TUESDAY, June 28 (HealthDay News) -- Obesity is a major risk factor for death among obese women who don't smoke, particularly low-income women, a new study finds.

It included more than 3,600 women aged 45 to 64 in Scotland who never smoked and were followed for 28 years. During that time, half the women died, including 916 (51 percent) from cardiovascular disease and 487 (27 percent) from cancer.

Researchers found that low-income women were more likely to be severely obese than women who were better off financially.

The study also found that those who were severely obese had the highest death rates, while non-smoking women who were not obese have relatively low death rates regardless of their socioeconomic status, according to the study, published June 28 online in the British Medical Journal.

Though women with low-income jobs were more likely than those with higher paying jobs to die of cardiovascular disease, the same didn't hold true for cancer.

Researchers also found that women who never smoked were much more likely to be overweight or obese than those who smoked. This suggests that high smoking rates a few decades ago may have obscured the extent of obesity in non-smoking women, and that recent declines in smoking rates may have contributed to the increase in overweight and obesity, the researchers said in a journal news release.

Despite the risks posed by obesity, "it is important not to forget that smoking is a much stronger risk factor for (death) than most other risk factors, including obesity," Professor Johan Mackenbach, of Erasmus Medical Center Rotterdam in the Netherlands, wrote in an accompanying editorial.

More information

The U.S. National Women's Health Information Center has more about overweight and obesity.