The purpose of the HHGL is to provide evidence-informed recommendations on how to achieve optimal housing standards that promote the health and well-being of occupants. While the GDG deems the access to safe and healthy housing a right for populations across all Member States, it also acknowledges that implementing these recommendations will be challenging and vary according to a country’s context (449). Therefore, the global guidance referring to structural aspects of healthy housing provided by these guidelines needs to be considered in the context of national and local priorities relating to the feasibility, acceptability, need and resources for implementing single recommendations. As such, successful implementation will require coordination between national, regional and local governments, and intersectoral collaboration between public, private and civil society actors, including implementing partners such as architects, urban planners, social housing services, consumer protecting agencies, and the building industry. Interventions reducing health risks from poor housing include direct changes to the built environment as well as the introduction of loans and subsidies to support these changes to the structural housing environment.
The implementation of housing standards also needs to take into consideration the life cycle of dwellings, i.e. construction of new buildings, inhabitation, renovation and demolition. Housing risks can also have an impact on health at different moments of a building’s life. Examples here are the use of asbestos and lead, as outlined in sections 8.5 and 8.6. Although the production and the control and management of asbestos during building retrofits and demolition is controlled, it is still a potential threat to health during habitation, and especially during the clean-up of damaged and destroyed buildings (e.g. after disasters such as tsunamis and earthquakes), and not only in low-income countries. The life course of the building is therefore an important dimension to be considered during the implementation of the guidelines, especially as some health-relevant guidance presented in the HHGL may not be implementable in some of the existing housing stock, or only at high cost.
Implementation of the guidelines will further vary depending on the geographical location of a country. While in some climate zones, a priority might be to protect people from excess indoor heat; in other regions the protection from indoor cold might be more important. As climate change is expected to reinforce the occurrence of extreme weather events and impact a country’s climatic conditions, the availability of safe and healthy housing offering protection from the consequences of climate change will become even more important. In addition, the socioeconomic circumstances of a country need to be taken into account. While there is growing evidence that the recommended interventions are cost-effective and cost-beneficial (see section 9.3), retrofitting existing housing or building a new housing stock adhering to the guidelines at large scale demands significant financial investment from governments, including subsidies to support communities and individual home owners in implementing new housing standards. Accordingly, the national implementation strategy needs to carefully assess the country’s needs and resources and accordingly prioritize those interventions that are the most feasible, appropriate and highly valued in the specific country context.
As the HHGL provide global guidance, they need to be adapted to the local context to best meet a country’s priorities and needs. WHO will provide technical assistance to its Member States for context-specific implementation of the HHGL. This will be done through joint efforts at all three levels of the organization and in close collaboration with other United Nations agencies involved in housing activities. A modular toolkit supporting the guidelines’ implementation at country-level is currently under development. This tailored implementation assistance will comprise tools to facilitate priority setting, needs assessment, stakeholder mapping, policy analysis, intersectoral dialogue, and outreach and advocacy activities. As implementation teams will be interdisciplinary, the toolkit will include various knowledge translation products, such as policy briefs and training materials, to enable intersectoral collaboration and mutual understanding.
9.1. Health in All Policies and housing
Housing interventions can represent a major opportunity to promote “primary prevention” through intersectoral action. The Health in All Policies approach emphasizes that ministries of health must act as stewards in other sectors to ensure that health objectives are considered in their policies (450). This includes advocating to promote access to social housing for vulnerable groups, ensuring standards for housing, and empowering vulnerable groups to enhance their security and ownership. To date, many ministries of health have not engaged fully with the health impacts of housing, in part because housing is often considered to be the responsibility of other departments of government, rather than health.
Implementing the HHGL entails different responsibilities for authorities, owners and occupiers in different Member States. Countries have distinctive administrative and legal environments, which may include central government departments, state departments, regional authorities or local authorities (municipalities). In some countries, responsibility for housing is spread across a number of government departments, including housing, construction, energy, urban planning, transport, public health, finance, industry and environment. In addition, policies in other departments affect housing supply and affordability, including those on immigration, wages and benefits, workforce training, and tax and monetary policy.
The HHGL demonstrate the interlinkages between housing and health and can serve as a starting point for ministries of health to work with other ministries to initiate policy processes to improve national and local housing standards. Effective policy coordination between government departments is therefore a critical step in implementing the HHGL.
This may include advocating for the importance of healthy housing and communicating potential health harms and benefits through closer involvement in housing assessments and building and renovation codes. In particular, the health sector can work to ensure that proposed housing interventions avoid harms and improve health and safety. It can identify individuals and households that could most benefit from housing assessments and interventions.
Implementing the HHGL is also an opportunity to strengthen the health sector’s engagement with the community, so as to generate a space for primary environmental action and to propose a political perspective that enables governmental organizations, nongovernmental organizations, communities, households, businesses and individuals to be part of the strategic planning, active monitoring and social control in the decision-making process and in the management of the healthy housing strategy. This may involve health advocates being represented in decision-making forums regarding construction and planning. WHO will work with ministries of health to support this role, and to ensure that health perspectives are strongly represented in policies related to housing. The implementation toolkit will provide training materials to promote such intersectoral dialogue and bring healthy housing to the agenda of policy-makers inside and outside the health sector.
9.2. Co-benefits from multifactorial interventions
The HHGL draw on systematic reviews of research that assessed the impact of specific exposures or interventions on health outcomes. This meant that some studies were not eligible for the systematic reviews because they reported the results of multifactorial interventions. Such interventions aim to address a number of housing risks at the same time, and sometimes seek to impact on other risks as well (e.g. to improve physical or mental functioning through exercise). While such multi-factorial interventions cannot ascribe a particular health effect to a particular part of the intervention, they can improve a range of health outcomes. Two illustrative examples are provided in Box 1.
Box 1
The Healthy Housing Programme in South Auckland, New Zealand, as a direct response to a type-B meningococcal disease epidemic, sought to reduce injuries, improve insulation and ventilation, and reduce crowding. This was found to be an efficient and cost-effective way of addressing multiple health risks at the same time, and there was a significant reduction in acute hospitalization for people aged under 34 years compared with the period before the multifactorial intervention (451).
The “breathe-easy homes” at High Point, Seattle, United States of America, were designed to reduce exposure to a range of environmental asthma triggers, using moisture-reduction features, enhanced ventilation systems, and materials that minimized dust and off-gassing. These measures reduced exposures to mould, rodents and moisture, and residents of the breathe-easy homes had more asthma-symptom-free days than previously after living for 1 year in the homes. The proportion of residents with an urgent asthma-related clinical visit in the previous 3 months decreased from 62% to 21% (452).
One study assessed the effects of providing upgraded housing to slum dwellers in El Salvador, Mexico and Uruguay (453). The upgraded housing had tin roofs and was made of insulated pinewood panels or aluminium, and was aimed at keeping occupants warm and protected from humidity, insects and rain. In addition, floors were raised above the ground to reduce dampness and protect occupants from floods and infestations. The housing therefore addressed a range of housing risk factors, and constituted a major improvement over other housing units in the informal settlements, which are typically constructed from poor materials such as cardboard and plastic, and have dirt floors. The analysis showed that people in households provided with upgraded housing were happier and more satisfied with the quality of their lives as compared with the control group. In El Salvador and Mexico, the analysis also showed improvements of child health.
When implementing the HHGL it will be helpful to take a multifactorial approach, addressing multiple risk factors at the same time in order to achieve a range of health benefits in the most efficient manner possible. This approach can reduce costs while improving health, and is consistent with the way housing improvements are often carried out. In addition, understanding the complex interactions associated with housing risk and interventions protects against unanticipated consequences, such as the decrease in indoor air quality associated with some early efforts to improve insulation in housing (454).
Currently, in some places, housing code inspectors or building assessors are often deployed based on a specific complaint, such as lack of heating or structural instability, and frequently only order corrections for that one violation of the building code. Similarly, health inspectors who examine housing conditions are often focused on specific issues, such as potable water and sewage, radon, lead or asbestos (358, 455, 456). Alternative regulatory approaches identify and treat multiple housing deficiencies that are often located within the same housing. Examples of the multifactorial approach include the English Housing Health and Safety Rating System, the United States National Healthy Housing Standard and the New Zealand Rental Warrant of Fitness (353–355). This approach can sometimes enable otherwise separate funding streams to be integrated, including, for example, funds intended to encourage energy efficiency and community development.
Such an approach is particularly suitable given that housing deficiencies often have the same root causes that together are associated with poor health outcomes. For example, excessive moisture can be simultaneously associated with: asthma and other respiratory conditions, due to increased exposure to mould; lead poisoning, due to paint failure; injuries, due to structural rot; increased exposure to pests such as cockroaches; and increased infiltration of radon from concrete, shale and soil (246, 457, 458). Thus, correction of moisture problems can lead to a variety of improvements in health outcomes via a variety of pathways. Similarly, correcting structural defects reduces the risk of injury, improves thermal temperature and reduces exposure to outdoor pollutants. The clear relationships between housing conditions and multiple different health risks, outlined in Chapter 1, emphasize that interventions can often easily and efficiently address multiple health risks at the same time. Therefore, policy-makers should have the co-benefits of multifactorial interventions in mind when enacting new regulations or subsidizing home modifications to maximize the efficiency of such policy interventions. The implementation toolkit will contain a repository of multifactorial interventions and their benefits, to facilitate evidence-informed decision-making by policy-makers.
9.3. Economic considerations for improving housing conditions
A recent systematic review highlights considerable evidence on the cost-effective health benefit of several housing interventions in several populations and country settings. For example, the five reviewed studies on lead removal for reducing lead poisoning showed that it was very cost-effective (459–463), and three studies on retrofitting insulation found that this was also highly cost-beneficial (40, 464, 465). An analysis of the New Zealand insulation subsidy programme reviewed in Chapter 4 showed that the benefits in savings to the health systems outweighed the cost of administrating and subsidizing the insulation scheme by almost 4 to 1, with higher benefit to cost ratios of 6 to 1 for children and older people (40); an earlier analysis with a smaller sample, and including energy savings and productivity benefits, found a benefit to cost ratio of 2 to 1 (464). Most analyses of home safety modification interventions have found these to be cost-effective (26, 359–366). For example, benefits outweighed costs in the cluster randomized trial of the impact of home modifications on falls in the New Zealand study reviewed in Chapter 6 (71). Drawing on insurance payments for medically treated home fall injuries, the benefits in terms of the value of DALYs averted and social costs of injuries saved outweighed the intervention by 6 to 1. The benefit–cost ratio can be at least doubled for older people and increased by 60% for those with a prior history of fall injuries (71).
A WHO cost–benefit analysis showed that improvements in water and sanitation access were cost-beneficial across all regions. In developing regions, the return on a US$ 1 investment was in the range US$ 5 to US$ 46, depending on the intervention. For the least developed regions, every US$ 1 invested to meet the combined water supply and sanitation Millennium Development Goals led to a return of at least US$ 5 (AFR-D, AFR-E, SEAR-D) or US$ 12 (AMR-B; EMR-B; WPR-B) (the letters refer to WHO subregional country groupings based on similar rates of child and adult mortality) (466). An analysis of water supply improvements in Manila, Philippines, found that improvements in water supply supported household finances, as residents were able to reallocate time saved in collecting water to income-generating activities (467). The Piso Firme programme replaced dirt floors with cement floors in some Mexican cities. Comparison of a control and treatment city showed that the programme significantly improved the health of young children, with a decreased incidence of parasitic infestations, diarrhoea, and the prevalence of anaemia, and a significant improvement in children’s cognitive development. People with cement floors reported improved satisfaction with housing, and reductions in self-assessed depression and stress scales. The authors found that the intervention was a more cost-effective policy for improving child cognitive development than Mexico’s cash transfer programme (468).
Multifactorial interventions have also been shown to be a good investment. For example, the South Auckland, New Zealand, multifactorial intervention found that reducing crowding, connecting housing occupants with health and social services, and improving housing quality reduces hospitalization rates, and had a positive benefit to cost ratio of 1.15 (451). A systematic review of multicomponent interventions aimed at reducing asthma morbidity concluded that these are a good investment, with each US$ 1 invested yielding US$ 5–14 in benefits (469). Since that review was carried out in 2011, further United States of America studies have shown that asthma home interventions yielded returns on investment of 1.90 (470), 1.46 (471) and 1.33 (472). In the United Kingdom, it has been estimated that reducing the number of dwellings where there are serious “category 1” hazards present (as defined under the Housing
Health and Safety Rating System, these include faulty wiring and boilers, very cold bedrooms, leaking roof, mould, pest infestation, broken steps, or lack of security due to badly fitting external doors or problems with locks) to an acceptable level would cost £10 billion, but the consequent improvements in occupant health would save the United Kingdom health services £1.4 billion in first-year treatment costs alone, allowing the investment to pay for itself in 7 years (240). In the European Union, it has been estimated that for every €3 invested in improving housing conditions, €2 would be recouped in 1 year from savings on health care and publicly funded services (473).
9.4. Training needs
Implementing the HHGL requires the training of a number of stakeholders. Health department professionals need evidence-based training and technical assistance programmes to help target communities living in substandard housing conditions and to provide solutions to combat hazards in their homes. The housing sector (in particular, housing agencies), need specialized training and technical assistance programmes to identify housing problems, to build better housing, and to remediate existing housing. Health and housing professionals have unique expertise to share, and cross-sector collaboration should be encouraged. The health and safety of workers involved in housing construction and remediation, as well the occupants of that housing, is imperative (247).
As part of the comprehensive implementation strategy, WHO and its partners will provide hands-on guidance and information tools, technical assistance, and training in order to help drive positive changes in health and housing policy and practice at the federal, state and local levels.
9.5. Dissemination
The HHGL recommendations will be disseminated with the co-operation of a broad network of international partners, including: WHO country and regional offices; ministries of health; ministries of building and construction; WHO collaborating centres; other United Nations agencies, particularly the United Nations Human Settlement Programme (UN-HABITAT); and nongovernmental organizations. They will also be available on the WHO website. In addition, an executive summary and other outreach materials aimed at staff in the health, building and planning sectors, and a wide range of policy-makers and programme managers, will be developed and disseminated through WHO country offices and their respective partners. Technical support for the adaptation and implementation of the HHGL in countries will be provided at the request of ministries of health or WHO regional or country offices.
9.6. Monitoring and evaluation: assessing the impact of the guidelines
Health gains will only be achieved if healthier and safer housing building materials, practices and principles are used widely, and if housing is maintained properly and replaced when necessary. Active monitoring and evaluation of the HHGL are therefore vital. Understanding where and to what extent the HHGL are implemented will provide insight into the distribution of progress arising from them, as well as an indication of their impact. A housing quality surveillance system, similar to a public health system, should be considered by Member States.
One way to monitor the impact of the HHGL will be to apply the environmental burden of disease approach to the healthy homes field. The Environmental burden of disease associated with inadequate housing: a method guide to the quantification of health effects of selected housing risks in the WHO European Region (2011), provides a methodological basis to be adopted at the global scale as well as extended to several additional risk factors. As the selection of the housing factors considered in the report was based primarily on whether the relevant data are available and amenable to the environmental burden of methodology, some of the potential risks from inadequate housing were not covered. However, because data availability has increased in recent years, the methodology could be expanded to those housing risk factors covered by the HHGL.
The impact of the HHGL can be evaluated within countries (i.e. monitoring and evaluation of the programmes implemented at national or regional scale) and across countries (i.e. adoption of the HHGL globally). The implementation toolkit will comprise guidance on monitoring and evaluation activities for integration into ongoing data collection processes, to avoid an additional burden on statistics offices and reporting bodies.
