Report on Socioeconomic Disparities in Heat Vulnerability Among Adults in Finland

Abstract

This study investigates the association between low socioeconomic status (SES) and heat vulnerability in Finland, a developed country with a cooler climate. Data from 1,828 participants aged 25 and over, collected via surveys in 2020 and 2021, were analyzed. Heat vulnerability was measured using a nine-item index, and SES was categorized as low or other. Adjusted linear regression models revealed that low SES is significantly associated with increased heat vulnerability (ß = 1.06, 95% CI: 0.90–1.21), with slightly higher effects observed in men and individuals aged 65 or older. These findings underscore the importance of addressing socioeconomic disparities to mitigate heat-related health risks, aligning with the Sustainable Development Goals (SDGs), particularly SDG 3 (Good Health and Well-being) and SDG 10 (Reduced Inequalities).

Introduction

Heatwaves have globally recognized adverse impacts on human health, including increased morbidity and mortality. Rising global temperatures and more frequent, severe heatwaves pose escalating risks. Vulnerability to heat is influenced by exposure, sensitivity, and adaptive capacity, with socioeconomic position potentially affecting all these factors. Notably, the elderly are particularly susceptible due to physiological changes and chronic illnesses. Despite Finland’s robust social welfare system, regional disparities and unemployment contribute to socioeconomic challenges. This study aims to explore the relationship between SES and heat vulnerability in Finland, contributing to SDG 3 and SDG 10 by identifying vulnerable populations and informing targeted interventions.

Methods

Design and Participants

A cross-sectional, population-based survey was conducted in 2020 and 2021 with a random sample of Finnish adults aged 25 and over. The survey included questions on heat, social, and health-related factors and was available in Finnish, Swedish, and English. The final analysis included 1,828 participants with complete data. Ethical approval was obtained, and informed consent was secured.

Heat Vulnerability Index

A nine-item heat vulnerability index was constructed based on self-reported variables reflecting sensitivity, exposure, and adaptive capacity, guided by WHO recommendations and literature. The variables included:

1. Living alone
2. Presence of multiple health disorders
3. Residence in a high-rise apartment building
4. Lack of active cooling devices at home
5. Obesity (BMI ≥ 30)
6. Inability to walk continuously for 1 km
7. Non-adherence to heat warnings
8. Lack of awareness of heat-related risk groups
9. Low education level

The index score ranged from 0 to 9, with higher scores indicating greater vulnerability.

Socioeconomic Status (SES)

SES was dichotomized into low and other categories using an equivalized household income threshold of €20,000/year, calculated via the OECD-modified scale. This threshold captures economic disadvantage relevant to SDG 1 (No Poverty) and SDG 10 (Reduced Inequalities).

Statistical Analyses

Descriptive statistics and chi-squared tests assessed associations between SES and vulnerability factors. Linear regression models adjusted for age, gender, and survey year examined the relationship between SES and heat vulnerability. Analyses were conducted using Stata 17.0.

Results

Participant Characteristics

• Median age: 63 years
• Approximately 25% classified as low income
• One-third lived in apartment buildings
• One-sixth were obese
• Nearly half had low education levels

Heat Vulnerability Distribution

About 12% scored 0 on the vulnerability index, indicating no heat vulnerability factors, while nearly 10% scored between 5 and 7, reflecting higher vulnerability.

Associations by Gender, Age, and SES

• Women were more likely to live alone and in apartment buildings.
• Men had lower education, were less likely to follow heat warnings, and had less awareness of heat risks.
• Older participants (≥65 years) had higher prevalence of chronic conditions, lived alone more often, lacked cooling devices, had reduced mobility, and lower education.
• Low SES individuals were older, more often lived alone, had more health disorders, resided more in apartments, lacked cooling devices, had walking difficulties, and lower education.
• Low SES was significantly associated with higher heat vulnerability index scores (median 4 vs. 2, p

Regression Analysis

Adjusted linear regression confirmed low SES as a significant predictor of increased heat vulnerability (ß = 1.06, 95% CI: 0.90–1.21). Stratified analyses showed slightly stronger associations in men (ß = 1.13) and participants aged 65 or older (ß = 1.09), though differences were not statistically significant.

Discussion

This study demonstrates a significant link between low SES and increased heat vulnerability in Finland, emphasizing the need to address socioeconomic disparities in climate adaptation strategies. The findings align with SDG 3 (Good Health and Well-being) by highlighting health risks related to heat and SDG 10 (Reduced Inequalities) by identifying vulnerable socioeconomic groups.

Key Findings

• Low SES individuals face multiple heat vulnerability factors, including poor housing conditions, lack of cooling, social isolation, and lower education.
• Older adults with low SES are particularly vulnerable due to physiological and social factors.
• Men with low SES may be more prone to neglect heat warnings and have lower awareness of heat risks.
• Despite Finland’s strong social welfare system (SDG 1: No Poverty, SDG 3, SDG 10), heat vulnerability disparities persist.

Implications for Sustainable Development Goals

• SDG 3 (Good Health and Well-being): The study underscores the importance of protecting vulnerable populations from heat-related health risks through targeted public health interventions and awareness campaigns.
• SDG 10 (Reduced Inequalities): Addressing socioeconomic disparities is critical to reducing heat vulnerability and ensuring equitable access to adaptive resources such as cooling devices and social support.
• SDG 11 (Sustainable Cities and Communities): Enhancing the heat resilience of housing and urban environments, especially in apartment buildings, is necessary to protect vulnerable groups.
• SDG 13 (Climate Action): Developing heat-health action plans and early warning systems supports climate adaptation and resilience.

Recommendations

1. Develop and implement national heat-health action plans incorporating early warning systems.
2. Promote public awareness campaigns focused on heat risks and preventive behaviors, targeting low SES and elderly populations.
3. Improve housing conditions and increase access to active cooling devices, particularly for economically disadvantaged groups.
4. Encourage community-based support networks to reduce social isolation during heatwaves.
5. Conduct further research on additional factors influencing heat vulnerability and evaluate intervention effectiveness.

Limitations

• Relatively low survey response rate (38%) may introduce non-response bias.
• Self-reported data may be subject to reporting bias.
• The vulnerability index may not capture all relevant factors such as greenspace availability and household overcrowding.

Conclusion

Low socioeconomic status is significantly associated with increased heat vulnerability among Finnish adults, highlighting the necessity to integrate socioeconomic considerations into heat adaptation strategies. Addressing these disparities is essential to achieving the Sustainable Development Goals related to health, inequality reduction, sustainable communities, and climate action.

Data Availability

The datasets analyzed in this study are available from the corresponding author upon reasonable request (ville.paivarinne@thl.fi).

1. Sustainable Development Goals (SDGs) Addressed or Connected

• SDG 3: Good Health and Well-being
  • The article focuses on health impacts of heatwaves, particularly morbidity and mortality risks associated with heat vulnerability.
  • It highlights the need to mitigate heat-related health risks, especially among vulnerable populations such as the elderly and low socioeconomic status groups.
• SDG 10: Reduced Inequalities
  • The study emphasizes socioeconomic disparities in heat vulnerability, showing that low socioeconomic status (SES) increases heat-related health risks.
  • It discusses regional disparities and the importance of addressing inequalities in adaptive capacity and access to resources like cooling devices.
• SDG 11: Sustainable Cities and Communities
  • The article mentions living conditions such as residing in apartment buildings and urban heat exposure, which relate to sustainable urban planning and resilience to climate hazards.
  • It suggests improving heat resilience of buildings and urban areas to adapt to warming climates.
• SDG 13: Climate Action
  • The article addresses the increasing frequency and severity of heatwaves due to climate change.
  • It calls for development of heat-health action plans and early warning systems to adapt to climate change impacts.

2. Specific Targets Under the Identified SDGs

1. SDG 3: Good Health and Well-being
   • Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination.
   • Target 3.d: Strengthen the capacity of all countries for early warning, risk reduction and management of national and global health risks.
2. SDG 10: Reduced Inequalities
   • Target 10.2: By 2030, empower and promote the social, economic and political inclusion of all, irrespective of age, sex, disability, race, ethnicity, origin, religion or economic or other status.
   • Target 10.3: Ensure equal opportunity and reduce inequalities of outcome, including by eliminating discriminatory laws, policies and practices.
3. SDG 11: Sustainable Cities and Communities
   • Target 11.5: By 2030, significantly reduce the number of deaths and the number of people affected and substantially decrease the direct economic losses relative to global gross domestic product caused by disasters, including water-related disasters, with a focus on protecting the poor and people in vulnerable situations.
   • Target 11.b: By 2020, substantially increase the number of cities and human settlements adopting and implementing integrated policies and plans towards inclusion, resource efficiency, mitigation and adaptation to climate change, resilience to disasters.
4. SDG 13: Climate Action
   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries.
   • Target 13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning.

3. Indicators Mentioned or Implied to Measure Progress

• Heat Vulnerability Index
  • Composite score based on nine variables including living alone, presence of disorders, residence type, use of cooling devices, BMI, physical ability, adherence to heat warnings, awareness of risks, and education level.
  • Used to assess individual vulnerability to heat-related health risks.
• Socioeconomic Status (SES) Indicator
  • Defined by equivalized household income using OECD-modified scale with a threshold of €20,000/year to categorize low SES.
  • SES is used as a key factor associated with heat vulnerability.
• Health Outcome Indicators
  • Heat-related morbidity and mortality rates referenced from epidemiological studies.
  • Hospital admissions related to heatwaves (e.g., cardiorespiratory admissions).
• Behavioral and Awareness Indicators
  • Adherence to heat warnings and awareness of at-risk groups as measures of adaptive capacity.
• Demographic Indicators
  • Age groups (especially 65+), gender, and living arrangements as factors influencing vulnerability.

4. Table of SDGs, Targets, and Indicators

Source: nature.com