Financial Hardship and Age-Related Decrements in Kidney Function among Black and White Adults in the Midlife in the United States (MIDUS) Study.

OBJECTIVES: This analysis examined if financial hardship was associated with age-related decrements in kidney function using a material-psychosocial-behavioral framework. We also tested if this association was mediated by comorbidity of cardiometabolic risk factors (obesity, elevated blood pressure, and insulin resistance). METHODS: Data from 1,361 Non-Hispanic (NH) Black and white adults (ages 26-94; NH Black = 258) were obtained from the Wave 3 and Refresher phases of the Midlife in the United States (MIDUS) project. Kidney function was based on serum creatinine-based estimated glomerular filtration rate (CKD-EPI formula without race adjustment). Financial hardship was evaluated in three domains: material (income to poverty line ratio, health insurance coverage, and public/government financial assistance), psychological (perceived financial status, control over financial status, and perceived financial strains), and behavioral responses (financial adjustment/coping such as sold possessions and cutting back on spending). RESULTS: More severe financial hardship (overall score and in each domain) was associated with age-related decrements in eGFR, even after adjusting for sociodemographic, education, and health-related covariates. The association between financial hardship and age-related decrements in eGFR was conditional on sex but not race. Finally, cardiometabolic risk factors mediated the association between financial hardship and age-related decrements in eGFR. CONCLUSIONS: These findings affirm the negative effects of financial hardship on age-related decrements in renal clearance. In addition to incorporating traditionally used indicators of SES, such as education and income, future research on social hallmarks of aging should also consider the role of financial hardship on the aging process and age-related diseases.

Dialysis Patients' Social Networks and Living Donation Offers.

Rationale & Objective: Most living kidney donors are members of a hemodialysis patient's social network. Network members are divided into core members, those strongly connected to the patient and other members; and peripheral members, those weakly connected to the patient and other members. We identify how many hemodialysis patients' network members offered to become kidney donors, whether these offers were from core or peripheral network members, and whose offers the patients accepted. Study Design: A cross-sectional interviewer-administered hemodialysis patient social network survey. Setting & Participants: Prevalent hemodialysis patients in 2 facilities. Predictors: Network size and constraint, a donation from a peripheral network member. Outcomes: Number of living donor offers, accepting an offer. Analytical Approach: We performed egocentric network analyses for all participants. Poisson regression models evaluated associations between network measures and number of offers. Logistic regression models determined the associations between network factors and accepting a donation offer. Results: The mean age of the 106 participants was 60 years. Forty-five percent were female, and 75% self-identified as Black. Fifty-two percent of participants received at least one living donor offer (range 1-6); 42% of the offers were from peripheral members. Participants with larger networks received more offers (incident rate ratio [IRR], 1.26; 95% CI, 1.12-1.42; P = 0.001), including networks with more peripheral members (constraint, IRR, 0.97; 95% CI, 0.96-0.98; P < 0.001). Participants who received a peripheral member offer had 3.6 times greater odds of accepting an offer (OR, 3.56; 95% CI, 1.15-10.8; P = 0.02) than those who did not receive a peripheral member offer. Limitations: A small sample of only hemodialysis patients. Conclusions: Most participants received at least one living donor offer, often from peripheral network members. Future living donor interventions should focus on both core and peripheral network members.

The ties that transplant: The social capital determinants of the living kidney donor relationship distribution.

The network perspective on social capital decomposes it into ego's network size, alters' relevant resources, and social factors moderating access to alters' resources, but rarely examines how it is distributed across relationship types. Using this approach, I investigate the situationally-relevant social capital relationship distribution and its association with health-related social support, with an application to the living kidney donor relationship distribution. Analyzing an original survey of transplant candidates (N = 72) and their reports on their family and friends (N = 1548), I compare the tie count, donation-relevant biomedical resource, and tie strength relationship distributions to administrative data on the national distribution of living kidney donor relationships. I find that the tie strength relationship distribution matches the completed living kidney donor relationship distribution far better than the tie count and donation-relevant biomedical resource relationship distributions. These conclusions are upheld in race- and gender-stratified analyses and are robust across alternative approaches.

Longitudinal electrocardiographic assessment in Brugada syndrome.

Background: The type 1 electrocardiographic (ECG) pattern diagnostic of Brugada syndrome (BrS) can be dynamic. Limited studies have rigorously evaluated the temporal stability of the Brugada ECG pattern. Objective: We sought to evaluate fluctuations of the Brugada pattern in serial resting ECGs from BrS patients managed within a large health care system. Methods: In our cohort of BrS patients with at least 2 standard, resting ECGs recorded on separate clinical encounters, we evaluated serial changes in the Brugada pattern and categorized patients into 1 of 3 groups: dynamic was defined as the presence of both type 1 and non-type 1 patterns in available ECGs; the provoked-only group was defined as having a non-type 1 Brugada pattern across resting ECGs; and the persistent group was defined as having a type 1 pattern on all ECGs. We also evaluated the clinical risk in this cohort according to the Shanghai risk score. Results: In 72 patients with BrS (mean age 46 ± 15 years, 69% male), 828 standard, resting ECGs were recorded over a median duration of 30.2 (interquartile range 6.3-68.1) months. The dynamic group comprised 50 (69% of the cohort) patients, the provoked-only group consisted of 17 patients (24% of the cohort), and the persistent group included 5 patients. No significant differences were detected in the total number of ECGs evaluated during the follow-up period between any of the groups. Only sinus node dysfunction and a prior cardiac arrest were associated with the persistent type 1 group. The majority of patients had a low annualized risk of lethal arrhythmic events. Conclusion: Most BrS patients have a dynamic Brugada pattern noted on longitudinal, resting ECGs. Expert consensus statements should provide clarity on the frequency of obtaining resting ECGs in patients suspected of having BrS during follow-up.

Racial/ethnic and prior willingness disparities in potential living kidney donors' self-assessed responses to advancing American kidney health regulation.

BACKGROUND: Racial/ethnic disparities in living donor kidney transplantation (LDKT) are large, and rates of LDKT may be limited by indirect costs of living donation. A 2019 Executive Order- Advancing American Kidney Health (AAKH)- sought to remove indirect costs through an expanded reimbursement program. We examine how potential living kidney donors in the U.S. believe regulation stemming from the AAKH initiative will impact their living donor evaluation likelihood, how these beliefs vary by minority race/ethnicity and prior willingness to be evaluated, and how differences are explained by ability to benefit or knowledge and attitudes. METHODS: Data from a 2019 online survey (Families of Renal Patients Survey) were used. Respondents are U.S. adult (> 18 years) members of the Qualtrics Survey Panel who reported having relatives with weak or failing kidneys (N = 590). Respondents' likelihood to be evaluated for living kidney donation are measured by self-report. Prior willingness is measured by past donation-related actions and current attitudes. Ability to benefit is measured by self-reported labor force participation and financial strain. Transplant knowledge is measured by self-report and a knowledge test, and transplant-related attitudes are measured by self-report. Average marginal effects of minority race/ethnicity and prior willingness for response to each provision in fully-adjusted models were estimated. Formal tests of mediation were conducted using the Karlson, Holm, and Breen (KHB) mediation model. Stata/MP 14.2 was used to conduct all analyses. RESULTS: Majorities of all groups report favorable responses to the provisions stipulated in AAKH regulation. Responses to provisions are significantly associated with race/ethnicity and prior willingness, with racial/ethnic minorities and those not previously willing to be evaluated less likely to report favorable responses to these provisions. Prior willingness differences are partially explained by group differences in ability to benefit and transplant-related knowledge and attitudes, but racial/ethnic differences largely are not. CONCLUSIONS: Regulation stemming from the AAKH initiative is likely to effectively promote LDKT, but may also exacerbate racial/ethnic disparities. Therefore, the regulation may need to be supplemented by efforts to address non-financial obstacles to LDKT in racial/ethnic minority communities in order to ensure equitable increases in LDKT rates and living donor support.

Life course pathways from parental education to age-related decrements in kidney function among Black and white American adults.

OBJECTIVE: Using cross-sectional data on Black and white adults, this analysis examined whether age-related decrements in kidney function across adulthood were associated with parental education, and whether the association was differentially influenced by race. Further, this study assessed racial differences in life course pathways from parental education to age-related decrements in kidney function, through current SES and health-related risk factors. METHOD: Data from the main survey and the Biomarker Project of the Midlife in the United States (MIDUS) Wave 2 and Refresher samples were combined, resulting in 1861 adults (54.5% female; age 25-84, Mage = 53.37) who self-identified as non-Hispanic Black (n = 326) and non-Hispanic white (n = 1535). Estimated glomerular filtration rate (eGFR) was based on serum creatinine, calculated using the CKD-EPI formula. Adults SES was based on education, income, and financial strains. Health-related risk factors included obesity, elevated blood pressure (BP), and insulin resistance. Hypotheses were tested by utilizing multiple linear regression and regression-based moderated mediation analysis. RESULTS: Lower parental education was associated with steeper age-related decrements in eGFR (B = 0.38, SE = 0.15, p = .013, 95%CI = 0.08, 0.68), due to higher eGFR among younger participants and lower eGFR among older participants. In addition, age-related decrements in kidney function were steeper among Black relative to white adults (B = 0.41, SE = 0.13, p < .01, 95%CI = 0.16, 0.66), driven by higher proportion of younger Black adults that met criterion for renal hyperfiltration. Furthermore, parental education and race were associated with age-related decrements in kidney function in an additive rather than interactive way. There were some racial differences in the life course pathways from parental education to age-related differences in eGFR, glucoregulation, and hypertension. Among Black adults, lower parental education was associated with elevated eGFR among younger participants through insulin resistance. Among white adults, lower parental education was linked to higher eGFR among younger adults and lower eGFR among older adults, and the association was mediated by current SES, elevated BP, and insulin resistance. DISCUSSION: Early life SES can have a long-lasting influence on the preclinical renal senescence that is associated with the normal biology of aging for both Black and white adults.

Childhood socioeconomic status, comorbidity of chronic kidney disease risk factors, and kidney function among adults in the midlife in the United States (MIDUS) study.

BACKGROUND: There is a lack of empirical effort that systematically investigates the clustering of comorbidity among known risk factors (obesity, hypertension, diabetes, hypercholesterolemia, and elevated inflammation) of chronic kidney disease (CKD) and how different types of comorbidity may link differently to kidney function among healthy adult samples. This study modeled the clustering of comorbidity among risk factors, examined the association between the clustering of risk factors and kidney function, and tested whether the clustering of risk factors was associated with childhood SES. METHODS: The data were from 2118 participants (ages 25-84) in the Midlife in the United States (MIDUS) Study. Risk factors included obesity, elevated blood pressure (BP), high total cholesterol levels, poor glucose control, and increased inflammatory activity. Glomerular filtration rate (eGFR) was estimated from serum creatinine, calculated with the CKD-EPI formula. The clustering of comorbidity among risk factors and its association with kidney function and childhood SES were examined using latent class analysis (LCA). RESULTS: A five-class model was optimal: (1) Low Risk (class size = 36.40%; low probability of all risk factors), (2) Obese (16.42%; high probability of large BMI and abdominally obese), (3) Obese and Elevated BP (13.37%; high probability of being obese and having elevated BP), (4) Non-Obese but Elevated BP (14.95%; high probability of having elevated BP, hypercholesterolemia, and elevated inflammation), and (5) High Risk (18.86%; high probability for all risk factors). Obesity was associated with kidney hyperfiltration, while comorbidity between obesity and hypertension was linked to compromised kidney filtration. As expected, the High Risk class showed the highest probability of having eGFR < 60 ml/min/1.73 m2 (P = .12; 95%CI = .09-.17). Finally, higher childhood SES was associated with reduced probability of being in the High Risk rather than Low Risk class (ß = - 0.20, SE = 0.07, OR [95%CI] = 0.82 [0.71-0.95]). CONCLUSION: These results highlight the importance of considering the impact of childhood SES on risk factors known to be associated with CKD.

Job Characteristics, Job Preferences, and Physical and Mental Health in Later Life.

Existing research linking SES with work primarily focuses on the precursors (educational attainment) and outcomes (income) of work, rather than asking how diverse facets of work influence health. Using four waves of data from the Wisconsin Longitudinal Study, we evaluate whether multiple measures of respondent job characteristics, respondent preferences for those characteristics, and their interaction substantially improve the fit of sociological models of men's and women's physical and mental health at midlife and old age compared to traditional models using educational attainment, parental SES, and income. We find that non-wage job characteristics predict men's and women's physical and mental health over the lifecourse, although we find little evidence that the degree to which one's job accords with one's job preferences matters for health. These findings expand what we know about how work matters for health, demonstrating how the manner and condition under which one works has lasting impacts on wellbeing.

The contribution of three dimensions of allostatic load to racial/ethnic disparities in poor/fair self-rated health.

OBJECTIVE: This study evaluates whether different dimensions of physiological dysregulation, modeled individually rather than additively mediate racial/ethnic disparities in self-reported health. METHODS: Using data from the National Health and Nutrition Examination Survey (2005-2010) and the Karlson, Hold, and Breen (KHB) mediation model, this paper explores what operationalization of biomarker data most strongly mediate racial/ethnic disparities in poor/fair self-rated health (SRH) among adults in the United States, net of demographic, socioeconomic, behavioral, and medication controls. RESULTS: Non-Hispanic blacks and Hispanics had significantly higher odds of reporting poor/fair self-rated health in comparison to non-Hispanic whites. Operationalizations of allostatic load that disaggregate three major dimensions of physiological dysregulation mediate racial/ethnic disparities strongly between non-Hispanic blacks and non-Hispanic whites, but not between Hispanics and non-Hispanic whites. Disaggregating these dimensions explains racial/ethnic disparities in poor/fair SRH better than the continuous score. Analyses on sex-specific disparities indicate differences in how individual dimensions of allostatic load contribute to racial/ethnic disparities in poor/fair SRH differently. All individual dimensions are strong determinants of poor/fair SRH for males. In contrast, for females, the only dimension that is significantly associated with poor/fair SRH is inflammation. For the analytic sample, additive biomarker scores fit the data as well or better than other approaches, suggesting that this approach is most appropriate for explaining individual differences. However, in sex-specific analyses, the interactive approach models fit the data best for men and women. CONCLUSIONS: Future researchers seeking to explain racial/ethnic disparities in full or sex-stratified samples should consider disaggregating allostatic load by dimension.

Contribution of Four Comorbid Conditions to Racial/Ethnic Disparities in Mortality Risk.

INTRODUCTION: The prevalence of key forms of morbidity such as obesity, diabetes, and chronic kidney disease have increased dramatically in the U.S. and elsewhere for decades. Hypertension is etiologically related but its prevalence has been reduced through improved treatment. These diseases are known to have higher than expected rates of comorbidity, but it is not known whether and how these cluster together differentially by race, nor the degree to which they contribute to racial disparities in mortality. METHODS: Using data from the National Health Interview Survey mortality follow-up (1997-2009, analyzed in 2016), this paper modeled interdependencies between each combination of these four types of morbidity, overall and net of demographic, socioeconomic, and behavioral controls. It then analyzed whether these diseases mediate the relationship between race/ethnicity and mortality risk using discrete time complementary log-log survival models. RESULTS: American Indians and blacks had significantly elevated rates of comorbidity compared with whites, and Asians' and Pacific Islanders' rates were often significantly lower than whites'. Controlling for these diseases significantly moderated the mortality risk disparity between African American, Hispanic, and Asian/Pacific Islanders and whites. This remained true when individual health behaviors and neighborhood fixed effects were statistically adjusted for. Notably, the full controls model statistically eliminated the association between African American race and mortality risk. CONCLUSIONS: These diseases contribute significantly to racial/ethnic mortality disparities, particularly between blacks and whites. Future research should consider the mediating role of these diseases for the relationship between social conditions and mortality risks.

Explaining the Persistence of Health Disparities: Social Stratification and the Efficiency-Equity Trade-off in the Kidney Transplantation System.

Why do health disparities persist when their previous mechanisms are eliminated? Fundamental-cause theorists argue that social position primarily improves health through two metamechanisms: better access to health information and technology. I argue that the general, cumulative, and embodied consequences of social stratification can produce another metamechanism: an efficiency-equity trade-off. A case in point is kidney transplantation, where the mechanisms previously thought to link race to outcomes--ability to pay and certain factors in the kidney allocation system--have been greatly reduced, yet large disparities persist. I show that these current disparities are rooted in factors that directly influence posttransplant success, placing efficiency and racial/ethnic equity at cross-purposes.

Siblings, friends, course-mates, club-mates: how adolescent health behavior homophily varies by race, class, gender, and health status.

Many unhealthy behaviors develop during adolescence, and these behaviors can have fundamental consequences for health and mortality in adulthood. Social network structure and the degree of homophily in a network affect how health behaviors and innovations are spread. However, the degree of health behavior homophily across different social ties and within subpopulations is unknown. This paper addresses this gap in the literature by using a novel regression model to document the degree of homophily across various relationship types and subpopulations for behaviors of interest that are related to health outcomes. These patterns in health behavior homophily have implications for which behaviors and ties should be the subjects of future research and for predicting how homophily may shape health programs focused on specific subpopulations (gender, race, class, health status) or a specific social context (families, peer groups, classrooms, or school activities).

What can genes tell us about the relationship between education and health?

We use genome wide data from respondents of the Health and Retirement Study (HRS) to evaluate the possibility that common genetic influences are associated with education and three health outcomes: depression, self-rated health, and body mass index. We use a total of 1.7 million single nucleotide polymorphisms obtained from the Illumina HumanOmni2.5-4v1 chip from 4233 non-Hispanic white respondents to characterize genetic similarities among unrelated persons in the HRS. We then used the Genome Wide Complex Trait Analysis (GCTA) toolkit, to estimate univariate and bivariate heritability. We provide evidence that education (h(2) = 0.33), BMI (h(2) = 0.43), depression (h(2) = 0.19), and self-rated health (h(2) = 0.18) are all moderately heritable phenotypes. We also provide evidence that some of the correlation between depression and education as well as self-rated health and education is due to common genetic factors associated with one or both traits. We find no evidence that the correlation between education and BMI is influenced by common genetic factors.

Of kin and kidneys: do kinship networks contribute to racial disparities in living donor kidney transplantation?

In the United States, racial disparities in kidney transplantation are large and especially stark for living donor transplants. Medical researchers frequently attribute this to the availability of medically compatible living kidney donors, who are usually kin. This paper evaluates this hypothesis by testing whether African American transplant candidates likely have lesser access to suitable living donors in their kinship networks than white candidates. This paper evaluates this hypothesis using a simulation design. Contrary to prior research on this topic, this simulation analysis concludes that black-white disparities in living donor kidney transplantation are unlikely to be the result of group differences in the availability of suitable donors. Although individual white kin are individually more likely to be suitable donors, African Americans' larger average kinship networks compensate for this difference.

Defining the environment in gene-environment research: lessons from social epidemiology.

In this article, we make the case that social epidemiology provides a useful framework to define the environment within gene-environment (G × E) research. We describe the environment in a multilevel, multidomain, longitudinal framework that accounts for upstream processes influencing health outcomes. We then illustrate the utility of this approach by describing how intermediate levels of social organization, such as neighborhoods or schools, are key environmental components of G × E research. We discuss different models of G × E research and encourage public health researchers to consider the value of including genetic information from their study participants. We also encourage researchers interested in G × E interplay to consider the merits of the social epidemiology model when defining the environment.

Compensating differentials, labor market segmentation, and wage inequality.

Two literatures on work and the labor market draw attention to the importance of non-pecuniary job amenities. Social psychological perspectives on work suggest that workers have preferences for a range of job amenities (e.g. Halaby, 2003). The compensating differentials hypothesis predicts that workers navigate tradeoffs among different job amenities such that wage inequality overstates inequality in utility (Smith, 1979). This paper joins these perspectives by constructing a new measure of labor market success that evaluates the degree to which workers' job amenity preferences and outcomes match. This measure of subjective success is used to predict workers' job satisfaction and to test the hypothesis that some degree of labor force inequality in wages is due to preference-based tradeoffs among all job amenities. Findings demonstrate that the new measure predicts workers' job satisfaction and provides evidence for the presence of compensating differentials in the primary and intermediate, but not secondary, labor markets.