Sabina Spigner says she's always known she wanted to be a doctor. But, as a premed student at the University of Pennsylvania, she found herself struggling to balance a heavy class load while also working as many as 20 hours a week.

"I was always working, because I didn't have money and I was a work-study student," says Spigner.

Her grades suffered as a result. In her junior year, she turned to her pre-med adviser for help. "She was like, well, you know, you're just not going to get into med school with that GPA, so I think you should consider something else. And she didn't really present me with many resources or options other than just giving up," Spigner says.

That conversation happened nearly eight years ago. Spigner — who is Black and Southeast Asian American — says when she recalled the experience on Twitter last month, "unfortunately, a lot of people shared similar stories."

"You know, this is something that's happening across the country and it's very, very common, especially for students of color, to experience discouragement," she says.

For decades, leading medical organizations have been trying to diversify the ranks of physicians, where Black and Hispanic doctors remain vastly underrepresented relative to their proportion of the U.S. population. That matters, because research has shown that people from underrepresented racial and ethnic groups can have better health outcomes when their doctors look like them.

But a recent study in the journal JAMA Health Forum highlights the factors, including financial pressures and discrimination, that can keep determined students of color from actually making it to medical school.

The study looked at responses from more than 81,000 students who took the Medical College Admission Test. The standardized exam is grueling: People study for it for months, if not years, says the study's first author, Dr. Jessica Faiz of the University of California, Los Angeles.

"You paid for the test. You took all that time to study. You are definitely quite committed to applying" to med school, says Faiz, an emergency physician and fellow with the National Clinician Scholars Program at UCLA.

Even so, Faiz and her colleagues found that Black and Hispanic test takers were significantly less likely to go on to apply and enroll in med school than white test takers. Not only that, but Black, Hispanic and Native American students were more likely to say they faced financial barriers, such as difficulty affording test prep materials and already having large student loans.

"Even further, they're more likely to face discouragement from advisers when applying to medical school compared to their white counterparts," says study co-author Dr. Utibe Essien, an assistant professor of medicine and health equity researcher at UCLA.

Another key finding: Black, Hispanic and Native American students were more likely to have parents without a college degree and more likely to go to a low-resourced college, which the researchers defined as a college with a less-selective admissions process and a majority of students living off campus.

Those factors "really trickle down to your social networks that are really integral in succeeding as a medical student," Faiz says. For instance, the study found that students of color were less likely to have shadowed a physician — an experience that can burnish a med school application. Faiz says that likely reflects a lack of the kinds of connections that make it easier to set up that kind of experience.

Essien notes that decades of research have found that patients of color can benefit from having a doctor of their own racial or ethnic background. For example, studies have found they were more likely to have received preventive care in the prior year and more likely to be satisfied with the health care they receive.

For minorities, says Essien, "having a doctor who looks like you makes you more likely to accept flu vaccination, to have a colonoscopy, to consider having a more invasive heart procedure."

There's even striking new evidence that Black people live longer if they reside in counties with more Black physicians. But that new study came with a sobering discovery: A little over half of U.S. counties were excluded from the national analysis because they didn't have a single Black primary care physician. Faiz says that finding, which was published on the same day as the study she led, underscores why it's so critical to better understand the factors that keep students of color from med school.

Adds Essien: "We're not just advocating diversity out of the goodness of our hearts. It really, literally is saving lives."

Dr. Jaya Aysola is executive director of Penn Medicine's Center for Health Equity Advancement. She wrote a commentary that accompanied the study in JAMA Health Forum. Aysola says the study sheds much-needed light on the financial barriers and unconscious biases that can block the path to med school for students of color.

"From who advises you to submit an application to who then eventually helps select your application, to those who interview you, there's bias all along those processes," Aysola says.

As for Sabina Spigner? She didn't let her premed adviser's discouragement stop her from pursuing her med school dreams. She decided to pursue graduate school first. She ended up with two master's degrees — in science and public health — before heading to the University of Pittsburgh School of Medicine. When she graduates next month, she'll officially be Dr. Spigner at last.

She says she lives by the philosophy that "only you can tell you if you can succeed or not. It's not somebody else's job to say that."

"I'm proof that there's a way," she adds.

She'll start her OB-GYN residency at Northwestern University in June.