Results of the CARDIA study suggest that higher dietary potassium may be kidney protective.

The association between dietary sodium and potassium intake with the development of kidney disease remains unclear, particularly among younger individuals. Here, we determined whether dietary sodium and potassium intake are associated with incident chronic kidney disease (CKD) using data from 1,030 adults (age 23-35 in 1990-1991) from the Coronary Artery Risk Development In Young Adults study, based on repeated measurements of estimated glomerular filtration rate (eGFR) and urinary albumin to creatinine ratio (ACR) from 1995 through 2015. Urinary sodium and potassium excretion (mg/day), calculated from three 24-hour urine collections in 1990-1991, were averaged to measure sodium and potassium intake. Serum creatinine was used to calculate eGFR using the CKD EPI equation; spot urine albumin and creatinine were used to calculate ACR, each at five visits from 1995-1996 through 2015-2016. CKD was defined as decreased eGFR (under 60 ml/min/1.73m2) or the development of albuminuria (ACR over 30 mg/g). We used log binomial regression models adjusted for socio-demographic, behavioral, and clinical factors to determine whether sodium and potassium intake were associated with incident CKD (decreased eGFR or developed albuminuria) among those free of CKD in 1995. Dietary sodium intake was not significantly associated with incident CKD. However, every 1,000 mg/day increment of potassium intake in 1990 was significantly associated with a 29% lower risk of incident albuminuria (relative risk 0.71, 95% confidence interval 0.53, 0.95), but not eGFR. Thus, higher dietary potassium intake may protect against the development of kidney damage, particularly albuminuria.

Ten-year association of coronary artery calcium with atherosclerotic cardiovascular disease (ASCVD) events: the multi-ethnic study of atherosclerosis (MESA).

Aims: While coronary artery calcium (CAC) has been extensively validated for predicting clinical events, most outcome studies of CAC have evaluated coronary heart disease (CHD) rather than atherosclerotic cardiovascular disease (ASCVD) events (including stroke). Also, virtually all CAC studies are of short- or intermediate-term follow-up, so studies across multi-ethnic cohorts with long-term follow-up are warranted prior to widespread clinical use. We sought to evaluate the contribution of CAC using the population-based MESA cohort with over 10 years of follow-up for ASCVD events, and whether the association of CAC with events varied by sex, race/ethnicity, or age category. Methods and results: We utilized MESA, a prospective multi-ethnic cohort study of 6814 participants (51% women), aged 45-84 years, free of clinical CVD at baseline. We evaluated the relationship between CAC and incident ASCVD using Cox regression models adjusted for age, race/ethnicity, sex, education, income, cigarette smoking status, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, diabetes, lipid-lowering medication, systolic blood pressure, antihypertensive medication, intentional physical exercise, and body mass index. Only the first event for each individual was used in the analysis. Overall, 500 incident ASCVD (7.4%) events were observed in the total study population over a median of 11.1 years. Hard ASCVD included 217 myocardial infarction, 188 strokes (not transient ischaemic attack), 13 resuscitated cardiac arrest, and 82 CHD deaths. Event rates in those with CAC = 0 Agatston units ranged from 1.3% to 5.6%, while for those with CAC > 300, the 10-year event rates ranged from 13.1% to 25.6% across different age, gender, and racial subgroups. At 10 years of follow-up, all participants with CAC > 100 were estimated to have >7.5% risk regardless of demographic subset. Ten-year ASCVD event rates increased steadily across CAC categories regardless of age, sex, or race/ethnicity. For each doubling of CAC, we estimated a 14% relative increment in ASCVD risk, holding all other risk factors constant. This association was not significantly modified by age, sex, race/ethnicity, or baseline lipid-lowering use. Conclusions: Coronary artery calcium is associated strongly and in a graded fashion with 10-year risk of incident ASCVD as it is for CHD, independent of standard risk factors, and similarly by age, gender, and ethnicity. While 10-year event rates in those with CAC = 0 were almost exclusively below 5%, those with CAC ≥ 100 were consistently above 7.5%, making these potentially valuable cutpoints for the consideration of preventive therapies. Coronary artery calcium strongly predicts risk with the same magnitude of effect in all races, age groups, and both sexes, which makes it among the most useful markers for predicting ASCVD risk.

Validity of Cardiovascular Data From Electronic Sources: The Multi-Ethnic Study of Atherosclerosis and HealthLNK.

BACKGROUND: Understanding the validity of data from electronic data research networks is critical to national research initiatives and learning healthcare systems for cardiovascular care. Our goal was to evaluate the degree of agreement of electronic data research networks in comparison with data collected by standardized research approaches in a cohort study. METHODS: We linked individual-level data from MESA (Multi-Ethnic Study of Atherosclerosis), a community-based cohort, with HealthLNK, a 2006 to 2012 database of electronic health records from 6 Chicago health systems. To evaluate the correlation and agreement of blood pressure in HealthLNK in comparison with in-person MESA examinations, and body mass index in HealthLNK in comparison with MESA, we used Pearson correlation coefficients and Bland-Altman plots. Using diagnoses in MESA as the criterion standard, we calculated the performance of HealthLNK for hypertension, obesity, and diabetes mellitus diagnosis by using International Classification of Diseases, Ninth Revision codes and clinical data. We also identified potential myocardial infarctions, strokes, and heart failure events in HealthLNK and compared them with adjudicated events in MESA. RESULTS: Of the 1164 MESA participants enrolled at the Chicago Field Center, 802 (68.9%) participants had data in HealthLNK. The correlation was low for systolic blood pressure (0.39; P<0.0001). In comparison with MESA, HealthLNK overestimated systolic blood pressure by 6.5 mm Hg (95% confidence interval, 4.2-7.8). There was a high correlation between body mass index in MESA and HealthLNK (0.94; P<0.0001). HealthLNK underestimated body mass index by 0.3 kg/m2 (95% confidence interval, -0.4 to -0.1). With the use of International Classification of Diseases, Ninth Revision codes and clinical data, the sensitivity and specificity of HealthLNK queries for hypertension were 82.4% and 59.4%, for obesity were 73.0% and 89.8%, and for diabetes mellitus were 79.8% and 93.3%. In comparison with adjudicated cardiovascular events in MESA, the concordance rates for myocardial infarction, stroke, and heart failure were, respectively, 41.7% (5/12), 61.5% (8/13), and 62.5% (10/16). CONCLUSIONS: These findings illustrate the limitations and strengths of electronic data repositories in comparison with information collected by traditional standardized epidemiological approaches for the ascertainment of cardiovascular risk factors and events.

Asthma predicts cardiovascular disease events: the multi-ethnic study of atherosclerosis.

OBJECTIVES: To identify and characterize an association between persistent asthma and cardiovascular disease (CVD) risk in the Multi-Ethnic Study of Atherosclerosis (MESA). APPROACH AND RESULTS: MESA is a longitudinal prospective study of an ethnically diverse cohort of individuals free of known CVD at its inception. The presence and severity of asthma were assessed in the MESA at examination 1. Persistent asthma was defined as asthmatics using controller medications (inhaled corticosteroids, leukotriene inhibitors, and oral corticosteroids) and intermittent asthma as asthmatics not using controller medications. Participants were followed up for a mean (SD) of 9.1 (2.8) years for development of incident CVD (coronary death, myocardial infarction, angina, stroke, and CVD death). Multivariable Cox regression models were used to assess associations of asthma and CVD. The 6792 participants were 62.2 (SD, 10.2) years old: 47% men (28% black, 22% Hispanic, and 12% Chinese). Persistent asthmatics (n=156), compared with intermittent (n=511) and nonasthmatics (n=6125), respectively, had higher C-reactive protein (1.2 [1.2] versus 0.9 [1.2] versus 0.6 [1.2] mg/L) and fibrinogen (379 [88] versus 356 [80] versus 345 [73] mg/dL) levels. Persistent asthmatics had the lowest unadjusted CVD-free survival rate of 84.1%, 95% confidence interval (78.9%-90.3%) compared with intermittent asthmatics 91.1% (88.5%-93.8%) and nonasthmatics 90.2% (89.4%-91%). Persistent asthmatics had greater risk of CVD events than nonasthmatics (hazard ratio [95% confidence interval], 1.6 [1.01-2.5]; P=0.040]), even after adjustment for age, sex, race, CVD risk factors, and antihypertensive and lipid medication use. CONCLUSIONS: In this large multiethnic cohort, persistent asthmatics had a higher CVD event rate than nonasthmatics.

Predictors of carotid thickness and plaque progression during a decade: the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND PURPOSE: Carotid artery intima-media thickness (IMT) and plaque are noninvasive markers of subclinical arterial injury that predict incident cardiovascular disease. We evaluated predictors of longitudinal changes in IMT and new plaque during a decade in a longitudinal multiethnic cohort. METHODS: Carotid IMT and plaque were evaluated in Multi-Ethnic Study of Atherosclerosis (MESA) participants at exams 1 and 5, a mean (standard deviation) of 9.4 (0.5) years later. Far wall carotid IMT was measured in both common and internal carotid arteries. A plaque score was calculated from all carotid segments. Mixed-effects longitudinal and multivariate regression models evaluated associations of baseline risk factors and time-updated medication use with IMT progression and plaque formation. RESULTS: The 3441 MESA participants were aged 60.3 (9.4) years (53% women; 26% blacks, 22% Hispanic, 13% Chinese); 1620 (47%) had carotid plaque. Mean common carotid artery IMT progression was 11.8 (12.8) µm/year, and 1923 (56%) subjects developed new plaque. IMT progressed more slowly in Chinese (ß=-2.89; P=0.001) and Hispanic participants (ß=-1.81; P=0.02), and with higher baseline high-density lipoprotein cholesterol (per 5 mg/dL; ß=-0.22; P=0.03), antihypertensive use (ß=-2.06; P=0.0004), and time on antihypertensive medications (years; ß=-0.29; P<0.0001). Traditional risk factors were associated with new plaque formation, with strong associations for cigarette use (odds ratio, 2.31; P<0.0001) and protection by black ethnicity (odds ratio, 0.68; P<0.0001). CONCLUSIONS: In a large, multiethnic cohort with a decade of follow-up, ethnicity was a strong, independent predictor of carotid IMT and plaque progression. Antihypertensive medication use was associated with less subclinical disease progression.

Clinical and biomarker modifiers of vitamin D treatment response: the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Different 25-hydroxyvitamin D [25(OH)D] thresholds for treatment with vitamin D supplementation have been suggested and are derived almost exclusively from observational studies. Whether other characteristics, including race/ethnicity, BMI, and estimated glomerular filtration rate (eGFR), should also influence the threshold for treatment is unknown. OBJECTIVES: The aim was to identify clinical and biomarker characteristics that modify the response to vitamin D supplementation. METHODS: A total of 666 older adults in the Multi-Ethnic Study of Atherosclerosis (MESA) were randomly assigned to 16 wk of oral vitamin D3 (2000 IU/d; n = 499) or placebo (n = 167). Primary outcomes were changes in serum parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D [1,25(OH)2D] concentrations from baseline to 16 wk. RESULTS: Among 666 participants randomly assigned (mean age: 72 y; 53% female; 66% racial/ethnic minority), 611 (92%) completed the study. The mean (SD) change in PTH was -3 (16) pg/mL with vitamin D3 compared with 2 (18) pg/mL with placebo (estimated mean difference: -5; 95% CI: -8, -2 pg/mL). Within the vitamin D3 group, lower baseline 25-hydroxyvitamin D [25(OH)D] was associated with a larger decline in PTH in a nonlinear fashion. With baseline 25(OH)D ≥30 ng/mL as the reference, 25(OH)D <20 ng/mL was associated with a larger decline in PTH with vitamin D3 supplementation (-10; 95% CI: -15, -6 pg/mL), whereas 25(OH)D of 20-30 ng/mL was not (-2; 95% CI: -6, 1 pg/mL). A segmented threshold model identified a baseline 25(OH)D concentration of 21 (95% CI: 13, 31) ng/mL as an inflection point for difference in change in PTH. Race/ethnicity, BMI, and eGFR did not modify vitamin D treatment response. There was no significant change in 1,25(OH)2D in either treatment group. CONCLUSIONS: Of characteristics most commonly associated with vitamin D metabolism, only baseline 25(OH)D <20 ng/mL modified the PTH response to vitamin D supplementation, providing support from a clinical trial to use this threshold to define insufficiency. This trial was registered at clinicaltrials.gov as NCT02925195.

The Multi-Ethnic Study of Atherosclerosis individual response to vitamin D trial: Building a randomized clinical trial into an observational cohort study.

The INdividual response to VITamin D (INVITe) trial was a randomized, placebo-controlled, parallel group trial of vitamin D3 supplementation (2000 IU daily) designed to determine clinical and genetic characteristics that modify the response to vitamin D supplementation. To enhance internal and external validity and reduce cost, the INVITe trial was nested within the Multi-Ethnic Study of Atherosclerosis (MESA), an ongoing prospective observational cohort study. The INVITe trial enrolled a community-based population of 666 racially and ethnically diverse participants from January 2017 to April 2019. This represents 30% of 2210 MESA participants approached for screening, and 96% of those found to be eligible. Barriers to enrollment included delayed initiation of the trial relative to scheduled MESA study visits, a lower number of available MESA participants than expected, and a high prevalence (18%) of high-dose vitamin D supplementation (>1000 IU daily, an exclusion criterion). The final study visit was attended by 611 participants (92%), and median adherence was 98%. Our experience suggests that integration of a randomized trial into an existing observational cohort study may leverage strengths of the source population and enhance enrollment, retention, and adherence, although with limited enrollment capacity. The INVITe trial will use rigorously-collected data to advance understanding of individual determinants of vitamin D response.

Associations of cortisol/testosterone and cortisol/sex hormone-binding globulin ratios with atherosclerosis in middle-age women.

BACKGROUND AND AIMS: The cortisol/testosterone (C/T) ratio has been hypothesized to be a better predictor of atherosclerosis than cortisol alone. No study has assessed whether the C/T and C/sex hormone-binding globulin (SHBG) ratios are associated with atherosclerosis in a U.S. population sample. METHODS: This substudy included 367 women who had both cortisol from year 15 and testosterone and SHBG at year 16 of the Coronary Artery Risk Development in Young Adults study, an ongoing observational cohort in the United States. Of these, intima-media thickness (IMT) was available at follow-up year 20 in 339 (n = 332 with measurement at carotid bulb), and 303 were free of prevalent coronary artery calcium (CAC) at year 15. Area under the curve (AUC) of salivary cortisol was available in 302 individuals. Ratios of AUCs of cortisol to total testosterone, free testosterone, and SHBG were categorized into tertiles. Associations with CAC and IMT were assessed by regression models adjusted for age, race, body mass index, systolic blood pressure, menopause, oral contraceptive use, diabetes, alcohol, and smoking. RESULTS: Only the highest tertile of the AUC/free testosterone ratio was positively associated with carotid bulb IMT (ß = 0.088, P = 0.006). This tertile was also positively associated with new onset CAC between year 15 and 25 (OR 3.45, 95% CI 1.18-10.06). Tertiles of cortisol or testosterone alone were not associated with new onset CAC. CONCLUSION: AUC/Free testosterone ratio may be more associated with atherosclerosis in women than either indicator alone. The ratio may serve as a suitable biomarker of cortisol-linked stress.