Body mass index (BMI) z-score, a metric of health, represents the calculation of an individual’s BMI on a scale for their age and sex. For instance, a six-year-old boy with a BMI of 16.5 would have a BMI z-score of 0. This means his weight is in line with other boys of his age and gender.
The BMI z-score is a crucial indicator for healthcare professionals, allowing them to track growth patterns, identify malnutrition, and monitor risk factors for chronic conditions like heart disease and diabetes. It was initially developed in the early 20th century by researchers seeking to establish a standardized method for assessing body composition.