Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 389

BMI of less than 22 kg/m² has been associated with a higher one‐year mortality rate and poorer functional status among older community‐dwelling people.²⁵ The risk for higher mortality in men older than 65 begins at a BMI of less than 22 kg/m² and increases to a 20% higher risk in men older than 75 with a BMI of less than 20.5 kg/m². Similarly, a higher mortality risk in women begins at a BMI of less than 22 kg/m² in women older than 65 and increases to a 40% higher risk in women older than 75 with a BMI of less than 18.5 kg/m².²⁶ BMI less than the 15th percentile is an independent predictor of 180‐day mortality following hospitalization.²⁷

Although there is a strong association between BMI and mortality, the key factor in mortality risk appears to be recent weight loss. After excluding subjects with weight loss of 10% or more of their body weight, there is little relationship between BMI and mortality. In people over 50 who reported an unintended loss of 10 lb (~3.7 kg) or more in the year before evaluation, the age‐adjusted death rate was much higher compared with people who voluntarily lost weight through diet or exercise or who maintained or gained weight.²⁸ Nearly all of the observational studies on body weight have found that any weight loss is associated with increased, rather than decreased, risk for death.

The data suggest that obesity in older adults may not be an important clinical target for reducing mortality and that a preferred public health emphasis for this age group would be to increase awareness that substantial weight loss after age 50 is a potential indicator for poor prognosis.