Blood Lead Levels Correlated With Chronic Pain Risk

Blood lead levels (BLL) can affect chronic pain risk, according to study results published in Pain and Therapy. The research shows greater lead exposure is positively correlated with chronic pain.

The study authors conducted a cross-sectional study across the country using data from 3 cycles of the National Health and Nutrition Examination Survey (NHANES) to determine chronic pain status. Pain was assessed using the values of variables MPQ100 and MPQ110 and characterized as “chronic” if it  persisted for longer than 3 months.

Univariate and multivariate logistic regression analyses examined the connection between BLL and chronic pain. Additionally, subgroup analyses were performed to uncover confounding factors that may have altered the association between chronic pain and blood lead levels.

Of the 31,126 participants in NHANES dataset, 13,485 answered questions regarding chronic pain and were included in the final analysis. Among these, 14.46% had chronic pain. Compared with participants in the lowest blood lead levels quartile (0.90 lg/dL), those in the highest BLL quartile (2.40 lg/dL) had a 29% higher chronic pain risk in the unadjusted model with an OR of 1.29 (95% CI, 1.12-1.49; P =.001).

The difference remained significant in the adjusted models. When analyzing subgroups, the connection between blood lead levels and the risk of chronic pain was affected by hypertension (with a P value for interaction of .018) and arthritis (with a P value for interaction of .004).

“The positive correlation between BLL and chronic pain implies the need to reduce lead exposure to ameliorate the impact of chronic pain on the economy and health. For those with hypertension or arthritis, BLL could be one of their health indicators,” the researchers explain. “A high BLL should be taken into consideration by practitioners when providing health education or giving medical advice since they might be more vulnerable to the negative effect of lead exposure on chronic pain.”

Among several limitations, the NHANES did not conduct a detailed assessment of self-reported chronic pain. As a cross-sectional study, it could not establish a cause-and-effect relationship between lead exposure and chronic pain. The NHANES stopped collecting information on chronic pain after 2004.