Color isn’t only skin deep. In fact, it can determine how long you’ll live. Researchers from the University of Southern California’s Davis School of Gerontology have found people of different races age differently from one another. Their findings appear in the journal of Social Science and Medicine.

“Our results showed that, on average, blacks tend to be more than three years older biologically than whites,” said Morgan Levine and Eileen Crimmins of the University of Southern California’s Davis School of Gerontology. “This is consistent with findings from previous studies reporting that blacks tend to have levels of biological risk factors that are indicative of someone significantly older chronologically.”

Researchers looked at the physical exams and lifestyle surveys from the National Health and Nutrition Examination Study, which included 7,644 Americans age 30 and older, who were 89 percent white, and the remaining were 11 percent black. They were surprised to find that even if two men were chronologically the same age, their bodies were telling them a different story, and the black man was physically three years older.

“Everyday stressors associated with being black may negatively impact physiological functioning and, under chronic exposure, accumulate over the lifespan and contribute to growing disparities in biological risk,” the authors wrote. “Furthermore, if such environmental, behavioral, and mental factors contribute to an acceleration of the aging process, we would expect that persons who are aging the fastest should have the highest risk of mortality, and thus (have a) lower life expectancy.”

The participants’ biological age was determined by looking at their total cholesterol, C-reactive protein, serum creatinine, glycosylated hemoglobin, systolic blood pressure levels along with their body-mass index (BMI), level of education, and whether or not they smoke or were former smokers.

“This suggests the most disadvantaged blacks may be accumulating poorer and poorer health as they age,” ultimately dying at earlier ages than otherwise similarly situated whites.

On average, the biological age for blacks was 53.16 years, compared to whites whose age was 49.84 years. The report took into the account an individual’s socioeconomic status and health behaviors, and noted that obesity rates are higher for blacks than whites and the excessive weight gain can biologically age someone much faster than someone with a healthy, normal weight.

According to the Centers for Disease Control and Prevention, blacks have the highest age-adjusted rates of obesity, weighing in at 47.8 percent of their population, compared to the total American adult population, which is 34.9 percent obese.

Researchers concluded “being black is associated with significantly higher biological age, and that this is a pathway to early death.”

Source: Levine ME, Crimmins EM. Evidence of accelerated aging among African americans and its implications for mortality. Social Science and Medicine. 2014.