Which one of the following is the correct formula for calculating a person's body mass index (BMI)?

GMCH Chandigarh - 2019

Applied Nutrition & Dietetics

Easy

Appeared in: GMCH Chandigarh - 2019

Explanation

The correct formula for Body Mass Index (BMI) is the weight in kilograms divided by the square of the height in meters (kg/m²).
This formula standardizes a person's weight relative to their height, providing a widely accepted index to screen for weight categories that may lead to health problems.
For example, an adult weighing 70 kg with a height of 1.75 m has a BMI of 70 / (1.75 * 1.75), which equals 22.9 kg/m², falling within the normal range.

Option A: This option incorrectly suggests multiplying weight and height. BMI is a ratio that involves division to assess weight relative to height.
Option C: This option is a common error. It correctly divides weight by height but fails to square the height measurement, which is a critical step in the BMI formula. This leads to a mathematically incorrect value.
Option D: This option is incorrect because a correct and standard formula for calculating BMI exists and is provided as one of the other options.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Body Mass Index (BMI) as background academic context rather than a clinical decision trigger.
Nurses frequently calculate BMI as part of the initial patient assessment to screen for nutritional risks and potential health problems like cardiovascular disease and diabetes.
It serves as a starting point for conversations with patients about healthy weight, nutrition, and physical activity.
What if? If a patient is an elderly person with sarcopenia (age-related muscle loss), their BMI might appear normal or even low, masking underlying health risks associated with low muscle mass and increased fat. In this case, a nurse should prioritize functional assessments and other body composition measures over relying solely on BMI.

How to Approach the Question

This is a factual recall question that requires knowledge of a standard medical formula.
First, identify the key term in the question: 'Body Mass Index (BMI)'.
Recall the specific formula used for its calculation. Remember the units involved (kilograms for weight, meters for height).
Carefully evaluate each option against the recalled formula. Pay close attention to the mathematical operations (multiplication vs. division) and whether any value is squared.
Option A (multiplication) is incorrect. Option C (division without squaring height) is incorrect. Option B correctly matches the formula: weight in kg divided by height in meters squared.
Eliminate the incorrect options to confirm the correct answer.

Concept Tested & Keywords

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