Impact of exposure to ambient air pollution on health related quality of life of rural elderly in western China – Nature

 

Executive Summary: Impact of Ambient Air Pollution on Health-Related Quality of Life in Rural Western China

This report details a study investigating the association between long-term exposure to ambient air pollution and the Health-Related Quality of Life (HRQoL) among 4,349 elderly residents in rural western China. The findings provide critical evidence for policymakers aiming to achieve Sustainable Development Goal 3 (Good Health and Well-being) and SDG 11 (Sustainable Cities and Communities). The study reveals a significant negative correlation between concentrations of air pollutants (PM_2.5, PM₁₀, SO₂, and O₃) and the health utility index of the elderly population. Specifically, SO₂ demonstrated the most substantial negative impact. The degradation in quality of life was primarily observed through diminished capacity for self-care, usual activities, and mobility. These results underscore the urgent need for targeted environmental and health interventions to protect vulnerable populations, reduce health inequalities (SDG 10), and advance the sustainable development agenda.

Introduction: Aligning Public Health with Sustainable Development Goals

Context: Air Pollution as a Barrier to SDG 3 and SDG 10

Ambient air pollution, exacerbated by urbanization, industrialization, and agricultural practices, remains a primary global public health challenge. It is a significant impediment to achieving SDG 3, particularly Target 3.9, which aims to substantially reduce deaths and illnesses from air pollution. The World Health Organization estimates that air pollution causes over 4 million premature deaths annually. This environmental burden disproportionately affects vulnerable populations, including the elderly and those with lower socioeconomic status, thereby widening health disparities and hindering progress on SDG 10 (Reduced Inequalities). While numerous studies have explored the link between air pollution and specific diseases, there is limited research on its long-term impact on the overall HRQoL of the rural elderly in developing regions like western China.

Study Objective: Quantifying Health Impacts for Policy Intervention

This study aims to address this research gap by examining the association between long-term exposure to ambient air pollution and the HRQoL of the elderly in rural Ningxia, western China. By quantifying this relationship, the research provides scientific evidence to support the formulation of effective health and environmental policies. Such policies are crucial for protecting high-risk groups, improving their quality of life, and ensuring that progress towards sustainable development is inclusive and leaves no one behind.

Methodology: Assessing Health and Environmental Factors

Study Population and Design

A cross-sectional study was conducted utilizing 2022 follow-up data from a long-term project in Ningxia. A multistage stratified cluster random sampling method was employed across four counties. The final analysis included 4,349 participants aged 60 years and older.

Environmental Data and SDG 11

To assess environmental conditions relevant to SDG 11 (Target 11.6: Reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality), data on the following pollutants were collected from the National Earth System Science Data Center:

• Particulate Matter (PM_2.5)
• Particulate Matter (PM₁₀)
• Sulfur Dioxide (SO₂)
• Ozone (O₃)

Average concentrations from 2019 to 2021 were matched to each respondent based on their village location.

Health Assessment and SDG 3

To measure HRQoL, a key indicator for SDG 3, the Chinese version of the EuroQol Five-Dimension Three-Level (EQ-5D-3L) instrument was used. This tool assesses five dimensions of health:

1. Mobility (MO)
2. Self-Care (SC)
3. Usual Activities (UA)
4. Pain/Discomfort (PD)
5. Anxiety/Depression (AD)

Responses were converted into a health utility index, with a value of 1 representing perfect health.

Statistical Analysis

The study employed several statistical models to analyze the data. A Tobit regression model was used to assess the association between air pollutants and the health utility index. Restricted Cubic Spline (RCS) models explored potential nonlinear dose-response relationships, and logistic regression was used to identify the specific health dimensions (pathways) affected by pollution.

Key Findings: The Detrimental Impact of Air Pollution on Well-being

Health-Related Quality of Life (HRQoL) Profile

The overall HRQoL of the elderly population in the study area was poor. The average health utility index was 0.93. The most frequently reported issue was Pain/Discomfort, affecting 34.24% of respondents. Women generally reported more health problems and a lower health utility index than men, highlighting an inequality within this vulnerable group that is relevant to SDG 10.

Correlation between Air Pollutants and Reduced HRQoL (SDG 3.9)

Tobit regression analysis revealed a clear negative association between long-term exposure to air pollutants and the HRQoL of the elderly. This directly supports the need for action under SDG Target 3.9.

• For every 1 µg/m³ increase in SO₂, the health utility index decreased by 0.010 (P < 0.05).
• For every 1 µg/m³ increase in PM_2.5, the health utility index decreased by 0.005.
• For every 1 µg/m³ increase in O₃, the health utility index decreased by 0.002.
• For every 1 µg/m³ increase in PM₁₀, the health utility index decreased by 0.001.

Other factors negatively associated with HRQoL included older age, physical inactivity, and the presence of chronic diseases.

Pathways of Impact: How Pollution Affects Daily Life

The study identified the specific pathways through which air pollution diminishes health utility. The loss of quality of life was not abstract but manifested in tangible daily struggles.

• SO₂ exposure was negatively correlated with the dimensions of Self-Care, Usual Activities, and Mobility.
• PM_2.5 and PM₁₀ exposure was negatively correlated with the dimensions of Self-Care and Usual Activities.

These findings indicate that air pollution directly impairs the ability of the elderly to perform basic daily tasks, care for themselves, and move freely, severely compromising their well-being and independence.

Discussion: Implications for Sustainable Development

Reinforcing the Link Between Environment and Health (SDG 3 & SDG 11)

This study provides robust evidence that environmental health is inseparable from human health. The negative impact of PM_2.5, PM₁₀, and SO₂ on the HRQoL of the rural elderly demonstrates that achieving SDG 3 (Good Health and Well-being) is contingent upon making progress on SDG 11 (Sustainable Cities and Communities), particularly its target on reducing air pollution. The findings show that pollutants impair physical functions related to mobility, self-care, and daily activities, leading to a lower quality of life.

Addressing Vulnerabilities and Inequalities (SDG 10)

The research highlights significant health inequalities, a core concern of SDG 10. The elderly in rural western China, a population with lower socioeconomic status, are shown to be particularly vulnerable to the effects of air pollution. Furthermore, factors such as age, chronic disease status, and lack of physical exercise exacerbate these negative health outcomes. Policies aimed at reducing air pollution must, therefore, incorporate an equity lens, prioritizing the protection of the most vulnerable groups to ensure no one is left behind.

Study Strengths and Limitations

The study’s strengths include its focus on a previously under-researched, vulnerable population and its detailed analysis of the pathways through which pollution affects health. A limitation is the cross-sectional design, which prevents the establishment of causality. However, the findings are consistent with a large body of international research and provide a strong basis for policy action.

Conclusion and Policy Recommendations for Achieving SDGs

The Health-Related Quality of Life for the elderly in rural western China is poor and is significantly worsened by exposure to ambient air pollution, particularly SO₂, PM_2.5, and PM₁₀. This environmental burden impairs fundamental aspects of daily living, including mobility, self-care, and usual activities.

To make meaningful progress towards SDG 3, SDG 10, and SDG 11, it is imperative to:

1. Formulate Integrated Environmental and Health Policies: Governments must develop and enforce policies that reduce the concentration of ambient air pollutants, such as promoting cleaner energy sources for heating and cooking in rural areas.
2. Implement Targeted Health Interventions: Public health programs should be designed to support vulnerable elderly populations. This includes promoting physical activity, improving chronic disease management, and raising awareness about the health risks of air pollution.
3. Strengthen Monitoring and Research: Continued monitoring of air quality and its health impacts on different population groups is necessary to evaluate policy effectiveness and adapt strategies over time.

By addressing the environmental determinants of health, policymakers can improve the quality of life for the rural elderly, reduce health inequalities, and build more sustainable and resilient communities for all.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The article primarily addresses issues related to the following Sustainable Development Goals (SDGs):

1. SDG 3: Good Health and Well-being

   This is the most central SDG in the article. The entire study is focused on the “association between ambient air pollution and health-related quality of life (HRQoL)”. It investigates how environmental pollution directly impacts the physical and mental health of the rural elderly population, mentioning increased morbidity and mortality from diseases like cardiovascular and respiratory conditions, and assessing well-being through the EQ-5D-3L health utility index.

2. SDG 11: Sustainable Cities and Communities

   Although the study is set in a rural area, SDG 11 is relevant through its focus on environmental quality in human settlements. The article discusses the impact of “ambient air pollution” from sources like “industrialization, forest fires, traffic congestion and agricultural burning”. It directly measures air quality, which is a key component of creating sustainable and healthy living environments for all populations, whether urban or rural.

3. SDG 10: Reduced Inequalities

   The article highlights significant inequalities. It specifically focuses on a vulnerable demographic: “the rural elderly population” in “western China”. It notes that “environmental pollution has a greater impact on people with lower socioeconomic status” and finds that factors like age, gender, education, and chronic disease status are associated with poorer health outcomes, thereby addressing the goal of reducing health inequalities among different population groups.

2. What specific targets under those SDGs can be identified based on the article’s content?

Based on the article’s focus, the following specific SDG targets can be identified:

• Target 3.9: Substantially reduce deaths and illnesses from pollution

  The article’s main objective is to investigate the “impact of environmental pollution on health”. It explicitly links exposure to air pollutants like PM₂.₅, PM₁₀, and SO₂ to a decrease in the “health utility index” and an increase in health problems. The introduction states that “ambient air pollution causes more than 4 million premature deaths per year worldwide” and leads to “increased morbidity and mortality from systemic diseases such as cardiovascular and respiratory diseases,” directly aligning with the goal of reducing illnesses and deaths from air pollution.

• Target 11.6: Reduce the environmental impact of cities (and settlements)

  This target aims to “reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality”. The study is a direct application of this target by measuring and analyzing the “annual average concentrations of PM₂.₅, PM₁₀, SO₂ and O₃” in the study area. The conclusion calls for policies to “reduce the concentration of air pollutants,” which is the core objective of this target.

• Target 3.4: Reduce mortality from non-communicable diseases and promote mental health

  The article connects air pollution to “cardiovascular and respiratory diseases” and notes that “chronic disease were negatively associated with the health utility index”. These are non-communicable diseases (NCDs). Furthermore, one of the five dimensions of health measured is “anxiety/depression,” directly addressing the mental health and well-being component of this target.

• Target 10.2: Promote universal social, economic and political inclusion

  The study’s focus on the “elderly population in rural areas of western China” and its findings that “age, exercise status, and chronic disease were negatively associated with the health utility index” highlight the health-related exclusion and vulnerability of this specific group. By providing evidence for this disparity, the research supports the need for inclusive policies that protect high-risk groups, as called for in the conclusion: “formulate stronger health policies… which can protect high-risk groups from the hazards of ambient air pollution”.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article mentions and uses several quantitative and qualitative indicators that align with official SDG indicators or serve as effective proxies:

• Indicator for Target 11.6 (and relevant to 3.9): Annual mean levels of fine particulate matter (Indicator 11.6.2)

  The article explicitly measures and reports the annual mean concentrations of key air pollutants. It states: “PM₂.₅ was 28.74 µg/m³, PM₁₀ was 73.18 µg/m³, SO₂ was 12.15 µg/m³, and O₃ was 105.91 µg/m³”. This data directly corresponds to Indicator 11.6.2, which tracks the annual mean levels of PM₂.₅ and PM₁₀ in human settlements.

• Indicator for Target 3.9: Mortality rate attributed to air pollution (Indicator 3.9.1)

  While not calculating a specific mortality rate for the study population, the article heavily implies this indicator by referencing global data (“ambient air pollution causes more than 4 million premature deaths per year worldwide”) and linking exposure to increased “morbidity and mortality from systemic diseases”. The study’s findings of a negative correlation between pollutants and health serve as a basis for estimating this mortality burden.

• Proxy Indicators for Target 3.4: Health-Related Quality of Life (HRQoL) and prevalence of NCDs

  The article uses the “health utility index” derived from the EQ-5D-3L scale as a comprehensive indicator of health and well-being. The five dimensions measured—”mobility, self-care, usual activities, pain/discomfort and anxiety/depression”—provide detailed metrics on physical and mental health. The study also uses “chronic disease status” as a key covariate, indicating the prevalence of NCDs within the population, which is directly related to the goals of Target 3.4.

4. Table of SDGs, Targets, and Indicators

SDGs	Targets	Indicators Identified in the Article
SDG 3: Good Health and Well-being	Target 3.9: Substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination. Target 3.4: Reduce by one third premature mortality from non-communicable diseases and promote mental health and well-being.	– Mortality and morbidity from air pollution (referenced from global data). – Health Utility Index (measured via EQ-5D-3L) as an indicator of overall health status. – Prevalence of problems in health dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. – Prevalence of chronic diseases (NCDs) in the study population.
SDG 11: Sustainable Cities and Communities	Target 11.6: Reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality.	– Annual mean concentrations of air pollutants: PM₂.₅ (28.74 µg/m³), PM₁₀ (73.18 µg/m³), SO₂ (12.15 µg/m³), and O₃ (105.91 µg/m³). (Directly corresponds to Indicator 11.6.2).
SDG 10: Reduced Inequalities	Target 10.2: Empower and promote the social, economic and political inclusion of all, irrespective of age, sex, disability, etc.	– Analysis of health outcomes (HRQoL) stratified by age (elderly), location (rural western China), and socioeconomic status. – Identification of vulnerable groups (elderly, women, those with chronic diseases) who experience disproportionately negative health impacts from pollution.

Source: nature.com