Waist-to-hip ratio (WHR) is a common index for judging central obesity, and is the result of measuring waist circumference and hip circumference and then making a ratio. Waist circumference is measured by having the subject stand upright with the feet naturally separated by 30-40cm, using a soft ruler with no elasticity and a minimum scale of 1mm placed at the midpoint of the line connecting the lower edge of the 12th rib and the anterior superior iliac spine in the right axillary midline, and measuring the length along the horizontal direction around the abdomen for one week, and reading the data accurately to 1mm; hip circumference is the measurement of the most prominent maximum circumference of the hip backward. It is usually greater than 0.9 for men and 0.8 for women, indicating central obesity.