Table 4.
Brisk walking for transport in relation to incident obesity overall and by baseline BMI
| Category | Hours/week | Cases | Person- years |
IRRa | 95% CI |
|---|---|---|---|---|---|
| All women | Little or no exercise | 2557 | 62,963 | 1.00 (ref) | — |
| 1–2 | 308 | 10,880 | 0.76 | 0.67, 0.87 | |
| 3–4 | 132 | 4,724 | 0.76 | 0.63, 0.91 | |
| 5–6 | 74 | 2,164 | 0.92 | 0.72, 1.16 | |
| ≥7 | 96 | 3,114 | 0.83 | 0.67, 1.03 | |
| BMI <25 | Little or no exercise | 725 | 45,415 | 1.00 (ref) | — |
| 1–2 | 88 | 8,294 | 0.70 | 0.55, 0.89 | |
| 3–4 | 39 | 3,651 | 0.67 | 0.47, 0.94 | |
| 5–6 | 24 | 1,620 | 0.94 | 0.62, 1.43 | |
| ≥7 | 23 | 2,395 | 0.61 | 0.39, 0.94 | |
| BMI ≥25 | Little or no exercise | 1832 | 17,548 | 1.00 (ref) | — |
| 1–2 | 220 | 2,586 | 0.81 | 0.69, 0.94 | |
| 3–4 | 93 | 1,073 | 0.82 | 0.66, 1.02 | |
| 5–6 | 50 | 544 | 0.89 | 0.67, 1.19 | |
| ≥7 | 73 | 719 | 0.99 | 0.77, 1.23 |
Note: p for trend: 0.070 for all women; 0.055 for BMI <25; 0.40 for BMI ≥25
a
Adjusted for age (single year); time period (questionnaire cycle); education (≤12, 13–15, ≥16 years); geographic region (Northeast, South, Midwest, West); smoking status (never, past, currently smoke <15 cigarettes/day, currently smoke ≥15 cigarettes/day); alcohol intake (currently drink <1, 1–3, 4–6, ≥7 drinks/week); parity (0, 1, 2, ≥3 births); fruit/vegetable dietary pattern score (quintiles); meat/fried foods dietary pattern score (quintiles); and vigorous exercise (1–2, 3–4, 5–6, ≥7 hours/week.