described and may reflect the onset of a more widespread pathologic process.

Parkinson's disease and depression: psychometric properties of the Beck Depression Inventory

Although the Beck Depression Inventory (BDI) is one of the most frequently employed measures of depression in Parkinsons disease, the somatic items included in the scale raise questions about its ability to differentiate depression from manifestations of the disease. The internal consistency and validity of the BDI as a measure of depression in a sample of 119 Parkinsons disease patients and 76 controls were studied. Results from an item analysis suggested that depression in Parkinsons disease patients is not a somatic artifact. Internal consistency reliability within the Parkinsons disease group was high. The factorial validity of the BDI was confirmed in both Parkinsons disease and control subjects. The results also indicated that Parkinsonian symptoms of depression can be measured separately from symptoms of the disease. These data suggest that the BDI including the somatic items is a reliable and valid measure of depression in Parkinsons disease and control subjects.

Prevalence of Diabetes Among Hispanics/Latinos From Diverse Backgrounds: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

OBJECTIVE We examine differences in prevalence of diabetes and rates of awareness and control among adults from diverse Hispanic/Latino backgrounds in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). RESEARCH DESIGN AND METHODS The HCHS/SOL, a prospective, multicenter, population-based study, enrolled from four U.S. metropolitan areas from 2008 to 2011 16,415 18–74-year-old people of Hispanic/Latino descent. Diabetes was defined by either fasting plasma glucose, impaired glucose tolerance 2 h after a glucose load, glycosylated hemoglobin (A1C), or documented use of hypoglycemic agents (scanned medications). RESULTS Diabetes prevalence varied from 10.2% in South Americans and 13.4% in Cubans to 17.7% in Central Americans, 18.0% in Dominicans and Puerto Ricans, and 18.3% in Mexicans (P < 0.0001). Prevalence related positively to age (P < 0.0001), BMI (P < 0.0001), and years living in the U.S. (P = 0.0010) but was negatively related to education (P = 0.0005) and household income (P = 0.0043). Rate of diabetes awareness was 58.7%, adequate glycemic control (A1C <7%, 53 mmol/mol) was 48.0%, and having health insurance among those with diabetes was 52.4%. CONCLUSIONS Present findings indicate a high prevalence of diabetes but considerable diversity as a function of Hispanic background. The low rates of diabetes awareness, diabetes control, and health insurance in conjunction with the negative associations between diabetes prevalence and both household income and education among Hispanics/Latinos in the U.S. have important implications for public health policies.

Physical symptoms, beliefs about medications, negative mood, and long-term HIV medication adherence

Background: Near-perfect levels of HIV medication adherence are necessary for treatment to be successful. However, many patients continue to report nonadherence to HIV treatment.Purpose: This study examines the relationship between symptoms of HIV and medication adherence and evaluates beliefs about HIV medications and negative mood states as potential mediators of this relationship.Methods: These relationships were tested with structural equation modeling using a 15-month longitudinal design. The ethnically diverse convenience sample included 325 HIV-infected men who have sex with men and women prescribed Highly Active Antiretroviral Therapy (HAART).Results: Results showed that a greater number of symptoms were associated with poorer medication adherence, and this relationship was partially mediated by increases in concerns about HAART. Contrary to expectations, negative mood states were not directly related to medication adherence. In the final model, concerns about HAART and general distrust of medications each predicted poorer HAART adherence. Necessity beliefs about HAART and level of educational attainment each predicted better adherence. The final model accounted for approximately 24% of the variance in HAART adherence.Conclusions: The results of this study suggest that Horne’s (1) necessity-concerns framework can be successfully applied to identify beliefs about medication that are important predictors of adherence to HAART over time. These findings have relevance for developing interventions to improve medication adherence among HIV-infected patients.

Associations of blood pressure with self-report measures of anger and hostility among Black and White men and women.

This study examined associations between blood pressure (BP) and dispositional variables pertaining to anger and hostility. Black and White 25- to 44-year old male and female normotensives and unmedicated mild to moderate hypertensives completed four reliable self-report scales--the Cook-Medley Hostility (Ho) Scale, the Trait Anger subscale of the State-Trait Anger Scale (STAS-T), and the Cognitive Anger and Somatic Anger subscales of the Cognitive-Somatic Anger Scale--plus the Framingham Anger Scale and the Harburg Anger Scale. They also engaged in three laboratory tasks--Type A Structured Interview (SI), a video game, and a cold pressor task--that elicit cardiovascular reactivity. Ambulatory BP readings at home and at work were also obtained from most subjects. Blacks had significantly higher Ho and lower STAS-T scores than did Whites. Women reported higher levels of somatic anger than did men. White women showed significant positive correlations between STAS-T and systolic BP (SBP) and diastolic BP (DBP) both at rest in the laboratory and during the SI. Black women revealed significant positive relationships between STAS-T and SBP and DBP at rest in the laboratory and at work as well as with DBP during the cold pressor test. For Black men, cognitive anger and DBP at rest were positively related. In contrast, White men revealed significant negative correlations between Ho scores and SBP at rest and during the video game; these men also showed significant negative relationships between somatic anger and SBP and DBP reactivity during the cold pressor test. Women, but not men, showed significant positive relationships between all four anger measures and ambulatory BP at work. Whereas main effects relating anger and cardiovascular measures were not apparent as a function of race, Blacks demonstrated significantly greater SBP and DBP reactivity than Whites during the cold pressor test, with the converse occurring during the SI. Men demonstrated significantly greater DBP reactivity than women during the video game. The present findings indicate that self-reports on anger/hostility measures and cardiovascular responses to behavioral tasks differ as a function of race but that relationships between anger and BP regulation need to take into account possible race-sex interactions and selection of anger/hostility measures.

Applying latent growth curve modeling to the investigation of individual differences in cardiovascular recovery from stress.

Objective This paper provides an introduction to latent growth curve (LGC) modeling, a modern method for analyzing data resulting from change processes such as cardiovascular recovery from stress. LGC models are superior to traditional approaches such as repeated measures analysis of variance and simple change scores. Methods The basic principles of LGC modeling are introduced and applied to data from 167 men and women whose systolic blood pressure was assessed before, during, and after the cold pressor and evaluated speech stressors and who had completed the Cook-Medley Hostility Inventory. Results The LGC models revealed that systolic blood pressure recovery follows a different nonlinear trajectory after speech relative to the cold pressor. The difference resulted not from the initial decline at the completion of the stressor, but from higher levels at the end of the stressor and slower rate of change in decline for the speech. Hostility predicted the trajectory for speech but not for cold pressor. This relationship did not differ as a function of gender, although men had larger systolic blood pressure responses than women to both stressors. Conclusions LGC modeling yields an understanding of the processes and predictors of change that is not attainable through traditional statistical methods. Although our application concerns cardiovascular recovery from stress, LGC modeling has many other potential applications in psychosomatic research.

Stress Management Intervention Reduces Serum Cortisol and Increases Relaxation During Treatment for Nonmetastatic Breast Cancer

Objective: To examine the effects of a cognitive-behavioral stress management (CBSM) intervention, which was composed of relaxation, cognitive restructuring, and coping skills training on late afternoon serum cortisol and relaxation indicators in women who were undergoing treatment for nonmetastatic breast cancer. Methods: Participants (N = 128) were randomly assigned to receive a 10-week CBSM group intervention or a 1-day psychoeducation seminar. Serum cortisol was collected and ability to relax was assessed at study entry and again at 6- and 12-month follow-up visits. Data were analyzed using latent growth curve modeling. Results: There was a significant effect of study condition on change across time for both cortisol and perceived ability to relax. Women receiving CBSM had significantly greater reductions in cortisol levels across the 12 months compared with those in the control group, who had no appreciable decline. Women receiving CBSM reported greater increases in ability to relax than controls across time. Perceived ability to relax did not mediate CBSM-related reductions in cortisol. Conclusions: Women who participate in a 10-week CBSM intervention during treatment for breast cancer show decreases in physiological stress in parallel with increases in perceived relaxation skills. This is the first study demonstrating well-maintained reductions in cortisol after a CBSM intervention in cancer patients during and just after treatment. CBSM = cognitive-behavioral stress management; MOCS = Measure of Current Status; MOCSrelax = relaxation subscale of the MOCS; LGM = latent growth curve modeling; HPA = hypothalamic-pituitary-adrenal.

Cardiovascular responsivity to stress in adolescents with and without persistently elevated blood pressure

Objectives The goal of this study was to compare the cardiovascular responses to behavioural stressors of three groups of adolescents who differed in blood pressure status across assessments. Design Casual blood pressure of adolescents who were identified as having elevated blood pressure during a school screen was re-evaluated in the laboratory. The adolescents were classified into two groups: (i) those with consistently elevated blood pressure across school and laboratory assessments and (i) those with labile blood pressure whose blood pressure in the laboratory was below 130/80 mmHg. A comparison group of adolescents with consistently normal blood pressure was also included. Methods Cardiovascular parameters were assessed during rest and during two behavioural stressors, the evaluated speaking task and the mirror tracing task. Results Adolescents with elevated blood pressure were more vascularly responsive across stressors than adolescents with labile blood pressure, who, in turn, were more reactive than adolescents with normal blood pressure. Conclusions These results suggest that vascular reactivity to behavioural stressors may be useful in predicting risk of hypertension because of its sensitivity in distinguishing adolescents with consistently elevated blood pressure from those with labile blood pressure and those with normal blood pressure.

Simultaneous single unit recording in the medial nucleus of the medial geniculate nucleus and amygdaloid central nucleus throughout habituation, acquisition, and extinction of the rabbit's classically conditioned heart rate.

The present study examined single neuron activity in the medial nucleus of the medial geniculate (mMG) and amygdaloid central nucleus (ACe) simultaneously across several phases of differential heart rate conditioning (habituation, acquisition, and extinction). Within the same animals, the magnitude of mMG and ACe unit responses to two tone conditioned stimuli (CS) exhibited habituation, differential acquisition, and extinction. Neurons in each area developed a differential response latency to the CSs during acquisition, suggesting that mMG and ACe may be involved in changes of synaptic efficacy. Units in both areas rapidly developed a differential response magnitude to the CSs (< 6 acquisition trials), however, mMG units responded to the CSs with a shorter latency than ACe units across all phases of training. This suggests that unlearned and learned CS information may access mMG before ACe. These results are consistent with the notion that conditioning-induced plasticity which occurs in mMG may influence the conditioning-induced plasticity that occurs further downstream in the amygdala.