Table 5.

Adjusted relative risks of death due to breast cancer among women in the California Teachers Study, by long-term combined strenuous and moderate physical activity, for baseline body mass index as a possible effect modifier

Long-term combined moderate and strenuous physical activity*P trendPhomogeneity
RR (95% CI)RR (95% CI)RR (95% CI)
BMIBreast cancer deaths
<25 kg/m2991.01.24 (0.65 -2.36)1.15 (0.58 -2.29)0.810.03
≥25 kg/m21001.00.52 (0.32 -0.86)0.41 (0.23 -0.74)0.004
BMIDeaths due to any cause
<25 kg/m22201.00.89 (0.62-1.29)0.83 (0.55-1.25)0.370.60
≥25 kg/m21911.00.79 (0.54-1.16)0.70 (0.46-1.08)0.12

NOTE: All models are stratified by age in years and adjusted for race, BMI, total caloric intake, number of comorbid conditions, and estrogen receptor status.

  • *Long-term strenuous and moderate activity summary variable classifies women with no activity >0.5 h/wk/y activity into the low group, those with at least one of moderate or strenuous activity >3 h/wk/y into the high group, and all others, that is, those with some activity that is >0.5 h/wk/y and ≤3 h/wk/y but not >3 h/wk/y into the intermediate group.

  • There were 22 cases excluded due to missing BMI.

  • There were 130 cases excluded due to missing BMI.