The prevalence of meniscal injuries is said to be on the rise[11]. Both conservative and surgical approaches are commonly employed for treatment[12]. In the case of minor meniscus injuries, conservative methods like rest, application of cold packs, pain relievers, and physical therapy can prove effective[13]. These techniques aid in alleviating pain and inflammation while promoting self-healing of meniscal injuries. Surgical intervention may become necessary for severe meniscal injuries characterized by extensive tears or limited joint functionality[14]. Surgery aims to repair or remove damaged meniscal tissue in order to restore normal joint function. Various factors contribute to the occurrence of meniscal injuries, making it crucial to identify these risk factors in clinical practice[15]. Recognizing the risk factors associated with meniscal injuries assists physicians in evaluating patient susceptibility and devising personalized treatment plans. Previous research has highlighted several risk factors linked to meniscal injuries including age, male gender, type of physical activity undertaken, higher body mass index, as well as delayed repair of accompanying anterior cruciate ligament injuries[16–20].
Cognitive impairment predominantly affects the population over 65 years of age, with Alzheimer's disease and vascular disease being the leading causes in the West[21]. With an estimated 135 million people worldwide expected to have dementia by 2050[22], cognitive impairment poses a significant challenge to global health and social care[23].
It is known that a significant decline in cognitive performance may be an observational risk factor for meniscal injuries, but the causality of this association is unclear. Our MR study aimed to elucidate the causal relationship between cognitive performance and meniscal injuries. The results of the two-sample MR showed a causal association between cognitive performance and meniscal injuries with an OR (95% CI) of 0.76 (0.66–0.88), P = 2*10− 4, suggesting that individuals with significant cognitive decline have a higher risk of meniscal injuries compared to the general population. Furthermore, statistical evidence from sensitivity analyses strongly supports our findings. Therefore, raising awareness of the dangers of cognitive impairment is important. Screening for meniscal injuries should be increased among individuals with cognitive impairment, enabling timely detection and treatment of meniscal injuries, which is beneficial for patient prognosis. For patients with meniscal injuries, improving cognitive ability should be advocated.
The underlying mechanism linking cognitive performance and meniscal injuries is unclear. This study is the first to examine the causal relationship between cognitive performance and meniscal injuries, concluding that a decline in cognitive performance increases the risk of meniscal injuries. Possible reasons include: First, cognitive decline may reduce athletic capacity and activity levels, increasing the risk of accidental falls and athletic injuries leading to meniscal injuries[24]. Second, cognitive impairment often accompanies a decline in balance and coordination, raising the risk of injury during daily activities, particularly to the meniscus[25]. Third, cognitive impairment may cause delays in attention and reaction time[26], elevating the risk of injuries in sports and daily activities. Fourth, cognitive impairment is often associated with other health problems, such as cardiovascular disease or diabetes[27–28], which may increase the risk of meniscus injury. Additionally, some cognitive impairment treatments may affect physical abilities and balance. Fifth, cognitive impairment may lead to unhealthy lifestyles and behaviors[29–31], such as physical inactivity and poor diet, indirectly increasing the risk of meniscus injury. Understanding the relationship between meniscus injuries and cognitive performance can enhance prevention strategies for meniscus injuries and mitigate the impact of cognitive impairment.
Our study has several limitations. First, due to data limitations, we did not stratify by age or sex. Second, the exposure and outcome analyses were confined to European populations. The generalizability of these findings to other populations needs further investigation. Significant GWAS data including participants from diverse ethnic groups is required. Finally, due to data source restrictions, we were unable to investigate different subtypes of cognitive impairment. Future research would benefit from larger, more comprehensive datasets.