Blood-Based Lead Biomarkers and Sarcopenia Indicators in Older Adults

Chronic exposure to low levels of lead (Pb) remains a widespread public health issue, especially among older adults. While its neurotoxic and cardiovascular effects are well recognized, its potential role in accelerating age-related musculoskeletal decline is less understood. Emerging evidence suggests Pb may contribute to sarcopenia, but epidemiological data, especially regarding the most informative biomarkers of exposure, are limited.

We analysed data from 11 842 participants aged ≥ 60 years across four population-based studies (NHANES III, NHANES 1999-2006, NHANES 2011-2012 and Seniors-ENRICA-2). Sarcopenia indicators included muscle strength (grip strength and chair stand test), muscle mass (dual-energy X-ray absorptiometry, calf circumference and arm circumference) and muscle function (gait speed and Short Physical Performance Battery scores). Sarcopenia was defined in the Seniors-ENRICA-2 using the European Working Group on Sarcopenia in Older People 2 criteria. Associations between Pb exposure (serum and whole blood) and sarcopenia indicators were estimated using multivariable regression and meta-analyses.

Pb levels were associated with residential environmental exposures such as traffic proximity, industrial emissions and soil contamination, explaining approximately 11% of variability in whole blood Pb and 9% in serum Pb. Both whole blood and serum Pb showed dose-dependent inverse associations with muscle sarcopenia indicators, including measures of strength, mass and function. Associations with lower limb outcomes were generally stronger for serum Pb compared with whole blood Pb. An interquartile range increase in serum Pb was associated with a 1.33-fold increase in the odds of confirmed or severe sarcopenia (95% CI: 1.02, 1.70), compared with a 1.20-fold increase for whole blood Pb (95% CI: 1.06, 1.36).

Environmental Pb exposure is associated with detrimental effects on musculoskeletal health and contributes to sarcopenia in older adults. Serum Pb may be a more sensitive biomarker of musculoskeletal aging than whole blood Pb and should be considered in future research and surveillance strategies.