Relations of bone and blood lead to cognitive function: the VA Normative Aging Study

Area of Science:

• Environmental Health
• Neuroscience
• Gerontology

Background:

• Lead exposure is a known neurotoxin, but its effects at low levels, particularly in aging populations, require further investigation.
• Accumulated lead in bone provides a long-term indicator of exposure.
• Cognitive decline is a significant concern in middle-aged and elderly populations.

Purpose of the Study:

• To examine the relationship between blood and bone lead levels and cognitive performance in middle-aged and elderly men.
• To determine if low-level lead exposure is associated with cognitive impairments.

Main Methods:

• A longitudinal study of aging involving 141 men.
• Measurement of circulating blood lead and bone lead (patella and tibia).
• Assessment of cognitive functions including attention, perceptual speed, memory, language, and spatial copying using various tests.

Main Results:

• Mean blood lead levels were low (5.5 µg/dL), with mean bone lead levels of 31.7 µg/g (patella) and 22.5 µg/g (tibia).
• Higher blood lead levels were associated with poorer word recall and definition, reduced object identification, and slower perceptual speed.
• Elevated blood and tibia lead levels correlated with less accurate spatial copying, and higher tibia lead levels were linked to slower pattern memory.

Conclusions:

• Low-level lead exposure is associated with cognitive impairments in elderly men.
• Both circulating and accumulated lead may contribute to cognitive deficits.
• These findings highlight the potential public health impact of environmental lead exposure on cognitive aging.