The investigators aim to investigate the relationship between lifestyle factors and cognitive decline among older Singaporeans and assess the feasibility and preliminary efficacy of a lifestyle intervention programme in delaying cognitive decline. Healthy lifestyle is a way of living that can lower down disease risk and promote health and wellbeing. Accumulating evidences support that lifestyle factors contribute to the development of dementia and hence modifying lifestyle could be a promising approach for dementia prevention. The intervention will focus on the promotion of a brain-healthy lifestyle, with special attention paid to common problems among local older adults. The investigators will assess cognitive and biological changes using the following outcome measures. Primary outcome: the processing speed domain Z score derived from raw scores of three tests including the symbol digit modality test, Colour trial test, and Stroop test (condition 2). Secondary outcome: i. epigenetic age (DNA methylation), ii. plasma-based markers of inflammation, iii. activities of daily living and instrumental activities of daily living, iv. Health-related quality of life measured by the EQ-5D-5L scale, v. wellbeing measured by the ICECAP-O (ICEpop CAPability measure for Older people), vi. other neurocognitive assessment tests. The investigators hypothesize that: 1. Lifestyle factors are associated with cognitive decline, epigenetic age, and systematic chronic inflammation. 2. Evidence-based lifestyle intervention focusing on common problems among local population can delay cognitive decline, slow epigenetic ageing, and produce favorable changes on chronic systemic inflammation. 3. Changes in biological markers will correlate with changes in cognitive function, and hence partially explains the observed clinical efficacy. 4. The interventions may also improve daily functioning, health-related quality of life, and wellbeing. 5. Interventions delivered in an individualized manner would produce more benefits than interventions delivered uniformly without considering individual's risk profile and personal and social context.