Community Noise and Health Study (CNHS)
Detailed information for 2013
The health effects reported by individuals living in communities in close proximity to noise sources such as traffic, airports, railways and wind turbine installations are not fully understood due to limited scientific research in this area. The CNHS was developed to address this gap by investigating the prevalence of health effects or health indicators among a sample of Canadians exposed to these noise sources using both self-reported and objective health measures.
Data release - November 6, 2014
The objectives of the study are to:
- Investigate the prevalence of health effects or health indicators among a sample of Canadians exposed to noise using both self-reported and objective health measures.
- Apply statistical modeling in order to derive exposure response relationships for noise levels as well as self-reported and objective health measures.
Data collection was conducted using a face-to-face personal interview on randomly selected participants between the age of 18 and 79 years and was followed by a series of health measurements. The personal interview collected self-reported information such as basic demographics, perception of noise, health and quality of life indicators. Responses to noise was also assessed through objective measures of health, including sleep disturbance, cortisol levels (a biological stress marker) and blood pressure.
This study aims to evaluate the dose response relationship between noise exposure and reported health outcomes. These relationships will be evaluated using both self-reported and objectively measured outcomes.
- Diseases and health conditions
Data sources and methodology
The target population was a sample of adults aged 18 to 79 who were living in Southwestern Ontario and Prince Edward Island (PEI) within 10 kilometers (km) of a wind turbine.
The questionnaire was designed by Health Canada and Statistics Canada in consultation with external experts in the area of acoustics, noise and health assessment, clinical medicine and epidemiology. Testing of the questionnaire was done by Statistics Canada's Questionnaire Design Research Centre (QDRC). A number of one-on-one interviews were conducted in both English and French by the QDRC in March 2012. It was also subjected to a review by members of the World Health Organization.
The questionnaire was designed to follow standard practices and wording, when applicable, in a computer-assisted interviewing environment. This included the automatic control of question wording and flows that depended upon answers to earlier questions and the use of online edits to check for logical inconsistencies and gross capture errors.
The computer application for data collection was subjected to extensive testing before its use in the study.
This is a sample survey with a cross-sectional design.
The CNHS was conducted using a computer assisted personal interview on a sample of 2,004 dwellings on two separate sites.
The selected sites were determined based on population density near noise sources. The frame was created using a combination of the Address Register and geographic location of various noise sources. The sample of dwellings was randomly selected from these sites and once a household was identified, one person in the household was randomly selected to take part in the study. This selection method has been designed to try to get similar number of respondents who fall into specified sound level exposure groupings (in decibels).
Data collection for this reference period: 2013-05-01 to 2013-09-11
Responding to this survey is voluntary.
Data are collected directly from survey respondents and extracted from administrative files.
The CNHS questionnaire was administered using a computer assisted personal interview (CAPI) in respondents' homes. The questionnaire included modules that probed endpoints such as noise annoyance, health effects, quality of life, sleep quality, perceived stress, lifestyle behaviours (e.g., cigarette smoking, alcohol consumption) and prevalent chronic diseases. Following completion of the questionnaire, subjects were invited to participate in the physical health measures collection portion of the study.
The physical measures component consisted of three measures:
- A wrist-worn actimeter (i.e. sleep watch) was used to provide measures of sleep onset, total sleep time, awakenings, sleep efficiency.
- Systolic and diastolic blood pressure and heart rate were measured electronically with an automated oscillometric device
- Respondents were asked to provide a small amount of hair (approximately 100 strands) for the measurement of cortisol concentrations to measure the level of chronic stress.
View the Questionnaire(s) and reporting guide(s) .
Most editing of the data was performed at the time of the interview by the CAPI application. It was not possible for interviewers to enter out-of-range values and flow errors were controlled through programmed skip patterns. In addition, warnings not requiring corrective action were also included to identify unusual (i.e., improbable rather than impossible) values as a means of catching potential errors and allowing correction at source.
At head-office, the data underwent a series of processing steps that resulted in some of the data being adjusted. For example, additional edits were performed to control for inconsistencies in the data. As a result, the final data were complete and contained reserve codes for responses of "not applicable", "don't know", "refusal" and "not stated".
No imputation is done for this statistical program.
The primary intended use of the study results is examination of the relationship between noise and health using multivariate techniques. Results using these techniques are valid within the study area (a small area of Southwestern Ontario and most of Prince Edward Island) but cannot be generalized more broadly (for example, to other wind farms, or at the provincial or national level).
Considerable time and effort was made to reduce non sampling errors in the study. Quality assurance measures were implemented at each step of the data collection and processing cycle to monitor the quality of the data. These measures include extensive training of interviewers with respect to the procedures and computer-assisted personal interviewing (CAPI) application, observation of interviewers to detect problems of questionnaire design or misunderstanding of instructions and testing of the CAPI application to ensure that range checks, edits and question flow were all programmed correctly.
To ensure consistency between interviewers on all measurement and collection techniques, an interviewer manual containing detailed protocols for each measure was developed. These protocols were developed in consultation with experts in each measurement field, ensuring the highest quality and least biased data collection. For standardization purposes, these protocols were covered thoroughly during staff training and scripted within the data capture application. Interviewers were required to review these protocols periodically during collection so as to keep themselves up to date.
Statistics Canada is prohibited by law from releasing any information it collects that could identify any person, business, or organization, unless consent has been given by the respondent or as permitted by the Statistics Act. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.
Revisions and seasonal adjustment
This methodology does not apply to this survey.
The CNHS sampled 2,004 dwellings. One of the first tasks was to determine the out-of-scope portion of the sample. Experience from previous surveys and the Census indicated that the out-of-scope dwelling rate would be higher in PEI than in Ontario. At the end of collection, 27% of dwellings were out-of-scope in PEI, the rate was 20% in Ontario. Overall, the out-of-scope rate for the CNHS was 22%. Most of the out-of-scope cases were due to "dwelling demolished," "dwelling vacant," or "seasonal or secondary dwelling." Of the 2,004 dwellings, 1,570 were in-scope and 1,238 people agreed to participate in the study. This produces a final response rate of 79%.