Preplanned Studies: Trends and Distribution of Life Expectancy and Health-Adjusted Life Expectancy — Asia-Pacific Region, 1990–2021

In recent decades, global total life expectancy (LE) has increased rapidly, from 65.49 years in 1990 to 71.74 in 2021, but the corresponding health-adjusted life expectancy (HALE) has grown relatively slowly, or even stagnated, from 57.05 years in 1990 to 62.20 years in 2021 (1). Although significant progress has been made in understanding and eliminating fatal diseases, research on the impact of mild and non-fatal diseases on lifespan has lagged. In the context of rapid population aging and health transitions, delaying the onset of functional impairment and shortening the period of dependency are critical to improving quality of life. Enhancing HALE, focusing more on quality of life, and narrowing the gap between LE and HALE are the common goal in the global health field.

The Asia-Pacific region is the most populous and diverse region in the world. It includes populous countries such as China, India, and Bangladesh, and also nations with the longest LE, such as Japan, Singapore, and the Republic of Korea. The region also includes areas like Afghanistan, which faces severe political and cultural conflicts and health threats, as well as regions like Fiji, which is threatened by metabolic and chronic diseases, and Papua New Guinea, with threats from communicable diseases, such as malaria. Analyzing the geographic distribution and trends in HALE in the Asia-Pacific region can reveal health disparities between different countries and regions, helping to understand the impact of various social, economic, cultural, and environmental factors on health. This study analyzed the distribution of HALE in different countries within the Asia-Pacific region, as well as trends in HALE changes from 1990 to 2021. Additionally, it examines the distribution of HALE and its changing trends across different SDI regions. The research results can provide references for contributing to the realization of the Putrajaya Vision of the Asia-Pacific region, including through the Aotearoa Plan of Action of “fostering quality growth that brings palpable benefits and greater health and wellbeing to all” and “preventing, detecting, responding to, and recovering from, pandemics.”

Data on LE and HALE were obtained from the Global Burden of Disease Study (GBD) 2021 (https://vizhub.healthdata.org/gbd-results/). GBD 2021 provided a standardized and comprehensive assessment of the global burden of 371 diseases and injuries in 204 countries and territories, using data sources identified from vital registration, verbal autopsy, registry, survey, police, and surveillance data across all countries and territories (2). This study focused on LE and HALE across the Asia-Pacific region and selected 29 major countries for analysis [data for China did not include Hong Kong Special Administrative Region (SAR), Macau SAR, or Taiwan, China] (3). LE was calculated using life tables, and HALE was estimated using Sullivan’s method (4), one of the most widely used methods to compute HALE. Although criticized for excluding the possibility of recovering from disability to health, Sullivan’s method can produce reliable estimations of health expectancy if no sudden or significant health events occur (5).

The estimated annual percentage change (EAPC) was determined using linear regression, formulated as y=α+βx+ ε, where x=year and y=ln(rate). The EAPC was calculated using the formula 100 × (e^β−1). LE and HALE were considered to increase if the EAPC value and the lower limit of the 95% confidence interval (CI) were above 0. Conversely, LE and HALE were considered to decrease if the EAPC value and the upper limit of the 95% CI were below 0. Otherwise, LE and HALE were considered stable over time. A joinpoint regression model with natural log-transformed rates was used to analyze the LE and HALE of the 29 countries between 1990 and 2021. A grid search method (GSM) and Monte Carlo permutation test were used to distinguish periods. This analysis was performed using the Joinpoint Regression Program (v4.9.10, Statistical Research and Applications Branch, National Cancer Institute, Washington, USA) (6-7). The sociodemographic index (SDI) is a socioeconomic indicator scored from 0 (worst) to 1 (best), measured by the total fertility rate of the population aged under 25 (TFU25), the average educational attainment of the population aged 15 and over (EDU15+), and the lag distribution of per capita income. Loess regression was employed to examine the association between LE or HALE and SDI. Data analysis and visualization were carried out using R version 4.3.3 (R Core Team, Vienna, Austria, 2024).

Across the Asia-Pacific region, LE at birth in 2021 ranged from 58.23 years [95% uncertainty interval (UI): 56.25, 60.27] in Afghanistan to 85.70 years (95% UI: 85.50, 85.90) in Singapore. HALE at birth in 2021 ranged from 49.87 years (95% UI: 46.94, 52.24) in Afghanistan to 74.96 years (95% UI: 71.74,77.63) in Singapore. Afghanistan was the only country with LE at birth less than 60 years and HALE at birth less than 50 years in 2021. Five countries, including Singapore, Japan, the Republic of Korea, Australia, and New Zealand, had LEs above 80 years and HALEs above 70 years in 2021. Afghanistan, Papua New Guinea, Pakistan, and Fiji had the lowest LE and HALE in 2021. According to EAPC, LE and HALE at birth increased significantly from 1990 to 2021 in all the studied countries. The largest LE increase was observed in the Lao People’s Democratic Republic (EAPC=0.93, 95% CI: 0.89, 0.97), and the smallest in the Philippines (EAPC=0.08, 95% CI: 0.04, 0.11). The largest HALE increase was observed in the Lao People’s Democratic Republic (EAPC=0.93, 95% CI: 0.89, 0.97), and the smallest in Fiji (EAPC=0.09, 95% CI: 0.07, 0.12). In addition, the EAPCs of HALE in the countries with the lowest LE and HALE were 0.58 (95% CI: 0.50, 0.66) for Afghanistan, 0.22 (95% CI: 0.19–0.25) for Papua New Guinea, and 0.25 (95% CI: 0.21, 0.29) for Pakistan (Table 1).

The Joinpoint regression analysis revealed that nearly all countries experienced increases in LE and HALE at birth from 1990 to 2021, with the average annual percentage change (AAPC) above zero. Exceptions included the Philippines, Fiji, and the Democratic People’s Republic of Korea (DPRK) for LE, and Fiji and the DPRK for HALE (Figure 1). The patterns of change in LE and HALE in Asia-Pacific countries between 1990 and 2021 can be broadly categorized as: 1) continuous increases, such as in China, Bhutan, and Australia; 2) declines in the first few years followed by upward trends and subsequent declines in the last few years, such as in Fiji, Mongolia, and Pakistan; and 3) upward trends for most of the period followed by downward trends in the last few years, such as in Cambodia, Bangladesh, and Viet Nam (Table 2).

Figure 1. 

Joinpoint analysis of LE (A) and HALE (B) in individuals at birth across Asia-Pacific countries, 1990 to 2021.

Abbreviation: AAPC=average annual percent change; LE=life expectancy; HALE=health-adjusted life expectancy; DPRK=Democratic People’s Republic of Korea.

Figure 2 shows the association between LE and HALE at birth and SDI across Asia-Pacific countries in 2021. In the Asia-Pacific region, LE and HALE at birth continually increased as SDI increased, although the rate of increase slowed around an SDI of 0.6. Based solely on SDI, LE and HALE at birth were much higher than expected in Maldives and lower in Fiji (Figure 2A and C). Regarding HALE, among the four Asia-Pacific countries with the lowest SDI, three (Afghanistan, Nepal, and Papua New Guinea) showed an inverted-U-curve pattern, while one country (Timor-Leste) experienced increasing HALE at birth. There were three different patterns in low-middle SDI and middle SDI quintile countries: an inverted-U-curve in four countries (India, Pakistan, Philippines, and Indonesia), a U-curve pattern in four countries (DPRK, Fiji, Mongolia, and Thailand), and an increasing growth pattern in seven countries (Bangladesh, Bhutan, Cambodia, Lao People’s Democratic Republic, Myanmar, Maldives, and Viet Nam). Of the countries with high-middle SDI, three (China, Malaysia, and Sri Lanka) exhibited an increasing pattern, while one country (Iran) showed an inverted-U-curve pattern. Of the six countries with the highest SDI, all (Australia, New Zealand, Japan, Republic of Korea, Singapore, and Brunei Darussalam) experienced a growth pattern (Figure 2D). Similarly, LE also exhibited a comparable association with SDI across these countries in the Asia-Pacific region.

Figure 2. 

Life expectancy (LE) and health-adjusted life expectancy (HALE) at birth across Asia-Pacific countries by SDI, 1990–2021. (A) LE, 2021; (B) LE, 1990–2021; (C) HALE, 2021; (D) HALE, 1990–2021.

Abbreviation: LE=life expectancy; HALE=health-adjusted life expectancy; SDI=sociodemographic index; DPRK=Democratic People’s Republic of Korea.