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.
Weight was defined as:
underwieght is a BMI of less than 18.5
normal is a BMI from 18.5 to 24.9,
overweight is a BMI from 25 to 29.9,
obesity 1 is a BMI of 30 to 34.9,
obesity 2 is a BMI 35 to 39.9,
and extreme obesity is a BMI 40 and higher.
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 per cent in all women in obesity category 1, while risk was increased 86 per cent 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."
(Adult BMI calculator) This calculator provides BMI and the corresponding BMI weight status category. Use this calculator for adults, 20 years old and older.
(Child and teen BMI calculator) This calculator provides BMI and the corresponding BMI-for-age percentile on a CDC BMI-for-age growth chart. Use this calculator for children and teens, aged 2 through 19 years old.