December 7, 2009
Children of parents who have Alzheimer's are at slightly increased risk of getting the disease. Now, a new study has found that offspring of those with Alzheimer's are more likely to have high blood pressure and signs of inflammation than those whose parents did not have Alzheimer's.
The findings, which appeared in The Archives of General Psychiatry, a journal from the American Medical Association, point to possible early signs that may be markers for late-onset Alzheimer's. Keeping blood pressure in check and reducing inflammatory markers through lifestyle measures like regular exercise and a heart-healthy diet, the authors suggest, may help to ward of Alzheimer's in old age.
High blood pressure and vascular disease during midlife have previously been linked to an increased risk of Alzheimer's. Inflammation, too, is increasingly being recognized as a risk factor for the disease. An earlier study from Hawaii found that those with high levels of C-reactive protein, a blood marker that signals inflammation, were more likely to have thinking and memory problems in old age.
While the early-onset form of Alzheimer's, which occurs in individuals before age 60, has been strongly linked to defective genes, the far more common late-onset Alzheimer's is more complex. Studies of twins have shown that as much as 60 percent of the risk for late-onset Alzheimer's disease is influenced by genes.
In the current study, doctors at the VU University Medical Center in Amsterdam measured levels of various vascular and inflammatory factors, including proteins known as cytokines in the blood. The researchers looked at 206 offspring of 92 families in which parents had Alzheimer's and compared these with measurements from 200 offspring of 97 families in which parents were free of the disease.
The researchers also measured blood pressure levels and obtained blood samples to assess genetic characteristics and levels of cholesterol, along with cytokines and other inflammation-related substances. In addition, they took extensive medical histories and collected information about demographics, diet, exercise and stress levels.
More individuals whose parents had Alzheimer's disease carried the APO-E4 gene, which was already known to be a risk factor for the disease, than did those whose parents did not have Alzheimer's (47 percent vs. 21 percent). In addition, those with a family history of Alzheimer's tended to a have higher blood pressure and higher levels of several inflammatory cytokines.
Other cardiovascular risk factors among the parents such as high blood cholesterol and high glucose levels, a sign of diabetes were not associated with their childrens' risk of Alzheimer's, although it is known that both high cholesterol and diabetes themselves are risk factors for Alzheimer's
"Our study shows that high blood pressure and an innate pro-inflammatory cytokine response in middle age significantly contribute to Alzheimer's disease," the authors wrote. "As these risk factors cluster in families, it is important to realize that early interventions could prevent late-onset Alzheimer's disease. One could argue for a high-risk--prevention strategy by identifying the offspring of patients with Alzheimer's disease, screening them for hypertension and vascular factors and implementing various non-pharmacological health measures."
Eric van Exel; Piet Eikelenboom; Hannie Comijs; Marijke Frölich; Johannes H. Smit; Max L. Stek; Philip Scheltens; Jan E. Eefsting; Rudi G. J. Westendorp:"Vascular Factors and Markers of Inflammation in Offspring With a Parental History of Late-Onset Alzheimer Disease." Archives of General Psychiatry. November 2009; Volume 66 (Number 11): pages 1263-1270.