Table 1

Guideline for prevention of AD: preliminary clinical suggestions*

Factors/interventions	Suggestion
Lifestyle
BMI and weight management	Adults aged <65 years should maintain or lose weight through an appropriate balance of physical activity, caloric intake and formal behavioural programmes when indicated to maintain/achieve a BMI between 18.5 and 24.9 kg/m² (Class I, level B) Adults aged >65 years should not to be too skinny (Class I, level A4) Adults aged >65 years with a trend of weight loss should be closely monitored for their cognitive status (Class I, Level B)
Physical exercise	Individuals, especially those aged ≥65 years, should stick to regular physical exercise (Class I, Level B*)
Cognitive activity	Mentally stimulating activities should be encouraged, such as reading, playing chess, etc (Class I, Level A4)
Smoking	People should not smoke and should avoid environmental tobacco smoke. Ccounselling, nicotine replacement and other pharmacotherapy as indicated should be provided in conjunction with a behavioural programme or formal smoking cessation programme (Class I, Level B)
Sleep	Get sufficient and good quality sleep and consult a doctor or receive treatment when you have problem with sleep (Class I, Level B)
Comorbidities
Diabetes	Stay away from diabetes via a healthier lifestyle and diabetic patients should be closely monitored for their cognitive decline (Class I, Level A4)
CVD	Maintain a good condition of the cerebral vessels via a healthier lifestyle or medications to avoid atherosclerosis, low cerebral perfusion and any CVD. Individuals with stroke, especially cerebral microbleeding, should be carefully monitored for their cognitive change and take preventative measures as indicated to protect cognition (Class I, level B)
Head trauma	Protect your head from injuries (Class I, level A4)
Frailty	Stay healthy and strong in late life. Those with increasing frailty should be especially monitored for their cognition (Class I, Level B)
Blood pressure	Individuals aged < 65 years should avoid hypertension via a healthier lifestyle (Class I, Level A4) Individuals with OH should be closely monitored for their cognition (Class I, Level A4)
Depression	Maintain a good condition of mental health and closely keep an eye on the cognitive status for those with depressive symptoms (Class I, Level A4)
AF	Maintain a good cardiovascular condition and manage AF using pharmaceuticals (Class I, level B)
Stress	Relax your mind and avoid daily stress (Class I, Level A4)
Other domains
Education	Receive as much education as possible in early life (Class I, level A4)
Hyperhomocysteinaemia	Have a regular blood examination for homocysteine level. Individuals with hyperhomocysteinaemia should be treated with vitamin B and/or folic acid and be followed with a focus on their cognition (Class I, Level A2)
Vitamin C	Vitamin C in the diet or taken as supplements might help (Class I, Level B)
Not recommended
ERT	Oestrogen replacement therapy should not be specifically used for AD prevention in postmenopausal women (Class III, Level A2)
ACI	ACI should not be used for AD prevention in cognitively impaired individuals (Class III, Level B)

*The risk of bias is rated as high mainly due to lack of a blinding method and allocation concealment, which however cannot be achieved in randomised controlled trials for interventions such as physical exercise. We therefore consider that the results are relatively more reliable than rated. Also, the content cannot be too detailed (especially for the dose and duration) for some factors and a very good trial is needed to replicate (pivotal studies). Also, these suggestions must be presented in the context of the limitations of the studies and continuing uncertainty among investigators.
ACI, acetylcholinesterase inhibitors; AF, atrial fibrillation; BMI, body mass index; CVD, cerebrovascular disease; ERT, estrogen replacement therapy; IMT, intima-media thickness; NSAIDs, non-steroidal anti-inflammatory drugs; OH, orthostatic hypotension.