TABLE 1.
Characteristics of the analysis sample from the Coronary Artery Risk Development in Young Adults (CARDIA) Study (n = 23,633 observations across 4995 individuals; 1985–1986 to 2000–2001)1
| Year 0: 1985–1986 (n = 4949) | Year 2: 1987–1988 (n = 4351) | Year 5: 1990–1991 (n = 3934) | Year 7: 1992–1993 (n = 3691) | Year 10: 1995–1996 (n = 3443) | Year 15: 2000–2001 (n = 3265) | |
| Body weight | ||||||
| Weight (kg)2 | 71.0 ± 16.33 | 72.9 ± 17.04 | 75.9 ± 18.24 | 78.2 ± 19.24 | 80.4 ± 20.04 | 83.9 ± 21.24 |
| Annual weight change (kg) | — | 0.97 ± 2.535 | 0.91 ± 2.135 | 1.02 ± 2.695 | 0.75 ± 2.025 | 0.70 ± 1.435 |
| BMI (kg/m2)2 | 24.5 ± 5.0 | 25.2 ± 5.44 | 26.1 ± 5.84 | 26.8 ± 6.24 | 27.5 ± 6.54 | 28.7 ± 6.84 |
| Physical activity6 | ||||||
| Walking score (EU)7 | 36.0 (4–108) | 28.0 (0–88)8 | 24.0 (0–80)8 | 28.0 (4–72) | 24.0 (0–72) | 32.0 (4–80)8 |
| Nonwalking physical activity score (EU)7 | 300.0 (147–512) | 272.0 (128–474)8 | 262.5 (120–480) | 222.0 (92–422)8 | 224.0 (80–420) | 234.0 (93–428) |
| Race (%) | ||||||
| Black | 49.8 | 47.7 | 46.4 | 46.4 | 46.2 | 45.2 |
| Sex (%) | ||||||
| Women | 55.7 | 54.8 | 55.6 | 55.2 | 55.0 | 55.6 |
| Age (y) | 24.9 ± 3.6 | 27.0 ± 3.6 | 30.1 ± 3.6 | 32.1 ± 3.6 | 35.1 ± 3.6 | 40.2 ± 3.6 |
| Marriage status (%) | ||||||
| Married9 | 22.6 | 30.5 | 40.5 | 44.1 | 50.5 | 60.6 |
| Education (%) | ||||||
| ≤High school | 39.1 | 33.6 | 30.8 | 28.3 | 27.9 | 22.2 |
| Smoking status (%) | ||||||
| Current | 30.2 | 29.4 | 28.0 | 26.3 | 24.5 | 21.2 |
| Former | 13.4 | 13.6 | 14.0 | 15.9 | 16.7 | 18.3 |
| Never | 56.4 | 57.0 | 58.0 | 57.8 | 58.8 | 60.5 |
| Energy intake (kcal/d)10 | 2834 ± 1348 | 2819 ± 1341 | 2805 ± 1334 | 2792 ± 1264 | 2788 ± 1249 | 2779 ± 1237 |
Full sample included 5115 subjects at baseline. Exclusion criteria: women pregnant at time of examination and subjects missing adjacent weight measures to derive weight change. EU, exercise units calculated on the basis of frequency and intensity of activity. Statistical testing applied when the P for trend was <0.01 by examination year. Testing only applied for outcome (body weight) and main exposure (physical activity) data. Differences between control variables were not tested.
Significant main effect of time, P < 0.00001 (one-factor ANOVA).
Mean ± SD (all such values).
Significantly different from previous examination year (eg, year 2 vs year 0), P < 0.01 (t tests with Bonferroni correction).
Significantly different from zero, P < 0.05 (t test with Bonferroni correction).
Values are medians (interquartile ranges) presented because of skewness of the physical activity score.
P for trend < 0.0001.
Significantly different from previous examination year (eg, year 2 vs year 0), P < 0.01 (Wilcoxon's signed-rank tests with Bonferroni correction).
Married or living with someone in a married-like relation.
Intake at examination years 0–5 is based on baseline intake; intake at examination years 7–15 is based on intake at year 7.