Association between heavy metal exposure and high-sensitivity C-reactive protein in the elderly: Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2017.

Background: Cardiovascular diseases (CVDs) are a primary cause of mortality in the elderly. Exposure to heavy metals such as lead, cadmium, and mercury has been suggested to increase CVD risk by inducing reactive oxygen species and inflammatory responses. The elderly are particularly susceptible to heavy metal exposure, which may increase their CVD risk. Despite this potential risk, evidence specifically focusing on the association between blood heavy metal levels and high-sensitivity C-reactive protein (hsCRP), a key predictor of CVDs, in the elderly remains limited. Therefore, the present study aimed to assess the relationship between blood lead, mercury, and cadmium concentrations and hsCRP in the elderly.

Methods: We analyzed 884 subjects (385 men, 499 women) aged 65 years and older without CVD history from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2017. Because KNHANES is a two-stage stratified clustered sample, all analyses applied stratum, cluster, and weight. Estimated geometric means (GMs) of hsCRP across demographic factors and heavy metal quartiles were compared using a complex samples general linear model (CSGLM). The association between blood heavy metals and hsCRP was examined using CSGLM, adjusting for age, sex, body mass index, estimated glomerular filtration rate, smoking status, alcohol consumption, education, physical activity, monthly income, and underlying diseases.

Results: The estimated GM of hsCRP differed significantly by blood lead quartile (p = 0.035) and showed a significant increasing trend (p for trend = 0.019). In CSGLM analysis, elevated blood lead concentrations were significantly associated with increased hsCRP (β = 0.176, p = 0.032) after adjustment. However, blood mercury and cadmium concentrations showed no significant associations with hsCRP.

Conclusions: The observed association between blood lead concentrations and hsCRP suggests that elevated blood lead may contribute to increased CVD risk in the elderly. Given the susceptibility of this population, subsequent investigations are warranted to confirm this association and develop preventive strategies.