Obesity is known to increase a person's risk of death and now, new findings
from a study of more than 90,000 women indicate that the risk continues to
increase as the severity of obesity worsens.
"It's not good enough to consider obesity alone," principal investigator Dr.
Kathleen McTigue of the University of Pittsburgh, Pennsylvania, told Reuters
Health. "You need to look at degree of obesity."
In a study published in the Journal of the American Medical Association,
McTigue and colleagues evaluated the impact of body weight on death risk in
90,185 women enrolled in the Women's Health Initiative Observational Study. On
average, the patients were followed for 7 years.
Body mass index (BMI), a measure of body weight for height, was used to
classify the women as normal weight, overweight, or obese. Normal weight was
defined as a BMI from 18.5 to 24.9 and overweight was a BMI from 25 to 29.9. The
investigators defined three categories of obesity: obesity 1 (BMI of 30 to
34.9), obesity 2 (BMI 35 to 39.9) and extreme obesity (BMI 40 and higher).
"The risks of extreme obesity have not been well-defined," McTigue noted. But
this study had enough subjects to assess that risk, she added.
As weight increases, so does the risk of death, but the risk is not
statistically significant until one becomes obese, McTigue said. Compared with
normal-weight women, she continued, "the risk of dying was increased 12 percent
in all women in obesity category 1, while risk was increased 86 percent over
seven years in women in obesity category 3."
In a University of Pittsburgh release, the researcher pointed out that
"earlier studies, which tended to reflect lower degrees of obesity, may
underestimate the risks of extremely obese individuals and overestimate the risk
for mildly obese individuals in diverse groups."
She concluded, "More accurately assessing weight-related health risk may both
improve policy decisions about obesity and assist women in making informed
decisions about their health."
