Activity Intensity
In exploratory multivariate adjusted analyses, stone risk did not differ between patients who primarily performed mild, moder- ate, and strenuous intensity exercise when stratified by total METs per week category. Furthermore, the protective effect of higher total METs per week of physical activity on incident kidney stones was similar for women in all primary exercise categories. No significant interaction was seen between weekly physical activ- ity, calibrated dietary energy intake, or BMI (physical activity3energy intake, P=0.49; energy intake3BMI, P=0.23; and physical activity3BMI, P=0.85). We found moderate cor- relation between calibrated energy intake and BMI (r=0.67) and minimal correlation between physical activity and energy intake (r=20.03) and between physical activity and BMI (r=20.24).