Dr Bollmann, Anti-Aging and Skin Care Specialist
Body Mass Index (BMI) is the ratio between height and weight. The number indicates whether a person is underweight, overweight, or within a normal weight range. Individuals with a BMI of 25.0 or greater are considered overweight and those with a BMI of 30.0 or greater are considered obese. Increased BMI is an established risk factor for several causes of death including ischemic heart disease, stroke, and certain cancers.
Researchers from the University of Oxford (United Kingdom) reported that a BMI above the normal range is associated with an increased risk of death. The team reviewed data from 57 prospective studies involving a total of 894,576 patients in western Europe and North America as part of the Prospective Studies Collaboration. Mortality was about 30% higher for each additional 5 kg/m2, and primarily was correlated to 40% increased risk for vascular disease and 60 to 120% raised risks for diabetic, renal, and hepatic diseases, as well as 10% increased risk of neoplastic death and a 20% increased risk of death from respiratory causes. The researchers explain that: “"By avoiding a further increase from 28 kg/m2 to 32 kg/m2, a typical person in early middle age would gain about two years of life expectancy. Alternatively, by avoiding an increase from 24 kg/m2 to 32 kg/m2, a young adult would on average gain about three extra years of life."
As a number calculated from a person's weight and height, Body Mass Index (BMI) is a fairly reliable indicator of body fatness for most people. It is used as a screening tool to identify possible weight problems for adults, and is generally considered one of the best methods for population assessment of overweight and obesity.