Health-related effects of education level: a Mendelian randomization study

Abstract

Background A deeper understanding of the causal links from education level to health outcomes may shed a light for disease prevention at a novel and efficient perspective. Methods We conducted a wide-angled Mendelian randomization to disentangle the causal role of education level from intelligence for 31 health outcomes and explore to what extent body mass index and smoking mediate the associations. Univariable and multivariable Mendelian randomization analyses were performed. Results Genetically higher education level was associated with lower risk of major mental disorders and most somatic diseases independent of intelligence. The intelligence-adjusted odds ratios for each additional standard deviation of education (4.2 years) were 0.48 (0.37, 0.62) for suicide attempts, 0.50 (0.36, 0.68) for large artery stroke, 0.51 (0.42, 0.63) for heart failure, 0.52 (0.42, 0.65) for lung cancer, 0.45 (0.33,0.61) for rheumatoid arthritis, and 0.48 (0.43, 0.55) for type 2 diabetes. Higher education level adjusted for intelligence was additionally associated with lower risk of insomnia, major depressive disorder, stroke, coronary artery disease, breast cancer, ovarian cancer and gout but with higher risk of obsessive-compulsive disorder, anorexia nervosa, bipolar disorder and prostate cancer. Moreover, higher education level was associated with modifiable health-related risk factors in a favorable manner. Adjustment for body mass index and smoking attenuated the associations between education level and several outcomes, especially for type 2 diabetes and heart failure. High education level exerts causal protective effects on major somatic diseases. Conclusions These findings emphasize the importance of education to reduce the burden of common diseases.

Modifiable lifestyle factors and risk of stroke: a Mendelian randomization analysis

“…Our analysis validates previously reported associations of the effect of education on ischaemic stroke from observational studies 23 and MR analyses, 24 as well as a recent MR analysis showing associations of education with large-artery stroke, small-vessel stroke, and intracerebral haemorrhage. 25 Our findings for the association of the lifetime smoking index with increased risk of ischaemic, large-artery, and small-vessel stroke is in concordance with previous observational studies 26 and MR analyses. 27 While earlier MR analyses of BMI with smaller sample sizes did not show clear evidence of a causal association with any ischaemic stroke subtype, 28 our analysis in a larger sample confirms the associations reported in a recent MR analysis of BMI with large-artery stroke and WHR with large-artery and small-vessel stroke.…”

“…2,31,32 This study also highlights the importance of promoting universal education, which would benefit everyone regardless of genetic makeup. 25 Interestingly, although BMI and WHR were significantly associated with increased risk of stroke, we did not identify significant associations for related lifestyle changes that could be adopted to help reduce adiposity measures, such as increased physical activity and reduced fat and sugar consumption. This may be due to the small number of genetic variants that were available to use as instrumental variables for physical activity and dietary components.…”

Mental Health and Recreation Opportunities

“…Historically, unemployment levels and poverty rates have been regarded as contributing factors for serious symptoms of depression requiring medical treatment. In addition, links between higher educational attainment and lower risk for depression have been confirmed by previous studies [ 55 , 56 ].…”

Using Mendelian randomization analysis to better understand the relationship between mental health and substance use: a systematic review

“…There was consistent evidence that higher educational attainment decreases the odds of initiating smoking (Carter et al, 2019 ; Davies et al, 2018a ; Davies et al, 2019 ; Ding, Barban, & Mills, 2019 ; Gage, Bowden, Davey Smith, & Munafo, 2018 ; Sanderson, Davey Smith, Bowden, & Munafò, 2019 ; Tillmann et al, 2017 ; Zeng et al, 2019 ; Zhou et al, 2019a ), increases the age at smoking initiation (Yuan, Xiong, Michaëlsson, Michaëlsson, & Larsson, 2020a ; Zhou et al, 2019a ), increases smoking heaviness, and decreases the odds of quitting (Gage et al, 2018 ; Sanderson et al, 2019 ; Zeng et al, 2019 ; Zhou et al, 2019a ). One study triangulated self-report measures with cotinine (a metabolite of nicotine) in blood samples and found weak evidence that higher educational attainment causes lower cotinine levels (Gage et al, 2018 ).…”