Research Differences in lipid profiles in two Hispanic ischemic stroke populations A. Arauz1*, J. G. Romano2, A. Ruiz-Franco1, T. Shang2, C. Dong2, T. Rundek2, S. Koch2, B. Hernández-Curiel1, J. Pacheco1, P. Rojas1, F. Ruiz-Navarro1, M. Katsnelson2, and R. L. Sacco2 Background and Purpose The study aims to compare lipid profiles among ischemic stroke patients in a predominantly Caribbean-Hispanic population in Miami and a Mestizo Hispanic population in Mexico City. Methods We analyzed ischemic stroke Hispanic patients with complete baseline fasting lipid profile enrolled contemporaneously in the prospective registries of two tertiary care teaching hospitals in Mexico City and Miami. Demographic characteristics, risk factors, medications, ischemic stroke subtype, and first fasting lipid profile were compared. Vascular risk factor definitions were standardized. Multiple linear regression analysis was performed to compare lipid fractions. Results A total of 324 patients from Mexico and 236 from Miami were analyzed. Mexicans were significantly younger (58·1 vs. 67·4 years), had a lower frequency of hypertension (53·4% vs. 79·7%), and lower body mass index (27 vs. 28·5). There was a trend toward greater prevalence of diabetes in Mexicans (31·5 vs. 24·6%, P = 0·07). Statin use at the time of ischemic stroke was more common in Miami Hispanics (18·6 vs. 9·4%). Mexicans had lower total cholesterol levels (169·9 ± 46·1 vs. 179·9 ± 48·4 mg/dl), lower low-density lipoprotein (92·3 ± 37·1 vs. 108·2 ± 40·8 mg/dl), and higher triglyceride levels (166·9 ± 123·9 vs. 149·2 ± 115·2 mg/dl). These differences remained significant after adjusting for age, gender, hypertension, diabetes, body mass index, smoking, ischemic stroke subtype, and statin use. Conclusion We found significant differences in lipid fractions in Hispanic ischemic stroke patients, with lower total cholesterol and low-density lipoprotein, and higher triglyceride levels in Mexicans. These findings highlight the heterogeneity of dyslipidemia among the Hispanic race-ethnic group and may lead to different secondary prevention strategies. Key words: cholesterol, Hispanics, ischemic stroke
Introduction Stroke in Hispanics has been described in population-based studies in the United States, showing greater incidence in Hispanics of Caribbean (1) and Mexican-American (2) descent and higher mortality at younger ages (3) when compared with non-Hispanic whites. In addition, stroke subtypes are different in Hispanics (1). Correspondence: Antonio Arauz*, Stroke Clinic, National Institute of Neurology and Neurosurgery Manuel Velasco Suárez, Insurgentes Sur 3877, Colonia La Fama, México City (DF), CP 14269, México. E-mail: [email protected], [email protected] 1 Stroke Clinic, Instituto Nacional de Neurología y Neurocirugía, Mexico City, Mexico 2 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA Received: 28 August 2013; Accepted: 29 October 2013; Published online 19 December 2013 Conflict of interest: None declared. DOI: 10.1111/ijs.12239
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Vol 9, June 2014, 394–399
Although the association between cholesterol and stroke mortality is not as strong as for other vascular events (4,5), accumulating evidence has demonstrated a strong association between lipid levels and atherosclerotic disease, including ischemic stroke (IS) (6), and the use of antilipidemic medication has reduced risk of stroke (7) and recurrence of cardiovascular events (8,9). It should be noted that these data come mostly from Caucasian populations. The 2010 US Census reported 50 million Hispanics in the United States, accounting for the largest minority in that country (10); it is estimated that by the year 2050 Hispanics, will constitute 30% of the US population (11). In addition, there are almost 600 million individuals in Latin America and the Caribbean (12). In spite of recent trends suggesting decreasing stroke incidence and mortality, the higher incidence of diabetes, obesity, physical inactivity, and stroke in Hispanics in the United States and Mexico raises significant concerns for increased stroke burden in Hispanics (13). However, very few studies on differences in stroke subtypes and risk factors between Hispanic subgroups have been conducted. In fact, Hispanics are considered as a homogeneous group in epidemiological studies, but they represent a complex and diverse group with differences in race ethnicity; country of origin; acculturation; cultural, biological, and environmental exposures. In a previous report, we described differences in stroke risk factors between Mexicans and Caribbean Hispanic stroke patients, including greater incidence of low-density lipoprotein in Caribbean Americans (14). The objective of this study is to further examine the differences in lipid fractions of IS patients across the two different Hispanic populations, a predominantly Caribbean-Hispanics in Miami and a Mestizo Hispanics in Mexico City.
Methods We analyzed consecutive Hispanic patients with IS admitted between October 2008 and July 2010 and included in the prospective Stroke Registries of two tertiary care teaching hospitals, the National Institute of Neurology and Neurosurgery (NINN) in Mexico City and Jackson Memorial Hospital/University of Miami Miller School of Medicine in Miami, Florida. The institutional review board at each institution approved the stroke registries. The NINN serves as a referral hospital in Mexico City where most inhabitants are mestizos of mixed European Spanish and Native American heritage. Metropolitan Miami has a diverse population where 64·4% is Hispanic with various countries of origin including Cuba with 34% of Hispanic population, Colombia 4·6%, Nicaragua 4·5%, and Puerto Rico 4% (15). For this analysis, we included patients from the registries who self-identified as Hispanic, with a clinical diagnosis of IS © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization
Research
A. Arauz et al. confirmed by brain imaging (computed tomography or magnetic resonance imaging), and a complete fasting lipid profile performed at baseline. Blood draw time for lipid testing was similar in both populations; draws were scheduled at 6 am while fasting, on the first morning after admission. Patients may have been started on a statin the day of admission if admitted early and after a successful dysphagia screen, but this was uncommon as statins are usually scheduled as ‘daily’ and are administered in the morning oral medication administration schedule. Stroke subtypes were categorized according to the modified Trial of Org 10 172 in Acute Stroke Treatment (TOAST) classification (16) and ascertained by a vascular neurologist. Body mass index (BMI) was calculated by standard definitions based on weight and height. Use of statins at the time of the stroke was documented. Definitions for vascular risk factor were standardized across both institutions. Hypertension was defined as a history of hypertension reported by the patient or documented in the chart, the prehospital use of antihypertensive agents, or at least two blood pressure measurements ≥140/90 mmHg after 72 h of admission. Diabetes mellitus was defined by previous diagnosis, treatment with insulin or oral hypoglycemic medications, a fasting plasma glucose level ≥126 mg/dl, or glycosylated hemoglobin (HbA1c) ≥6·5. Tobacco use was categorized as nonsmoker, current, or former smoker; smoking cessation for at least two-years preceding admission characterized a former smoker. We included total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TG). Non-HDL cholesterol, TC to HDL ratio, and LDL to HDL ratio were calculated. Data were expressed as means and standard deviations for continuous variables and percentages for categorical variables. Univariate analyses were performed with Student’s t-test to compare the mean differences in age, BMI, TC, LDL, HDL, TG, non-HDL cholesterol, and the ratios TC to HDL and LDL to HDL, and with chi-square test to examine the frequency differences in gender, TOAST subtype, and the vascular risk factors between the two populations. Stratified analysis by IS subtypes was performed. However, as this analysis included few patients per subtype, we conducted a multiple linear regression analysis to compare the differences in lipid levels between two populations with four models. The first model (1) was adjusted by age, gender, hypertension, diabetes, and smoking. The second model (2) was adjusted for the covariates in model 1 as well as stroke subtype. The third model (3) was adjusted for the covariates in the model 2 and the previous use of statins. The last model (4) was adjusted for covariates in the model 3 and for BMI.
Results A total of 560 Hispanic patients were analyzed, including 324 from Mexico and 236 from Miami. Mexicans were all mestizos. Miami Hispanics originated from 18 different countries; the majority was of Caribbean origin (72%), where Cubans predominated (63%), followed by Central America (14%) and South America (8%). The rest originated from Mexico, Spain, and the United States; a country of origin could not be determined in five individuals. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization
Table 1 Baseline characteristics of study population
Age Male Body mass index Diabetic Hypertensive Prior use of statin Smoking Never Former Current Stroke subtype Cardio embolism Large vessel Small vessel Cryptogenic Other
Mexico (n = 324) %/Mean ± SD
Miami Hispanic (n = 236) %/Mean ± SD
58·1 ± 17·0 50·9 27·0 ± 4·5 31·5 53·4 9·4
67·4 ± 13·8 63·6 28·5 ± 6·7 24·6 79·7 18·6
55·2 14·2 30·6
53·0 14·0 33·0
26·5 21·9 17·3 17·9 16·4
31·4 23·3 17·4 11·0 16·9
P value
Introduction Stroke in Hispanics has been described in population-based studies in the United States, showing greater incidence in Hispanics of Caribbean (1) and Mexican-American (2) descent and higher mortality at younger ages (3) when compared with non-Hispanic whites. In addition, stroke subtypes are different in Hispanics (1). Correspondence: Antonio Arauz*, Stroke Clinic, National Institute of Neurology and Neurosurgery Manuel Velasco Suárez, Insurgentes Sur 3877, Colonia La Fama, México City (DF), CP 14269, México. E-mail: [email protected], [email protected] 1 Stroke Clinic, Instituto Nacional de Neurología y Neurocirugía, Mexico City, Mexico 2 Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA Received: 28 August 2013; Accepted: 29 October 2013; Published online 19 December 2013 Conflict of interest: None declared. DOI: 10.1111/ijs.12239
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Vol 9, June 2014, 394–399
Although the association between cholesterol and stroke mortality is not as strong as for other vascular events (4,5), accumulating evidence has demonstrated a strong association between lipid levels and atherosclerotic disease, including ischemic stroke (IS) (6), and the use of antilipidemic medication has reduced risk of stroke (7) and recurrence of cardiovascular events (8,9). It should be noted that these data come mostly from Caucasian populations. The 2010 US Census reported 50 million Hispanics in the United States, accounting for the largest minority in that country (10); it is estimated that by the year 2050 Hispanics, will constitute 30% of the US population (11). In addition, there are almost 600 million individuals in Latin America and the Caribbean (12). In spite of recent trends suggesting decreasing stroke incidence and mortality, the higher incidence of diabetes, obesity, physical inactivity, and stroke in Hispanics in the United States and Mexico raises significant concerns for increased stroke burden in Hispanics (13). However, very few studies on differences in stroke subtypes and risk factors between Hispanic subgroups have been conducted. In fact, Hispanics are considered as a homogeneous group in epidemiological studies, but they represent a complex and diverse group with differences in race ethnicity; country of origin; acculturation; cultural, biological, and environmental exposures. In a previous report, we described differences in stroke risk factors between Mexicans and Caribbean Hispanic stroke patients, including greater incidence of low-density lipoprotein in Caribbean Americans (14). The objective of this study is to further examine the differences in lipid fractions of IS patients across the two different Hispanic populations, a predominantly Caribbean-Hispanics in Miami and a Mestizo Hispanics in Mexico City.
Methods We analyzed consecutive Hispanic patients with IS admitted between October 2008 and July 2010 and included in the prospective Stroke Registries of two tertiary care teaching hospitals, the National Institute of Neurology and Neurosurgery (NINN) in Mexico City and Jackson Memorial Hospital/University of Miami Miller School of Medicine in Miami, Florida. The institutional review board at each institution approved the stroke registries. The NINN serves as a referral hospital in Mexico City where most inhabitants are mestizos of mixed European Spanish and Native American heritage. Metropolitan Miami has a diverse population where 64·4% is Hispanic with various countries of origin including Cuba with 34% of Hispanic population, Colombia 4·6%, Nicaragua 4·5%, and Puerto Rico 4% (15). For this analysis, we included patients from the registries who self-identified as Hispanic, with a clinical diagnosis of IS © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization
Research
A. Arauz et al. confirmed by brain imaging (computed tomography or magnetic resonance imaging), and a complete fasting lipid profile performed at baseline. Blood draw time for lipid testing was similar in both populations; draws were scheduled at 6 am while fasting, on the first morning after admission. Patients may have been started on a statin the day of admission if admitted early and after a successful dysphagia screen, but this was uncommon as statins are usually scheduled as ‘daily’ and are administered in the morning oral medication administration schedule. Stroke subtypes were categorized according to the modified Trial of Org 10 172 in Acute Stroke Treatment (TOAST) classification (16) and ascertained by a vascular neurologist. Body mass index (BMI) was calculated by standard definitions based on weight and height. Use of statins at the time of the stroke was documented. Definitions for vascular risk factor were standardized across both institutions. Hypertension was defined as a history of hypertension reported by the patient or documented in the chart, the prehospital use of antihypertensive agents, or at least two blood pressure measurements ≥140/90 mmHg after 72 h of admission. Diabetes mellitus was defined by previous diagnosis, treatment with insulin or oral hypoglycemic medications, a fasting plasma glucose level ≥126 mg/dl, or glycosylated hemoglobin (HbA1c) ≥6·5. Tobacco use was categorized as nonsmoker, current, or former smoker; smoking cessation for at least two-years preceding admission characterized a former smoker. We included total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TG). Non-HDL cholesterol, TC to HDL ratio, and LDL to HDL ratio were calculated. Data were expressed as means and standard deviations for continuous variables and percentages for categorical variables. Univariate analyses were performed with Student’s t-test to compare the mean differences in age, BMI, TC, LDL, HDL, TG, non-HDL cholesterol, and the ratios TC to HDL and LDL to HDL, and with chi-square test to examine the frequency differences in gender, TOAST subtype, and the vascular risk factors between the two populations. Stratified analysis by IS subtypes was performed. However, as this analysis included few patients per subtype, we conducted a multiple linear regression analysis to compare the differences in lipid levels between two populations with four models. The first model (1) was adjusted by age, gender, hypertension, diabetes, and smoking. The second model (2) was adjusted for the covariates in model 1 as well as stroke subtype. The third model (3) was adjusted for the covariates in the model 2 and the previous use of statins. The last model (4) was adjusted for covariates in the model 3 and for BMI.
Results A total of 560 Hispanic patients were analyzed, including 324 from Mexico and 236 from Miami. Mexicans were all mestizos. Miami Hispanics originated from 18 different countries; the majority was of Caribbean origin (72%), where Cubans predominated (63%), followed by Central America (14%) and South America (8%). The rest originated from Mexico, Spain, and the United States; a country of origin could not be determined in five individuals. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization
Table 1 Baseline characteristics of study population
Age Male Body mass index Diabetic Hypertensive Prior use of statin Smoking Never Former Current Stroke subtype Cardio embolism Large vessel Small vessel Cryptogenic Other
Mexico (n = 324) %/Mean ± SD
Miami Hispanic (n = 236) %/Mean ± SD
58·1 ± 17·0 50·9 27·0 ± 4·5 31·5 53·4 9·4
67·4 ± 13·8 63·6 28·5 ± 6·7 24·6 79·7 18·6
55·2 14·2 30·6
53·0 14·0 33·0
26·5 21·9 17·3 17·9 16·4
31·4 23·3 17·4 11·0 16·9
P value
