Michael J. Sulik

Physical Performance and Frailty in Chronic Kidney Disease

Background: Poor physical performance and frailty are associated with elevated risks of death and disability. Chronic kidney disease (CKD) is also strongly associated with these outcomes. The risks of poor physical performance and frailty among CKD patients, however, are not well established. Methods: We measured the Short Physical Performance Battery (SPPB; a summary test of gait speed, chair raises and balance; range 0-12) and the five elements of frailty among 1,111 Chronic Renal Insufficiency Cohort participants. Adjusting for demographics and multiple comorbidities, we fit a linear regression model for the outcome of SPPB score and an ordinal logistic regression model for frailty status. Results: Median (interquartile range, IQR) age was 65 (57-71) years, median estimated glomerular filtration rate (eGFR) for non-dialysis patients was 49 (36-62) ml/min/1.73 m2, and median SPPB score was 9 (7-10). Seven percent of participants were frail and 43% were pre-frail. Compared with the SPPB score for eGFR >60 ml/min/1.73 m2, the SPPB was 0.51 points lower for eGFR 30-59; 0.61 points lower for eGFR 15-29, and 1.75 points lower for eGFR <15 (p < 0.01 for all comparisons). eGFR 30-59 (odds ratio, OR 1.45; p = 0.024), eGFR 15-29 (OR 2.02; p = 0.002) and eGFR <15 (OR 4.83; p < 0.001) were associated with worse frailty status compared with eGFR >60 ml/min/1.73 m2. Conclusions: CKD severity was associated with poor physical performance and frailty in a graded fashion. Future trials should determine if outcomes for CKD patients with frailty and poor physical performance are improved by targeted interventions.

Associations between body composition and bone density and structure in men and women across the adult age spectrum.

BACKGROUND/PURPOSE The objective of this study was to identify independent associations between body composition and bone outcomes, including cortical structure and cortical and trabecular volumetric bone mineral density (vBMD) across the adult age spectrum. METHODS This cross-sectional study evaluated over 400 healthy adults (48% male, 44% black race), ages 21-78years. Multivariable linear regression models evaluated associations between whole-body DXA measures of lean body mass index (LBMI) and fat mass index (FMI) and tibia peripheral quantitative CT (pQCT) measures of cortical section modulus, cortical and trabecular vBMD and muscle density (as a measure of intramuscular fat), adjusted for age, sex, and race. All associations reported below were statistically significant (p<0.05). RESULTS Older age and female sex were associated with lower LBMI and muscle strength. Black race was associated with greater LBMI but lower muscle density. Greater FMI was associated with lower muscle density. Cortical section modulus was positively associated with LBMI and muscle strength and negatively associated with FMI. Adjustment for body composition eliminated the greater section modulus observed in black participants and attenuated the lower section modulus in females. Greater LBMI was associated with lower cortical BMD and greater trabecular BMD. FMI was not associated with either BMD outcome. Greater muscle density was associated with greater trabecular and cortical BMD. Associations between body composition and bone outcomes did not vary by sex (no significant tests for interaction). CONCLUSIONS These data highlight age-, sex- and race-specific differences in body composition, muscle strength and muscle density, and demonstrate discrete associations with bone density and structure. These data also show that age-, sex- and race-related patterns of bone density and strength are independent of differences in body composition. Longitudinal studies are needed to examine the temporal relations between changes in bone and body composition.

Emotion-Related Self-Regulation in Children

In this article, the authors review basic conceptual issues in research on children’s emotion-related self-regulation, including the differentiation between self-regulation that is effortful and voluntary and control-related processes that are less amenable to effortful control. In addition, the authors summarize what researchers know about developmental changes in self-regulatory capacities, give examples of various methods used to assess these abilities, and summarize findings on the relations between self-regulation or effortful control and positive adjustment and maladjustment. Finally, the authors discuss some strategies for effectively teaching students about emotion regulation.

FGF23 Modifies the Relationship between Vitamin D and Cardiac Remodeling

Background—There is growing evidence to support an important role for vitamin D and related hormones, parathyroid hormone and fibroblast growth factor 23 (FGF23), on cardiac remodeling in chronic kidney disease. Our objective was to determine the relationships between vitamin D and cardiac remodeling in chronic kidney disease and the effects of parathyroid hormone and FGF23 on these associations. Methods and Results—In 1431 participants from the Chronic Renal Insufficiency Cohort study, we measured 25-hydroxyvitamin D (25(OH)D), 1,25-dihyroxyvitamin D (1,25(OH)2D), FGF23, and parathyroid hormone and performed quantitative echocardiography. Using linear regression methods, we determined significant negative interactions between 25(OH)D and FGF23 on left ventricular (LV) mass (P=0.016), end-diastolic volume (P=0.029), and end-systolic volumes (P=0.021). In participants with an FGF23 level greater than the median of 123.5 RU/mL, each doubling of 25(OH)D was associated with a 2.5% (95% confidence interval, −4.8, −0.2) lower LV mass. This association was less pronounced with FGF23 levels less than the median (0.4%; 95% confidence interval, −1.9, 2.7). Conversely, in participants with deficient 25(OH)D levels <20 ng/mL, each doubling of FGF23 was associated with a 3.4% (95% confidence interval, 1.2, 5.6) greater LV mass compared with only a 1.6% (95% confidence interval, −0.2, 3.5) difference in participants with sufficient 25(OH)D. Similar findings were observed with 25(OH)D and volumes (P<0.05), and 1,25(OH)2D and LV mass and volumes (P<0.005). There was no effect modification by parathyroid hormone. Conclusions—We identified significant interactions among 25(OH)D, 1,25(OH)2D, and FGF23 on cardiac remodeling. Increased LV mass and cavity dilatation were observed with low 25(OH)D and high FGF23. Our findings suggest that consideration of both hormones is crucial to understanding the role of either in cardiac remodeling, and may have important therapeutic implications.

How the study of regulation can inform the study of coping

It is advantageous to study regulation and coping and their development at multiple levels of expression and origin simultaneously. We discuss several topics of current interest in the emotion-related regulation literature that are relevant to coping, including conceptual issues related to definitions and types of coping, types of physiological responses deemed to tap emotion regulation that could be pursued in work on coping, and findings on the socialization of self-regulation that have implications for understanding the development of coping.

Comment: Is Self–Other Overlap the Key to Understanding Empathy?

Preston and Hofelich (2012) suggested that researchers disagree on the role of self–other overlap in empathy due to a failure to differentiate among neural overlap, subjective resonance, and personal distress; they also developed a framework for tying neural and subjective overlap to various aspects of functioning they include in the construct of empathy. Although we found their discussion of different processes that have been labeled empathy interesting and helpful, we found their discussion of self–other overlap to be somewhat less useful for conceptualizing differences among empathy-related processes. In addition, we provide an alternative perspective to their reasoning regarding the role of experience and neural overlap in an aspect of empathy-related responding (e.g., concern or compassion).

Associations between respiratory sinus arrhythmia (RSA) reactivity and effortful control in preschool-age children.

We tested whether respiratory sinus arrhythmia (RSA) reactivity in response to each of three self-regulation tasks (bird and dragon; knock-tap; and gift wrap) would predict self-regulation performance in a sample of 101 preschool-age children (M age = 4.49, SD = .64). While controlling for baseline RSA, decreases in RSA from bird and dragon to knock-tap (but not from baseline to bird and dragon) predicted a latent variable measuring self-regulation. Furthermore, increases in RSA from the knock-tap to gift wrap-the only task involving delay of gratification-were related to concurrent task performance while controlling for the relation between RSA reactivity and the latent self-regulation variable. Results suggest that the relations between RSA reactivity and self-regulatory ability are influenced by task-specific demands and possibly by task order. Furthermore, RSA reactivity appears to relate differently to performance on motivationally salient self-regulation tasks such as delay of gratification relative to cool executive function tasks.

Coping Across the Transition to Adolescence: Evidence of Interindividual Consistency and Mean-Level Change

The goal of this study was to examine various forms of coping across the transition to adolescence, with a focus on interindividual (correlational) consistency of coping and mean-level changes in coping. Adolescents’ emotional coping, problem solving, positive cognitive restructuring, avoidance, and support seeking in response to everyday stressors were assessed via a daily diary beginning when participants (N = 155) were approximately 9 years old and continued every 2 years for a total of four assessments. Most indices of coping demonstrated some interindividual consistency across time. Emotional coping and support-seeking coping declined over time, whereas positive cognitive restructuring and avoidance increased as adolescents aged. The discussion focuses on the implications of the findings and suggestions for advancing this line of inquiry.

Catechol-O-methyltransferase Val158met polymorphism interacts with early experience to predict executive functions in early childhood

Numerous studies demonstrate that the Methionine variant of the catechol-O-methyltransferase Val158Met polymorphism, which confers less efficient catabolism of catecholamines, is associated with increased focal activation of prefrontal cortex (PFC) and higher levels of executive function abilities. By and large, however, studies of COMT Val158Met have been conducted with adult samples and do not account for the context in which development is occurring. Effects of early adversity on stress response physiology and the inverted U shape relating catecholamine levels to neural activity in PFC indicate the need to take into account early experience when considering relations between genes such as COMT and executive cognitive ability. Consistent with this neurobiology, we find in a prospective longitudinal sample of children and families (N = 1292) that COMT Val158Met interacts with early experience to predict executive function abilities in early childhood. Specifically, the Valine variant of the COMT Val158Met polymorphism, which confers more rather than less efficient catabolism of catecholamines is associated with higher executive function abilities at child ages 48 and 60 months and with faster growth of executive function for children experiencing early adversity, as indexed by cumulative risk factors in the home at child ages 7, 15, 24, and 36 months. Findings indicate the importance of the early environment for the relation between catecholamine genes and developmental outcomes and demonstrate that the genetic moderation of environmental risk is detectable in early childhood.

The association of individual characteristics and neighborhood poverty on the dental care of American adolescents

OBJECTIVE The purpose of this study was to explore the extent to which neighborhood poverty was associated with the utilization of dental care by American adolescents. METHODS To accomplish the study goals we conducted multilevel modeling analyses of two nationally representative data sets: National Longitudinal Study of Adolescent Health (Add Health) and the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (ECLS-K). RESULTS As hypothesized, neighborhood poverty predicted frequency of dental care in both studies (t = 6.06; P < 0.001; t = 2.44; P < 0.05). Even after accounting for individual level predictors such as household income, health insurance, and parental education, adolescents living in poor neighborhoods are less likely than their counterparts in non-poor neighborhoods to utilize dental care. CONCLUSIONS The findings from this study indicate that neighborhoods influence dental care utilization patterns in adolescents.