Mindy J. Kim-Miller, MD, PhD
There is growing evidence for a link between cardiovascular (heart) disease and Alzheimer’s disease (AD). Both diseases share common risk factors including hypertension (high blood pressure), cholesterol, diabetes, obesity, smoking, and ApoE4 (a gene which has been associated with atherosclerosis, AD, and possibly vascular dementia). The intriguing part of these findings is that it may be possible to prevent cognitive decline and AD by targeting these cardiovascular risk factors.
It is well known that hypertension is a direct risk factor for stroke and vascular dementia. However recent studies have suggested that hypertension during midlife is also a risk factor for the development of AD; those with hypertension are twice as likely to develop AD. Other studies suggest that high systolic pressure with low diastolic pressure in older adults is associated with an increased risk of developing of AD. In the proposed mechanism, atherosclerosis due to long-standing hypertension leads to poor blood flow to the brain, which may contribute to the development of dementia. Low diastolic blood pressure in late-life may further worsen blood flow to the brain. Peripheral arterial disease (narrowed arteries leading to poor circulation in the arms or legs) has also been associated with a two-fold increase in the risk for AD, further supporting the theory that inadequate blood circulation may contribute to AD. Other modifiable risk factors include cholesterol level, obesity, and smoking. High cholesterol levels (≥ 6.5 mmol/L or 250 mg/dL) during midlife have been associated with a two- to three-fold increase in the risk for AD. Diabetes, obesity, and smoking also roughly double the risk for dementia.
These cardiovascular risk factors appear to have an additive effect. Therefore if you have two of these risk factors, your risk of AD increases by about four times, and if you have three risk factors, your risk for AD increases by about six times, and so on. Some of these risk factors also affect the rate of progression of AD. Specifically, atrial fibrillation, hypertension, and angina have been associated with a greater rate of decline among people with AD.
It is important to recognize the link between cardiovascular disease and AD, because cardiovascular disease is often preventable or treatable. By managing cardiovascular disease, it may be possible to decrease the risk of developing AD. Those at high risk of developing AD include those with hypertension, high cholesterol, diabetes, obesity, smoking, and/or atrial fibrillation (see Table 1). Studies have shown that treating high blood pressure with antihypertensive medication reduces not only the risk of stroke but also of vascular dementia and AD. A class of antidiabetic drugs called thiazolidinediones have been shown to decrease the risk of dementia in people with diabetes, and preliminary studies suggest that these drugs may slow AD progression in people without diabetes as well. Some studies suggest that treating high cholesterol with a class of drugs called statins may decrease the risk of AD, but this remains controversial. Research into the effect of treating cardiovascular risk on the risk of AD is ongoing. But based on the available evidence, managing cardiovascular risk factors should be an integral part of managing AD.
Cardiovascular Risk Factors Associated with Dementia
- Hypertension (high blood pressure)
- Hyperlipidemia (high fats including cholesterol in the bloodstream)
- Atrial fibrillation
Tips for Decreasing Cardiovascular Risk Factors
- Eat a heart-healthy diet that is
- nutritious and well-balanced
- low in saturated fat, trans fat, cholesterol, and salt
- high in fruits, vegetables, and whole grains
- Maintain a healthy weight
- Don’t eat more calories than you use every day
- If you are overweight, start a weight loss program that includes exercise and a healthy, lean diet
- Get at least a total of 30 minutes of moderate physical activity on most days of the week or, if possible, every day
- Quit smoking or do not start to smoke
- Minimize stress
- Get regular physical examinations, at least yearly
For more information on healthy nutrition and lifestyles, see the American Heart Association, the FDA Food and Drug Administration’s Heart Health Online, the US Department of Health and Human Services.
Bergmann C, Sano M. (2006). Cardiac risk factors and potential treatments in Alzheimer’s disease. Neurol Res. 28(6):595-604.
Corder EH et al. (1993). “Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer’s disease in late onset families”. Science 261 (5123): 921-3.
Forette F et al. (1998). Prevention of dementia in randomised double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial. Lancet. 352(9137):1347-51.
Frishman WH. (2002). Are antihypertensive agents protective against dementia? A review of clinical and preclinical data. Heart Dis. 4(6):380-6.
Kalmijn S, Feskens EJM, Launer LJ, Kromhout D. (1996). Cerebrovascular disease, the apolipoprotein ε4 allele, and cognitive decline in a community-based study of elderly men. Stroke. 27: 2230-5.
Kivipelto et al. (2001). Midlife vascular risk factors and Alzheimer’s disease in later life: longitudinal, population based study. BMJ. 322(7300):1447-51.
Kivipelto et al. (2005). Obesity and vascular risk factors at midlife and the risk of dementia and Alzheimer disease. Arch Neurol. 62(10):1556-60.
Kuller LH. (2007). Statins and dementia. Curr Atheroscler Rep. 9(2):154-61.
Launer LJ et al. (2000). Midlife blood pressure and dementia: the Honolulu-Asia aging study.
Neurobiol Aging. 21(1):49-55.
Mielke MM et al. (2007). Vascular factors predict rate of progression in Alzheimer disease. Neurol. 69:1850-8.
Miida T, Takahashi A, Ikeuchi T. (2007). Prevention of stroke and dementia by statin therapy: experimental and clinical evidence of their pleiotropic effects. Pharmacol Ther. 113(2):378-93.
Newman et al. (2005 ). Dementia and Alzheimer’s disease incidence in relationship to cardiovascular disease in the Cardiovascular Health Study cohort. J Am Geriatr Soc. 53(7):1101-7.
Notkola et al. (1998). Serum total cholesterol, apolipoprotein E epsilon 4 allele, and Alzheimer’s disease. Neuroepidemiology. 17(1):14-20.
Patterson et al. (2001). The recognition, assessment and management of dementing disorders: conclusions from the Canadian Consensus Conference on Dementia. Can J Neurol Sci. 28 Suppl 1:S3-16.
Qiu C, Winblad B, Fratiglioni L. (2005). The age-dependent relation of blood pressure to cognitive function and dementia. Lancet Neurol. 4(8):487-99.
Van Broeck B, Van Broeckhoven C, Kumar-Singh S. (2007). Current insights into molecular mechanisms of Alzheimer disease and their implications for therapeutic approaches. Neurodegener Dis.;4(5):349-65.
Wolozin B, Bednar MM. (2006). Interventions for heart disease and their effects on Alzheimer’s disease. Neurol Res. 2006 Sep;28(6):630-6.