Lehto, K. | Search bioRxiv

bioRxiv2019

Neuroticism as a predictor of frailty in old age: a genetically informative approach

ObjectiveNeuroticism is associated with poor health outcomes, but its contribution to the accumulation of health deficits in old age, i.e. frailty, is largely unknown. We aimed to explore associations between neuroticism and frailty cross-sectionally and over up to 29 years, and to investigate the contribution of shared genetic influences. MethodData were derived from the UK Biobank (UKB, n=502,631), the Australian Over 50s Study (AO50, n=3,011) and the Swedish Twin Registry (SALT n=23,744, SATSA n=1,637). Associations between neuroticism and the Frailty Index were investigated using regression analysis cross-sectionally in UKB, AO50 and SATSA, and longitudinally in SALT (25-29y follow-up) and SATSA (6 and 23y follow-up). The co-twin control method was applied to explore the contribution of underlying shared familial factors (SALT, SATSA, AO50). Genome-wide polygenic risk scores for neuroticism in all samples were used to further assess whether common genetic variants associated with neuroticism predict frailty. ResultsHigh neuroticism was consistently associated with greater frailty cross-sectionally (adjusted {beta}, 95% confidence intervals in UKB= 0.32, 0.32-0.33; AO50= 0.35, 0.31-0.39; SATSA= 0.33, 0.27-0.39) and longitudinally up to 29 years (SALT= 0.24; 0.22-0.25; SATSA 6y= 0.31, 0.24-0.38; SATSA 23y= 0.16, 0.07-0.25). When controlling for underlying shared genetic and environmental factors the neuroticism-frailty association remained significant, although decreased. Polygenic risk scores for neuroticism significantly predicted frailty in the two larger samples (meta-analyzed total {beta}= 0.06, 0.05-0.06). ConclusionHigh neuroticism is associated with the development and course of frailty. Both environmental and genetic influences, including neuroticism-associated genetic variants, contribute to this relationship.

epidemiology↗

bioRxiv2019

Asthma and affective traits in adults: a genetically informative study

Depression, anxiety and high neuroticism (affective traits) are often comorbid with asthma. A causal direction between the affective traits and asthma is difficult to determine, however, it may be that there is a common underlying pathway attributable to shared genetic factors. Our aim was to determine whether a common genetic susceptibility exists for asthma and each of the affective traits. An adult twin cohort from the Swedish Twin Register underwent questionnaire-based health assessments (n=23 693) and genotyping (n=15 908). Firstly, questionnaire-based associations between asthma and affective traits were explored. This was followed by genetic analyses: a) polygenic risk scores (PRS) for affective traits were used as predictors of asthma, and b) linkage-disequilibrium score regression based on genome-wide association results from UK Biobank was used to quantify genetic correlations. Analyses found that the questionnaire-based associations between asthma and each affective trait were associated (OR 1.7, 95%CI 1.5-1.9 major depression, OR 1.5, 95%CI 1.3-1.6 anxiety, and OR 1.6, 95% 1.4-1.8 high neuroticism). Genetic susceptibility for neuroticism explained the variance in asthma with a dose response effect; that is, those in the highest neuroticism PRS quartile were more likely to have asthma than those in the lowest quartile (OR 1.4, 95%CI 1.2-1.6). Genetic correlations were found between depression and asthma (rg= 0.17), but not for anxiety or neuroticism score. We conclude that the observed comorbidity between asthma and the affective traits may in part be due to shared genetic influences between asthma and depression and neuroticism, but not anxiety.

genetics↗