Household crowding

This section presents data and statistics on household crowding in New Zealand.  Household crowding increases the risk of infectious diseases spreading, particularly among children. 

Household crowding is defined as needing one or more bedrooms; severe household crowding is defined as needing two or more bedrooms. Household crowding is measured with Census data, using the Canadian National Occupancy Standard. 

One in ten people lives in crowded conditions

In 2013, 10.1% of New Zealanders (398,300 people) lived in a crowded house (Figure 1). This is a decrease from 1991, when household crowding affected 11.9% of the population. 

In 2013, 3.3% of people lived in severely crowded houses (needing 2 or more bedrooms) (129,100 people).  

Māori and Pacific are more affected

Many Māori and Pacific people live in crowded houses.  In 2013, household crowding affected:

• 40% of Pacific people
• 20% of Māori 
• 5% of people of European/Other ethnicity.

The proportion of people living in crowded houses decreased in all ethnic groups from 1991 to 2013. However, large ethnic differences still remain.  

Figure 1: Percentage of the population living in crowded households, by ethnic group, 1991-2013

Many children living in crowded conditions

Children (0–14 years) are disproportionately affected by household crowding in New Zealand (Figure 2).

About one in seven children (15.9%) lived in crowded houses and a third of these children (5.2%) lived in severely crowded households (needing two or more bedrooms). 

Māori and Pacific children were more affected by household crowding than children of other ethnic groups. Over 40% of Pacific children (43%) and 25% of Māori children lived in crowded houses in 2013. 

Figure 2: Percentage of children (0-14 years) living in crowded households, by total response ethnic group, 2013

Household crowding is not evenly distributed in New Zealand

Geographically, household crowding is worse in the North Island, where 11.7% of the population lived in crowded households in 2013. In the South Island, 5.1% of the population lived in crowded households in 2013 (Figure 3).

In 2013, Kawerau District had the highest proportion of people living in crowded households (17.3%), followed by Opotiki District (16.7%) and Porirua City (15.6%) (Figure 3).

Figure 3: Percentage of population living in crowded households, by territorial authority (TA), 2013

In 2013, Counties Manukau District Health Board (DHB) had the highest proportion of population living in crowded households (21.8%), followed by Auckland DHB (15.5%) and Tairawhiti DHB (14.8%) (Figure 4).

Figure 4: Percentage of population living in crowded households, by District Health Board (DHB), 2013

Other at-risk population groups

Household crowding is very unevenly distributed in New Zealand. Along with children and Māori and Pacific ethnicity, risk factors for household crowding include [1]:

• living in rental houses
• multi-family households
• low equivalised household income
• being unemployed
• lack of educational qualifications.

Health effects from household crowding

Household crowding can increase the spread of infectious diseases. In particular, household crowding is a risk factor for [2]:

• lower respiratory tract infections (including pneumonia and RSV bronchiolitis)
• meningococcal disease
• gastroenteritis
• Haemophilus influenzae (Hib) disease
• Hepatitis A
• Helicobacter pylori infection
• tuberculosis.

Evidence also suggests that household crowding is a risk factor for upper respiratory tract infections and trachoma (eye infections) [2].  

Children are more at risk from these diseases. Some children are disproportionately affected by these diseases: infants, Māori and Pacific children, and children living in the most deprived areas.  

Infectious burden of disease due to household crowding

In 2007–2011, an estimated 1,343 hospital admissions for infectious diseases were caused by household crowding annually in New Zealand [2].

Crowded households were an important risk factor for Māori and Pacific, and especially for meningococcal disease.

The main conditions contributing to attributable hospital admissions were: bronchiolitis from respiratory syncytial virus (RSV), pneumonia/lower respiratory tract infections, upper respiratory tract infections, Helicobacter pylori infections and gastroenteritis.  

Information about the data

Household crowding

Source: Census (1991, 1996, 2001, 2006, 2013). Results for household crowding published in The Distribution of Household Crowding in New Zealand: An analysis based on 1991 to 2006 Census data [1].

Definition: A household is generally considered overcrowded if at least one more bedroom is needed. We used the following definitions for this indicator:

• household crowding: at least one more bedroom is needed (1+ bedroom deficit)
• severe household crowding: at least two more bedrooms are needed (2+ bedroom deficit).

In New Zealand, the number of bedrooms needed is defined using the Canadian National Occupancy Standard.  These criteria are:

• there should be no more than two people per bedroom; parents or couples share a bedroom
• children younger than 5 years, either of the same or opposite sex, may reasonably share a bedroom
• children under 18 years, of the same sex, may reasonably share a bedroom
• a child aged 5-17 years should not share a bedroom with one aged under 5 years of the opposite sex
• single adults 18 years or over, and any unpaired children, require a separate bedroom.

References

1. Baker MG, Goodyear R, Telfar Barnard L, Howden-Chapman P. 2012. The Distribution of Household Crowding in New Zealand: An analysis based on 1991 to 2006 Census data. Wellington: He Kainga Oranga / Housing and Health Research Programme, University of Otago, Wellington. Available online: http://www.healthyhousing.org.nz/publications/

2. Baker MG, McDonald A, Zhang J, Howden-Chapman P. 2013. Infectious Diseases Attributable to Household Crowding in New Zealand: A systematic review and burden of disease estimate. Wellington: He Kainga Oranga/ Housing and Health Research Programme, University of Otago. Available online: http://www.healthyhousing.org.nz/publications