Waist to Hip ratio is simply a measurement of waist size compared to hip size. Long-term follow-up studies showed that so-called “abdominal obesity” was strongly associated with an increased risk of type 2 diabetes, cardiovascular disease and death, even after controlling for body mass index (BMI).
According to the World Health Organization, abdominal obesity is defined as Women: > 0.85, Men: > 0.9 in Waist-to-hip ratio. Scientists have long debated which measure of abdominal fat is the best predictor of health risk: Waist size alone or waist-to-hip ratio. The research to date has been mixed. In practice, it is easier to measure and interpret waist circumference than it is to measure both waist and hip. That makes waist circumference the better choice for many settings as stated by Harvard. edu.