Diet, physical activity and behavioural disinhibition in middle-aged and older adults: a UK Biobank study

Background and aims: Behavioural disinhibition is a prominent feature of multiple psychiatric disorders, and has been associated with poor long-term somatic health outcomes. Modifiable lifestyle factors including diet and moderate-to-vigorous physical activity (MVPA) may be associated with behavioural disinhibition, but their shared and unique contributions have not previously been quantified. Methods: N=157,354 UK Biobank participants who completed the online mental health assessment were included (age 40-69, 2006-2010). Using principal component analyses, we extracted a single disinhibition score and four dietary component scores (prudent diet, elimination of wheat/dairy/eggs, meat consumption, full-cream dairy consumption). In addition, latent profile analysis assigned participants to one of five empirical dietary groups: moderate-healthy, unhealthy, restricted, meat-avoiding, low-fat dairy. Participants self-reported MVPA in minutes/week. Disinhibition was regressed on the four dietary components, the dietary grouping variable and MVPA. Results: In men and women, behavioural disinhibition was negatively associated with prudent diet scores, and positively associated with wheat/dairy/eggs elimination. In men only, disinhibition was associated with consumption of meat and full-cream dairy products. Comparing groups, disinhibition was lower in the moderate-and-prudent diet (reference) group compared to all other groups. Absolute {beta}s ranged from 0.02-0.13 indicating very weak effects. Disinhibition was not associated with MVPA. Conclusions: Among middle-aged and older adults, behavioural disinhibition is associated with multiple features of diet. While the observational nature of UK Biobank does not allow causal inference, our findings foster specific hypotheses (e.g. early malnutrition, elevated immune-response, dietary restraint) to be tested in alternative study designs.