Overweight, Obesity, and Musculoskeletal Symptom Burden in Chile: A Population-Based Cross-Sectional Study

Background/Objectives: Musculoskeletal symptoms (MSS) are among the leading causes of pain and functional limitation worldwide, yet population-level evidence linking excess body weight to MSS in Latin America remains scarce. This study examined the association between body mass index (BMI) and the prevalence of non-traumatic MSS in the Chilean population. Methods: A cross-sectional secondary analysis was conducted using data from the 2009-2010 Chilean National Health Survey (n = 4689). MSS were assessed with the validated COPCORD CCQ-ILAR questionnaire, covering 12 anatomical regions over the previous seven days. BMI was categorized as <25, 25 to <30, and ≥30 kg/m². Survey-weighted negative binomial and logistic regression models were fitted, adjusting for age, sex, educational level, and area of residence. Results: Over half the sample (55.26%) reported at least one MSS. Each one-unit increase in BMI was associated with a 2.8% higher expected symptom count (CR = 1.028; 95% CI: 1.019-1.037). Compared with participants with BMI < 25 kg/m², those with overweight and obesity had 55.7% and 98.4% higher odds of reporting ≥1 MSS, respectively. The knee, shoulder, lower back, and ankle showed the steepest prevalence gradients across BMI strata. After correction for multiple comparisons, overweight remained associated with lower-back, finger, and knee symptoms, whereas obesity remained associated with shoulder, wrist, finger, knee, and ankle symptoms. Age and female sex were also independently associated with greater symptom burden. Conclusions: Higher BMI was positively associated with a greater overall MSS burden. Region-specific analyses identified robust associations in selected weight-bearing and upper-limb regions after correction for multiple comparisons. Because of the cross-sectional design, these findings do not establish that reducing BMI would reduce MSS. In addition, as the data were collected in 2009-2010, the prevalence estimates should not be interpreted as representing the current MSS burden in Chile.