Integrative evidence linking excessive daytime sleepiness, narcolepsy, and hypertension: insights from NHANES, Mendelian randomization, and proteomics.

Background: This study aimed to explore associations and causality between excessive daytime sleepiness (EDS), narcolepsy, and hypertension.

Methods: Publicly available data from the National Health and Nutrition Examination Survey (NHANES), genome-wide association studies (GWAS), and protein quantitative trait locus (pQTL) data sets were used for analysis. Logistic regression models assessed the association between different frequencies of EDS and hypertension, and sex-stratified subgroup analyses were also performed. Bi-directional Mendelian randomization (MR) evaluated the causal effect of narcolepsy on hypertension. Proteome-wide MR and colocalization analyses were conducted to identify potential protein biomarkers and shared genetic variants.

Results: EDS with different frequencies is associated with hypertension after adjusting for the covariates (rarely: OR = 1.383, 95% CI 1.013-1.889, P = 0.041; sometimes: OR = 1.487, 95% CI 1.105-1.999, P = 0.009; often: OR = 2.041, 95% CI 1.468-2.839, P < 0.001; almost always: OR = 1.581, 95% CI 1.076-2.323, P = 0.020). Subgroup analysis suggested that this effect is significant in males. MR analysis revealed a causal association between narcolepsy and hypertension (OR = 1.038, 95% CI 1.006-1.071, P = 0.019), with no evidence of reverse causality. The protein OLFML3 was causally associated with the increased risk of both narcolepsy (OR = 2.412, 95% CI 1.070-5.436, P = 0.034) and hypertension (OR = 1.237, 95% CI 1.106-1.384, P < 0.001) in proteome-wide MR analysis.

Conclusions: This study provides integrative evidence of a causal relationship between narcolepsy and hypertension, highlighting OLFML3 as a potential biomarker for both conditions.