Associations Between Social Drivers of Health and Intervention Reach During Implementation of a Supervised Walking Program.

Psychiatric disorders have emerged as a significant public health concern, characterized by high morbidity and mortality rates. It is estimated that the global burden of psychiatric disorders accounts for nearly 21.2% to 32.4% of years lived with disability. Despite advancements, the management of psychiatric disorders in clinical settings remains challenging, often focusing on symptomatic relief rather than addressing the underlying etiologies. Consequently, there is an urgent need for a deeper understanding of the pathophysiology and potential risk factors of psychiatric disorders to develop innovative prevention and intervention strategies. The etiology of psychiatric disorders remains largely enigmatic. Emerging evidence suggests that the causes are multifactorial, encompassing environmental and genetic factors, as well as parental psychopathological conditions. Recently, there has been a surge of interest in the relationship between ocular diseases, particularly cataract, and psychiatric disorders. Cataract, characterized by the progressive opacification of the lens within the eye, is a prevalent cause of vision impairment and loss. Mental illness is more common in people with cataracts. For instance, previous observational studies have indicated that children and adolescents with 5 severe structural eye diseases, including cataract, are at a higher risk of psychiatric disorders compared to their peers without these conditions. In another study, children with cataract were found to have nearly double the incidence of psychiatric disorders, with a fourfold increase in the risk of anxiety disorders, especially if diagnosed before age 3. Some cross-sectional studies have observed higher rates of cataract, glaucoma, and dry eye syndrome in veterans with serious psychiatric disorders compared to those without. These studies suggest a correlation between cataract and psychiatric disorders, although the associations may be influenced by the inherent biases and confounding factors. Furthermore, the debate continues on whether cataract is a cause or a downstream effect of psychiatric disorders, and thus, the potential causal relationships warrant further investigation. Mendelian randomization (MR), a genetic epidemiological approach, serves as a valuable tool for assessing the causal role of cataract in mental illness. Utilizing genetic variants such as single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for modifiable disease risk factors or exposures, MR can enhance the causal inference on an exposure-outcome association. Genetic variants are randomly allocated during gamete formation, making them less susceptible to confounding factors. Additionally, since genotypes are immutable to the development of disease, MR minimizes the impact of confounding factors and reverse causation. To elucidate the association between cataract and psychiatric disorders and to evaluate the direction of such associations, we conducted a 2-sample bidirectional MR study using genome-wide association studies (GWASs).