Even though African-American adults are more likely to develop diabetes than white adults, the increased risk is largely due to obesity and other risk factors that may be possible to change, a new study suggests.

Researchers followed 4,251 black and white men and women starting when they were 18 to 30 years old; none of them had diabetes to start with. After an average follow-up of more than 24 years, 504 of the participants developed diabetes.

Compared to white women, African-American women were almost three times more likely to develop diabetes, researchers reported in the Journal of the American Medical Association. Black men, meanwhile, had 67 percent higher odds of becoming diabetic than white men.

However, there was no longer a meaningful difference in diabetes risk between black and white people once researchers accounted for a variety of factors that can contribute to this disease, including obesity, neighborhood segregation and poverty levels, depression, education and employment.

“Our work suggests that if we can eliminate these differences in traditional risk factors between blacks and whites, then we can reduce the race disparities in the development of diabetes,” said lead study author Michael Bancks, a researcher at Northwestern University Feinberg School of Medicine in Chicago.

This isn’t an easy fix, Dr. Bancks acknowledged.

“To eliminate the higher rate of diabetes, everybody needs to have access to healthy foods, safe spaces for physical activity and equal economic opportunity to have enough money to afford these things and live in communities that offer this,” Dr. Bancks stated in an email.

“Prior research by our team has shown that black adults live in neighborhoods that have higher rates of poverty, fewer grocery stores and (fewer) safe places for physical activity,” Dr. Bancks added. “These neighborhood factors contribute directly to the health behaviors, such as physical activity and diet, that can lead to obesity and diabetes.”

At the start of the study, participants were about 25 years old on average, and white participants were more likely to be married, employed full time and have at least some college education.

During the study, 189 white people and 315 black people developed diabetes.

This translates into 86 cases of diabetes for every 1,000 white people, compared with 152 cases for every 1,000 African-Americans.

Among all of the risk factors that helped explain this difference, biological factors such as obesity and fasting blood sugar levels played the biggest role, the study found.

The study wasn’t a controlled experiment designed to prove whether or how various risk factors might influence the odds of developing diabetes or explain racial disparities.

Another limitation is that researchers relied on data from blood sugar tests or diabetes medication prescriptions to determine whether people had been diagnosed with the disease, the authors noted. Current definitions of the blood sugar levels that indicate diabetes are different than they were during much of the study, and prescription records don’t always offer a complete picture of who has been diagnosed with this disease, the researchers pointed out.

Even so, the results offer fresh evidence that long-documented racial disparities in diabetes rates in the United States might be reduced by focusing on risk factors that are possible to change, said Dr. Daniel Lackland, a researcher at the Medical University of South Carolina in Charleston.

“It is important for black patients and individuals to recognize the disease risk disparities and excess burden for African-Americans but also know these risks can successfully be reduced by knowing their blood pressure and blood glucose levels; taking medication as prescribed; not smoking; exercise; reducing excess body weight; and consuming a healthy diet,” said Dr. Lackland, who wasn’t involved in the study.

“These are interventions individuals could implement regardless of income level,” Dr. Lackland added, “for example, having blood pressure measured and knowing numbers; walking in safe areas such as shopping malls; and eating a healthy diet.”