TABLE 3.
Correlations Between Body Mass Index and Physical Activity by 1-SD Change in Average County Sprawl Index, Stratified by Potential Effect Modifiers: United States, Nurses’ Health Study, 2000
| Modifier | No. | Total Activity, B (95% CI) | P for Interaction | Walking, B (95% CI) | P for Interaction | Combined Walking, Bicycling, Jogging, and Running, B (95% CI) | P for Interaction | BMI, B (95% CI) | P for Interaction |
|---|---|---|---|---|---|---|---|---|---|
| Age, y | <.001 | .141 | <.001 | .926 | |||||
| 53.5–60.4 | 17 272 | 0.44 (0.01, 0.87) | 0.27 (0.10, 0.44) | 0.45 (0.22, 0.68) | −0.07 (−0.18, 0.04) | ||||
| 60.5–66.1 | 17 029 | 0.76 (0.31, 1.22) | 0.32 (0.15, 0.49) | 0.49 (0.25, 0.72) | −0.10 (−0.19, 0.00) | ||||
| 66.2–72.5 | 17 633 | −0.12 (−0.54, 0.30) | 0.23 (0.07, 0.39) | 0.22 (0.00, 0.44) | −0.08 (−0.18, 0.01) | ||||
| 72.6–81.3 | 17 319 | −0.23 (−0.57, 0.11) | 0.17 (0.02, 0.31) | 0.08 (−0.11, 0.28) | −0.10 (−0.19, −0.01) | ||||
| Race | .054 | .023 | .111 | .824 | |||||
| White | 67 411 | 0.34 (0.06, 0.61) | 0.27 (0.17, 0.37) | 0.36 (0.22, 0.50) | −0.08 (−0.14, −0.02) | ||||
| Black | 1 075 | 0.02 (−0.77, 0.81) | −0.02 (−0.35, 0.31) | 0.16 (−0.23, 0.55) | −0.04 (−0.24, 0.16) | ||||
| Asian | 598 | −0.27 (−1.60, 1.06) | 0.04 (−0.53, 0.60) | −0.04 (−0.84, 0.76) | −0.21 (−0.44, 0.02) | ||||
| Other | 169 | −0.19 (−4.23, 3.85) | 1.28 (−0.40, 2.97) | 1.22 (−0.76, 3.21) | −0.33 (−1.10, 0.44) | ||||
| Husband’s educational level | .004 | .729 | .025 | .948 | |||||
| ≤ high school | 23 099 | −0.32 (−0.66, 0.03) | 0.15 (0.01, 0.29) | 0.08 (−0.11, 0.26) | −0.02 (−0.11, 0.07) | ||||
| ≥ College | 29 356 | 0.19 (−0.18, 0.56) | 0.31 (0.18, 0.45) | 0.34 (0.15, 0.52) | −0.13 (−0.20, −0.05) | ||||
| Smoking status | .074 | .486 | .136 | .797 | |||||
| Never | 30 429 | 0.44 (0.11, 0.77) | 0.25 (0.13, 0.38) | 0.42 (0.24, 0.59) | −0.09 (−0.17, −0.01) | ||||
| Past | 32 504 | 0.01 (−0.33, 0.34) | 0.23 (0.10, 0.36) | 0.21 (0.04, 0.38) | −0.09 (−0.17, −0.02) | ||||
| Current | 6 320 | 0.05 (−0.51, 0.62) | 0.22 (−0.01, 0.45) | 0.35 (0.05, 0.65) | −0.05 (−0.19, 0.08) | ||||
| Previous cancer, diabetes, or heart disease | .071 | .204 | .212 | .013 | |||||
| No | 50 863 | 0.44 (0.15, 0.74) | 0.23 (0.12, 0.34) | 0.39 (0.23, 0.54) | −0.06 (−0.12, 0.00) | ||||
| Yes | 18 390 | −0.10 (−0.45, 0.25) | 0.33 (0.19, 0.47) | 0.22 (0.02, 0.41) | −0.16 (−0.27, −0.06) |
Note. BMI = body mass index; CI = confidence interval; Models adjusted for age, smoking, race, and husband’s education, except where they were the stratifying variable.