Here below the main achievements resulting for the Sex Dimorphism project:
• Exhaustive description of observational associations in males and females with cardiometabolic traits and risk factors.
Cardiometabolic diseases exhibit some degree of sex differences, including differences in incidence or prevalence, age of onset, severity, disease progression, susceptibility, response to treatment and pharmacological adverse events. Previous studies showed that for some of the related risk factors, these sex differences are not static, but rather age-dependent and thus change over life course. A better understanding of these trajectories in all populations and for all cardiometabolic risk factors is essential for the design of personalized prevention strategies. I performed a systematic analysis of sex and age-dependent sex differences for 70 cardiometabolic risk factors included in the SardiNIA cohort such as blood test parameters, anthropometric measurements, blood pressure, echocardiogram and electrocardiogram measures.
The findings of this objective can be summarized in three main messages: (1) males and females exhibit linear differences in the 84% of the phenotypes analyzed; (2) in general, sex differences are pronounced before 60 years old and tend to decrease in a proportional way with the increase of age; (3) 37% of the phenotypes analyzed showed a significant non-linear age by sex interaction.
Overall, this study highlights the importance of conducting sex-specific epidemiological research as a route to implementing sex-specific tailored preventive strategies and to aid correct identification of people at risk to develop cardiometabolic disease
• Causal inference analyses of sex specific protein quantitative trait loci (pQTL) with sex-specific GWAS summary statistics of lipids
Lipid traits are known to be sex-differential, but the underlying molecular players are largely unknown. Since protein levels are downstream products of gene expression, proteomics data can be crucial to understand etiology of sex-differences in lipids metabolism. I used sex-specific pQTL summary statistics for 2,923 circulating proteins measured in the UK Biobank Pharma Proteomics Project, along with sex-specific summary statistics of lipids from the Global Lipids Genetics Consortium. I combined these using two-sample Mendelian Randomization analyses and applied stringent multiple testing p-values correction and sensitivity analyses.
The main achievement of this section are the following: (1) I identified a total of 82 and 82 robust causal protein-lipids links that are specific to females and males; (2) a total of 38 protein–lipids links that showed sex-differentiated causal effects; (3) the identified links corresponding to 127 unique proteins, specifically 116 sex-specific, 21 acting in sex-differentiated manner on lipid levels and 10 acting as sex-specific or sex-differentiated depending on the outcome. Most sex-specific proteins within each sex were outcome-specific and not shared across the five lipid-related outcomes analyzed. I also observed an higher proportion of sex-specific relationships in males for all traits (except for LDL and non-HDL), suggesting that, in females, regulation of lipids is more strongly influenced by non-genetic factors, for example sex hormones fluctuations during life stage. Of note, the difference in discovery is unlikely to be due to differences in statistical power, since the sample size of females-only GWASs was overall similar than the males-GWAS for both proteins and lipid GWASs. Intriguingly, several of the sex-specific proteins were previously shown to be involved in inflammation and cardiometabolic disease, such as Apolipoprotein(a) and lipoprotein lipase. These results provide insight into potential genetic drivers of sex dimorphism in lipid metabolism.
The results of this objectives are part of the manuscript titled “Exploring sex-specific causal links between thousands of proteins and lipid metabolism using the UK Biobank Pharma proteomics data” available on MedrXiv at this link
https://medrxiv.org/cgi/content/short/2025.09.16.25335948v1(s’ouvre dans une nouvelle fenêtre)