The Scottish Health Survey 2021 - volume 1: main report
Presents results for the Scottish Health Survey 2021, providing information on the health and factors relating to health of people living in Scotland.
Introduction
Victoria Wilson
Policy Context
As a study of public health, the Scottish Health Survey (SHeS) plays an important role in assessing health outcomes, health risks and the extent of health inequalities in Scotland and how these have changed over time. While positive changes have been recorded, Scotland continues to record a significantly lower life expectancy compared to other countries in the UK and Western Europe, as well as continued disparity in health outcomes between those living in the most and least deprived areas.[1] Improving the health and wellbeing of Scotland's population continues to be a key challenge at both the local and national level.
In 2018, the Scottish Government launched six inter-related public health priorities designed to improve the health of the population and reduce health inequalities in Scotland over the next decade.[2] In the same year, a revised National Performance Framework (NPF)[3] was also launched containing eleven National Outcomes that link with several of the United Nation's Sustainable Development Goals,[4] including several health outcomes. Underpinning the outcome focused exclusively on health - 'we are healthy and active' - are several National Indicators. SHeS is used to monitor progress towards indicators relating to mental wellbeing, healthy weight, health risk behaviours, physical activity, child wellbeing and happiness and food insecurity.
The impact of the COVID-19 pandemic is likely to be felt for some time, with both physical health and mental and emotional wellbeing being affected, and a disproportionate impact on several groups in Scotland.[5] The Scottish Government's A stronger and more resilient Scotland: the Programme for Government 2022 to 2023,[6] published on 6th September 2022, includes commitments to publish a new Mental Health and Wellbeing Strategy and to invest in the long COVID Support Fund to assist those living with long-term effects of infection. Other commitments include continuing work to reduce the public health emergency of drug deaths, introducing legislation to restrict the promotion and marketing of junk foods to make it easier for people to spend less and make healthier food choices and driving forward the actions in the Women's Health Plan.[7]
The Scottish Health Survey (SHeS) Series
SHeS has been carried out annually since 2008 and prior to this was carried out in 1995,[8] 1998,[9] and 2003.[10] Due to disruption to the survey at the onset of the pandemic, the survey data collected in 2020 was published as experimental statistics and was not comparable with the time series.[11] This data has not been included in the survey trends.
Commissioned by the Scottish Government Health Directorates, the SHeS series aims to provide regular information on aspects of the public's health and factors related to health which cannot be obtained from other sources. The SHeS series was designed to:
- estimate the prevalence of particular health conditions in Scotland
- estimate the prevalence of certain risk factors associated with these health conditions and to document the pattern of related health behaviours
- look at differences between regions and subgroups of the population in the extent of their having these particular health conditions or risk factors, and to make comparisons with other national statistics for Scotland and England
- monitor trends in the population's health over time
- make a major contribution to monitoring progress towards health targets
Each survey in the SHeS series has a set of core questions and measurements (height and weight and, if applicable, blood pressure, waist circumference, and saliva samples), plus modules of questions on specific health conditions and health risk factors that vary from year to year. Each year the main sample has been augmented by an additional boosted sample for children.
The 2018 to 2021 surveys were undertaken by ScotCen Social Research, with the Office of National Statistics (ONS) sharing fieldwork. Survey contributors have included the MRC/CSO Social and Public Health Sciences Unit (MRC/CSO SPHSU) based in Glasgow, The Centre for Population Health Sciences at the University of Edinburgh, and The Public Health Nutrition Research Group at Aberdeen University.
The 2021 Survey
At the time of interviewing for the 2021 survey (April 2021 – March 2022), restrictions due to COVID-19 meant that an alternative way of sourcing data was needed than the usual face-to-face approach. Therefore, similar to 2020, data for 2021 was collected via a telephone survey, with potential respondents initially contacted by letter and asked to opt-in to an interview conducted over the phone. For the final third of fieldwork, interviewers were able to visit households on the doorstep to encourage response to the telephone interview, significantly increasing levels of response, this is known as a knock-to-nudge approach. Further details on the fieldwork approach can be found in Chapter 1 of the Scottish Health Survey 2021- volume 2: technical report.
The SHeS series now has trend data going back over two decades and providing time series data remains an important function of the survey. However, it should be noted that due to the difference in method for 2021, caution should be applied when comparing results from this survey year to those for previous years. Caution is advised due to:
- The use of an opt-in approach resulting in a lower proportion of respondent households in the most deprived areas and a lower proportion of respondents in the youngest age group than in previous survey years. Interviews achieved as part of the knock-to-nudge sample brought the overall achieved sample a bit closer to the profile in previous years. The weighting strategy adjusted the results to be representative of the household population as a whole as far as possible.
- Changes in the mode of survey administration to telephone with knock-to-nudge recruitment resulting in:
- Reduced opportunity to build interviewer rapport
- Possible changes to the way the respondents answer some questions including the potential for greater honesty when providing potentially sensitive information
- The use of self-reported height and weight data in place of objective measurements taken by interviewers. Whilst for adults some adjustment has been made for this, the mode of data collection requires the continued use of caution when interpreting such data.
- Changes to the sampling approach such as the use of an unclustered sample.
For further detail, please refer to Chapter 2 of the Scottish Health Survey 2021- volume 2: technical report.
Topics
Cardiovascular disease (CVD) and related risk factors remains the principal focus of the survey. The main components of CVD are ischaemic heart disease (IHD) (or coronary heart disease) and stroke, both of which remain clinical priorities for the NHS in Scotland,[12],[13] particularly in light of the impact of the pandemic. CVD is one of the leading causes of death in Scotland. In 2021, this included 11% of deaths which are caused by IHD, with a further 6% caused by cerebrovascular disease (including stroke).[14] The incidence rate of cerebrovascular disease has fallen by 9% over the last decade,[15] however, stroke remains one of the biggest killers in Scotland and the leading cause of disability.[16] In addition, while the coronary heart disease mortality rate has decreased by 22% in the last ten years, the rate of decline has slowed in the last five years[17] and there remains concern about continuing inequalities in relation to morbidity and mortality linked to these conditions.[18]
Many of the key behavioural risk factors for CVD are in themselves of particular interest to health policy makers, public health professionals and the NHS; poor diet, obesity, lack of physical activity, smoking, and problematic alcohol and/or drug use are all the subject of specific strategies targeted at improving Scotland's health. SHeS includes detailed measures of all these factors which are reported on separately in Chapters 4-8. The other five chapters focus on health conditions and experiences which have the potential to influence health outcomes in later life - General Health, Cardiovascular Disease and CPR Training (Chapter 1), Mental Wellbeing (Chapter 2), Respiratory Conditions including COVID-19 (Chapter 3), Gambling (Chapter 9) and Accidents (Chapter 10).
Sample
The Scottish Health Survey is designed to yield a representative sample of the general population living in private households in Scotland every year.
The current survey design also means that estimates at NHS Health Board level are available, usually by combining four consecutive years of data. Due to some comparability issues with the results collected from the short telephone survey conducted in 2020, NHS board results have been produced using data from the 2017, 2018, 2019 and 2021 surveys combined. These have been published within the survey dashboard at the same time as this report.
Those living in institutions, who are likely to be older and, on average, in poorer health than those in private households, were outwith the scope of the survey. This should be borne in mind when interpreting the survey findings.
An initial sample of 64,524 addresses was drawn from the Postcode Address File (PAF) in 2021 on the basis of the survey being conducted by opt-in. These addresses comprised three sample types: main (core) sample version A, main (core) sample version B and the child boost screening sample. This sample was split into nine monthly waves of fieldwork, from April to December. For the core samples, only the first six months were issued, as the sample was superseded by a smaller knock-to-nudge sample for the final three months (the sample for knock-to-nudge was smaller due to higher expected levels of response for this approach). The child boost sample was used for the whole nine months.
Replacement core sample (3,839 addresses) was drawn for the last three months of 2021 to be issued as knock-to-nudge.
Fieldwork
For Phase 1 of the survey, participants were asked to opt-in using an online portal, or by contacting the NatCen freephone team. They were asked to leave a telephone number on which an interviewer would call them back. Addresses were only assigned to interviewers after the household had opted into the survey. Assignments comprised up to 10 addresses and a mix of all sample types.
For Phase 2 of the survey, the 3,839 addresses were grouped into 134 interviewer assignments, with around 44 assignments being issued to interviewers each month between October and December 2021.
Each sampled address was sent an advance letter that introduced the survey and for the knock-to-nudge sample, to let the resident know that an interviewer would be calling to seek permission to interview. A number of versions of the advance letter were used in 2021; one for the core version A addresses, one for core version B addresses (with the biological module), and one for child boost addresses. There was a version of each of these letters for each organisation conducting interviews (ScotCen Social Research and ONS), as well as for the opt-in and knock-to-nudge samples. A copy of the survey leaflet was included with every advance letter. The survey leaflet introduced the survey, described its purpose in more detail and included some summary findings from previous surveys.
For copies of the advance letters and survey leaflet, see the documents listed in Appendix A.
For the main sample, all adults aged 16 and over in responding households were eligible for interview. To ease respondent burden, for child interviews for both the main and the child boost samples a maximum of two children were interviewed at each household. If a household contained more than two children, then two were randomly selected for interview.
Data collection involved a main computer assisted telephone interview (CATI), and online or paper self-completion questionnaire.
As interviews were conducted by telephone, no height and weight measurements or biological measures could be taken. Participants were asked to estimate their own height and weight during the interview. In previous years, the core version B sample completed a biological module, and these addresses were only assigned to trained bio interviewers. For 2021, as no biological measurement could be taken the only real differences between the core version A and version B interviews were a slightly longer telephone interview for version A to cover the rotating modules (those not asked every year) and a slightly longer self-completion for version B to cover the depression, anxiety, self-harm and attempted suicide questions which are included in the biological module.
Participants aged 16 and above were also invited to complete two online dietary recalls using Intake24. Participants were asked to provide verbal consent, which was recorded in CAPI. Respondents were also sent a leaflet with some key information about Intake24 included. If the respondent indicated to the interviewer that they had not read the Intake24 information leaflet (sent with their advance letter), the interviewer read out key information from this before obtaining consent. Those who agreed were invited to complete two dietary recalls, either independently or via a phone call with Cambridge University. Further information about Intake24 is provided in Chapter 2 of the Scottish Health Survey 2021- volume 2: technical report.
Survey response
In 2019, across all sample types, interviews were held in 3,688 households with 4,557 adults (aged 16 and over), and 1,600 children (aged 0-15). The number of participating households and adults in 2021 is presented separately for the opt-in and knock-to-nudge samples in the tables below. Further details on survey response in 2021 are presented in Chapter 2 of the Scottish Health Survey 2021- volume 2: technical report.
When considering the household response rate, households classed as "responding" were those where at least one eligible person opted-in/consented to interview and was interviewed.
It should be noted that due to lower expected response rates for both the opt-in and knock-to-nudge approaches, larger samples were required for both, which impacted on the response rates for 2021.
| Main adult sample | |
|---|---|
| Participating households | 2,050 |
| Eligible households responding | 10% |
| Adult interviews | 2,984 |
| Child boost sample | |
| Participating households | 542 |
| Eligible households responding | 10% |
| Child interviews (child boost sample only) | 823 |
| Child interviews (main sample) | 500 |
| Main sample | |
|---|---|
| Participating households | 1,096 |
| Eligible households responding | 31% |
| Adult interviews | 1,573 |
| Child interviews (core only) | 277 |
Ethical Approval
Ethical approval for the 2021 survey was obtained from the REC for Wales committee (reference number 17/WA/0371).
Data Analysis
Weighting
Since addresses and individuals did not all have equal chances of selection, the data had to be weighted for analysis. SHeS comprises of a general population (main sample) and a boost sample of children screened from additional addresses. Therefore, slightly different weighting strategies were required for the adult sample (aged 16 or older) and the child main and boost samples (aged 0-15). The address selection weights were calculated to compensate for unequal probabilities of selection of addresses in different survey strata, within the opt-in and knock-to-nudge samples. Additional weights have been created for use on combined datasets. A detailed description of the weights is available in Chapter 1 of the Scottish Health Survey 2021- volume 2: technical report.
Weighted and unweighted data and bases in report tables
All data in the report are weighted. For each table in the report both weighted and unweighted bases are presented. Unweighted bases indicate the number of participants involved. Weighted bases indicate the relative sizes of sample elements after weighting has been applied.
Standard analysis variables
As in all previous SHeS reports, data for men, women, boys, and girls are presented separately where possible. Many of the measures are also reported for the whole adult or child population. Survey variables are tabulated by age groups and in some cases by Scottish Index of Multiple Deprivation (SIMD) or other variables such as household type.
Statistical information
SHeS 2021 used a partially clustered, stratified multi-stage sample design (for the knock-to-nudge element). In addition, weights were applied when obtaining survey estimates. One of the effects of using the complex design and weighting is that standard errors for survey estimates are generally higher than the standard errors that would be derived from an unweighted simple random sample of the same size. The calculations of standard errors shown in tables, and comments on statistical significance throughout the report, have taken the clustering, stratification and weighting into account. Full details of the sample design and weighting are given in Chapter 1 of the Scottish Health Survey 2021- volume 2: technical report.
Presentation of trend data
In this report, trends based on the fourteen surveys from 2003 onwards are presented for all adults aged 16 and over. Prior to this the survey eligibility criteria were set at a maximum age of 64 in 1995 and then a maximum age of 74 in 1998. Unless specified otherwise, trends for children are based on the 2-15 years age group from 1998 onwards, and 0-15 years from 2003 onwards.
Presentation of results
Commentary in the report highlights differences that are statistically significant at the 95% confidence level. Statistical significance is not intended to imply substantive importance. A summary of findings is presented at the beginning of each chapter. Each chapter then includes a brief overview of the relevant policy area. These overviews should be considered alongside the higher-level policies noted above and related policy initiatives covered in other chapters. A description of the methods and key definitions are detailed in Chapter 2 of the Scottish Health Survey 2021- volume 2: technical report. A link to the tables showing the results discussed in the text is included at the end of each chapter.
Availability of further data and analysis
As with surveys from previous years, a copy of the SHeS 2021 data will be deposited at the UK Data Archive along with copies of the combined datasets for 2019/2021 and 2017/2018/2019/2021. In addition, a detailed set of web tables for 2021, providing analysis by age, area deprivation, equivalised income and long-term condition for a large range of measures is available on the Scottish Government website.[19]
Key indicators for local areas are available in the Scottish Health Survey Dashboard published on the Scottish Government website alongside this report.
Further breakdowns are also available for smoking, long-term conditions, general health, and caring indicators from the Scottish Survey Core Questions, which asks harmonised questions across the three major Scottish Government household surveys.
Comparability with other UK statistics
Guidance on the comparability of statistics across the UK is included in the introductory section of individual chapters.
Content of this Report
This volume contains chapters with substantive results from SHeS 2021, and is one of two volumes based on the survey, published as a set as 'The Scottish Health Survey 2021':
Volume 1: Main Report
1. General Health, CVD and CPR Training
2. Mental Health and Wellbeing
3. Respiratory Conditions including COVID-19
Volume 2: Technical Report
Volume 2 includes a detailed description of the survey methods including: survey design and response; sampling and weighting procedures.
Both volumes along with a summary report of the key findings from the 2021 report are available on the Scottish Government website.
References and notes
1. Scottish Government: Population Health Directorate. Health improvement. [Online]
2. Scottish Government: Population Health Directorate. Scotland's Public Health Priorities. [Online]
3. See National Performance Framework
4. United Nations (2015). Transforming Our World: The 2030 Agenda for Sustainable Development. [Online]
5. Priestly, A. (2021) Health Inequality and Covid-19 in Scotland. Edinburgh, the Scottish Parliament.
6. A stronger and more resilient Scotland: the Programme for Government 2022 to 2023 Edinburgh, the Scottish Government.
7. Women's health plan. Edinburgh, the Scottish Government.
8. Dong W and Erens B. The 1995 Scottish Health Survey. Edinburgh:The Stationery Office. 1997.
9. Shaw A, McMunn A and Field J. The 1998 Scottish Health Survey. Edinburgh:The Stationery Office. 2000.
10. Bromley C, Sproston K and Shelton N [eds]. The Scottish Health Survey 2003. Edinburgh: The Scottish Executive. 2005.
11. Scottish Health Survey – telephone survey – August/September 2020: main report. Edinburgh, the Scottish Government.
12. Heart Disease Improvement Plan. Edinburgh, Scottish Government. 2021.
13. Stroke Improvement Plan. Edinburgh, Scottish Government. 2014.
14. See Section 6: Deaths - Causes
15. Public Health Scotland. (2021). Scottish Stroke Statistics.
16. NSS Information and Intelligence, NHS National Services Scotland (2018). Scottish Stroke Improvement Programme: 2018 Report. [Online]
17. Information Services Division (2021). Scottish Heart Disease Statistics.
18. Public Health Reform (2020). The reform programme: why reform is important [Online]
19. See Scottish Health Survey
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