Final answer:
Factors relevant to BMI include activity, lifestyle, and health conditions, which can influence body composition and weight. Age, while influencing body fat percentage, plays a less direct role than these variable factors. Reference weight and height are part of the BMI formula itself, not factors that affect it.
Step-by-step explanation:
When considering factors affecting BMI (body mass index), the following are relevant: Activity, lifestyle, and illness. BMI is a measure used to classify people in terms of weight and body fat based on their weight and height. The normal BMI range is 18-24.9 kg/m2, with overweight being 25-29.9 kg/m2 and obesity defined as a BMI over 30 kg/m2. Factors influencing BMI and body composition include diet, physical activity, genetics, and underlying health conditions. Socioeconomic status and the physical environment also contribute by affecting diet and exercise opportunities. Malnutrition, a form of poor diet, and geographical disparities in food availability and lifestyle can impact BMI as well.
Likewise, reference weight and height are inherently part of the BMI calculation, although they are not variable factors. The calculation of BMI itself relies on a fixed ratio of weight to height squared.
Age can also impact BMI to a certain extent, older adults tend to have a higher body fat percentage for the same BMI compared to younger individuals. However, lifestyle choices such as diet and physical activity play a more direct and variable role in determining BMI than the static measure of age.