America is growing more diverse. People who identify as black, Hispanic, or Native American make up nearly one-third of the population. That figure will grow to over 40 percent within the next 40 years.

The nation's doctor corps is bucking this trend. Only about 13 percent of primary care doctors are black, Hispanic, or Native American. That share is unlikely to budge, as the current pool of medical students is disproportionately white and well-off.

The lack of diversity among doctors is a problem -- and not just one of optics. There's evidence that a diverse physician workforce can yield better outcomes for patients -- and save lives.

Medical schools don't reflect American society. The United States will become a "majority-minority" nation by 2045. In 2017, less than 6 percent of U.S. medical graduates were black -- even though African-Americans account for 12 percent of the U.S. population.

Linguistic diversity is lacking, too. Nearly 40 million Americans speak Spanish at home. But in 2017, less than 5 percent of U.S. medical graduates were Hispanic. The ratio of Latino doctors to Latino patients has fallen by more than 20 percent since 1980.

America's doctors-in-training lack socioeconomic diversity. Between 2007 and 2017, more than 75 percent of medical school graduates came from households with annual incomes of more than $75,000 a year. Only 5 percent came from the bottom quintile, or up to $24,000 a year.

This disconnect between the composition of American society and the doctor workforce threatens public health.

First, patients report greater levels of satisfaction with their care when treated by physicians with similar racial backgrounds, according to a study in the Journal of Health and Social Behavior.

Consider a recent study from Stanford. Researchers randomly assigned black and non-black male doctors to a group of over 1,300 black men in Oakland, California. They found that patients treated by black doctors were more likely to seek preventive services than those treated by non-black doctors. Patients were also more likely to discuss other health issues with doctors of the same race.

The study concluded that increasing the number of black doctors "could help reduce cardiovascular mortality by 16 deaths per 100,000 per year" among black men.

Second, language barriers can increase the risk of health complications. In a 2007 study of six hospitals, patients with limited English proficiency were 66 percent more likely than English speakers to experience harm from "adverse events."

Third, doctors tend to practice in communities similar to the ones they've come from. Upper middle-class med students from the suburbs tend not to set up shop in poor urban or rural areas.

As a study published in the Journal of Health Care for the Poor and Underserved put it, minority physicians "are more likely to practice in areas federally designated as medically underserved or experiencing health professional shortages than white physicians."

Some medical schools are trying to diversify their ranks. The Yale Department of Psychiatry announced plans to establish a new program dedicated to training minorities who provide treatment to patients in high-need, underserved areas.

The CityDoctors scholarship program at St. George's University in Grenada -- the school I lead -- covers tuition for certain students from the New York metropolitan area who commit to working in the city's public hospital system after graduation. The program helps make medical school affordable for students committed to addressing inequity in our healthcare system.

Diversity saves lives. It's time we make diversifying our doctor workforce a bigger priority.