For people who are overweight or underweight for their height, shopping for pants can be a difficult experience. With the range of inseams for a given waistband often limited, it may be necessary to have your pants altered or purchase them at a specialty store if you fall outside this range. While this applies equally whether you are currently outside your recommended weight range or have a specific body type, the relationship between waist size and height generally holds for most people.
Height and Bone Structure
Although variations exist at any height range, taller people generally have thicker, heavier bones. To account for the effects of bone structure at different heights, people are generally classified as having small, medium or large body frames. Derived from a combination of your wrist circumference and height, these body scales reflect the differences in bone structure with height. For example, a small frame for a woman under 5 feet, 2 inches is defined by a wrist circumference under 5.5 inches, while a woman over 5 feet, 5 inches is considered to have a small frame with a wrist smaller than 6.25 inches.
Given the general increases in body frame size with height, it may not come as a surprise that waist circumference also increases with height. As both bone structure and body fat contribute to your waist circumference, the use of BMI or waist circumference on their own to determine if you are at a healthy size may be inaccurate. As suggested in a 2008 study by Sarah Garnett and colleagues at The Children's Hospital at Westmead Clinical School in Westmead, Australia, the use of waist-to-height ratio, or WHtR, may be both easier and more accurate in determining risks associated with being overweight.
Benefits of WHtR
In a 2011 study, a team headed by Yong Liu of Shengjing Hospital of China Medical University in Shenyang, China studied the effectiveness of waist circumference, BMI and WHtR in predicting obesity-associated health risks. While they found all three to be effective, they note that WHtR may be the most accurate indicator of a variety of cardiovascular and other health risks associated with excess body fat. In addition to its predictive accuracy, Sarah Garnett and her team point out that WHtR is the simplest index of body fat-related health risks. Regardless of your weight, age or sex, they suggest that maintaining a waist circumference that is less than half of your height is an easy way to reduce your risks of cardiovascular disease.
WHtR and General Considerations
In general, your waist circumference grows larger as you become taller. Using WHtR, for example, a waist circumference of 34 inches may be healthy for someone who is 5 feet, 10 inches but indicate body fat-related health risks for someone who is 5 feet, 5 inches. Although such measurements can be used as general guidelines, you should not use WHtR alone to determine whether or not you are at a healthy weight and size. Depending on your body type, body fat percentage and other factors, a potentially healthy waist circumference for other people who are your height may not be ideal for you.