NEW YORK (Reuters Health) – Emphysema and similar lung diseases seem to put African Americans at particularly high risk for developing lung cancer, a new study suggests.

Chronic obstructive pulmonary disease (COPD) – a collection of lung diseases that includes emphysema and chronic bronchitis – is most often caused by smoking, and it's known that people who develop COPD face a greater chance of developing lung cancer.

In the new study, though, researchers at the University of Texas found that among the nearly 1,000 African Americans they assessed, COPD was a particularly strong risk factor for lung cancer.

African Americans with a history of COPD were more than six times as likely as those without the disease to develop lung cancer. This risk is on par with that linked to smoking, and is twice as high as the risk linked to COPD in whites, according to the researchers.

The findings, published in the journal Cancer Prevention Research, are part of a "risk prediction model" the researchers developed to more precisely estimate lung cancer risk in African Americans.

For the most part, previous studies that have developed methods of predicting individuals' lung cancer risk have focused on white adults. However, the various risk factors for lung cancer do not necessarily each carry the same weight in all racial groups, according to the researchers. "The one size fits all risk prediction clearly does not work," lead researcher Dr. Carol Etzel, of the UT M.D. Anderson Cancer Center, said in a written statement.

She and her colleagues based their findings on assessments of 491 African Americans with lung cancer and 497 African Americans who were matched to the patients for age and sex, but were free of cancer.

Smoking, the major risk factor for lung cancer, was as strongly linked to the disease in black adults as it has been in whites in previous studies. Current smokers were more than six times as likely as non-smokers to develop lung cancer, and former smokers had a more than three-fold increase in their risk.

Etzel said the risk prediction model her team developed is part of a larger effort to develop such tools for different ethnic groups; they are currently working on one for Hispanic adults.

The model they developed in this study considers a person's history of smoking, COPD, hay fever – which is linked to a lower lung cancer risk — and exposures to asbestos or wood dust, which raise the risk of the disease.

This model, the researchers found, was more accurate in predicting black adults' lung cancer risk compared with a similar model that was previously developed from data on white patients.