TABLE 2.
Causal links between breakfast skipping and correlated traits analyzed through the use 1- and 2-sample MR1
| IVW | MR Egger | Weighted median | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Outcome | Study | PubMed ID | SNPs | β | SE | P value | β | SE | P value | β | SE | P value |
| Body fat, % | N/A | 26833246 | 5 | 0.261 | 0.167 | 0.12 | −0.154 | 0.702 | 0.84 | 0.104 | 0.211 | 0.62 |
| BMI, kg/m2 | GIANT | 25673413 | 5 | 0.304 | 0.153 | 0.046 | 1.151 | 0.589 | 0.15 | 0.439 | 0.131 | 0.001 |
| Chronotype, evening | UK Biobank | N/A | 6 | 0.074 | 0.177 | 0.67 | −1.082 | 0.563 | 0.13 | 0.076 | 0.157 | 0.63 |
| Coronary heart disease, log OR | C4D | 21378988 | 3 | −0.387 | 0.726 | 0.59 | 10.590 | 11.880 | 0.54 | −0.049 | 0.834 | 0.95 |
| Depressive symptoms, log OR | SSGAC | 27089181 | 6 | 0.289 | 0.146 | 0.049 | 0.642 | 0.706 | 0.42 | 0.367 | 0.126 | 0.004 |
| Insomnia, log OR | UK Biobank | N/A | 6 | 0.052 | 0.042 | 0.22 | −0.082 | 0.180 | 0.67 | 0.028 | 0.054 | 0.61 |
| Lung cancer, log OR | ILCCO | 24880342 | 5 | 0.155 | 0.713 | 0.83 | −1.423 | 3.169 | 0.68 | 0.260 | 0.634 | 0.68 |
| Rheumatoid arthritis, log OR | N/A | 24390342 | 2 | −1.271 | 1.609 | 0.43 | N/A | N/A | N/A | N/A | N/A | N/A |
| Smoking (ever vs never), log OR | TAG | 20418890 | 5 | 0.974 | 0.311 | 0.002 | 0.626 | 1.380 | 0.68 | 0.914 | 0.397 | 0.02 |
| Type 2 diabetes, log OR | DIAGRAM | 24509480 | 4 | 0.431 | 0.790 | 0.59 | 2.722 | 3.473 | 0.52 | 0.696 | 0.680 | 0.31 |
| Schooling, y | SSGAC | 27225129 | 6 | −0.118 | 0.103 | 0.25 | −0.482 | 0.392 | 0.29 | −0.170 | 0.080 | 0.03 |
| Breakfast skipping [exposure: chronotype (23&Me participants only)] | UK Biobank | Present | 338 | 0.019 | 0.006 | 9.36 × 10–4 | 0.018 | 0.014 | 0.20 | 0.035 | 0.016 | 0.02 |
β is the estimated effect of change on outcome in units indicated or log OR for case-control traits using the SNPs associated with breakfast skipping (or evening chronotype) and effect estimates for breakfast skipping from the UK Biobank GWAS of breakfast skipping. Number of SNPs used in each analysis is in the SNPs column. Each outcome was obtained from publicly available GWAS summary data, except for chronotype and insomnia. The number of SNPs used varies for each outcome because of not being able to find some of the 6 SNPs (or proxies) in the summary data. Three MR methods were used. Two-sample MR was used for all outcomes, except for chronotype and insomnia. C4D, Coronary Artery Disease Genetics Consortium; DIAGRAM, DIAbetes Genetics Replication And Meta-analysis consortium; GIANT, Genetic Investigation of ANthropometric Traits; GWAS, genome-wide association study; ILCCO, International Lung Cancer Consortium; MR, Mendelian randomization; N/A, not applicable/available; SNP, single nucleotide polymorphism; SSGAC, Social Science Association Consortium; TAG, Tobacco and Genetics Consortium; IVW, inverse variance weighted.