Establishing a Cohort to Investigate Health Disparities: RESULTS

26 Oct
2009

A high level of participant enrollment was achieved in the CHCs. The calculation of a standard response rate, however, is not possible, due to the recruitment strategies employed by the interviewers. In addition to randomly approaching single individuals, some interviewers found that a successful means of recruitment was to speak to an entire CHC lobby at once, explaining the study and its eligibility requirements, then enrolling the resulting volunteers. Moreover, we found that there were various routes by which potential participants came to the interviewer already prescreened for interest and eligibility: 1) through word-of-mouth referrals from previous participants; 2) through referrals from the CHC receptionists or medical staff; and 3) from volunteers who sought out the interviewer in response to seeing posters, flyers, brochures or even articles and adver­tisements placed in local newspapers by some CHCs.

As of October 31, 2004, 32,632 participants had enrolled in the SCCS from 25 CHCs. Enrollment figures by sex, race and age are shown in Table 1. Fifty-nine percent of the enrollees were female and 80% were African-American. The vast majority of the non-African Americans were non-Hispanic whites. The mean (SD) age of participants at the time of enrollment was 51.5 (8.7) years. Eighty-six percent of cohort members were born in one of the 11 enrollment states, suggesting that we successfully recruited long-term residents of this area. cheap generic cialis

Table 1. Distribution of initial Southern Community Cohort Study Members by Race, Sex and Age Group (N=32,632), 2002-2004

Age Group (Years)
Race/Ethnicity40-4950-5960-6970-79Total
N%N%N%N%N%
Mates (N=13,360)
Black/ African-American

6,235

(84.0)

3,332

(82.2)

1,110

(74.9)

284

(71.2)

10,961

(82.0)

White

1,002

(13.5)

627

(15.5)

335

(22.6)

104

(26.1)

2,068

(15.5)

Hispanic/Latino

49

(0.7)

14

(0.4)

6

(0.4)

3

(0.8)

72

(0.5)

Asian or Pacific Islander

3

(0.0)

0

(0.0)

0

(0.0)

0

(0.0)

3

(0.0)

American Indian or Alaska Native 12

(0.2)

12

(0.3)

5

(0.3)

2

(0.5)

31

(0.2)

Other racial group

26

(0.4)

20

(0.5)

8

(0.5)

3

(0.8)

57

(0.4)

Mixed race

91

(1.2)

45

(1.1)

16

(1.1)

3

(0.8)

•   155

(1.2)

Unknown

8

(0.1)

3

(0.1)

2

(0.1)

0

(0.0)

13

(0.1)

Total

7,426

(100.0)

4,053

(100.0)

1,482

(100.0)

399

(100.0)

13,360

(100.0)

Females (N=19,272)
Black/African-American

7,500

(80.6)

4,720

(76.8)

2,063

(72.4)

710

(73.4)

14,993

(77.8)

White

1,577

(17.0)

1,274

(20.7)

709

(24.9)

231

(23.9)

3,791

(19.7)

Hispanic/Latino

38

(0.4)

21

(0.3)

23

(0.8)

5

(0.5)

87

(0.5)

Asian or Pacific Islander

9

(0.1)

9

(0.2)

2

(0.1)

0

(0.0)

20

(0.1)

American Indian or Alaska Native 19

(0.2)

12

(0.2)

2

(0.1)

1

(0.1)

34

(0.2)

Other racial group

30

(0.3)

15

(0.2)

8

(0.3)

6

(0.6)

59

(0.3)

Mixed race

116

(1.3)

79

(1.3)

33

(1.2)

12

(1.2)

240

(1.3)

Unknown

15

(0.2)

20

(0.3)

10

(0.4)

3

(0.3)

48

(0.3)

Total

9,304

(100.0)

6,150

(100.0)

2,850

(100.0)

968

(100.0)

19,272

(100.0)

Nearly all (99%) of the enrolled participants completed the entire CAPI, and the mean length of an interview was 50 minutes for females (average 273 questions) and 48 minutes for males (average 255 questions). Supplemental data on measured weight, height and for 25%, 18% and 24% of participants, respectively, was available for abstraction from medical records. A biologic specimen was donated by 91% of the cohort members. Because 7% self-reported hepatitis or HIV (and thus were not asked for a specimen), 99% of cohort members eligible to do so donated a specimen. More than half of the study participants (51%) donated a blood sample, 42% donated a buccal cell sample, and 1% donated both.

Table 2. Selected Baseline Characteristics of initial Southern Community Cohort Study Members by Sex and Race (N=32,571), 2002-2004

MalesFemales
AANon-AA*AANon-AA*Total
N%N%N%N%N%
Education
<9 years

1,030

(9.4)

275

(11.5)

1,260

(8.4)

406

(9.6)

2,971

(9.1)

9-11 years

2,883

(26.3)

478

(20.0)

3,732

(24.9)

880

(20.8)

7,973

(24.5)

High school/GED

4,002

(36.5)

780

(32.7)

5,049

(33.7)

1,450

(34.3)

11,281

(34.6)

Vocational/technical/business training 583

(5.3)

120

(5.0)

867

(5.8)

250

(5.9)

1,820

(5.6)

Some college or junior college

1,739

(15.9)

487

(20.4)

2,794

(18.6)

832

(19.7)

5,852

(18.0)

Graduated from college

521

(4.8)

166

(7.0)

897

(6.0)

282

(6.7)

1,866

(5.7)

Graduate school

202

(1.8)

79

(3.3)

389

(2.6)

130

(3.1)

800

(2.5)

Unknown

1

(0.0)

1

(0.0)

5

(0.0)

1

(0.0)

00

(0.0)

Total

10,961

(100.0)

2,386

(100.0)

14,993

(100.0)

4,231

(100.0)

32,571

(100.0)

Income
<$ 15,000

6,982

(63.7)

1,439

(60.3)

9,314

(62.1)

2,499

(59.1)

20,234

(62.1)

$15,000-$24,999

2,371

(21.6)

534

(22.4)

3,458

(23.1)

846

(20.0)

7,209

(22.1)

$25,000-$49,999

1,146

(10.5)

275

(11.5)

1,551

(10.3)

525

(12.4)

3,497

(10.7)

>$50,000

344

(3.1)

128

(5.4)

456

(3.0)

305

(7.2)

1,233

(3.8)

Unknown

118

(1.1)

10

(0.4)

214

(1.4)

56

(1.3)

398

(1.2)

Total

10,961

(100.0)

2,386

(100.0)

14,993

(100.0)

4,231

(100.0)

32,571

(100.0)

Selected Conditions
Obesity

2,865

(26.2)

752

(31.6)

8,554″

(57.7)

2,002

(47.7)

14,173

(43.8)

Hypertension*

5,245

(47.9)

1,106

(46.4)

9,463

(63.2)

2,112

(50.0)

17,926

(55.1)

Diabetes*

1,772

(16.2)

464

(19.5)

3,641

(24.3)

872

(20.7)

6,749

(20.8)

High cholesterol*

2,200

(20.1)

727

(30.5)

4,605

(30.8)

1,653

(39.1)

9,185

(28.2)

Current cigarette smoker

6,730

(61.4)

1,369

(57.4)

4,978

(33.3)

1,671

(39.6)

13,497

(45.3)

Table 2 shows selected baseline characteristics of the cohort members by race (African-American, non-African-American) and sex. The overall educational level of the participants was low, with about one-third having completed <12 years of schooling, about 40% having a high-school diploma or equivalent (including vocational school), and about one-quarter having had some education beyond high school. The population was also one of very low income, with 62% reporting a total household income of<$15,000.

The prevalence of obesity and serious chronic disease among the cohort members was substantial. Forty-four percent of cohort members overall were obese, defined as a body mass index of 30 kg/m2 or greater, with the highest prevalence observed among black females (58%). Fifty-five percent of the cohort reported physician-diagnosed hypertension, 28% reported physician-diagnosed high cholesterol, and 21% reported physician-diagnosed. The prevalence of current smoking in the cohort was high (45% overall), particularly among men (61% for black men and 57% for nonblack men).

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