The number of older people, including those living with dementia, is rising, as younger age mortality declines. However, the age-specific incidence of dementia has fallen in many countries, probably because of improvements in education, nutrition, health care, and lifestyle changes.
Overall, a growing body of evidence supports the nine potentially modifiable risk factors for dementia modelled by the 2017 Lancet Commission on dementia prevention, intervention, and care: less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and low social contact.
We now add three more risk factors for dementia with newer, convincing evidence. These factors are excessive alcohol consumption, traumatic brain injury, and air pollution. We have completed new reviews and meta-analyses and incorporated these into an updated 12 risk factor life-course model of dementia prevention. Together the 12 modifiable risk factors account for around 40% of worldwide dementias, which consequently could theoretically be prevented or delayed.
The potential for prevention is high and might be higher in low-income and middle-income countries (LMIC) where more dementias occur. Our new life-course model and evidence synthesis has paramount worldwide policy implications. It is never too early and never too late in the life course for dementia prevention. Early-life (younger than 45 years) risks, such as less education, affect cognitive reserve; midlife (45–65 years), and later-life (older than 65 years) risk factors influence reserve and triggering of neuropathological developments.
Culture, poverty, and inequality are key drivers of the need for change. Individuals who are most deprived need these changes the most and will derive the highest benefit.
The US Surgeon General’s office has released a report emphasizing the importance of making hypertension control a national public health priority. Vice Admiral Jerome Adams, MD, MPH, the 20th US Surgeon General, discusses the report’s background and recommendations.
Recorded October 7, 2020.
“We are learning that tactics to avoid dementia begin early and continue throughout life, so it’s never too early or too late to take action,” says commission member and AAIC presenter Lon Schneider, MD, co-director of the USC Alzheimer Disease Research Center‘s clinical core and professor of psychiatry and the behavioral sciences and neurology at the Keck School of Medicine of USC.
LOS ANGELES — Modifying 12 risk factors over a lifetime could delay or prevent 40% of dementia cases, according to an updated report by the Lancet Commission on dementia prevention, intervention and care presented at the Alzheimer’s Association International Conference (AAIC 2020).
Twenty-eight world-leading dementia experts added three new risk factors in the new report — excessive alcohol intake and head injury in mid-life and air pollution in later life. These are in addition to nine factors previously identified by the commission in 2017: less education early in life; mid-life hearing loss, hypertension and obesity; and smoking, depression, social isolation, physical inactivity and diabetes later in life (65 and up).
Schneider and commission members recommend that policymakers and individuals adopt the following interventions:
- Aim to maintain systolic blood pressure of 130 mm Hg or less from the age of 40.
- Encourage use of hearing aids for hearing loss and reduce hearing loss by protecting ears from high noise levels.
- Reduce exposure to air pollution and second-hand tobacco smoke.
- Prevent head injury (particularly by targeting high-risk occupations).
- Limit alcohol intake to no more than 21 units per week (one unit of alcohol equals 10 ml or 8 g pure alcohol).
- Stop smoking and support others to stop smoking.
- Provide all children with primary and secondary education.
- Lead an active life into mid-life and possibly later life.
- Reduce obesity and the linked condition of diabetes.
From an American Heart Assoc. Journal study (Feb 28, 2020):
Seasonal variation in blood pressure has been known for 40 years, but, to our knowledge, for the first time we show here that this occurs independently of temperature. The reduction in blood pressure is more marked with a rise in UVB than UVA, and in whites than black people. Dermatological concerns about the skin cancer inducing effects of UV radiation need to be balanced against the observed blood pressure lowering effects of sunlight, particularly given the greatly higher burden of disease caused by hypertension.
Sunlight exposure appears to lower blood pressure; insufficient exposure to natural ultraviolet radiation and/or active avoidance of sunlight may be new risk factors for hypertension.
Hypertension remains a leading global cause for premature death and disease. Most treatment guidelines emphasize the importance of risk factors, but not all are known, modifiable, or easily avoided. Population blood pressure correlates with latitude and is lower in summer than winter. Seasonal variations in sunlight exposure account for these differences, with temperature believed to be the main contributor. Recent research indicates that UV light enhances nitric oxide availability by mobilizing storage forms in the skin, suggesting incident solar UV radiation may lower blood pressure. We tested this hypothesis by exploring the association between environmental UV exposure and systolic blood pressure (SBP) in a large cohort of chronic hemodialysis patients in whom SBP is determined regularly.