- Email: [email protected]
Prevalence of stroke and associated risk factors in Asian Indians living in the state of Georgia, United States of America
TABLE 2 Combined Effect of Cold Pressor Test (CPT) and Handgrip Isometric Exercise (HIE) in Studied Subjects (n ⫽ 8) Effect Measured PWV (m/s) Augmentation index Systolic arterial pressure (mm Hg) Diastolic arterial pressure (mm Hg) Mean arterial pressure (mm Hg)
Rest
CPT
HIE
CPT ⫹ HIE
p (ANOVA)
7.9 ⫾ 1.2 ⫺0.23 119 ⫾ 13 80 ⫾ 8 97 ⫾ 10
8.7 ⫾ 1.2 ⫺0.004 129 ⫾ 14 90 ⫾ 11 108 ⫾ 13
9.5 ⫾ 1.6 0.05 130 ⫾ 11 88 ⫾ 10 106 ⫾ 11
10.1 ⫾ 1.7 0.14 138 ⫾ 15 95 ⫾ 12 113 ⫾ 13
⬍0.01 ⬍0.01 ⬍0.01 ⬍0.01 0.01
Abbreviation as in Table 1.
FIGURE 4. Relation between changes in PWV from CPT or HIE. Patients who had a greater response to CPT also had a greater response to HIE and vice versa.
result in decreased myocardial perfusion. Thus, in certain cases, an increase in PWV and reflected wave velocity may be of clinical significance. 1. Boudoulas H, Wooley CF. Aortic function. In: Boudoulas H, Toutouzas PK,
Wooley CF, eds. Functional Abnormalities of the Aorta. Armonk, NY: Futura, 1996:3–8.
2. Simon AC, O’Rourke M, Levenson J. Arterial distensibility and its effect on wave reflection and cardiac loading in cardiovascular disease. Coron Artery Dis 1991;2:1111–1120. 3. Ohtsuka S, Kakihana M, Watanabe H, Sugishita Y. Chronically decreased aortic distensibility causes deterioration of coronary perfusion during increased left ventricular contraction. J Am Coll Cardiol 1994;24:1406 –1414. 4. Nabel EG, Ganz P, Gordon JB, Alexander RW, Selwyn AP. Dilatation of normal and constriction of atherosclerotic coronary arteries caused by the cold pressor test. Circulation 1988;77:43–52. 5. Breithaupt-Grogler K, Lings M, Boudoulas H, Beltz GG. Protective effect of chronic garlic intake on elastic properties of aorta in the elderly. Circulation 1997;96:2649 –2655. 6. Lewis RP, Rittgers SE, Forester WF, Boudoulas H. A critical review of the systolic time intervals. Circulation 1977;56:146 –158. 7. Boudoulas H. Systolic time intervals. Eur Heart J 1990;11(suppl I):93–104. 8. Hirata K, Triposkiadis F, Sparks E, Bowen J, Wooley CF, Boudoulas H. The Marfan syndrome: abnormal aortic elastic properties. J Am Coll Cardiol 1991; 18:57–63. 9. Nichols WW, O’Rourke MF. Aging, high blood pressure and disease in humans. In: Nichols WW. O’Rourke MF, eds. McDonald’s Blood Flow in Arteries. Philadelphia, PA: Edward Arnold, 1990:398 –420. 10. Boudoulas H, Reynolds JC, Mazzaferri E, Wooley CF. Metabolic studies in mitral valve prolapse syndrome. Circulation 1980;61:1200 –1205. 11. Strizik B, Chiu S, Ilercil A, Alaeddini J, Oomen R, DiBitetto T, Strom J, Shirani J. Usefulness of isometric handgrip during treadmill exercise stress echocardiography. Am J Cardiol 2002;90:420 –422. 12. Corretti MC, Plotnick GD, Vogel RA. Correlation of cold pressor and flow-mediated brachial artery diameter responses with the presence of coronary artery disease. Am J Cardiol 1995;75:783–787. 13. Stefanadis C, Wooley CF, Bush CA, Kolibash AJ, Boudoulas H. Aortic distensibility abnormalities in coronary artery disease. Am J Cardiol 1987;59: 1300 –1304. 14. Stefanadis C, Vlachopoulos C, Karayannacos P, Boudoulas H, Stratos C, Filippides T, Agapitos M, Toutouzas P. Effects of vasa-vasorum flow on structure and function of the aorta in experimental animals. Circulation 1995;91:2669 – 2678. 15. Murgo JP, Westerhof N, Giolma JP, Abtobeli SA. Aortic input impedance in normal man: relationship to pressure wave forms. Circulation 1980;105–116.
Prevalence of Stroke and Associated Risk Factors in Asian Indians Living in the State of Georgia, United States of America Gurpreet Baweja,
MD,
Navin C. Nanda, MD, Naresh Parikh, and Rajesh Venkataraman, MD
This study is the first attempt to assess the prevalence of stroke and associated risk factors in Asian Indians living in the United States. The overall prevalence of stroke is 2.77% (men 3.72% and women 1.77%). From the Division of Cardiovascular Disease, The University of Alabama at Birmingham, Birmingham, Alabama. Dr. Nanda’s address is: The University of Alabama at Birmingham, Heart Station, SW/S102, 619 S 19th St, Birmingham, Alabama 35249. E-mail: nanda@ uab.edu. Manuscript received August 4, 2003; revised manuscript received and accepted September 29, 2003. ©2004 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 93 January 15, 2004
MD,
Vishal Bhatia,
MD,
Stroke was significantly associated with systemic hypertension, diabetes mellitus, coronary artery disease, end-stage renal disease, and family history of stroke and myocardial infarction. 䊚2004 by Excerpta Medica, Inc. (Am J Cardiol 2004;93:267–269)
lthough Asian Indian immigrants currently represent slightly ⬎1% (1.9 million) of the total A United States population, they are one of the fastest 1
0002-9149/04/$–see front matter doi:10.1016/j.amjcard.2003.09.50
267
TABLE 2 Prevalence of Stroke and Associated Risk factors in Men and Women Variable Stroke Systemic hypertension Diabetes mellitus Myocardial infarction Hypercholesterolemia End-stage renal disease
Men (%) (n ⫽ 537) 20 141 121 44 111 20
(3.72%) (26.3%) (22.5%) (8.2%) (20.7%) (3.7%)
Women (%) (n ⫽ 509)
p Value*
9 107 69 24 82 8
0.10 0.05 ⬍0.001 0.025 0.10 0.03
(1.76%) (21.0%) (13.6%) (4.7%) (16.1%) (1.6%)
*Chi-square test for differencing between men and women.
FIGURE 1. Age distribution of study population. The overall prevalence of stroke in Asian Indians living in Georgia was 2.77% (men 3.72% and women 1.77%). Stroke was significantly associated with hypertension, diabetes mellitus, coronary artery disease, end-stage renal disease, and family history of stroke and myocardial infarction.
TABLE 1 Baseline Characteristics of the Participants Characteristic
Total (n ⫽ 1,046)
Stroke (n ⫽ 29)
No Stroke (n ⫽ 1,017) p Value*
Men Women Mean age (yrs) Men Women Mean BMI (kg/m2) Men Women
537 509 52.8 (11.3)† 53.7 (11.3) 51.9 (11.3) 26.1 (4.7) 26.2 (4.2) 25.9 (5.2)
20 9 57.2 (9.5) 60.4 (11.3) 57.5 (8.4) 26.4 (4.5) 24.9 (3.0) 27.9 (4.0)
517 500 51.9 (11.4) ⬍0.001 53.4 (11.2) 0.005 51.8 (11.3) 0.130 26.0 (4.7) 0.656 26.3 (4.3) 0.162 25.9 (5.2) 0.309
*Difference between stroke and nonstroke groups. † Numbers in parentheses are confidence limits.
growing ethnic minorities in this country. Review of published reports has failed to find any study evaluating the prevalence of stroke in this community. Moreover, the estimation of the prevalence of stroke in Asian Indian immigrants presents a unique problem because they are not classified separately in any United States national health surveys or hospital data banks. •••
The Asian Indian population living in and around the Atlanta, Georgia, metropolitan area was surveyed during religious and social gatherings at Bochasanwasi Shri Akshar Purushottam Swaminarayan Sanstha temple. Bochasanwasi Shri Akshar Purushottam Swaminarayan Sanstha is a prominent sect of the Hindu religion and an international sociospiritual organization that conducts humanitarian work through a worldwide network. We developed a multi-item structured questionnaire that included the following demographic characteristics: age, gender, height and weight, history of stroke, and common risk factors, such as systemic hypertension, diabetes mellitus, hypercholesterolemia, myocardial infarction, end-stage renal disease, history of coronary artery bypass surgery/balloon angioplasty, and family history of stroke, 268 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 93
diabetes mellitus, and myocardial infarction. The questionnaire items were written in simple layperson’s language to ensure that they would be clearly understood by the surveyed population. The subjects were asked to report if their physician had ever diagnosed them with high blood pressure, diabetes, heart attack, high cholesterol, or the need for continued long-term dialysis. The questionnaire was limited to a length of 1 page to improve the compliance of the surveyed subjects. To avoid ambiguity, the responses only allowed a choice between “yes” and “no.” The investigators and physician colleagues, who were experienced in conducting community-based surveys, reviewed all questions and responses. Nonmedical personnel were trained by local physicians to conduct the survey under their supervision. A subject was considered to have stroke if he or she reported ever having been told by a physician that he or she had had a stroke. Body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters. The crude prevalence of stroke was calculated in various age and gender groups. Using the population of Asian Indians in Georgia1 (n ⫽ 46,132), we estimated that a sample of 1,046 would achieves 80% power to detect a difference of 1.0% between the null hypothesis prevalence of 1.7% (based on National Health and Nutrition Examination Survey III data on prevalence of stroke in the United States2) and the alternative hypothesis prevalence of 0.7% with 95% confidence limits. We performed descriptive statistics on the surveyed population. We also reported odds ratios with 95% confidence intervals for the influence of risk factors on the prevalence of stroke. All statistical analyses were performed using SPSS for window version 10.1 software (SPSS Inc., Chicago, Illinois). As we performed multiple comparisons, the Bonferroni correction was applied, and a p value ⬍0.005 was used as the level of significance for the bivariate analysis. For all other statistical tests, a p value ⬍0.05 was used as the level of significance. The total population surveyed was 1,046 and included 537 men (51.3%) and 509 women (48.7%) and a male-to-female ratio of 1.06. Ages ranged from 17 to 87 years (mean 52.8 ⫾ 11.3), and 74.1% of subjects were ⬎45 years of age (Figure 1). Baseline characteristics of the participants are shown in Table 1. The overall prevalence of stroke was 2.77% (men 3.72% JANUARY 15, 2004
TABLE 3 Distribution of Risk Factors of Atherosclerosis in Stroke and Control Group Stroke (n ⫽ 29)
Risk Factors Systemic hypertension (%) Diabetes mellitus Hypercholesterolemia Myocardial infarction Coronary artery disease* Coronary bypass surgery/ Balloon angioplasty End-stage renal disease Family history of stroke Family history of diabetes mellitus Family history of myocardial infarction (%)
Control (n ⫽ 1017)
Overall (n ⫽ 1046)
Odds Ratio (95% CI)
p Value†
16 10 8 12 17 13
(55.1%) (34.4) (27.6) (41.3) (58.6) (44.8)
232 180 185 56 123 99
(22.8%) (17.7) (18.2) (5.5) (12.1) (9.7)
248 190 193 68 140 1046
(23.7%) (18.7) (18.4) (6.5) (13.4) (10.6)
4.16 2.44 1.71 12.11 10.29 7.53
(1.97–8.78) (1.19–5.35) (0.74–3.92) (5.51–26.59) (4.80–22.07) (3.52–16.12)
⬍0.001 0.021 0.199 ⬍0.001 ⬍0.001 ⬍0.001
3 14 9 9
(10.3) (48.3) (31.0) (31.0%)
25 80 228 162
(2.4) (7.8) (22.4) (15.9%)
28 94 237 171
(2.6) (8.9) (22.6) (16.3%)
4.58 10.93 1.55 2.37
(1.29–16.12) (5.09–23.45) (0.69–3.46) (1.06–5.30)
0.009 ⬍0.001 0.275 0.030
*Defined as subjects with myocardial infarction, coronary bypass surgery, or balloon angioplasty. † Significant at p ⬍0.005 using the Bonferroni correction. CI ⫽ confidence interval; OR ⫽ odds ratio.
and women 1.77%). The prevalence rate of stroke increased with age: it was 3.10% for those ⬎35 years of age, 3.48% for those ⬎45 years of age, and 5.5% for those ⬎60 years of age. Using the 1990 census data,3 the age-adjusted prevalence of stroke in our study was 1.77%, which is comparable with the 1.87% reported in the United States in 1991.4 No study has assessed the prevalence of stroke in Asian Indians living in the United States, and few have evaluated its prevalence in other ethnic groups living in the United States. In 1 study,5 the overall crude prevalence of stroke for patients ⬎35 years of age was 2.95% in blacks versus 2.12% in whites; in another study it was 3.21% in Hispanics ⬎45 years of age. These prevalence rates are comparable with what we found in our study in the same age groups. Other studies that have evaluated various ethnic groups in the United States for stroke either do not provide the crude prevalence2 or have a disproportionately higher white population.6 Interestingly, the prevalence of stroke in our study is much higher than that reported in Asian Indians living in India, which has ranged from 0.22% to 0.63%.7–10 •••
In our study, there was no statistically significant difference in the prevalence of stroke between men and women. However, the prevalence of systemic hypertension, myocardial infarction, diabetes mellitus, and end-stage renal disease was statistically higher in men (Table 2). Bivariate analysis showed that subjects with stroke had increased odds of having several risk factors for atherosclerosis, including systemic hypertension, diabetes mellitus, myocardial infarction, endstage renal disease, coronary artery disease (defined as subjects with myocardial infarction, coronary bypass surgery, or balloon angioplasty), and family history of stroke and myocardial infarction. However, there was no association with hypercholesterolemia or obesity
(Table 3). The BMI of the surveyed population ranged from 18 to 38 kg/m2 (mean 26.1 ⫾ 4.7). Only 1/5 of the subjects were obese (BMI ⬎30 kg/m2). The United States data on various risk factors for stroke in different ethnic groups is scarce. Recently, the Northern Manhattan Stroke Study11 showed that systemic hypertension, diabetes mellitus, and coronary artery disease were independent predicting factors for stroke in blacks and Hispanics. The data on various risk factors for stroke in India are also very limited. The Indian Council of Medical Research conducted a multicenter prospective stroke study12 a few years ago that showed systemic hypertension and diabetes mellitus, but not hypercholesterolemia, to be important risk factors for stroke. 1. United States Census Bureau, Census 2000, Special tabulations. 2. Muntner P, Garrett E, Klag MJ, Coresh J. Trends in stroke prevalence between
1973 and 1991 in the US population 25 to 74 years of age. Stroke 2002;33:1209 – 1213. 3. United States Census Bureau, Census 1990, Special tabulations. 4. Schoenberg BS, Anderson DW, Haerer AF. Racial differentials in the prevalence of stroke. Copiah County, Mississippi. Arch Neurol 1986;43:565–568. 5. Gillum RF. Epidemiology of stroke in Hispanic Americans. Stroke 1995;26: 1707–1712. 6. Friday G, Lai SM, Alter M, Sobel E, LaRue L, Gil-Peralta A, McCoy RL, Levitt LP, Isack T. Stroke in the Lehigh Valley: racial/ethnic differences. Neurology 1989;39:1165–1168. 7. Brown RD, Whisnant JP, Sicks JD, O’Fallon WM, Wiebers DO. Stroke incidence, prevalence, and survival: secular trends in Rochester, Minnesota, through 1989. Stroke 1996;27:373–380. 8. Razdan S, Koul RL, Motta A, Kaul S. Cerebrovascular disease in rural Kashmir, India. Stroke 1989;20:1691–1692. 9. Dhamija RK, Dhamija SB. Prevalence of stroke in rural community—an overview of Indian experience. J Assoc Physicians India 1998;46:351–354. 10. Banerjee TK, Mukherjee CS, Sarkhel A. Stroke in urban population of Calcutta—an epidemiological study. Neuroepidemiology 2001;20:201–207. 11. Sacco RL, Boden-Albala B, Abel G, Lin I-F, Elkind M, Hauser WA, Paik MC, Shea S. Race-ethnic disparities in the impact of stroke risk factors: The Northern Manhattan Stroke Study. Stroke 2001;32:1725–1731. 12. Dalal PM, Dalal KP, Rao SV, Parikh BR. Strokes in west-central India: a prospective case-control study of “risk factors.” In: Bartko D, Gerstenbrand F, Turcani P., eds. Neurology in Europe. London, UK: Libbey, 1989:16 –20.
BRIEF REPORTS
269
Rest
CPT
HIE
CPT ⫹ HIE
p (ANOVA)
7.9 ⫾ 1.2 ⫺0.23 119 ⫾ 13 80 ⫾ 8 97 ⫾ 10
8.7 ⫾ 1.2 ⫺0.004 129 ⫾ 14 90 ⫾ 11 108 ⫾ 13
9.5 ⫾ 1.6 0.05 130 ⫾ 11 88 ⫾ 10 106 ⫾ 11
10.1 ⫾ 1.7 0.14 138 ⫾ 15 95 ⫾ 12 113 ⫾ 13
⬍0.01 ⬍0.01 ⬍0.01 ⬍0.01 0.01
Abbreviation as in Table 1.
FIGURE 4. Relation between changes in PWV from CPT or HIE. Patients who had a greater response to CPT also had a greater response to HIE and vice versa.
result in decreased myocardial perfusion. Thus, in certain cases, an increase in PWV and reflected wave velocity may be of clinical significance. 1. Boudoulas H, Wooley CF. Aortic function. In: Boudoulas H, Toutouzas PK,
Wooley CF, eds. Functional Abnormalities of the Aorta. Armonk, NY: Futura, 1996:3–8.
2. Simon AC, O’Rourke M, Levenson J. Arterial distensibility and its effect on wave reflection and cardiac loading in cardiovascular disease. Coron Artery Dis 1991;2:1111–1120. 3. Ohtsuka S, Kakihana M, Watanabe H, Sugishita Y. Chronically decreased aortic distensibility causes deterioration of coronary perfusion during increased left ventricular contraction. J Am Coll Cardiol 1994;24:1406 –1414. 4. Nabel EG, Ganz P, Gordon JB, Alexander RW, Selwyn AP. Dilatation of normal and constriction of atherosclerotic coronary arteries caused by the cold pressor test. Circulation 1988;77:43–52. 5. Breithaupt-Grogler K, Lings M, Boudoulas H, Beltz GG. Protective effect of chronic garlic intake on elastic properties of aorta in the elderly. Circulation 1997;96:2649 –2655. 6. Lewis RP, Rittgers SE, Forester WF, Boudoulas H. A critical review of the systolic time intervals. Circulation 1977;56:146 –158. 7. Boudoulas H. Systolic time intervals. Eur Heart J 1990;11(suppl I):93–104. 8. Hirata K, Triposkiadis F, Sparks E, Bowen J, Wooley CF, Boudoulas H. The Marfan syndrome: abnormal aortic elastic properties. J Am Coll Cardiol 1991; 18:57–63. 9. Nichols WW, O’Rourke MF. Aging, high blood pressure and disease in humans. In: Nichols WW. O’Rourke MF, eds. McDonald’s Blood Flow in Arteries. Philadelphia, PA: Edward Arnold, 1990:398 –420. 10. Boudoulas H, Reynolds JC, Mazzaferri E, Wooley CF. Metabolic studies in mitral valve prolapse syndrome. Circulation 1980;61:1200 –1205. 11. Strizik B, Chiu S, Ilercil A, Alaeddini J, Oomen R, DiBitetto T, Strom J, Shirani J. Usefulness of isometric handgrip during treadmill exercise stress echocardiography. Am J Cardiol 2002;90:420 –422. 12. Corretti MC, Plotnick GD, Vogel RA. Correlation of cold pressor and flow-mediated brachial artery diameter responses with the presence of coronary artery disease. Am J Cardiol 1995;75:783–787. 13. Stefanadis C, Wooley CF, Bush CA, Kolibash AJ, Boudoulas H. Aortic distensibility abnormalities in coronary artery disease. Am J Cardiol 1987;59: 1300 –1304. 14. Stefanadis C, Vlachopoulos C, Karayannacos P, Boudoulas H, Stratos C, Filippides T, Agapitos M, Toutouzas P. Effects of vasa-vasorum flow on structure and function of the aorta in experimental animals. Circulation 1995;91:2669 – 2678. 15. Murgo JP, Westerhof N, Giolma JP, Abtobeli SA. Aortic input impedance in normal man: relationship to pressure wave forms. Circulation 1980;105–116.
Prevalence of Stroke and Associated Risk Factors in Asian Indians Living in the State of Georgia, United States of America Gurpreet Baweja,
MD,
Navin C. Nanda, MD, Naresh Parikh, and Rajesh Venkataraman, MD
This study is the first attempt to assess the prevalence of stroke and associated risk factors in Asian Indians living in the United States. The overall prevalence of stroke is 2.77% (men 3.72% and women 1.77%). From the Division of Cardiovascular Disease, The University of Alabama at Birmingham, Birmingham, Alabama. Dr. Nanda’s address is: The University of Alabama at Birmingham, Heart Station, SW/S102, 619 S 19th St, Birmingham, Alabama 35249. E-mail: nanda@ uab.edu. Manuscript received August 4, 2003; revised manuscript received and accepted September 29, 2003. ©2004 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 93 January 15, 2004
MD,
Vishal Bhatia,
MD,
Stroke was significantly associated with systemic hypertension, diabetes mellitus, coronary artery disease, end-stage renal disease, and family history of stroke and myocardial infarction. 䊚2004 by Excerpta Medica, Inc. (Am J Cardiol 2004;93:267–269)
lthough Asian Indian immigrants currently represent slightly ⬎1% (1.9 million) of the total A United States population, they are one of the fastest 1
0002-9149/04/$–see front matter doi:10.1016/j.amjcard.2003.09.50
267
TABLE 2 Prevalence of Stroke and Associated Risk factors in Men and Women Variable Stroke Systemic hypertension Diabetes mellitus Myocardial infarction Hypercholesterolemia End-stage renal disease
Men (%) (n ⫽ 537) 20 141 121 44 111 20
(3.72%) (26.3%) (22.5%) (8.2%) (20.7%) (3.7%)
Women (%) (n ⫽ 509)
p Value*
9 107 69 24 82 8
0.10 0.05 ⬍0.001 0.025 0.10 0.03
(1.76%) (21.0%) (13.6%) (4.7%) (16.1%) (1.6%)
*Chi-square test for differencing between men and women.
FIGURE 1. Age distribution of study population. The overall prevalence of stroke in Asian Indians living in Georgia was 2.77% (men 3.72% and women 1.77%). Stroke was significantly associated with hypertension, diabetes mellitus, coronary artery disease, end-stage renal disease, and family history of stroke and myocardial infarction.
TABLE 1 Baseline Characteristics of the Participants Characteristic
Total (n ⫽ 1,046)
Stroke (n ⫽ 29)
No Stroke (n ⫽ 1,017) p Value*
Men Women Mean age (yrs) Men Women Mean BMI (kg/m2) Men Women
537 509 52.8 (11.3)† 53.7 (11.3) 51.9 (11.3) 26.1 (4.7) 26.2 (4.2) 25.9 (5.2)
20 9 57.2 (9.5) 60.4 (11.3) 57.5 (8.4) 26.4 (4.5) 24.9 (3.0) 27.9 (4.0)
517 500 51.9 (11.4) ⬍0.001 53.4 (11.2) 0.005 51.8 (11.3) 0.130 26.0 (4.7) 0.656 26.3 (4.3) 0.162 25.9 (5.2) 0.309
*Difference between stroke and nonstroke groups. † Numbers in parentheses are confidence limits.
growing ethnic minorities in this country. Review of published reports has failed to find any study evaluating the prevalence of stroke in this community. Moreover, the estimation of the prevalence of stroke in Asian Indian immigrants presents a unique problem because they are not classified separately in any United States national health surveys or hospital data banks. •••
The Asian Indian population living in and around the Atlanta, Georgia, metropolitan area was surveyed during religious and social gatherings at Bochasanwasi Shri Akshar Purushottam Swaminarayan Sanstha temple. Bochasanwasi Shri Akshar Purushottam Swaminarayan Sanstha is a prominent sect of the Hindu religion and an international sociospiritual organization that conducts humanitarian work through a worldwide network. We developed a multi-item structured questionnaire that included the following demographic characteristics: age, gender, height and weight, history of stroke, and common risk factors, such as systemic hypertension, diabetes mellitus, hypercholesterolemia, myocardial infarction, end-stage renal disease, history of coronary artery bypass surgery/balloon angioplasty, and family history of stroke, 268 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 93
diabetes mellitus, and myocardial infarction. The questionnaire items were written in simple layperson’s language to ensure that they would be clearly understood by the surveyed population. The subjects were asked to report if their physician had ever diagnosed them with high blood pressure, diabetes, heart attack, high cholesterol, or the need for continued long-term dialysis. The questionnaire was limited to a length of 1 page to improve the compliance of the surveyed subjects. To avoid ambiguity, the responses only allowed a choice between “yes” and “no.” The investigators and physician colleagues, who were experienced in conducting community-based surveys, reviewed all questions and responses. Nonmedical personnel were trained by local physicians to conduct the survey under their supervision. A subject was considered to have stroke if he or she reported ever having been told by a physician that he or she had had a stroke. Body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters. The crude prevalence of stroke was calculated in various age and gender groups. Using the population of Asian Indians in Georgia1 (n ⫽ 46,132), we estimated that a sample of 1,046 would achieves 80% power to detect a difference of 1.0% between the null hypothesis prevalence of 1.7% (based on National Health and Nutrition Examination Survey III data on prevalence of stroke in the United States2) and the alternative hypothesis prevalence of 0.7% with 95% confidence limits. We performed descriptive statistics on the surveyed population. We also reported odds ratios with 95% confidence intervals for the influence of risk factors on the prevalence of stroke. All statistical analyses were performed using SPSS for window version 10.1 software (SPSS Inc., Chicago, Illinois). As we performed multiple comparisons, the Bonferroni correction was applied, and a p value ⬍0.005 was used as the level of significance for the bivariate analysis. For all other statistical tests, a p value ⬍0.05 was used as the level of significance. The total population surveyed was 1,046 and included 537 men (51.3%) and 509 women (48.7%) and a male-to-female ratio of 1.06. Ages ranged from 17 to 87 years (mean 52.8 ⫾ 11.3), and 74.1% of subjects were ⬎45 years of age (Figure 1). Baseline characteristics of the participants are shown in Table 1. The overall prevalence of stroke was 2.77% (men 3.72% JANUARY 15, 2004
TABLE 3 Distribution of Risk Factors of Atherosclerosis in Stroke and Control Group Stroke (n ⫽ 29)
Risk Factors Systemic hypertension (%) Diabetes mellitus Hypercholesterolemia Myocardial infarction Coronary artery disease* Coronary bypass surgery/ Balloon angioplasty End-stage renal disease Family history of stroke Family history of diabetes mellitus Family history of myocardial infarction (%)
Control (n ⫽ 1017)
Overall (n ⫽ 1046)
Odds Ratio (95% CI)
p Value†
16 10 8 12 17 13
(55.1%) (34.4) (27.6) (41.3) (58.6) (44.8)
232 180 185 56 123 99
(22.8%) (17.7) (18.2) (5.5) (12.1) (9.7)
248 190 193 68 140 1046
(23.7%) (18.7) (18.4) (6.5) (13.4) (10.6)
4.16 2.44 1.71 12.11 10.29 7.53
(1.97–8.78) (1.19–5.35) (0.74–3.92) (5.51–26.59) (4.80–22.07) (3.52–16.12)
⬍0.001 0.021 0.199 ⬍0.001 ⬍0.001 ⬍0.001
3 14 9 9
(10.3) (48.3) (31.0) (31.0%)
25 80 228 162
(2.4) (7.8) (22.4) (15.9%)
28 94 237 171
(2.6) (8.9) (22.6) (16.3%)
4.58 10.93 1.55 2.37
(1.29–16.12) (5.09–23.45) (0.69–3.46) (1.06–5.30)
0.009 ⬍0.001 0.275 0.030
*Defined as subjects with myocardial infarction, coronary bypass surgery, or balloon angioplasty. † Significant at p ⬍0.005 using the Bonferroni correction. CI ⫽ confidence interval; OR ⫽ odds ratio.
and women 1.77%). The prevalence rate of stroke increased with age: it was 3.10% for those ⬎35 years of age, 3.48% for those ⬎45 years of age, and 5.5% for those ⬎60 years of age. Using the 1990 census data,3 the age-adjusted prevalence of stroke in our study was 1.77%, which is comparable with the 1.87% reported in the United States in 1991.4 No study has assessed the prevalence of stroke in Asian Indians living in the United States, and few have evaluated its prevalence in other ethnic groups living in the United States. In 1 study,5 the overall crude prevalence of stroke for patients ⬎35 years of age was 2.95% in blacks versus 2.12% in whites; in another study it was 3.21% in Hispanics ⬎45 years of age. These prevalence rates are comparable with what we found in our study in the same age groups. Other studies that have evaluated various ethnic groups in the United States for stroke either do not provide the crude prevalence2 or have a disproportionately higher white population.6 Interestingly, the prevalence of stroke in our study is much higher than that reported in Asian Indians living in India, which has ranged from 0.22% to 0.63%.7–10 •••
In our study, there was no statistically significant difference in the prevalence of stroke between men and women. However, the prevalence of systemic hypertension, myocardial infarction, diabetes mellitus, and end-stage renal disease was statistically higher in men (Table 2). Bivariate analysis showed that subjects with stroke had increased odds of having several risk factors for atherosclerosis, including systemic hypertension, diabetes mellitus, myocardial infarction, endstage renal disease, coronary artery disease (defined as subjects with myocardial infarction, coronary bypass surgery, or balloon angioplasty), and family history of stroke and myocardial infarction. However, there was no association with hypercholesterolemia or obesity
(Table 3). The BMI of the surveyed population ranged from 18 to 38 kg/m2 (mean 26.1 ⫾ 4.7). Only 1/5 of the subjects were obese (BMI ⬎30 kg/m2). The United States data on various risk factors for stroke in different ethnic groups is scarce. Recently, the Northern Manhattan Stroke Study11 showed that systemic hypertension, diabetes mellitus, and coronary artery disease were independent predicting factors for stroke in blacks and Hispanics. The data on various risk factors for stroke in India are also very limited. The Indian Council of Medical Research conducted a multicenter prospective stroke study12 a few years ago that showed systemic hypertension and diabetes mellitus, but not hypercholesterolemia, to be important risk factors for stroke. 1. United States Census Bureau, Census 2000, Special tabulations. 2. Muntner P, Garrett E, Klag MJ, Coresh J. Trends in stroke prevalence between
1973 and 1991 in the US population 25 to 74 years of age. Stroke 2002;33:1209 – 1213. 3. United States Census Bureau, Census 1990, Special tabulations. 4. Schoenberg BS, Anderson DW, Haerer AF. Racial differentials in the prevalence of stroke. Copiah County, Mississippi. Arch Neurol 1986;43:565–568. 5. Gillum RF. Epidemiology of stroke in Hispanic Americans. Stroke 1995;26: 1707–1712. 6. Friday G, Lai SM, Alter M, Sobel E, LaRue L, Gil-Peralta A, McCoy RL, Levitt LP, Isack T. Stroke in the Lehigh Valley: racial/ethnic differences. Neurology 1989;39:1165–1168. 7. Brown RD, Whisnant JP, Sicks JD, O’Fallon WM, Wiebers DO. Stroke incidence, prevalence, and survival: secular trends in Rochester, Minnesota, through 1989. Stroke 1996;27:373–380. 8. Razdan S, Koul RL, Motta A, Kaul S. Cerebrovascular disease in rural Kashmir, India. Stroke 1989;20:1691–1692. 9. Dhamija RK, Dhamija SB. Prevalence of stroke in rural community—an overview of Indian experience. J Assoc Physicians India 1998;46:351–354. 10. Banerjee TK, Mukherjee CS, Sarkhel A. Stroke in urban population of Calcutta—an epidemiological study. Neuroepidemiology 2001;20:201–207. 11. Sacco RL, Boden-Albala B, Abel G, Lin I-F, Elkind M, Hauser WA, Paik MC, Shea S. Race-ethnic disparities in the impact of stroke risk factors: The Northern Manhattan Stroke Study. Stroke 2001;32:1725–1731. 12. Dalal PM, Dalal KP, Rao SV, Parikh BR. Strokes in west-central India: a prospective case-control study of “risk factors.” In: Bartko D, Gerstenbrand F, Turcani P., eds. Neurology in Europe. London, UK: Libbey, 1989:16 –20.
BRIEF REPORTS
269