Exposure to racist or discriminatory behaviors over a lifetime can be harmful to overall mental and physical health, according to a new study in the American Journal of Public Health. Such health detriments are disproportionately heaped upon ethnic and racial minorities (especially people of color in Western countries), because they are more likely to be the subjects of such behaviors.

The study authors pointed out that similar studies looking at single experiences of discrimination might have underestimated the impact of long-term racism on health. These researchers tried to look at the dose-sensitive effects of systemic racism on a person’s health over a longer period of time, across different educational, professional and social settings.

The negative effects of this stress also included the mere fear of such discrimination, “which likely captures not only the previous experiences of racial discrimination as described earlier but also the vigilance and anticipatory stress of a possible future racist encounter,” the study authors pointed out.

Researchers reviewed the data of about 40,000 British households taken from the U.K. Household Longitudinal Study between 2009 and 2013 (including about 4,000 ethnic minority households), which showed that black Caribbean, Pakistani and Bangladeshi British people have a six- to nine-year shorter disability-free life expectancy at birth than white British people.

Experiences of discrimination were taken from extra questions about ethnic heritage, harassment, mental health and other health outcomes. Mental health fitness was given a 0 to 100 (low functioning to high functioning) score and then compared with respondents’ ethnicities and frequency of reports of discrimination to determine a casual effect.

The group of white people were given a mean mental health score of 49.6. People of Indian descent included in the survey were found to have a similar mean mental health score at 49.4, and black respondents had a mean score of 50.9.

However, the same groups who were shown to have shorter life expectancies than white people (black Caribbean, Pakistani and Bangladeshi British) were also found to have “significantly higher levels of distress”: 48.3, 45.9 and 46.5, respectively.

The analysis also found that the people who reported more instances of racial discrimination also tended to show lower-functioning mental health scores, perhaps indicating a dose-sensitive response to racism exposure. Experiencing racism during more than one of the U.K. Household Longitudinal Household Study questionnaire time periods decreased respondents’ mental health scores by almost six points, while experiencing racial harassment during only one of those time periods showed a 3.4-point drop in mental health scores. And the ethnic minorities who experienced any racial discrimination at all had an eight-point deficit in mental health scores over those who didn’t.

According to the researchers, the effects of poor mental health as related to racial discrimination can also manifest in poor physical health outcomes as shown by other studies. That can mean that “chronic exposure to everyday racial discrimination is associated with poor sleep, coronary artery calcification and altered diurnal cortisol patterns and higher cortisol awakening response.”  

The study authors also pointed out that this research likely didn’t capture all of the ways discrimination and racism could contribute to poor health outcomes. For example, the researchers here tried to correct for income differences between and in ethnic groups, but some effects of low socioeconomic status could be similar to the effects of racial discrimination. On the other hand, a lower socioeconomic status could be associated with long-term effects of racism.

Based on the U.K. data, the study authors speculated that similar outcomes from the effects of living in a system that “unfairly disadvantages while advantaging others” based on ethnic background could be seen in racial minority populations in the U.S. and elsewhere. These results might also vary based on the history and context in particular locations, depending on which ethnic or racial groups tend to face the most discrimination.