Association Between Atopic Dermatitis, Asthma, and Serum Lipids: A UK Biobank Based Observational Study and Mendelian Randomization Analysis

BACKGROUND: Both atopic diseases and dysregulation of serum lipids (SLs) add to significant health burden, but evidences about their association are inconsistent. OBJECTIVE: This work is to evaluate the association between asthma/atopic dermatitis (AD) and SLs and investigate the potential causal relationship. METHODS: A large-scale cross-sectional study based on the UK Biobank (UKB) and then examined the casual relationships between SLs with asthma/AD based on a Mendelian randomization (MR) analysis. RESULTS: A total of 502,505 participants were included in analysis. After full adjustment, AD was associated with lower TG (β = −0.006; 95%CI, −0.010 to −0.002; P = 0.006), lower LDL (β = −0.004; 95%CI, −0.006 to −0.002, P < 0.001), and lower TC (β = −0.004; 95%CI, −0.005 to −0.002; P < 0.001) but insignificantly correlated to HDL (P = 0.794). Asthma was also inversely correlated to TG (β = −0.005; 95%CI, = −0.007 to −0.003; < 0.001), LDL (β = −0.003; 95%CI, −0.004 to −0.002; P < 0.001), and TC (β = −0.002; 95%CI, −0.003 to −0.002; P < 0.001), but was positively correlated to HDL (β = 0.004; 95%CI, 0.003 to 0.005; P < 0.001), respectively. In subsequent MR analysis, both allergic diseases and asthma showed a protective effect on TC. Allergic diseases, asthma, and AD all showed a negative effect on LDL. CONCLUSION: Collectively, we identify a protective causal effect of allergic diseases on serum lipids, as well as a potentially positive association of HDL with asthma. Owing to the largest sample size and the application of IVs in causal inference, this study will provide a robust evidence for the management of asthma and AD and the prevention of dyslipidemia.