Eating a diet high in sugar not only raises the risk for diabetes, but also boosts the odds of developing lung cancer.

That’s the upshot of new research by the University of Texas MD Anderson Cancer Center that found consuming a diet with a high glycemic index — a classification of how rapidly carbohydrates elevate blood sugar levels — increased the risk of developing lung cancer in non-Hispanic whites.

The study — published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research — is the largest study to investigate potential links between glycemic index (GI) and lung cancer.

The findings are the first time to link GI with lung cancer risk in people who never smoked and those diagnosed with the squamous cell carcinoma (SCC) subtype of lung cancer.

Nationally, lung cancer is the second most common cancer in both men and women, causing more than 150,000 deaths each year, according to the American Cancer Society. While tobacco use is the leading cause of lung cancer, it fails to account for all cases, particularly in those who never smoked.

Dr. Xifeng Wu, a professor of epidemiology and senior author of the study, said a growing body of evidence suggests dietary factors are linked with lung cancer development. Diets high in fruits and vegetables may decrease risk, while increased consumption of red meat, saturated fats and dairy products have been shown to increase lung cancer risk.

"Diets high in glycemic index result in higher levels of blood glucose and insulin, which promote perturbations in the insulin-like growth factors (IGFs)," said Stephanie Melkonian, a fellow with Wu's team and lead author of the study. "Previous research suggests increased levels of IGFs are associated with increased lung cancer risk. However, the association between glycemic index and lung cancer risk was unclear."

For the study, researchers surveyed 1,905 MD Anderson lung cancer patients and 2,413 other healthy individuals. They tracked the participants’ dietary habits and health histories.

"We observed a 49 percent increased risk of lung cancer among subjects with the highest daily GI compared to those with the lowest daily GI," said Wu. "The associations were more pronounced among subjects who were never smokers, diagnosed with squamous cell carcinoma or had less than 12 years of education."

While specific dietary recommendations cannot be made on the basis of these results, the authors suggest limiting foods and beverages with high GI — such as white bread or bagels, corn flakes, and puffed rice — for a more balanced diet and to lower the risk for lung cancer and chronic diseases.

Examples of low GI foods include whole-wheat or pumpernickel bread and rolled or steel-cut oatmeal

"The results from this study suggest that, besides maintaining healthy lifestyles, such as avoiding tobacco, limiting alcohol consumption and being physically active, reducing the consumption of foods and beverages with high glycemic index may serve as a means to lower the risk of lung cancer," said Wu.

The study was funded, in part, by the National Institutes of Health