BMI & Health Risk

Your body mass index, a figure derived from your weight compared to your height, provides an approximate indication of your total body fat. High BMIs indicate health risk particularly when linked to certain patterns of fat distribution, weight gain since age 20 and sleep apnea. If your BMI is above 25, indicating overweight, or above 30, indicating obesity, your doctor may want you to try to aim for the healthy range, from 18.5 to 24.9.

Considerations

Assessment of whether you are overweight and facing health risks involves three key measures, according to the National Heart Lung and Blood Institute. Your health care provider will also look at, in addition to BMI, waist circumference, which indicates the presence of more risky abdominal fat, and a constellation of other factors. Additional factors linking obesity to health risks include cigarette smoking, lack of exercise, family history of heart disease, high blood pressure, high cholesterol or high triglycerides.

Types

If you are overweight or obese, you have a greater chance of developing high blood pressure, high blood cholesterol, Type 2 diabetes, stroke, heart disease and certain cancers, including endometrial, colon, gall bladder, prostate and kidney cancer. Extra weight may also link to sleep apnea, osteoarthritis, gallbladder and liver disease and irregular menstrual periods.

Time Frame

The U.S. Office of the Surgeon General attributes an estimated 300,000 deaths per year to obesity and indicates obese people have a 50 percent to 100 percent risk of premature death from all causes.

Effects

High blood pressure is twice as common in adults who are obese than in those who are at a healthy weight. Obese persons also have elevated triglycerides (blood fat) and decreased HDL cholesterol, or "good" cholesterol, the Office of the Surgeon General notes. More than 80 percent of people with diabetes are overweight or obese. Women who gain more than 20 lbs. from age 18 to midlife double their risk of postmenopausal breast cancer, compared to women whose weight remains stable.

Expert Insight

A high BMI may not translate to increased health risk for people under 40, according to an analysis of national health survey data by Brent Jarrett, a doctoral student in neuroscience at Ohio State University, and colleagues. Jarrett looked at the use of prescribed medications for physical illness as an indication of current health. Study participants under 40 did not have serious illness linked to overweight BMIs. Medication use increased for overweight men and women between the ages of 40 and 70. The Office of the Surgeon General, however, notes that overweight adolescents have a 70 percent chanceof becoming overweight or obese adults, a risk which increases to 80 percent if one or both parents are overweight or obese.