Final answer:
The waist circumference is the most common measurement to assess health risk based on an individual's circumference. The waist-to-hip ratio is calculated using the waist circumference and is a better predictor of disease risk.
Step-by-step explanation:
When assessing health risk based on an individual's circumference measurement, it is most common to take the measurement at the waist. The waist circumference is used to calculate the waist-to-hip ratio, which is a better predictor of disease risk than waist circumference alone. A higher waist-to-hip ratio, indicating more weight around the waist (an "apple-shaped" body), is associated with greater health risks.