Association between urinary cadmium and chronic musculoskeletal pain in residents of cadmium-contaminated area in Northwest Thailand.

Cadmium exposure is known to cause adverse health effects in different organs of the human body but whether the effects result in chronic musculoskeletal pain (CMP) remain inclusive. The present study, therefore, aims to examine the relationship between urinary cadmium levels and CMP. An observational retrospective cohort study was conducted in two areas having different levels of cadmium contamination for comparison. The subjects enrolled into the study were individuals ages 18 and above who have lived in the studied areas for 1 year or more. The evaluation of chronic pain was carried out using a questionnaire and urine samples were collected for analysis of urinary cadmium levels. The data were analyzed using multiple logistic regression. The likelihood of CMP increased in a correlation with elevations in urinary cadmium from < 0.359, 0.359-0.753, 0.754-1.742, and ≥ 1.743 μg/g creatinine, adjusted odds ratio 1.07 (95% CI 0.62-1.86), 1.33 (95% CI 0.76-2.32), and 2.26 (95% CI 1.28-3.99) respectively. A positive association was found in our study between urinary cadmium level and CMP suggesting that cadmium exposure might cause neurological damage and/or tissue/muscle injury which in turn causing CMP.