A Multiple‐Imputation Analysis of a Case‐Control Study of the Risk of Primary Cardiac Arrest Among Pharmacologicallytreated Hypertensives

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146847/1/rssc02669.pd

Sleep Disturbances and Glucose Metabolism in Older Adults: The Cardiovascular Health Study.

ObjectiveWe examined the associations of symptoms of sleep-disordered breathing (SDB), which was defined as loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia with glucose metabolism and incident type 2 diabetes in older adults.Research design and methodsBetween 1989 and 1993, the Cardiovascular Health Study recruited 5,888 participants ≥65 years of age from four U.S. communities. Participants reported SDB and insomnia symptoms yearly through 1989-1994. In 1989-1990, participants underwent an oral glucose tolerance test, from which insulin secretion and insulin sensitivity were estimated. Fasting glucose levels were measured in 1989-1990 and again in 1992-1993, 1994-1995, 1996-1997, and 1998-1999, and medication use was ascertained yearly. We determined the cross-sectional associations of sleep symptoms with fasting glucose levels, 2-h glucose levels, insulin sensitivity, and insulin secretion using generalized estimated equations and linear regression models. We determined the associations of updated and averaged sleep symptoms with incident diabetes in Cox proportional hazards models. We adjusted for sociodemographics, lifestyle factors, and medical history.ResultsObserved apnea, snoring, and daytime sleepiness were associated with higher fasting glucose levels, higher 2-h glucose levels, lower insulin sensitivity, and higher insulin secretion. The risk of the development of type 2 diabetes was positively associated with observed apnea (hazard ratio [HR] 1.84 [95% CI 1.19-2.86]), snoring (HR 1.27 [95% CI 0.95-1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13-2.12]). In contrast, we did not find consistent associations between insomnia symptoms and glucose metabolism or incident type 2 diabetes.ConclusionsEasily collected symptoms of SDB are strongly associated with insulin resistance and the incidence of type 2 diabetes in older adults. Monitoring glucose metabolism in such patients may prove useful in identifying candidates for lifestyle or pharmacological therapy. Further studies are needed to determine whether insomnia symptoms affect the risk of diabetes in younger adults

The association of calcium supplementation and incident cardiovascular events in the Multi-ethnic Study of Atherosclerosis (MESA)

Many US adults use calcium supplements to address inadequate dietary intake and improve bone health. However, recent reports have suggested that use of calcium supplements may elevate cardiovascular disease (CVD) risk. In this study, we examined associations between baseline calcium supplement use and incident myocardial infarction (MI) (n=208 events) and CVD events (n=641 events) over 10.3 years in men and women from the Multi-Ethnic Study of Atherosclerosis (MESA) cohort (n=6,236), with dietary calcium intake at baseline also examined as a supplementary objective

Physical Activity, Physical Fitness, and Leukocyte Telomere Length: The Cardiovascular Health Study.

INTRODUCTION: The influence of physical activity (PA) and physical fitness (PF) at older ages on changes in telomere length (TL)--repetitive DNA sequences that may mark biologic aging--is not well-established. Few prior studies (mainly cross-sectional) have been conducted in older adults, and few studies have evaluated PF. METHODS: We investigated cross-sectional and prospective associations of PA and PF with leukocyte TL among 582 older adults (mean ± SD age, 73 ± 5 yr at baseline) in the Cardiovascular Health Study, with serial TL measures and PA and PF assessed multiple times. Cross-sectional associations were assessed using multivariable repeated-measures regression, in which cumulatively averaged PA and PF measures were related to TL. Longitudinal analyses assessed cumulatively averaged PA and PF against later changes in TL, and changes in cumulatively averaged PA and PF against changes in TL. RESULTS: Cross-sectionally, greater walking distance and chair test performance, but not other PA and PF measures, were each associated with longer TL (P trend = 0.007 and 0.04, respectively). In longitudinal analyses, no significant associations of baseline PA and PF with change in TL were observed. In contrast, changes in leisure-time activity and chair test performance were each inversely associated with changes in TL. CONCLUSIONS: Cross-sectional analyses suggest that greater PA and PF are associated with longer TL. Prospective analyses show that changes in PA and PF are associated with differences in changes in TL. Even later in life, changes in certain PA and PF measures are associated with changes in TL, suggesting that leisure-time activity and fitness could reduce leukocyte telomere attrition among older adults.This research was supported by contracts HHSN268201200036C, HHSN268200800007C, N01 HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086, and grant U01HL080295 from the National Heart, Lung, and Blood Institute (NHLBI), with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided by R01AG023629 the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org. Luisa Soares-Miranda is supported by the Portuguese Foundation of Science and Technology (FCT), SFRH/BPD/76947/2011, PTDC/DES/099018/2008 - FCT/FCOMP-01- 0124-FEDER-009573, and The Research Centre in Physical Activity Health and Leisure is supported by UID/DTP/00617/2013. Dr Imamura received support from the Medical Research Council Epidemiology Unit Core Support (MC_UU_12015/5).This is the author accepted manuscript. The final version is available from Wolters Kluwer via http://dx.doi.org/10.1249/MSS.000000000000072

Accuracy of QT(c) and QTI for detection of autonomic dysfunction

Background: Correlates of QT interval duration have been described although their effects on its ability to identify autonomic neuropathy have not. Methods: We examined the ability of QT(c) and QTI to detect pharmacologically simulated autonomic dysfunction (PSAD) in persons without bundle branch block, U waves, or long QT syndrome by reviewing 249 articles published through 1996 describing the influence of adrenergic beta antagonists or atropine on QT duration. Six of the articles described effects of intravenous drug administration on the ECG among 94 individuals in sinus rhythm. Autonomic dysfunction was pharmacologically simulated in a subset of 30 men and women via coadministration of both drugs. We used logistic regression to estimate accuracy of QT(c) and QTI for PSAD, reported as area under summary receiver operating characteristic curves (AUC [95% CI]) and sensitivity (95% CI) of test thresholds with specificity of 0.80. Results: Sensitivity of QT(c) > 436 ms(1/2) was 0.20 (0.09-0.38) and AUC(QTc), 0.54 (0.41-0.66). A QTI < 95% was similarly insensitive, 0.30 (0.16-0.48), and AUC(QTI) equally low. However, stratum-specific AUC(QTI) was higher than overall AUC(QTI), 0.69 (0.64-0.74) when age ≤ mean (37.7 years), 0.77 (0.73- 0.81) in males, and 0.87 (0.77-0.97) in participants without history of arrhythmia. Sensitivity of QTI thresholds in these strata, range 0.41 to 0.62, was 2.2 to 7.8 times greater than sensitivity, range 0.08 to 0.19, of equally specific QT(c) thresholds. In a model combining age (y), gender, and arrhythmia, AUC(QTI) was 0.88 (0.86-0.90). Conclusions: In isolation, QT(c) and QTI inaccurately detect PSAD. When confounding is taken into consideration, low QTI identifies PSAD with greater sensitivity and accuracy than high QT(c)

Contribution of Major Lifestyle Risk Factors for Incident Heart Failure in Older Adults: The Cardiovascular Health Study.

OBJECTIVES: The goal of this study was to determine the relative contribution of major lifestyle factors on the development of heart failure (HF) in older adults. BACKGROUND: HF incurs high morbidity, mortality, and health care costs among adults ≥65 years of age, which is the most rapidly growing segment of the U.S. METHODS: We prospectively investigated separate and combined associations of lifestyle risk factors with incident HF (1,380 cases) over 21.5 years among 4,490 men and women in the Cardiovascular Health Study, which is a community-based cohort of older adults. Lifestyle factors included 4 dietary patterns (Alternative Healthy Eating Index, Dietary Approaches to Stop Hypertension, an American Heart Association 2020 dietary goals score, and a Biologic pattern, which was constructed using previous knowledge of cardiovascular disease dietary risk factors), 4 physical activity metrics (exercise intensity, walking pace, energy expended in leisure activity, and walking distance), alcohol intake, smoking, and obesity. RESULTS: No dietary pattern was associated with developing HF (p > 0.05). Walking pace and leisure activity were associated with a 26% and 22% lower risk of HF, respectively (pace >3 mph vs. <2 mph; hazard ratio [HR]: 0.74; 95% confidence interval [CI]: 0.63 to 0.86; leisure activity ≥845 kcal/week vs. <845 kcal/week; HR: 0.78; 95% CI: 0.69 to 0.87). Modest alcohol intake, maintaining a body mass index <30 kg/m(2), and not smoking were also independently associated with a lower risk of HF. Participants with ≥4 healthy lifestyle factors had a 45% (HR: 0.55; 95% CI: 0.42 to 0.74) lower risk of HF. Heterogeneity by age, sex, cardiovascular disease, hypertension medication use, and diabetes was not observed. CONCLUSIONS: Among older U.S. adults, physical activity, modest alcohol intake, avoiding obesity, and not smoking, but not dietary patterns, were associated with a lower risk of HF.Role of the funding source: This research was supported by contracts HHSN268201200036C, HHSN268200800007C, N01 HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086, and grant HL080295 from the National Heart, Lung, and Blood Institute (NHLBI), with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided by AG023629 from the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org. Fumiaki Imamura was supported by Medical Research Council Unit Programme number MC_UU_125015/5.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.jchf.2015.02.00

Lack of association between first myocardial infarction and past use of erythromycin, tetracycline, or doxycycline.

To evaluate the association of prior treatment with antibiotics active against Chlamydia pneumoniae with the risk for incident myocardial infarction, we conducted a population-based case-control study. We found that use of erythromycin, tetracycline, or doxycycline during the previous 5 years was not associated with risk for first myocardial infarction. These results suggest little or no association between the use of these antibiotics and the risk for first myocardial infarction in the primary prevention setting

Association between Cystatin C and MRI Measures of Left Ventricular Structure and Function: Multi-Ethnic Study of Atherosclerosis

Introduction. Reduced kidney function, approximated by elevated cystatin C, is associated with diastolic dysfunction, heart failure, and cardiovascular mortality; however, the precise mechanism(s) that account for these relationships remains unclear. Understanding the relationship between cystatin C and subclinical left ventricular (LV) remodeling, across ethnically diverse populations, may help explain the mechanisms underlying the association of kidney dysfunction with heart failure and cardiovascular mortality. Methods. Measures of cystatin C and LV parameters were obtained from the multi-ethnic study of atherosclerosis (MESA) cohort at baseline (N = 4, 970 with complete data on cystatin C and LV parameters). LV parameters; LV end-diastolic (LVEDV) and end-systolic volumes (LVESV), LV mass (LVM), concentricity (LV mass/LV end-diastolic volume), and LV ejection fraction (LVEF) were measured using magnetic resonance imaging. Nested linear models were used to examine the relationship between higher quartiles of cystatin C and LV parameters, with and without adjustment for demographics, height, and weight, and traditional cardiovascular risk factors. Similar analyses were performed stratified by ethnicity and gender. Results. A fully adjusted model demonstrated a linear relationship between higher quartiles of cystatin C and lower LVEDV, (Mean ± SE, 128 ± 0.7, 128 ± 0.7, 126 ± 0.7, 124 ± 0.8 mL; P = 0.0001). Associations were also observed between higher quartiles of cystatin C and lower LVESV (P = 0.04) and concentricity (P = 0.0001). In contrast, no association was detected between cystatin C and LVM or LVEF. In analyses stratified by race and gender, the patterns of association between cystatin C quartiles and LV parameters were qualitatively similar to the overall association. Conclusion. Cystatin C levels were inversely associated with LVEDV and LVESV with a disproportionate decrease in LVEDV compared to LVM in a multi-ethnic population. This morphometric pattern of concentric left ventricular remodeling, may in part explain the process by which kidney dysfunction leads to diastolic dysfunction, heart failure and cardiovascular mortality

Toenail Selenium and Incidence of Type 2 Diabetes in U.S. Men and Women

OBJECTIVE Compelling biological pathways suggest that selenium (Se) may lower onset of type 2 diabetes mellitus (T2DM), but very few studies have evaluated this relationship, with mixed results. We examined the association between toenail Se and incidence of T2DM. RESEARCH DESIGN AND METHODS We performed prospective analyses in two separate U.S. cohorts, including 3,630 women and 3,535 men, who were free of prevalent T2DM and heart disease at baseline in 1982–1983 and 1986–1987, respectively. Toenail Se concentration was quantified using neutron activation analysis, and diabetes cases were identified by biennial questionnaires and confirmed by a detailed supplementary questionnaire. Hazard ratios of incident T2DM according to Se levels were calculated using Cox proportional hazards. RESULTS During 142,550 person-years of follow-up through 2008, 780 cases of incident T2DM occurred. After multivariable adjustment, the risk of T2DM was lower across increasing quintiles of Se, with pooled relative risks across the two cohorts of 1.0 (reference), 0.91 (95% CI 0.73–1.14), 0.78 (0.62–0.99), 0.72 (0.57–0.91), and 0.76 (0.60–0.97), respectively (P for trend = 0.01). Results were similar excluding the few individuals (4%) who used Se supplements. In semiparametric analyses, the inverse relationship between Se levels and T2DM risk appeared to be linear. CONCLUSIONS At dietary levels of intake, individuals with higher toenail Se levels are at lower risk for T2DM. Further research is required to determine whether varying results in this study versus prior trials relate to differences in dose, source, statistical power, residual confounding factors, or underlying population risk