Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease (1, 2). PD is rare in individuals under 50, and its prevalence increases with age (3). It is projected that the number of cases will reach between 8.7 million and 9.3 million by 2030 (3, 4). Main clinical features of PD include muscle rigidity, static tremor, bradykinesia, postural instability and gait disorders (5). Postural instability accompanied by increased postural swing and impaired response to external disturbances may lead to impaired balance, and with the disease progression, patients may lose their self-care ability and their physical and mental health may be affected (5, 6).

Among motor and non-motor symptoms of PD, the gait and posture symptoms deteriorate at faster rates, and the muscle and core control functions in PD patients gradually become impaired due to declined balance and postural reflex (7–9). Balance is a complex body function of multi-system coordination (10). Impaired balance is the principal cause of falls (11) among PD patients, resulting in injury, fracture and even disability, which will severely limit their ability to perform activities of daily living, and negatively affect their quality of life and self-care confidence (12, 13).

Balance dysfunction in PD patients leads to fall injuries, fractures and even disability, which are important reasons for increased healthcare costs (14–16). Over the past 20 years, the total number of PD patients has reached 3.62 million (in 2020) in China, which will continue to rise in the future, resulting in further increased burden from PD in the next few decades with the population aging (17–19). Thoroughly understanding the status quo and influencing factors of PD has become a major health issue of global concern, which is critical to intervening in the factors affecting declined balance, ameliorating the balance and improving the functional capacity of PD patients (20).

Given the increasing prevalence of PD and its associated motor symptoms, particularly balance dysfunction, it is crucial to understand the factors influencing balance in middle-aged and older PD patients. Although existing research has emphasized various aspects of balance in PD, little is known about how specific risk factors, such as age, gender, smoking history, comorbidities (such as hypertension and diabetes), and physical activity (such as walking), affect balance in this population. Therefore, based on the 2015, 2018, and 2020 China Health and Retirement Longitudinal Study (CHARLS) database, we aim to provide evidence on the specific impacts of these factors and identify potential intervention strategies to help improve balance and reduce the risk of falls in PD patients.

The results indicate that several factors significantly influence balance in middle-aged and older adults with PD. These include age, gender, smoking history, history of falls, hypertension, diabetes, and physical activity levels. Old age, male gender, a history of smoking, prior falls, and the presence of hypertension and diabetes are associated with worse balance. Conversely, engaging in light physical activity, such as walking, is positively correlated with better balance. The findings suggest that balance dysfunction in PD is influenced by multiple risk factors, and that managing these factors, especially encouraging physical activity, may help improve balance and reduce fall risk in this population.

Balance disorder, as a common dysfunction of PD, is associated with abnormalities in the nigrostriatal and vestibular neural pathways (15, 25). Early clinical detection of balance abnormalities and assessment of falls are conducive to the comprehensive management of PD patients. Through measurement with dynamic balance instrument, Jong Moon Lee et al. (26) found that patients with early PD had accompanying balance disorder, which might be associated with age and disease course. PD is accompanied by a history of falls, which tend to increase gradually with the disease progression, resulting in post-fall injuries such as fractures, limited activities and psychological disorders (27). Successful standing on one leg for 10 s is conducive to predicting survival in middle-aged and older adults (28).

Fall events in PD are the result of interactions among multiple factors, of which balance disorder is regarded as the major cause, as well as an important factor for the limited activities of daily living and social participation in PD patients (8, 9, 11, 29). Research has shown that the dynamic and static center of mass (COM) trajectories and motion speeds in PD patients were prominently prolonged and accelerated, while the limits of stability were reduced, indicating balance dysfunction in the early- and middle-stage PD patients, which further affected their postural control and gait stability (30, 31). In particular, PD patients often face impaired balance and compromised motor coordination with age, which can lead to postural instability, difficulty walking and higher probability of falls (6, 8, 11, 25, 32, 33). The study by Murueta-Goyena et al. suggests that female patients are at a higher risk of falling due to issues with motor fluctuations and postural stability. This may explain why middle-aged and old male Parkinson’s disease patients tend to exhibit better balance than their female counterparts (34). Some studies have demonstrated an association between long-term smoking and a lower risk of PD, with the duration and intensity of smoking being more important, while the number of cigarettes smoked per day is generally irrelevant to the risk of PD (35–38). Although smoking may be associated with a lower risk of PD in some cases, it can interfere with neurological function and adversely affect balance control in middle-aged and older PD patients (37). This study found worse balance dysfunction in the fall group than in the non-fall group, showing consistency with the conclusion of Bekkers (6), who found that compared to the control group, PD patients with freezing of gait might have difficulty in sensing the speed difference in motor band. When the human body is about to fall due to smaller and slower disturbances, it mainly relies on the ankle joint control to restore postural stability (ankle strategy). A decreased sense of proprioception at ankle joint affects the implementation of ankle strategy, which may also be the reason why patients are more prone to fall. Currently, the association between the hypertension and the risk of PD remains controversial (6). Hypertensive patients are more likely to develop PD compared to non-hypertensive participants (39, 40). The prevalence of peripheral neuropathy in Parkinson’s disease patients ranges from 4.8 to 55%, which is significantly higher than that in the general population. When diabetic neuropathy coexists with Parkinson’s disease, the pathological mechanisms of both conditions may overlap, further worsening balance function (41).

Many studies have shown that rehabilitation training has a preferable effect on improving postural imbalance in PD patients and reducing the occurrence of falls (42–46). M. Rossi et al. (47) found that vestibular rehabilitation training under the movement and visual changes of dynamic postural balance platform could improve the postural imbalance of PD patients to the greatest extent and reduce their risk of falls (48, 49). This study also found that light physical activities, such as walking, may help reduce the risk of balance dysfunction in Parkinson’s disease patients, providing an important foundation for improving their quality of life. This is consistent with the research by Nascimento et al. (50), which showed that walking training, especially when combined with external cues, can improve gait fluency and reduce gait freezing. It offers a low-cost, low-risk intervention for the overall health, motor function, and non-motor symptoms of Parkinson’s disease patients, with significant benefits (51).In clinical practice, attention should be paid to old patients who smoke, falls, lack physical activities and have hypertension or diabetes. For these patients, corresponding interventions should be given to improve their quality of life.

While our study provides valuable insights into the relationship between balance ability and various health factors in Parkinson’s disease, several limitations should be considered. First, the CHARLS dataset lacks detailed information on medication status, which could affect balance, particularly in populations with conditions like Parkinson’s disease. This limits our ability to analyze how medication use or timing might impact balance. Second, the dataset does not categorize Parkinson’s disease patients by clinical subtypes, which restricts our ability to examine differences in balance problems across subtypes, such as tremor-dominant or postural instability and gait failure types. Additionally, the use of self-reported PD diagnosis, rather than clinical verification, could introduce selection bias, as individuals may misreport or have inaccuracies in their diagnosis. Although we controlled for potential confounders such as age, gender, and physical activity, other unmeasured factors, such as socioeconomic factors and pre-existing conditions, may also influence balance and physical activity levels. Furthermore, the relationship between smoking and balance may be influenced by other lifestyle factors, such as diet or weight differences. Finally, the use of a two-point scale for balance assessment may not fully capture the degree of balance dysfunction. Future research could employ more detailed assessment methods to better understand balance problems.

Balance impairment is a significant issue for middle-aged and older adults with PD. Our results indicate that age, gender, smoking, history of falls, hypertension, diabetes, and physical activity are important factors influencing balance in PD patients. Specifically, old age, male gender, light physical activity, and lower risks of hypertension and diabetes are associated with better balance. We recommend that clinicians focus on managing these risk factors, particularly for older PD patients, and emphasize interventions that promote light physical activity (such as walking) to improve balance. Addressing these factors can significantly enhance the quality of life and reduce the risks associated with falls and postural instability in this population. Future research should explore targeted interventions and the mechanisms underlying these associations to better guide clinical practice.