Publications

BACKGROUND

Because racial discrimination is a form of chronic psychological stress that might unfavorably affect health, we examined whether perceived experiences of racism among black women are associated with mortality.

METHODS

We followed 48 924 participants in the Black Women's Health Study (mean age, 40.5 years) for 8 years to assess the risk of all-cause mortality associated with perceived experiences of racism. Subanalyses of cancer and cardiovascular mortality were also conducted. Perceived racism was evaluated by 8 questions about institutionalized racism (unfair treatment on the job, in housing, or by the police) and everyday experiences of racism (eg, others acting as if the woman was not intelligent). We estimated the relative risk of death with Cox proportional hazard models, adjusting for traditional and socioenvironmental risk factors.

RESULTS

During 412 224 person years of follow-up from 1997 to 2005, there were 920 deaths, including 277 due to cancer and 195 due to cardiovascular causes. All-cause mortality was not associated with institutionalized racism (relative risk, 1.0; 95% confidence interval, 0.8-1.2) for the highest category vs the lowest or with everyday racism (relative risk, 0.9; 95% confidence interval, 0.8-1.2) for the highest quartile compared with the lowest. Risk estimates for the highest categories of perceived racism relative to the lowest were greater than 1.0 for cancer deaths and less than 1.0 for cardiovascular disease death but were not statistically significant.

CONCLUSIONS

In this large prospective study of black women, reported experiences of racism were not significantly related to mortality. Longer follow-up of this relatively young cohort and further work is warranted in this complex area of research because continued race/ethnic disparities in mortality are not entirely explained by traditional risk factors.

Mycobacterium tuberculosis is an obligate human pathogen capable of persisting in individual hosts for decades. We sequenced the genomes of 21 strains representative of the global diversity and six major lineages of the M. tuberculosis complex (MTBC) at 40- to 90-fold coverage using Illumina next-generation DNA sequencing. We constructed a genome-wide phylogeny based on these genome sequences. Comparative analyses of the sequences showed, as expected, that essential genes in MTBC were more evolutionarily conserved than nonessential genes. Notably, however, most of the 491 experimentally confirmed human T cell epitopes showed little sequence variation and had a lower ratio of nonsynonymous to synonymous changes than seen in essential and nonessential genes. We confirmed these findings in an additional data set consisting of 16 antigens in 99 MTBC strains. These findings are consistent with strong purifying selection acting on these epitopes, implying that MTBC might benefit from recognition by human T cells.