Exposure to lead in early childhood and adolescence may contribute to hypertension-related decline that can impair a person's cognitive abilities.
Both lead exposure and hypertension have been associated with cognitive impairments in older adults. The study indicates that the interaction between lead exposures early in life combined with high blood pressure in working age adults may lead to diminishing cognitive abilities in later life.
To determine cognitive function, researchers used the digit symbol substitution, a complex test of mental abilities that considers time and accuracy in completing the task.
The interaction of pulse pressure and blood lead levels on performance of the digit task was significant after controlling for other variables. There was an inverse relationship between the mental tests and the highly significant and adverse effects on performance of the digit task pulse pressure, blood lead level, and C-reactive protein.
Other neurobehavioral tests included measures of reaction time and reaction time variance. Results suggested slower and less stable reaction time associated with increases in pulse pressure and blood lead levels.
Additional findings suggested that socio-economic status and/or nutritional status may influence the accumulation of lead in the body, and may mediate the interaction between lead load and pulse pressure on cognitive performance in middle-aged adults.
The aging process alone does not lead to automatic decline in cognitive ability. It can happen, however when the aging process is associated with hypertension and the presence of other diseases and/or environmental exposures to factors such as lead exposure.
There's a need to better understand the relationships between blood pressure and blood lead levels.