Table 2.
Associations of baseline and adolescent recreational physical activity with breast cancer risk in the Prospective Family Study Cohort (N=15,550)
| Continuous Age-Adjusted | Quintiles of Age-Adjusted Recreational Physical Activity |
Active (Q2-Q5) vs. Inactive (Q1)b | ||||||
|---|---|---|---|---|---|---|---|---|
| METs per Week | Q1 | Q2 | Q3 | Q4 | Q5 | p-trend | ||
| HR (95% CI)a | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | ||
| Baseline Recreational Physical Activity | ||||||||
| Model 1c | 0.92 (0.86, 0.98) | 1.00 (ref.) | 0.81 (0.66, 1.00) | 0.85 (0.70, 1.03) | 0.81 (0.66, 1.00) | 0.84 (0.69, 1.03) | 0.03 | 0.83 (0.71, 0.97) |
| Model 2d | 0.92 (0.87, 0.98) | 1.00 (ref.) | 0.80 (0.65, 0.99) | 0.86 (0.70, 1.04) | 0.82 (0.67, 1.01) | 0.86 (0.70, 1.05) | 0.05 | 0.83 (0.71, 0.98) |
| Model 3e | 0.90 (0.85, 0.96) | 1.00 (ref.) | 0.77 (0.63, 0.95) | 0.82 (0.67, 1.00) | 0.78 (0.63, 0.96) | 0.81 (0.66, 1.00) | 0.02 | 0.80 (0.68, 0.93) |
| Model 4f | 0.90 (0.85, 0.96) | 1.00 (ref.) | 0.77 (0.63, 0.95) | 0.82 (0.67, 0.96) | 0.78 (0.63, 0.96) | 0.81 (0.66, 1.00) | 0.01 | 0.80 (0.68, 0.93) |
| Adolescent Recreational Physical Activityg | ||||||||
| Model 1c | 1.01 (0.94, 1.09) | 1.00 (ref.) | 0.85 (0.68, 1.06) | 0.98 (0.79, 1.22) | 0.81 (0.65, 1.01) | 1.13 (0.92, 1.40) | 0.59 | 0.94 (0.79, 1.12) |
| Model 2d | 1.01 (0.94, 1.09) | 1.00 (ref.) | 0.84 (0.67, 1.05) | 0.99 (0.80, 1.24) | 0.81 (0.65, 1.02) | 1.16 (0.94, 1.43) | 0.44 | 0.95 (0.80, 1.13) |
| Model 3e | 1.00 (0.93, 1.07) | 1.00 (ref.) | 0.81 (0.65, 1.02) | 0.96 (0.77, 1.19) | 0.79 (0.63, 0.99) | 1.12 (0.91, 1.39) | 0.64 | 0.92 (0.77, 1.10) |
| Model 4f | 1.00 (0.93, 1.07) | 1.00 (ref.) | 0.81 (0.65, 1.02) | 0.96 (0.77, 1.19) | 0.78 (0.62, 0.98) | 1.12 (0.90, 1.38) | 0.67 | 0.92 (0.77, 1.09) |
Hazard ratio (HR) reflects association for a one standard deviation (SD) change in continuous log-transformed and age-adjusted metabolic equivalents (METs) per week (baseline SD=1.98; adolescent SD=1.62)
Refer to eTable 1 in the supplemental materials for the minimum number of metabolic equivalents (METs) required to be classified as active for a given age at baseline.
Adjusted for race and ethnicity; study center; and baseline age; model stratified by birth cohort.
Adjusted for race and ethnicity; study center; baseline age; and lifetime familial breast cancer risk; model stratified by birth cohort.
Adjusted for race and ethnicity; study center; baseline age; lifetime familial breast cancer risk; education; parity and breastfeeding;, and use of alcohol, cigarettes, hormonal birth control and menopausal hormone therapy; model stratified by birth cohort.
Adjusted for race and ethnicity; study center; baseline age; lifetime familial breast cancer risk; education; parity and breastfeeding; use of alcohol, cigarettes, hormonal birth control, and menopausal hormone therapy; and body mass index; model stratified by birth cohort.
Quintile 1 (Q1) includes the least physically active women in the sample during adolescence with METs ranging from 0-14 per week, Q2=15-27 METs per week, Q3=28-44 METs per week, and Q5=47-72 METs per week. N=14,619 (cases=852) because 931 participants missing data on recreational physical activity during adolescence.