Table 1.
Selected characteristics of study participants at screening
| Variable | Blacks | Whites |
|---|---|---|
| Total n (%) | 1000 (100) | 996 (100) |
| Median age, y (range) | 48 (40-79) | 48 (40-79) |
| Age group, y, n (%) | ||
| Less than 43 | 202 (20.2) | 224 (22.5) |
| 43-47.99 | 284 (28.4) | 263 (26.4) |
| 48-54.99 | 259 (25.9) | 235 (23.6) |
| 55 or more | 255 (25.5) | 274 (27.5) |
| BMI* group, kg/m2, n (%) | ||
| Less than 25 | 249 (24.9) | 248 (24.9) |
| 25-29.99 | 251 (25.1) | 249 (25.0) |
| 30-34.99 | 250 (25.0) | 250 (25.1) |
| 35 or higher | 250 (25.0) | 249 (25.0) |
| Education status, n (%) | ||
| Did not attend college | 736 (73.6) | 718 (72.1) |
| Attended at least some college | 264 (26.4) | 278 (27.9) |
| Annual household income, n (%) | ||
| Less than $15 000 | 622 (62.2) | 594 (59.6) |
| At least $15 000 | 369 (36.9) | 398 (40.0) |
| Household size, n (%) | ||
| 1 person | 204 (20.4) | 229 (23.0) |
| 2 persons | 307 (30.7) | 356 (35.7) |
| 3 persons | 202 (20.2) | 189 (19.0) |
| 4 or more persons | 287 (28.7) | 222 (22.3) |
| Cigarette smoking, n (%) | ||
| Current smoker | 378 (37.8) | 444 (44.6) |
| Former smoker | 204 (20.4) | 223 (22.4) |
| Never smoked | 417 (41.7) | 327 (32.8) |
| Diabetes mellitus, n (%) | ||
| Yes | 220 (22.0) | 164 (16.5) |
This study was based on the large population-based SCCS cohort, which has been described previously (www.southerncommunitystudy.org).13 In brief, at entry into the SCCS, trained interviewers administered a comprehensive in-person baseline interview that elicited information, such as demographics, anthropometry, medication use, and medical history. Participants were asked to donate a blood sample at study enrollment. A 20-mL venous blood sample was donated by 59% of those eligible to provide one. The blood was separated into its components and stored at −86°C. The 1996 SCCS subjects made available for inclusion in this study were drawn from a stratified random sample selected by the SCCS for another project of obesity biomarkers and reflect the combination of 2 previously sampled groups. The first group of 395 women (enrolled from 2002 to 2004) had been randomly selected within strata defined by race (black/white), smoking status (never, former, current), and body mass index (BMI, 18-24.99 kg/m2, 25-29.99 kg/m2, 30-45 kg/m2). The second group (n = 1605, enrolled from 2002 to 2006) represents a similarly stratified random sample by race (black/white), BMI (18.5-24.99 kg/m2, 25.0-29.99 kg/m2, 30.0-34.99 kg/m2, 35.0-44.99 kg/m2), and menopausal status (premenopausal/postmenopausal). Four women were removed because they had a recorded preceding lymphoproliferative malignancy,14 resulting in our final study population of 1996 subjects.
All study subjects had information on self-reported weight and height. As stated in “Results and discussion,” for approximately 25% of the cohort, medical record-abstracted weight and height (measured on the day of study enrollment at the community health center) were also available. When we compared BMI values calculated from self-reported height and weight compared with BMI calculated from the medical record data, we found a very high concordance (Pearson correlation > 0.95). This provides the assurance about the reliability of the self-report.