corpulence index corpulence index the corpulence index (ci) (also ponderal index (pi) or rohrer's index) is a measure of corpulence, or of leanness in other variants, of a person calculated as a relationship between mass and height. it was first proposed in 1921 as the "corpulence measure" by swiss physician fritz rohrer and hence is also known as rohrer's index. it is similar to the body mass index, but the mass is normalized with the third power of body height rather than the second power. in 2015, sultan babar showed that ci does not need to be adjusted for height after adolescence. c i = m a s s h e i g h t 3 = } ^ part of a series onhuman body weight general concepts obesity (epidemiology) overweight underweight body shape weight gain weight loss gestational weight gain diet (nutrition) weight management overnutrition childhood obesity (epidemiology) medical concepts adipose tissue classification of obesity genetics of obesity metabolic syndrome (epidemiology of metabolic syndrome) metabolically healthy obesity obesity paradox set point theory measurements body adiposity index body mass index body fat percentage body shape index corpulence index lean body mass relative fat mass waist–hip ratio waist-to-height ratio related conditions diabetes (type 1) eating disorder (anorexia • bulimia • binge eating disorder) food addiction hyperthyroidism malnutrition red-s starvation (starvation response) pcos obesity-associated morbidity arteriosclerosis atherosclerosis fatty liver disease gerd gynecomastia heart disease hypertension obesity and cancer osteoarthritis prediabetes sleep apnea type 2 diabetes management of obesity anti-obesity medication bariatrics bariatric surgery dieting (list of diets) caloric deficit exercise (outline) liposuction obesity medicine weight loss camp weight loss coaching yo-yo effect social aspects comfort food fast food (criticism) fat acceptance movement fat fetishism health at every size hunger obesity and the environment obesity and sexuality sedentary lifestyle social determinants of obesity social stigma of obesity weight cutting weight class with m a s s } in kilograms and h e i g h t } in metres, giving a measure with the same dimensions as density. the corpulence index yields valid results even for very short and very tall persons, which is a problem with bmi — for example, an ideal body weight for a person 152.4 cm tall (48 kg) will render bmi of 20.7 and ci of 13.6, while for a person 200 cm tall (99 kg), the bmi will be 24.8, very close to the "overweight" threshold of 25, while ci will be 12.4. because of this property, it is most commonly used in pediatrics. (for a baby, one can take crown-heel length for the height.) the normal values for infants are about twice as high as for adults, which is the result of their relatively short legs. it does not need to be adjusted for age after adolescence. it has also been shown to have a lower false positive rate in athletes. the corpulence index is variously defined (the first definition should be preferred due to the use of si-units kg and m) as follows: formula units values considered normal or typical for a 12-month-old infant beyond infancy ci = m a s s h e i g h t 3 = } ^ kg/m3 24 12 ci = h e i g h t m a s s 3 = } }}}} pound * inch -1/3 12.49 to 13.92 significance it plays a role in assessing whether the intrauterine growth restriction of a child is symmetrical or asymmetrical. ci has been shown to have higher sensitivity, specificity, and positive and negative predictive values than body mass index for determining adiposity. it is used to calculate ectomorphy in the heath–carter formula.