Waist–hip ratio
WHR is used as a measurement of obesity, which in turn is a possible indicator of other more serious health conditions. The WHO states that abdominal obesity is defined as a waist-hip ratio above 0.90 for males and above 0.85 for females, or a body mass index (BMI) above 30.0. The National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) states that women with waist-hip ratios of more than 0.8, and men with more than 1.0, are at increased health risk because of their fat distribution.
Waist-to-height ratio
A WHtR of over 0.5 is critical and signifies an increased risk; a 2010 systematic review of published studies concluded that "WHtR may be advantageous because it avoids the need for age-, sex- and ethnic-specific boundary values". For people under 40 the critical value is 0.5, for people aged 40–50 the critical value is between 0.5 and 0.6, and for people over 50 the critical values start at 0.6. 
As a comparative, the following table categorises the boundaries of persons in terms of health: