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.