Social determinants of health contribute to racial disparities in premature deaths

Key takeaways:

• Premature death rates in Black vs. white adults dropped from 59% to 0% after adjusting for social determinants of health.
• The data suggest social determinants should be targets for tackling racial disparities.

Disparities in premature mortality rates among Black adults are heavily driven by social determinants of health, a study published in Lancet Public Health found.

It is the first time that causations behind significant racial and ethnic differences in mortality have been explained, Joshua D. Bundy, PhD, MPH, an assistant professor at the University of Tulane School of Public Health and Tropical Medicine, said in a press release.

“We didn’t expect that, and we were excited about that finding because it suggests social determinants should be the primary targets for eliminating health disparities,” he said.

According to Bundy and colleagues, Black individuals had a 20% greater rate of all-cause mortality than white individuals in 2019.

However, “race is a social, rather than biological, construct, and is not causally related to mortality but reflects underlying social factors,” they wrote.

Previous research has shown that various socioeconomic factors, such as poverty, are linked to higher mortality rates.

“Therefore, the importance of social determinants of health (SDoH) in addressing health inequities is increasingly recognized,” Bundy and colleagues wrote.

Using 1999 to 2018 National Health and Nutrition Examination Survey data, the researchers examined a sample of 48,170 participants, analyzing premature mortality rates while adjusting for eight self-reported SDoH:

• employment;
• food security;
• family income;
• access to health care;
• health insurance;
• home security;
• level of education; and
• marital relationship.

Among the participants, 21.9% were Black, while the mean age was 44 years.

Bundy and colleagues found that Black adults had a higher premature mortality rate than any other racial or ethnic group, with 852 (95% CI, 727-1000) premature deaths per 100,000 person-years. In contrast, white and Hispanic adults had a rate of 546 (95% CI, 474-630) and 445 (95% CI, 349-574) premature deaths per 100,000 person-years, respectively.

Each SDoH except home security and access to health care were linked to premature mortality risk. Associations with premature mortality were seen in those with:

• one unfavorable SDoH (HR = 1.93; 95% CI, 1.61-2.31);
• two unfavorable SDoH (HR = 2.24; 95% CI, 1.87-2.68);
• three unfavorable SDoH (HR = 3.98; 95% CI, 3.34-4.73);
• four unfavorable SDoH (HR = 4.78; 95% CI, 3.98-5.74);
• five unfavorable SDoH (HR = 6.08; 95% CI, 5.06-7.31); and
• six or more unfavorable SDoH (HR = 7.82; 95% CI, 6.60-9.26).

Notably, after all SDoH were adjusted, the risk for premature mortality in Black adults compared with white adults decreased from 59% (95% CI, 1.44-1.76) to 0% (95%, 0.91-1.10).

“Compared with white adults, Black adults were more likely to have unfavourable levels of all SDoH,” Bundy and colleagues wrote.

They added that Black adults were also one to six times more likely than white adults to have a family income-to-poverty ratio below 300%, “which was associated with almost 50% greater premature mortality.”

The researchers concluded that efforts to address SDoH and health disparities “require concerted efforts to initiate structural, multilevel policy interventions targeting the underlying causes of death among all people, and particularly those from historically marginalized populations.

“Future research should examine the effects of SDoH on global disparities in mortality and identify major determinants for intervention,” they wrote.

References:

• Bundy J, et al. Lancet Public Health. 2023;doi:10.1016/S2468-2667(23)00081-6
• Study finds that eight factors put Black adults at greater risk of early death. https://www.eurekalert.org/news-releases/990231. Published May 25, 2023. Accessed May 26, 2023.