BMI for the Elderly (60+)

BMI for the elderly: adjusted cutoffs

Once someone is over 65, the usual WHO BMI cutoffs (< 18.5 underweight, 25 overweight) stop being a good fit. The Brazilian Society of Geriatrics and Gerontology (SBGG) and the Lipschitz reference use a different set: BMI < 22 underweight, 22 − 27 eutrophic, and > 27 overweight. Say an older adult weighs 70 kg at 1.70 m. That gives BMI = 70 / 1.70² ≈ 24.2 kg/m², which counts as eutrophic for the elderly even though the WHO adult scale would call it overweight.

Clinical context

Aging reshapes the body in several ways. Lean mass drops off (sarcopenia), visceral fat builds up, and height falls a bit as the vertebrae compress. The higher cutoffs exist because, in this age group, carrying a moderate amount of weight actually protects against mortality. You'll see the measure used for nutritional screening at UATI, ILPI, in primary care, and when assessing frailty or sarcopenia. Still, BMI on its own doesn't tell the whole story; pair it with calf circumference, gait speed, and the MNA.

FAQ

From what age? 60 years under WHO/Brazil criteria, or 65 in most international references. The SBGG cutoffs kick in from 60 onward.

Does BMI detect sarcopenia? No. A "normal" BMI can mask sarcopenic obesity. Back it up with calf circumference (< 31 cm flags risk) and handgrip strength.

What does "underweight" mean for an elderly person? It signals a higher risk of mortality, falls, infection, and a longer hospital stay. That's a cue to start a nutritional and clinical workup.