The landscape of health disparities in the UK Biobank

Sex-Specific Association Between Polymorphisms in Estrogen Receptor Alpha Gene (ESR1) and Depression: A Genome-Wide Association Study of All of Us and UK Biobank Data

Major depressive disorder (MDD) is prevalent worldwide, substantially and negatively impacting both the quality and length of life of 280 million people globally. The genetic risk factors of MDD have been studied in various previous research, but the findings lack consistency. Sex/gender and racial/ethnic disparities have been reported; however, many previous genetic studies, represented by large-scale genome-wide association studies (GWASs) are known to lack diversity in the study cohorts. All of Us is a biorepository aiming to focus on the historically underrepresented groups. We perform GWASs for the MDD phenotype, using over 200,000 participants' genotypes and carry out sex- and racial/ethnic-specific subgroup studies. We identified a risk locus (chr6:151945242) in Estrogen Receptor Alpha Gene (ESR1) (p = 1.70 × 10 - 9 $1.70\times {10}^{-9}$ ), and further confirmed the genetic association is sex-specific. The single-nucleotide polymorphism (SNP) chr6:151945242 was significant only in the male group, but not in the female group. These findings were replicated in the UK Biobank and echo with existing studies on the ESR1 gene and depressive disorders. Our results indicate that the All of Us program is a reliable resource for GWAS, as well as shedding light on further investigation of sex- and racial/ethnic-specific genome association, especially in underrepresented groups of the US population.

Observational and Genetic Analyses of Traumatic Experiences and Endometriosis

Importance

Although psychological traumas have been associated with endometriosis, limited information is available regarding the role of trauma type and genetic predisposition.

Objective

To examine the relationship between traumatic experiences and endometriosis using observational and genetically informed analyses.

Design, Setting, and Participants

For this case-control study, the analyses were performed between May 13, 2023, and September 30, 2024. Genotypic and phenotypic information was combined from UK Biobank individual-level data (up to 8276 patients with endometriosis and 240 117 female controls) with genome-wide information available from a large meta-analysis (European ancestry: 21 779 patients and 449 087 female controls; East Asian ancestry: 1713 patients and 1581 female controls) and the FinnGen cohort (16 588 patients and 111 583 female controls of European descent).

Main Outcomes and Measures

Phenotypic associations via multiple regression; latent-class analysis (LCA) to investigate the co-occurrence patterns of different traumatic experiences in endometriosis cases and controls; genetic correlation and polygenic risk scoring (PRS) analyses to assess pleiotropy linking traumatic events to endometriosis.

Results

Up to 8276 women with endometriosis (mean [SD] age, 53.2 [13.0] years) and 240 117 female controls (mean [SD] age, 56.5 [9.6] years) were investigated in the study. Women with endometriosis were more likely to report childhood and adulthood traumatic experiences and stressful events (eg, contact trauma odds ratio [OR], 1.28; 95% CI, 1.02-1.26). Our LCA highlighted the association of endometriosis with emotional and physical trauma (225 [8%] vs 3948 [5%]; P < 2.2 × 10-16) and sexual trauma (414 [5%] vs 3158 [4%]; P = 2.9 × 10-3). Unaffected women (controls) were more likely assigned to the "no trauma" latent class (563 [20%] vs 18 949 [24%]; P = 7.4 × 10-14). Our genetic correlation (rg) analyses linked endometriosis to multiple trauma-related outcomes, including posttraumatic stress disorder (meta-analysis rg = 0.31, P = 7.1 × 10-16; FinnGen rg = 0.26, P = 4.7 × 10-15) and childhood maltreatment (meta-analysis rg = 0.23, P = 1.3 × 10-6; FinnGen rg = 0.16, P = 1 × 10-4). Endometriosis PRS was associated with increased odds of the disease (β = 0.31, P < 2.2 × 10-16), but no interaction was observed with different types of trauma events.

Conclusions and Relevance

The present study comprehensively investigated the impact of childhood and adulthood traumatic experiences and stressful events on endometriosis. In particular, our findings highlight the potential association between contact traumas and endometriosis, which appears to be independent of the disease genetic predisposition.

Discordance Analysis of VLDL-C and ApoB in UK Biobank and Framingham Study: A Prospective Observational Study

BACKGROUND

Recent observational and Mendelian randomization analyses have reported significant effects of VLDL-C (very-low density lipoprotein cholesterol) on risk that is independent of ApoB (apolipoprotein B). We aim to determine the independent association of VLDL-C and ApoB with the risk of new onset cardiovascular events in the UK Biobank and Framingham Heart Study cohorts.

METHODS

We included 294 289 UK Biobank participants with a median age of 56 years, 42% men, and 2865 Framingham Heart Study participants (median age, 53 years; 47% men). The residual resulting from regressing VLDL-C on ApoB expresses the portion of VLDL-C not explained by ApoB, while the residual from regressing ApoB on VLDL-C expresses the portion of ApoB not explained by VLDL-C. Cox proportional hazards models for atherosclerotic cardiovascular disease incidence were created for residual VLDL-C and residual ApoB. Models were analyzed with and without high-density lipoprotein cholesterol (HDL-C). Furthermore, we investigated the independent effects of VLDL-C after accounting for ApoB and HDL-C and of HDL-C after accounting for ApoB and VLDL-C.

RESULTS

In the UK Biobank, ApoB was highly correlated with VLDL-C (r=0.70; P<0.001) but weakly negatively correlated with HDL-C (r=-0.11; P<0.001). The ApoB residual and the VLDL-C residual were significantly associated with new-onset atherosclerotic cardiovascular disease (hazard ratio [HR], 1.08 and 1.05, respectively; P<0.001). After adjusting for HDL-C, the ApoB residual remained similar in magnitude (HR, 1.10; P<0.001), whereas the effect size of the VLDL-C residual was reduced (HR, 1.02; P=0.029). The independent effect of HDL-C (after accounting for ApoB and VLDL-C) remained robust (HR, 0.86; P<0.0001), while the independent effect of VLDL-C (after accounting for ApoB and HDL-C) was modest (HR, 1.02; P=0.029). All results were consistent in the Framingham cohort.

CONCLUSIONS

When adjusted for HDL-C, the association of VLDL-C with cardiovascular risk was no longer clinically meaningful. Our residual discordance analysis suggests that adjustment for HDL-C cannot be ignored.

Sick individuals, sick populations revisited: a test of the Rose hypothesis for type 2 diabetes disparities

Introduction

The Rose hypothesis predicts that since genetic variation is greater within than between populations, genetic risk factors will be associated with individuals' risk of disease but not population disparities, and since socioenvironmental variation is greater between than within populations, socioenvironmental risk factors will be associated with population disparities but not individuals' disease risk.

Methods

We used the UK Biobank to test the Rose hypothesis for type 2 diabetes (T2D) ethnic disparities in the UK. Our cohort consists of 26 912 participants from Asian, black and white ethnic groups. Participants were characterised as T2D cases or controls based on the presence or absence of T2D diagnosis codes in electronic health records. T2D genetic risk was measured using a polygenic risk score (PRS), and socioeconomic deprivation was measured with the Townsend Index (TI). The variation of genetic (PRS) and socioeconomic (TI) risk factors within and between ethnic groups was calculated using analysis of variance. Multivariable logistic regression was used to associate PRS and TI with T2D cases, and mediation analysis was used to analyse the effect of PRS and TI on T2D ethnic group disparities.

Results

T2D prevalence differs for Asian 23.34% (OR=5.14, CI=4.68 to 5.65), black 16.64% (OR=3.81, CI=3.44 to 4.22) and white 7.35% (reference) ethnic groups in the UK. Both genetic and socioenvironmental T2D risk factors show greater within (w) than between (b) ethnic group variation: PRS w=64.60%, b=35.40%; TI w=71.18%, b=28.19%. Nevertheless, both genetic risk (PRS OR=1.96, CI=1.87 to 2.07) and socioeconomic deprivation (TI OR=1.09, CI=1.08 to 1.10) are associated with T2D individual risk and mediate T2D ethnic disparities (Asian PRS=22.5%, TI=9.8%; black PRS=32.0%, TI=25.3%).

Conclusion

A relative excess of within-group versus between-group variation does not preclude T2D risk factors from contributing to T2D ethnic disparities. Our results support an integrative approach to health disparities research that includes both genetic and socioenvironmental risk factors.