With more than half of the world’s population already living in cities and further growth expected, the health of urban dwellers is decisive to global well-being.

The value of linking urban environment and health and wellbeing outcomes is now well recognized, but the myriad relationships are far from being understood scientifically.

Urban environments are multi-faceted, diverse, dynamic, complex and evolving, same as the underlying features for human health and wellbeing. Globally, health status is better in urban areas than in rural areas, and the many positive aspects of urban life, such as employment, higher incomes, better opportunities for education, and access to health care, encourage rural to urban migration.

However, recent studies have shown that such advantages of urban health status can be dilapidated due to the adverse impacts of the urban environment, increased fat and sugar in the diet, and sedentary ways of living.

Potential urban hazards with associated health risks include substandard housing, crowded living conditions, contaminated food, unclean water, inadequate sanitation, poor solid waste disposal services, air pollution, etc…

Health inequality is the curse of many countries. Although improved living standards have reduced the toll of infectious disease over the years, the world’s poorest urban dwellers remain vulnerable to outbreaks like cholera and Zika virus. Slums provide the ideal place for pathogens to thrive.

City Facts

  • More than half the world’s population now live in cities.
  • By 2030, 6 out of 10 people will be city dwellers. This figure will even rise to seven out of every 10 people by 2050.
  • The urban population of developing countries is growing by an average of 1.2 million people per week, or around 165,000 people every day.
  • One out of three urbanites lives in slums, or a total of 1 billion people worldwide.
  • Globally, road traffic injuries are the ninth leading cause of death, and most road traffic deaths occur in cities (especially, of low- and middle-income countries).
  • Urban air pollution kills around 1.2 million people each year around the world. This is mainly due to cardiovascular and respiratory diseases, and a major proportion of urban air pollution is caused by motor vehicles. Industrial pollution, electricity generation and in the least developed countries household fuel combustion are also major contributors.
  • Urban environments tend to discourage physical activity. It also promotes unhealthy food consumption. In urban regions, participation in physical activity is made difficult by a variety of urban factors including overcrowding, high-volume traffic, heavy use of motorized transportation, poor air quality and lack of safe public spaces and recreation/sports facilities.
  • Tuberculosis (TB) incidence is much higher in big cities. For example, in New York City, TB incidence is 4x the national average, and in the Democratic Republic of the Congo, 83% of people with TB live in cities.

Linkages Between Urban Environment And Wellbeing

The health risks associated with the urban environment are diverse, and many cities face at least five types of health threats:

  1. Infectious diseases that bloom when people are crowded together in substandard living conditions;
  2. Acute and chronic diseases such as respiratory disease and pulmonary cancer that are related to industrial pollution;
  3. Chronic, non-communicable diseases that are on the rise in unhealthy urban lifestyles due to physical inactivity, unhealthy diets, tobacco smoking, and harmful use of alcohol;
  4. Injuries resulting from road accidents, violence, and crime; and
  5. Climate change-related health risks, like, heat stress and changed patterns of infectious disease, which are considered as one of the biggest health risks in the 21st century.

These linkages are by no means unidirectional, and there is a strong case for an enhanced focus on human health and wellbeing in achieving urban sustainability.

Health and wellbeing of citizens including physical and emotional health, is at the center of the sustainability plan, as social and economic pillars of sustainability cannot be achieved without the total wellbeing of the community.

Health Equity Issues Related To Living Environment In Urban Areas

Epidemiological studies have acknowledged increased morbidity and mortality from motor vehicle air pollution, and poor people often live in the most exposed areas.

In Bangkok, as much as 29% of all deaths related to cardiovascular disease may be because of current air pollution. In children and young people, injuries related to motor vehicle traffic are among the most common causes of death. Unfortunately, this problem is rapidly increasing in developing countries contributing to health inequity.

Walking and cycling as a natural part of daily transport has diminished and lack of daily physical activity contributes to increasing body weight in many nations.

Car use is also implicated in changing dietary patterns with increasing consumption of high-energy and high-fat “fast foods. Major visible economic inequalities within cities contribute to social tensions and pervasive fear of crime. This further limits outdoor physical activities.

Cities require constant energy and resource inputs, as well as constant waste disposal to be able to sustain human life, and in order to achieve sustainability, modern cities need to be planned and managed with these resource and waste issues in mind.

An important contemporary resource depletion issue is global climate change, of which cities contribute to climate change through their large energy demands. The health effects of a warming world are likely to be overwhelmingly negative.

Some health effects like effects of reduced local food production, affect rural people more than urbanites, whereas other effects are more prominent in cities (e.g the effects of heat waves which are exacerbated by the urban “heat island” effect).

Urbanization also involves a shift in consumption from wild game meat or small landholder/householder reared poultry and pork to industrially reared beef, pork, and chickens, which has shown to have numerous health and environmental consequences.

For example, land-clearing, extensive use of fertilizers, pesticides, the recycling of feathers, carcass, and waste, and the use of veterinary antibiotics and large numbers of livestock has contributed to methane production (a more potent greenhouse gas than carbon dioxide).

Stress

Statistics, as mentioned above, correlate with negative health outcomes in cities around the world. About 40% of the city’s children (and 62% of adults) are overweight or obese.

To improve the health of city residents, cities must transform their physical and social environments to improve the health of citizens. Everything from their parks and housing, to the way that community members participate in their city’s governance.

Toxic stress: For many years, researchers have worked to solidify the links between chronic psychological stress and physical health, and in 1996, a genomics researcher at the University of California, Los Angeles, noticed that HIV progressed faster in gay men who concealed their homosexuality than in men who were open about it.

This showed that men who concealed their sexuality were more psychologically sensitive to social threats, and to stress correlated with increased activity of the sympathetic nervous system (SNS).

The basis of the body’s fight-or-flight response kicks into action by releasing adrenaline and noradrenaline, readying the body for physical activity. This flight or fight activation also shuts down proteins involved in fighting viruses, called interferons, allowing HIV and similar infections to replicate without impediment.

Epidemiologists knew that asthma was disproportionately common in children from poor urban communities, even when family history and air quality were controlled for.

Studies have shown that children with asthma from poorer backgrounds, and in more stressful situations, tended to have higher counts of white blood cells called eosinophils.

When given the right allergic trigger, eosinophils kick off the production of molecules that constrict the airways as well as mucus production, resulting in shortness of breath. And eosinophil recruitment, the researchers found, follows the fight or flight activation and the subsequent production of the inflammatory molecule interleukin-5.

Biological connections to chronic stress have also been found in conditions such as cardiovascular disease and type-2 diabetes, and people from low socioeconomic communities regularly show signs of chronic stress.

Psychological stress among the urban poor is distinct from that of those who live in rural areas. Income disparity is not as obvious in rural areas. However, Cities expose you to inequality, and you see what apartments in rich neighborhoods look like, which you cannot afford.

You also know how much food costs at restaurants in those places, and cannot help but make comparisons. Well-being is heavily impacted by comparisons and impacts your evaluation of self-worth and self-identity.

Reducing The Burden

Green space:

Urban green spaces have value beyond their beauty and environmental importance since nature improves mental health, and people are less depressed when they have better access to green spaces.

green space

The beneficial effect is not just a matter of physical exercise (although that is part of the picture), there is something about natural environments that improve people’s well-being, and being in nature feels good.

Spending time outdoors in natural environments not only improves people’s mental health, but it could also help to reduce health inequalities between the rich and the poor. Being around nature makes people feel better mentally, and that is an important policy implication.

Poor mental health is one of the biggest public-health problems in Western nations, and statistics showed that mental-health conditions such as depression cost the United Kingdom £70 billion (US$100 billion) annually in health-care spending and lost productivity.

A 2010 meta-analysis showed that urbanites are roughly 20% more likely to develop anxiety disorders than their rural counterparts, and nearly 40% more likely to develop mood disorders.

Workplace Hazard Interventions

Numerous reports describe prevention methods for specific work-related hazards like lead, asbestos, organic solvents, silica dust, accidents/injuries, etc., including materials from the occupational health and safety programs of WHO and International Labor Organization (ILO).

Low-income people generally end up working in jobs in the unprotected informal sector with the greatest health risks.

What Can Cities Do in Order to Meet The Challenges?

  • Uphold urban planning for healthy behaviors and safety.
  • Improve urban living conditions, like access to adequate shelter and sanitation for all.
  • Involve local urbanites and communities in local decision- making.
  • Make urban areas resilient to emergencies and disasters, and
  • Ensure cities are accessible and age-friendly.

Key Messages

  • Clean and sufficient drinking water, proper sanitation and drains for wastewater, and proper solid waste management are the key health equity interventions in deprived urban areas.
  • Household energy supply is a major environmental health issue, and alternative fuels for cooking and heating need to be made available, to provide great benefits for health.
  • Availability and access to public transport is a key element in improving transport equality and reducing the negative health impacts of the “car society.”
  • Interventions to create a sustainable food supply based on principles of resource conservation and environmental protection is a solution for future health equity.
  • Global climate change is likely to affect the health of all, especially, poor people in both rural and urban areas. Actions to reduce its severity are therefore actions to improve the well-being of urban dwellers.

Conclusion

A timely improvement in the living environment for all is necessary for wellbeing and health equity. This will require a greater transfer of financial and technical resources from the affluent to the less affluent.

Reference:

  • UN-Habitat. The Challenge of Slums: Global Report on Human Settlements. Nairobi, Kenya, UN: Habitat; 2003.
  • Kirdar U. Cities Fit for People. New York: UNDP; 1997.
  • Galea S, Vlahov D. Handbook of Urban Health. New York: Springer; 2005.
  • Kawachi I, Wamala S. Globalization and Health. New York: Oxford University Press; 2007.
  • Kjellstrom, T, Corvalan, C. Framework for the development of environmental health indicators. World Health Stat Q. 1995;48:144–154. [PubMed]
  • Corvalan C, Briggs D, Kjellstrom T. Development of environmental health indicators. In: Briggs D, Corvalan C, Nurminen M, eds. Linkage Methods for Environment and Health Analysis. Geneva: World Health
  • Making a Difference: Indicators to Improve Children’s Environmental Health. Geneva: World Health Organization; 2003.
  • From Theory to Action: Implementing the WSSD Global Initiative on Children’s Environmental Health Indicators. Geneva: World Health Organization; 2004.
  • Commission for Environmental Cooperation. Children’s Health and the Environment in North America. Montreal: Commission for Environmental Cooperation (produced in collaboration with PAHO); 2006.
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