Shia T. Kent

Underutilization of high-intensity statin therapy after hospitalization for coronary heart disease.

BACKGROUND National guidelines recommend use of high-intensity statins after hospitalization for coronary heart disease (CHD) events. OBJECTIVES This study sought to estimate the proportion of Medicare beneficiaries filling prescriptions for high-intensity statins after hospital discharge for a CHD event and to analyze whether statin intensity before hospitalization is associated with statin intensity after discharge. METHODS We conducted a retrospective cohort study using a 5% random sample of Medicare beneficiaries between 65 and 74 years old. Beneficiaries were included in the analysis if they filled a statin prescription after a CHD event (myocardial infarction or coronary revascularization) in 2007, 2008, or 2009. High-intensity statins included atorvastatin 40 to 80 mg, rosuvastatin 20 to 40 mg, and simvastatin 80 mg. RESULTS Among 8,762 Medicare beneficiaries filling a statin prescription after a CHD event, 27% of first post-discharge fills were for a high-intensity statin. The percent filling a high-intensity statin post-discharge was 23.1%, 9.4%, and 80.7%, for beneficiaries not taking statins pre-hospitalization, taking low/moderate-intensity statins, and taking high-intensity statins before their CHD event, respectively. Compared with beneficiaries not on statin therapy pre-hospitalization, multivariable adjusted risk ratios for filling a high-intensity statin were 4.01 (3.58-4.49) and 0.45 (0.40-0.52) for participants taking high-intensity and low/moderate-intensity statins before their CHD event, respectively. Only 11.5% of beneficiaries whose first post-discharge statin fill was for a low/moderate-intensity statin filled a high-intensity statin within 365 days of discharge. CONCLUSIONS The majority of Medicare beneficiaries do not fill high-intensity statins after hospitalization for CHD.

Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study

BackgroundPossible physiological causes for the effect of sunlight on mood are through the suprachiasmatic nuclei and evidenced by serotonin and melatonin regulation and its associations with depression. Cognitive function involved in these same pathways may potentially be affected by sunlight exposure. We evaluated whether the amount of sunlight exposure (i.e. insolation) affects cognitive function and examined the effect of season on this relationship.MethodsWe obtained insolation data for residential regions of 16,800 participants from a national cohort study of blacks and whites, aged 45+. Cognitive impairment was assessed using a validated six-item screener questionnaire and depression status was assessed using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to find whether same-day or two-week average sunlight exposure was related to cognitive function and whether this relationship differed by depression status.ResultsAmong depressed participants, a dose-response relationship was found between sunlight exposure and cognitive function, with lower levels of sunlight associated with impaired cognitive status (odds ratio = 2.58; 95% CI 1.43–6.69). While both season and sunlight were correlated with cognitive function, a significant relation remained between each of them and cognitive impairment after controlling for their joint effects.ConclusionThe study found an association between decreased exposure to sunlight and increased probability of cognitive impairment using a novel data source. We are the first to examine the effects of two-week exposure to sunlight on cognition, as well as the first to look at sunlights effects on cognition in a large cohort study.

Heat Waves and Health Outcomes in Alabama (USA): The Importance of Heat Wave Definition

Background: A deeper understanding of how heat wave definition affects the relationship between heat exposure and health, especially as a function of rurality, will be useful in developing effective heat wave warning systems. Objective: We compared the relationships between different heat wave index (HI) definitions and preterm birth (PTB) and nonaccidental death (NAD) across urban and rural areas. Methods: We used a time-stratified case-crossover design to estimate associations of PTB and NAD with heat wave days (defined using 15 HIs) relative to non–heat wave control days in Alabama, USA (1990–2010). ZIP code–level HIs were derived using data from the North American Land Data Assimilation System. Associations with heat wave days defined using different HIs were compared by bootstrapping. We also examined interactions with rurality. Results: Associations varied depending on the HI used to define heat wave days. Heat waves defined as having at least 2 consecutive days with mean daily temperatures above the 98th percentile were associated with 32.4% (95% CI: 3.7, 69.1%) higher PTB, and heat waves defined as at least 2 consecutive days with mean daily temperatures above the 90th percentile were associated with 3.7% (95% CI: 1.1, 6.3%) higher NAD. Results suggest that significant positive associations were more common when relative—compared with absolute—HIs were used to define exposure. Both positive and negative associations were found in each rurality stratum. However, all stratum-specific significant associations were positive, and NAD associations with heat waves were consistently positive in urban strata but not in middle or rural strata. Conclusions: Based on our findings, we conclude that a relative mean-temperature-only heat wave definition may be the most effective metric for heat wave warning systems in Alabama. Citation: Kent ST, McClure LA, Zaitchik BF, Smith TT, Gohlke JM. 2014. Heat waves and health outcomes in Alabama (USA): the importance of heat wave definition. Environ Health Perspect 122:151–158; http://dx.doi.org/10.1289/ehp.1307262

Comparative effects of biologics on cardiovascular risk among older patients with rheumatoid arthritis

Objectives To compare the coronary heart disease risk among patients with rheumatoid arthritis (RA) initiating common biologic disease-modifying antirheumatic drugs of different mechanisms. Methods We conducted a retrospective cohort study of patients with RA enrolled in Medicare, a public health plan covering >90% of US residents 65 years or older, from 2006 to 2012 who (1) initiated a biologic, (2) had complete medical and pharmacy coverage for at least 12 months before biologic initiation and (3) were free of coronary heart disease at the time of initiation. We compared the incidence rates (IRs) of (1) acute myocardial infarction (AMI) and (2) a composite outcome of AMI or coronary revascularisation and used multivariable adjusted Cox regression models to examine the associations between the type of biologic and the two outcomes. Results We identified 47 193 eligible patients with RA with mean age 64 (SD 13) years; 85% were women. Crude IRs for AMI ranged from 5.7 to 8.8 cases per 1000 person-years (PYs). AMI risk was significantly elevated among antitumour necrosis factor (anti-TNF) initiators overall (adjusted HR (aHR) 1.3; 95% CI 1.0 to 1.6) and individually among etanercept (aHR 1.3; 95% CI 1.0 to 1.8) and infliximab (aHR 1.3; 95% CI 1.0 to 1.6) compared with abatacept initiators. Crude IRs for the composite outcome ranged from 7.6 to 14.5 per 1000 PYs. Tocilizumab initiators were at reduced risk of the composite outcome compared with abatacept initiators (aHR 0.64, 95% CI 0.41 to 0.99). Discussion Findings from this observational study of patients with RA suggested that anti-TNF biologics may be associated with higher AMI risk compared with abatacept.

Association of Serum Lipids and Coronary Heart Disease in Contemporary Observational Studies

Background— The use of statins increased among US adults with high coronary heart disease (CHD) risk after publication of the 2001 cholesterol treatment guidelines. Methods and Results— We analyzed the association between lipids and CHD among 9578 REasons for Geographic And Racial Differences in Stroke (REGARDS) study participants and 346 595 Kaiser Permanente Southern California (KPSC) members with baseline lipid measurements in 2003 to 2007. We performed the same analyses among 14 590 Atherosclerosis Risk In Communities (ARIC) study participants with lipid measurements in 1987 to 1989. Analyses were restricted to blacks and whites 45 to 64 years of age without CHD who were not taking statins at baseline. Total cholesterol, high-density lipoprotein cholesterol, and triglycerides were measured at baseline. Low-density lipoprotein cholesterol, non–high-density lipoprotein cholesterol, and ratios of total to high-density lipoprotein cholesterol and triglycerides to high-density lipoprotein cholesterol were calculated. The prevalence of diabetes mellitus, history of stroke, and antihypertensive medication use increased at higher low-density lipoprotein cholesterol in ARIC but not in REGARDS or KPSC. Over 8.9 years of follow-up, 225 CHD events occurred in REGARDS, 6547 events in KPSC, and 583 events in ARIC. After multivariable adjustment, less favorable lipid levels were associated with higher hazard ratios for CHD in ARIC. These associations were attenuated in REGARDS and KPSC. For example, the hazard ratio associated with the highest versus lowest quartile of low-density lipoprotein cholesterol (≥146 versus ⩽102 mg/dL) was 1.89 (95% confidence interval, 1.42–2.51) in ARIC, 1.25 (95% confidence interval, 0.81–1.92) in REGARDS, and 1.49 (95% confidence interval, 1.38–1.61) in KPSC. Conclusion— The association between lipids and CHD in contemporary studies may be attenuated by the preferential use of statins by high-risk individuals.

The association of remotely-sensed outdoor temperature with blood pressure levels in REGARDS: a cross-sectional study of a large, national cohort of African-American and white participants.

BackgroundEvidence is mounting regarding the clinically significant effect of temperature on blood pressure.MethodsIn this cross-sectional study the authors obtained minimum and maximum temperatures and their respective previous week variances at the geographic locations of the self-reported residences of 26,018 participants from a national cohort of blacks and whites, aged 45+. Linear regression of data from 20,623 participants was used in final multivariable models to determine if these temperature measures were associated with levels of systolic or diastolic blood pressure, and whether these relations were modified by stroke-risk region, race, education, income, sex hypertensive medication status, or age.ResultsAfter adjustment for confounders, same-day maximum temperatures 20°F lower had significant associations with 1.4 mmHg (95% CI: 1.0, 1.9) higher systolic and 0.5 mmHg (95% CI: 0.3, 0.8) higher diastolic blood pressures. Same-day minimum temperatures 20°F lower had a significant association with 0.7 mmHg (95% CI: 0.3, 1.0) higher systolic blood pressures but no significant association with diastolic blood pressure differences. Maximum and minimum previous-week temperature variabilities showed significant but weak relationships with blood pressures. Parameter estimates showed effect modification of negligible magnitude.ConclusionsThis study found significant associations between outdoor temperature and blood pressure levels, which remained after adjustment for various confounders including season. This relationship showed negligible effect modification.

Area-level risk factors for adverse birth outcomes: trends in urban and rural settings

BackgroundSignificant and persistent racial and income disparities in birth outcomes exist in the US. The analyses in this manuscript examine whether adverse birth outcome time trends and associations between area-level variables and adverse birth outcomes differ by urban–rural status.MethodsAlabama births records were merged with ZIP code-level census measures of race, poverty, and rurality. B-splines were used to determine long-term preterm birth (PTB) and low birth weight (LBW) trends by rurality. Logistic regression models were used to examine differences in the relationships between ZIP code-level percent poverty or percent African-American with either PTB or LBW. Interactions with rurality were examined.ResultsPopulation dense areas had higher adverse birth outcome rates compared to other regions. For LBW, the disparity between population dense and other regions increased during the 1991–2005 time period, and the magnitude of the disparity was maintained through 2010. Overall PTB and LBW rates have decreased since 2006, except within isolated rural regions. The addition of individual-level socioeconomic or race risk factors greatly attenuated these geographical disparities, but isolated rural regions maintained increased odds of adverse birth outcomes. ZIP code-level percent poverty and percent African American both had significant relationships with adverse birth outcomes. Poverty associations remained significant in the most population-dense regions when models were adjusted for individual-level risk factors.ConclusionsPopulation dense urban areas have heightened rates of adverse birth outcomes. High-poverty African American areas have higher odds of adverse birth outcomes in urban versus rural regions. These results suggest there are urban-specific social or environmental factors increasing risk for adverse birth outcomes in underserved communities. On the other hand, trends in PTBs and LBWs suggest interventions that have decreased adverse birth outcomes elsewhere may not be reaching isolated rural areas.

Fine Particulate Matter and Incident Cognitive Impairment in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort

Studies of the effect of air pollution on cognitive health are often limited to populations living near cities that have air monitoring stations. Little is known about whether the estimates from such studies can be generalized to the U.S. population, or whether the relationship differs between urban and rural areas. To address these questions, we used a satellite-derived estimate of fine particulate matter (PM2.5) concentration to determine whether PM2.5 was associated with incident cognitive impairment in a geographically diverse, biracial US cohort of men and women (n = 20,150). A 1-year mean baseline PM2.5 concentration was estimated for each participant, and cognitive status at the most recent follow-up was assessed over the telephone using the Six-Item Screener (SIS) in a subsample that was cognitively intact at baseline. Logistic regression was used to determine whether PM2.5 was related to the odds of incident cognitive impairment. A 10 µg/m3 increase in PM2.5 concentration was not reliably associated with an increased odds of incident impairment, after adjusting for temperature, season, incident stroke, and length of follow-up [OR (95% CI): 1.26 (0.97, 1.64)]. The odds ratio was attenuated towards 1 after adding demographic covariates, behavioral factors, and known comorbidities of cognitive impairment. A 10 µg/m3 increase in PM2.5 concentration was slightly associated with incident impairment in urban areas (1.40 [1.06–1.85]), but this relationship was also attenuated after including additional covariates in the model. Evidence is lacking that the effect of PM2.5 on incident cognitive impairment is robust in a heterogeneous US cohort, even in urban areas.

Measuring personal heat exposure in an urban and rural environment

Previous studies have linked heat waves to adverse health outcomes using ambient temperature as a proxy for estimating exposure. The goal of the present study was to test a method for determining personal heat exposure. An occupationally exposed group (urban groundskeepers in Birmingham, AL, USA N=21), as well as urban and rural community members from Birmingham, AL (N=30) or west central AL (N=30) wore data logging temperature and light monitors clipped to the shoe for 7 days during the summer of 2012. We found that a temperature monitor clipped to the shoe provided a comfortable and feasible method for recording personal heat exposure. Ambient temperature (°C) recorded at the nearest weather station was significantly associated with personal heat exposure [β 0.37, 95%CI (0.35, 0.39)], particularly in groundskeepers who spent more of their total time outdoors [β 0.42, 95%CI (0.39, 0.46)]. Factors significantly associated with lower personal heat exposure include reported time indoors [β -2.02, 95%CI (-2.15, -1.89)], reported income>20K [β -1.05, 95%CI (-1.79, -0.30)], and measured % body fat [β -0.07, 95%CI (-0.12, -0.02)]. There were significant associations between income and % body fat with lower indoor and nighttime exposures, but not with outdoor heat exposure, suggesting modifications of the home thermal environment play an important role in determining overall heat exposure. Further delineation of the effect of personal characteristics on heat exposure may help to develop targeted strategies for preventing heat-related illness.

Use of Remotely Sensed Data to Evaluate the Relationship between Living Environment and Blood Pressure

Background Urbanization has been correlated with hypertension (HTN) in developing countries undergoing rapid economic and environmental transitions. Objectives We examined the relationships among living environment (urban, suburban, and rural), day/night land surface temperatures (LST), and blood pressure in selected regions from the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. Also, the linking of data on blood pressure from REGARDS with National Aeronautics and Space Administration (NASA) science data is relevant to NASA’s strategic goals and missions, particularly as a primary focus of the agency’s Applied Sciences Program. Methods REGARDS is a national cohort of 30,228 people from the 48 contiguous United States with self-reported and measured blood pressure levels. Four metropolitan regions (Philadelphia, PA; Atlanta, GA; Minneapolis, MN; and Chicago, IL) with varying geographic and health characteristics were selected for study. Satellite remotely sensed data were used to characterize the LST and land cover/land use (LCLU) environment for each area. We developed a method for characterizing participants as living in urban, suburban, or rural living environments, using the LCLU data. These data were compiled on a 1-km grid for each region and linked with the REGARDS data via an algorithm using geocoding information. Results REGARDS participants in urban areas have higher systolic and diastolic blood pressure than do those in suburban or rural areas, and also a higher incidence of HTN. In univariate models, living environment is associated with HTN, but after adjustment for known HTN risk factors, the relationship was no longer present. Conclusion Further study regarding the relationship between HTN and living environment should focus on additional environmental characteristics, such as air pollution. The living environment classification method using remotely sensed data has the potential to facilitate additional research linking environmental variables to public health concerns.