## 4 Discussion  
This cross-sectional study, based on SHARE data, found a clear gradient of functional limitation linked to pain distribution: Individuals with WP showed the highest number of limitations in BADLs and IADLs, followed by those with LP, and lastly, those without pain. These associations remained significant after adjusting for sociodemographic, physical, cognitive, and psychosocial variables. The findings underscore the role of pain, particularly when widespread, as a key determinant of daily functioning in older adults. The relationship between pain and functional decline in both BADLs and IADLs has been extensively documented in various epidemiological contexts. Studies across diverse populations have consistently shown that chronic pain compromises independent performance in ADLs. For instance, a large-scale study conducted in an Indian older adult population reported that individuals experiencing pain had a significantly higher likelihood of encountering difficulties in both BADLs and IADLs. In addition, condition-specific research has demonstrated the impact of pain on functional status. A study involving patients with systemic lupus erythematosus found that more than half reported  
Figure 4: Multivariate Poisson regression including the number of limitations in the Instrumental Activities of Daily Living as the dependent variable. CI: confidence interval; **_p_-value \(<\) 0.01; and ***_p_-value \(<\) 0.001.  
limitations in BADLs and IADLs, closely related to the severity of pain [38]. These findings are consistent with those of the present study, reinforcing the evidence that chronic pain functions as a risk factor for global functional impairment. A study conducted in a sample of 230 women with endometriosis also reported that pain intensity was closely associated with limitations in both BADLs and IADLs, with additional influence from fatigue and other biopsychosocial factors [39]. This convergence of findings across distinct clinical conditions and geographic regions highlights the broad impact of pain on functional performance, regardless of its underlying etiology. These findings further underscore several latent issues identified in our study, such as the influence of sex and the relevance of biopsychosocial factors. Beyond primary functional disability, our results also highlight the strong psychosocial dimension of pain, which contributes to exacerbating limitations in ADLs. Perceived loneliness, identified in our analysis as a particularly relevant factor among individuals with WP, has previously been recognized in the scientific literature as a key element in the progression of functional decline. A longitudinal study conducted in the general population demonstrated that persistent pain is associated with an increasing risk of developing loneliness, thus establishing a negative feedback loop that heightens both functional and emotional vulnerability in older adults [40]. Similarly, another study in a British sample found that older adults with widespread musculoskeletal pain were twice as likely to report loneliness and low social support, both of which negatively impacted their daily functional capacity [41]. Our study found a higher proportion of women in both pain groups, particularly in the WP group (70%). This pattern aligns with previous evidence reporting a consistently higher prevalence of chronic pain among women [42; 43] and supports the need to consider gender differences when addressing functional outcomes related to pain [44]. With regard to physical factors, the associations between pain and anthropometric parameters proved to be complex and non-linear. Although excess body weight has traditionally been linked to a higher prevalence of musculoskeletal pain, our findings revealed heterogeneous patterns depending on pain type.