A new tool has been developed to map how various features of where we live influence public health.

The HLI shows healthy and unhealthy elements in New Zealand's cities. It gives important lessons for how we plan and modify our cities to increase physical activity levels and tackle important issues such as obesity and mental health.

The obesogenic environment

New Zealand has one of the highest rates of obese people in the world. From the previous year, there was a significant increase in both childhood and adult Obesity.

5 percent of all global deaths are caused by Obesity and it is a major public health concern. The global economic impact of being overweight is estimated at US$2 trillion.

In terms of personal responsibility, health issues like this are often thought of. The approach diverts focus away from health systems, governments and physical environments.

Since 1980 the global rise in Obesity has not been caused by genetic or biological factors. It may be a normal response to environments that provide easy access to energy-dense, nutrient-poor foods and a range of unhealthy options that require us to use a lot of energy.

Maintaining good health in our current environment requires a lot of effort. Why?

Because healthy choices are more difficult than convenient ones, be that trying to avoid fast-food outlets or conveniently placed liquor stores, the lack of access to fresh fruit and vegetables, or deciding to cycle rather than drive the car.

This is an obesogenic environment and needs to be changed.

The Healthy Location Index

The change begins with an understanding of how things currently stand.

Fast-food outlets, dairies, convenience stores, alcohol outlets and gaming venues are some of the features that data used in our index includes.

Five features that we quantify are green spaces, blue spaces, physical activity facilities, fruit and vegetable outlets, and supermarkets.

The index shows a rank for every neighborhood in New Zealand based on access to positive and negative features.

Out of New Zealand's three major urban regions, Wellington is the most health-promoting and health-constraining environments, with a high proportion of people living in more health-constraining environments.

The healthy location index is in New Zealand. Matthew Hobbs and Lukas Marek.

Environmental injustice

The bigger picture created by the HLI supports previous evidence that shows a disproportionate number of features that restrict health, such as fast-food outlets and liquor stores.

In the most deprived areas, the distance to health-constraining features was half what it was in the least deprived areas.

This phenomenon is a form of environmental injustice, which stems from a lack of equity in the development, implementation and enforcement of environmental laws, regulations and policies.

The index shows how areas of New Zealand with quick and easy access to health-constraining features are worse off in terms of both mental and physical health outcomes.

The index shows that the most deprived areas of New Zealand often have access to health-constraining features, but it is not universal. It varies from place to place.

The number of health-promoting environments is decreasing in Wellington. There are more health-constraining places in Wellington than in Christchurch.

Knowledge offers a way to change

We intend to add more features in the future and this is our first iteration of the index. We hope the data provided in the index will encourage important conversations to help understand how our cities are shaped.

We need to ask ourselves if we really need a fast-food outlet or a liquor store in the same neighborhood. We hope the index will help policy makers decide how to shape more health-friendly cities by regulating or adding features.

The protection and promotion of public health is a core responsibility of the government and should not be left to individuals, families or communities.

Matthew and Lukas are both Senior Lecturers in Public Health and Co-Directors of the GeoHealth Laboratory at the University of Canterbury.

This article is free to use under a Creative Commons license. The original article is worth a read.