Chronic Physical Conditions, Multimorbidity, and Mild Cognitive Impairment in Low- and Middle-Income Countries

Objectives: To assess the association between chronic physical conditions and multimorbidity and mild cognitive impairment (MCI) in low‐ and middle‐income countries (LMICs). Design: Nationally representative, cross‐sectional, community‐based study. Setting: Six countries that participated in the World Health Organization Study on Global Ageing and Adult Health. Participants: Individuals aged 50 and older (N=32,715; mean age 62.1 ± 15.6; 51.7% female). Measurements: The definition of MCI was based on the recommendations of the National Institute on Ageing and Alzheimer's Association. Ten chronic conditions were assessed (angina pectoris, arthritis, asthma, cataract, chronic lung disease, diabetes mellitus, edentulism, hearing problems, hypertension, stroke). Multivariable logistic regression analysis was conducted to assess the association between chronic physical conditions, multimorbidity (≥2 chronic conditions), and MCI. Results: The prevalence of multimorbidity was 49.8% (95% confidence interval (CI)=48.1–51.5%) and of MCI was 15.3% (95% CI=14.4–16.3%). After adjustment for potential confounders, edentulism (odds ratio (OR)=1.24), arthritis (OR=1.24), chronic lung disease (OR=1.29), cataract (OR=1.33), stroke (OR=1.94), hearing problems (OR=2.27), and multimorbidity (OR=1.40) were significantly associated with MCI. There was a gradual increase in the likelihood of MCI (1 condition: OR=1.21, 95% CI=1.03–1.42; ≥4 conditions: OR=2.07, 95% CI=1.70–2.52). Conclusion: These results highlight the need to investigate the underlying mechanisms linking chronic conditions and MCI and whether prevention or treatment of chronic conditions or multimorbidity can reduce the onset of cognitive decline and subsequent dementia, especially in LMICs

Occlusal force predicts global motion coherence threshold in adolescent boys

Background: Beneficial effects of mastication on cognitive abilities in the elderly have been shown in human studies. However, little is currently known about the effect of masticatory stimulation on cognitive and perceptual ability in younger populations. The purpose of the present study is to investigate the influences of masticatory stimulation on perceptual ability in adolescent boys. Methods: The present study examined the relationship between occlusal force (i.e., masticatory stimulation) and visual perception ability in adolescent boys. Visual perception ability was quantified by measuring global motion coherence threshold using psychophysical method. As an index of masticatory stimulation, occlusal force was measured by pressure sensitive film. We also measured participants\u27 athletic ability, e.g. aerobic capacity and grip strength, as potential confounding factor. Results: The multiple regression analysis revealed a significant negative correlation between global motion coherence threshold and occlusal force, which persisted after controlling for confounding factors such as age and aerobic capacity. Conclusions: This finding indicates that masticatory stimulation enhances visual perception in adolescent boys, indicating the possibility that beneficial effects of masticatory stimulation are observed not only in the elderly but in developing population consistently with the findings of the previous animal studies