Measuring blood levels of placental growth factor (PIGF), a molecule that prompts the development of new blood vessels, can help distinguish whether cognitive problems stem predominantly from vascular issues or another cause, such as Alzheimer disease, according to an analysis of 335 patients.

The researchers, who reported their findings in Alzheimer and Dementia, found that participants whose PIGF levels fell in the top quartile were about 3 times as likely to have cognitive impairment or dementia and more than twice as likely to have imaging evidence of cerebral small vessel disease. Moreover, each unit increase in PIGF was tied to a 22% increase in the likelihood of cognitive impairment and a 16% increase in likelihood of imaging evidence of cerebral small vessel disease.