Asian Americans are among the fastest growing ethnic groups in the United States, projected to comprise nearly 40 million individuals by 20601 in six main subgroups: Chinese, Filipino, Japanese, Korean, Vietnamese, and Indian (U.S. Census Bureau 2015).1 The San Francisco Bay Area has one of the largest and most diverse Asian populations in America, approaching 2 million individuals in its five core counties (San Francisco, San Mateo, Santa Clara, Alameda, and Contra Costa). Individuals age 65 and older are projected to compose 30% of the growing Asian American community in Santa Clara County by 2060—the highest proportion of seniors in any ethnic category—indicating an urgent need to understand and improve cardiovascular health in this population and each of its subgroups.2
The cardiovascular health of Asian Americans has been less thoroughly investigated than that of other ethnic groups3, but observational studies indicate that rates of cardiovascular diseases (CVD) vary considerably between each subgroup of national origin.4 Prior studies show that Asian Americans exhibit elevated rates of type II diabetes and that Korean-, Japanese-, and Filipino-Americans are at especially high risk, with local diabetes prevalence of 16%, 13%, and 13%, respectively.2, 4 Incidence of diabetes and metabolic syndrome5 increases at lower body mass index (BMI) in Asian Americans than in other ethnic groups, causing an observed diabetes prevalence that is 60% higher than non-Hispanic whites after adjustment for BMI.6 Dyslipidemia, a major risk factor for heart attack or stroke, occurs at higher rates among Asian Americans in Northern California, varying considerably between each subgroup and likely exacerbated by lower rates of treatment than among non-Hispanic whites.7, 8 Prediction of cardiovascular disease risk among Asian Americans is notably less accurate, since the Framingham Risk Score and other risk calculators may poorly model disease incidence and therefore require ethnic-specific refinements to improve applicability to this population and its subgroups.3
Several trends have highlighted the critical need for a better understanding of the mechanisms underlying CVD risk in this population. A recent study in Los Angeles County found that rates of hypertension among Asian Americans increased by 18% between 2005 and 2015 and noted an especially high prevalence among Filipinos (32.7%) and Vietnamese (35.1%).9 Diabetes prevalence has also risen, especially among Filipinos, and presents at lower BMI than non-Hispanic whites.10 Although subgroup-specific data is limited, studies of total Asian Americans have shown that proportionate mortality for many cardiovascular diseases is elevated and rates of health improvement are slower than among non-Hispanic whites.11
In order to understand these divergences in cardiovascular risk, we propose a prospective cohort study that will evaluate the underlying mechanisms of elevated CVD in Asian Americans. The purpose of this proposal is to initiate an internet-enhanced research project using the Eureka Mobile Health platform at Zuckerberg San Francisco General Hospital (ZSFG) and UCSF in order to build the foundation of our cohort and obtain critical preliminary data for NIH grant proposals along with data to advocate for possible donor/philanthropic support in the near future. Our group will adapt the well-established infrastructure that allows us to undertake cardiovascular research within the diverse HIV/AIDS community at ZSFG to study the unique mechanisms underlying CVD in the Asian American population with the ultimate goal of improving cardiovascular health.
Study Design: Initial Cohort of Chinese- and Filipino-Americans in San Francisco
We plan to follow a model similar to the Mediators of Atherosclerosis in South Asians Living in America (MASALA) Study at UCSF, which is an ongoing prospective cohort study of cardiovascular health specifically among Indian- and Pakistani-Americans.12 We will leverage existing research infrastructure established by Dr. Priscilla Hsue at Zuckerberg San Francisco General, which she uses to conduct many prospective studies and clinical trials in individuals with HIV. This project will be covered initially using Dr. Hsue’s discretionary funds for preliminary data in order to demonstrate feasibility of recruitment and study design. After completing this initial study, we plan to apply for NIH grants to support a larger cohort study utilizing the same infrastructure provided by Eureka Mobile Health platform.
We will begin with an initial cohort of 50 Chinese-Americans and 50 Filipino-Americans recruited through UCSF, SFGH, and local community partners such as North East Medical Services (NEMS), the Chinatown Public Health Clinic, the Asian Health Institute, and the Asian American Research Center on Health. Potential participants will be screened according to 1) Chinese or Filipino ancestry, defined by ≥3 grandparents born in China/Taiwan or the Philippines, respectively; 2) age between 40 and 79 years; 3) ability to speak and/or read English, Cantonese, Mandarin, or Tagalog. Individuals will be excluded from our study according to the same criteria used in the Multi-Ethnic Study of Atherosclerosis (MESA) and MASALA studies12; namely, we will not enroll those with prior history of major adverse cardiovascular events, ongoing cancer diagnosis, life expectancy under 5 years due to any illness, impaired cognitive capacity, or plans to leave the study region.13
After enrollment, our study team will use the Eureka Mobile Health platform to administer a detailed questionnaire gathering information about dietary habits, lifestyle factors, medical history, and socioeconomic circumstances for each participant. Given the unique challenges faced by our population of interest, we will also assess culturally relevant topics like primary language, country/province of origin, timeline of residence in the United States, use of traditional medicine, effects of discrimination,14, 15 and other measures of acculturation that are known to affect health outcomes in ethnic minority populations.16 A baseline visit at ZSFG will include vitals and anthropometric measurements. We will also draw and store blood from participants for future testing of genomic, metabolomic, proteomic, and inflammatory markers.
Individuals will be recruited to use the KardiaMobile home EKG monitor, which has been shown to accurately detect atrial fibrillation burden in recent studies.17 These participants will also receive home monitoring devices for blood pressure and Ziopatch monitoring. All participants will use the monitoring devices for 6 months. We will link output data from each of these mobile devices with the questionnaire data mentioned above using the Eureka Mobile Health platform. Previous studies have shown that usage of home monitoring or smartphone engagement devices positively influences rates of diagnosis18-20 and improves treatment compliance, healthy behavioral modifications, and utilization of healthcare resources.21-23 Interventions that increase access, diagnosis, and treatment are especially important in the Asian American population, since previous studies have shown reduced access to healthcare within some Asian subgroups.24, 25
Our primary goal is to provide better insight into risk factors and develop interventional modalities for improving Asian American cardiovascular health. This initial cohort will also allow us to gather critical preliminary data for a future grant submission to support a larger cohort study. With expanded funding, we hope to assess lipids, inflammatory markers, and metabolic measurements alongside genetic profiling, proteomics, and other newer markers of cardiovascular health such as clonal hematopoiesis of indeterminate potential (CHIP). In order to probe the underlying mechanism of CVD in the Asian population, we plan to evaluate coronary artery calcium and plaque burden using CT angiography, along with assessment of carotid intima media thickness to evaluate vascular disease. We plan to assess the association between clinical characteristics gathered using the Eureka Mobile Health platform and these imaging indices in order to better understand the pathophysiology underlying increased CV risk in Asian American individuals. As a corollary to this work, we hope to establish a center of cardiovascular excellence for the Asian American population, which can provide clinical care for Asians with underlying CVD. In addition, this clinic could serve as the impetus for launching implementation studies in the future aimed at risk reduction including smoking cessation, BP control, lipid control, diet and exercise. Importantly, our research effort and clinical center would also provide significant research and clinical opportunities for trainees in the future.
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