Introduction

Ageing, a complex biological process influenced by multiple factors, significantly impacts individuals’ health and lifestyles. The global demographic shift towards an ageing population, exemplified by countries like Japan and Singapore, necessitates a proactive approach towards addressing age-related health challenges. According to the World Population Prospects 2019, one in six people will be over 65 years old by 2050. Particularly in Singapore, one in four will be 65 or older by 2030. This demographic shift necessitates a focus on healthy ageing to manage the increasing number of older adults. Despite varying definitions of healthy ageing, indices like the Healthy Ageing Index (HAI) offer a comprehensive assessment based on physiological parameters. The HAI, an evolution of the Physiologic Index of Comorbidity, serves as a reliable predictor of mortality and cardiovascular issues, demonstrating its utility as a marker for ageing.

The Importance of Healthy Ageing

Ageing is a natural process influenced by various factors. As people age, they become more susceptible to various comorbidities, cognitive decline, and physical deterioration, affecting their overall well-being. Furthermore, cognitive decline and frailty, once associated with advanced age, now manifest in younger individuals due to changing lifestyle patterns. Thus, the need for tailored therapeutic interventions to manage age-related conditions is paramount in ensuring healthy ageing trajectories and disease prevention.

Components of the Healthy Ageing Index

The HAI is a summary measure based on physiological parameters from five systems: cardiovascular, respiratory, metabolic, urinary, and neurological. It was developed to address the limitations of existing comorbidity indices. The HAI uses accessible tests, such as systolic blood pressure and the Modified Mini-Mental Status Examination (MMSE), to assess health. In examining the association between HAI and potential risk factors, a recent study in Singapore revealed intriguing correlations. They employed two linear regression models to explore the cross-sectional relationships between risk factors and the HAI. The first model was a univariate analysis (Model I), and the second model (Model II) included adjustments to account for potential confounding variables.

Healthy Ageing Index and Health Outcomes

Factors such as age, ethnicity, education levels, and health history significantly influenced HAI scores, reflecting varying degrees of health status. According to the study, lower HAI scores, indicating poorer health, were associated with older age, Malay and Indian ethnicity with respect to Chinese, and unemployment.  Moreover, certain health conditions like heart diseases and hypercholesterolemia showed associations with lower HAI scores. Notably, higher HAI scores were linked to better health outcomes, emphasising the role of socioeconomic factors in shaping overall health.

The alignment of HAI with outcomes like peripheral artery disease (PAD), muscle strength, health-related quality of life (HRQoL), and psychological distress shows its utility in assessing diverse health dimensions. Associations between HAI and Ankle-Brachial Index (ABI), Kessler psychological distress scale (K10) scores, and EQ-5D dimensions highlight the index’s potential as a screening tool for age-related diseases and health risks.

Conclusion

The HAI is a valuable tool for assessing the health of older adults. It helps predict age-related outcomes and informs strategies for promoting healthy ageing. Higher HAI scores were linked to better health and higher education levels. The HAI can serve as a non-invasive screening tool to identify individuals at risk for age-related diseases. This can inform interventions and strategies to promote healthy ageing and improve quality of life. Future research should explore how the HAI evolves over time and its impact on different health outcomes across diverse ethnic groups.