Scottish Health Survey – telephone survey – August/September 2020: technical report

1.9 methods and definitions

1.9.1 General survey methods and definitions

Household

A household was defined as one person or a group of people who have the accommodation as their only or main residence and who either share at least one meal a day or share the living accommodation.

Questions regarding the age, sex and date of birth, as well as employment details, were collected from the first adult to be interviewed in the house only.

1.9.2 Chapter 1: General health, long-term conditions and caring

Self-assessed general health

All participants were asked to rate their health in general with answer options ranging from ‘very good’ to ‘very bad’.

CVD conditions and diabetes

Participants were asked whether they had ever suffered from any of the following conditions: diabetes, angina, heart attack, stroke, heart murmur, irregular heart rhythm, or ‘other heart trouble’. Most of the questions on cardiovascular conditions were not followed up with confirmation as to whether the condition had been diagnosed by a doctor.

The results presented in the SHeS 2020 telephone survey report are inclusive of all who responded affirmatively to any of these conditions, irrespective of whether they had ever been told they had the condition by a doctor and whether they had experienced the conditions in the previous 12 months. Follow up questions were asked for women aged 16-49 who reported having diabetes, high blood pressure or angina in order to determine whether a doctor diagnosis was given during pregnancy in order to exclude such instances from the figures reported.

It is important to note that no attempt was made to verify these self-reported diagnoses objectively.

Any CVD condition

Participants were classified as having ‘any CVD’ if they reported ever having any of the following conditions: angina, heart attack, stroke, heart murmur, abnormal heart rhythm, or ‘other heart trouble’.

Diabetes

Participants were classified as having diabetes if they self-reported having this condition. Women whose diabetes occurred only during pregnancy were excluded from the classification. Unlike the face-to-face SHeS surveys where they have been asked since 2018, no questions were included asking participants to report if they had been told they had Type 1 or Type 2 diabetes in the telephone survey.

Any CVD condition or diabetes

A summary measure of the above conditions is presented in the tables as ‘any CVD condition or diabetes’.

Ischaemic heart disease (IHD)

Participants were classified as having IHD if they self- reported ever having angina or a heart attack. All tables refer to ever having had the condition.

Stroke

Participants were classified as having a stroke if they self-reported ever having had a stroke.

IHD or stroke

A summary measure of the above conditions is presented in the tables as ‘IHD or stroke’.

Asthma diagnosis

Participants were asked to report if they had ever been told by a doctor that they had asthma. No objective measures were used to confirm these reported diagnoses.

Chronic Obstructive Pulmonary Disease (COPD)

COPD is defined by the World Health Organisation as ‘a pulmonary disease characterised by chronic obstruction lung airflow that interferes with normal breathing and is not fully reversible.’ It is associated with symptoms and clinical signs that in the past have been called ‘chronic bronchitis’ and ‘emphysema,’ including regular cough (at least three consecutive months of the year) and production of phlegm.

It should be noted that, unlike the face-to-face SHeS surveys, due to time constraints, the telephone survey did not collect data on whether the COPD reported was doctor-diagnosed.

1.9.3 Chapter 2: Mental wellbeing

Depression and anxiety

Details on symptoms of depression and anxiety are collected via a standardised instrument, the Revised Clinical Interview Schedule (CIS-R). The CIS-R is a well-established tool for measuring the prevalence of mental disorders^[7]. The complete CIS-R comprises 14 sections, each covering a type of mental health symptom and asks about presence of symptoms in the week preceding the interview. Prevalence of two of these mental illnesses - depression and anxiety - were introduced to the Scottish Health Survey in 2008.

It should be noted that the way in which these questions were asked was different for the telephone survey. Given the potentially sensitive nature of these topics, they were included in the nurse interview part of the survey prior to 2012^[8]. Since 2012, the questions have been as part of the face-to-face interviews in the biological module, with participants completing the questions themselves on the interviewer laptop (CASI). For the SHeS 2020 telephone survey, these questions were asked by the interviewer rather than via a self-completion mode.

General Health Questionnaire 12 (GHQ-12)

GHQ-12^[9] is a widely used standard measure of mental distress and mental ill-health consisting of 12 questions on concentration abilities, sleeping patterns, self-esteem, stress, despair, depression, and confidence in the previous few weeks. Responses to each of the GHQ-12 items are scored, with one point allocated each time a particular feeling or type of behaviour is reported to have been experienced 'more than usual' or 'much more than usual' over the previous few weeks.

These scores are combined to create an overall score of between zero and twelve. A score of four or more (referred to as a high GHQ-12 score) has been used here to indicate the presence of a possible psychiatric disorder. A score of zero on the GHQ-12 questionnaire can, in contrast, be considered to be an indicator of psychological wellbeing. GHQ-12 measures deviations from people's usual functioning in the previous few weeks and therefore cannot be used to detect chronic conditions.

It should be noted that these questions are asked using a paper self-completion questionnaire for the face-to-face SHeS surveys, but were asked by interviewers in the 2020 telephone survey.

Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS)

Wellbeing is measured using the WEMWBS questionnaire. It has 14 items designed to assess: positive affect (optimism, cheerfulness, relaxation) and satisfying interpersonal relationships and positive functioning (energy, clear thinking, self-acceptance, personal development, mastery and autonomy)^[10]. The scale uses positively worded statements with a five-item scale ranging from ‘1 - none of the time’ to ‘5 - all of the time’. The lowest score possible is therefore 14 and the highest score possible is 70; the tables present mean scores.

The scale was not designed to identify individuals with exceptionally high or low levels of positive mental health, so cut-off points have not been developed^[11].

WEMWBS is used to monitor the National Indicator 'mental wellbeing’^[12] and the mean score of parents of children aged 15 years and under on WEMWBS is included in the mental health indicator set for children^[13].

It should be noted that these questions are asked using a paper self-completion questionnaire in the face-to-face SHeS surveys, but were asked by interviewers in the 2020 telephone survey.

1.9.4 Chapter 3: Social capital and loneliness

Social capital

Social capital is a term used to describe the social connections that provide support (social networks, workplaces etc.) and that are beneficial to the quality of life, health, safety, economy and wellbeing of individuals and the neighbourhoods in which they live. The SHeS 2020 telephone survey included questions on frequency of contact with other people and the number of people that participants could turn to in a crisis.

It should be noted that these questions were asked using a paper self-completion questionnaire for the face-to-face SHeS surveys in 2019, but were asked by interviewers in the 2020 telephone survey.

Loneliness

A question was included to measure levels of loneliness experienced in the two weeks prior to being interviewed, with five answer options ranging from ‘all of the time’ to ‘never’.

It should be noted that this question is asked using a paper self-completion questionnaire for the face-to-face SHeS surveys, but were asked by interviewers in the 2020 telephone survey.

1.9.5 Chapter 4: Diet, obesity and food insecurity

Height, weight and Body Mass Index (BMI)

BMI is a widely accepted measure that allows for differences in weight due to height. It is defined as weight (kg)/square of height (m²). This has been used as a measure of obesity in SHeS since its inception in 1995. BMI has some limitations and does not, for example, distinguish between mass due to body fat and mass due to muscular physique^[14].

However, it was not possible to obtain these measurements using a face-to-face approach. Therefore, where they were happy to do so, participants were asked to estimate their height and weight, with these self-reported measures used to calculate estimated BMI. So, while these estimates have been calculated, this data should be used with caution given the self-reported nature of these measures.

Work undertaken to analyse data from the Health Survey for England (HSE) and Active Lives Surveys found that, on average, participants overestimated their height and underestimated their weight^[15]. Adjustments have been made to account for this and while these corrections appear to remove some bias from the estimates, caution is advised in interpreting this data.

It would not have been possible to collect accurate information for waist circumference, therefore, this was not included in the telephone survey.

Based on their BMI (calculated from self-reported height and weight), adult participants were classified into the following groups based on the World Health Organisation (WHO) classification^[16]:

BMI (kg/m2)	Description
Less than 18.5	Underweight
18.5 to less than 25	Normal
25 to less than 30	Overweight, excluding obese
30 to less than 40	Obese, excluding morbidly obese
40+	Morbidly obese

Both mean BMI and prevalence for the five categories outlined in the table above are presented for adults in this report. Although obesity has the greatest ill-health and mortality consequences, overweight is also a major public health concern, not least because overweight people are at high risk of becoming obese. Being underweight can also have negative health consequences.

The BMI data presented in the report and the data tables is based on data that has been adjusted according to the formula from this HSE and Active Lives work referenced previously. A comparison of the unadjusted and adjusted weighted data for all adults interviewed as part of the survey is presented in the table below.

BMI category (kg/m2)	Unadjusted	Adjusted
Less than 18.5	3%	1%
18.5 to less than 25	44%	37%
25 to less than 30	32%	35%
30 to less than 40	18%	23%
40+	3%	4%
Mean	26.6	27.7

Food insecurity

Food insecurity is ‘the inability to acquire or consume an adequate quality or sufficient quantity of food in socially acceptable ways, or the uncertainty that one will be able to do so’. Participants in the telephone survey answered three routed questions on food insecurity asking whether they had worried about running out of food, had eaten less than they should have or had actually run out of food in the last 12 months.

It should be noted that these questions are asked using a paper self-completion questionnaire for the face-to-face SHeS surveys, but were asked by interviewers in the 2020 telephone survey.

1.9.6 Chapter 5: Physical Activity

IPAQ Physical Activity

Information on physical activity was collected using the Short-Form International Physical Activity Questionnaire (IPAQ). This questionnaire defines activity levels based on reported moderate or vigorous physical activity (MVPA) but uses a less detailed set of questions that those included in the face-to-face SHeS surveys. The derived variable related to adherence to MVPA guidelines has therefore been calculated using these questions.

While the data regarding the amount of time spent participating in moderate and/or vigorous physical activity is reported using the same breakdowns as in previous SHeS reports, it should be noted that differences in the questions used to collect the data in the telephone survey means that this is not comparable with the face-to-face survey approach.

1.9.7 Chapter 6: Alcohol

Measuring alcohol consumption in surveys

The alcohol consumption estimates discussed in this chapter are based on self-reported data collected during the survey interview regarding alcohol consumption in the seven days prior to being interviewed. Non-drinkers were defined in this survey as those who reported that they did not drink alcohol 'nowadays' whereas the face-to-face SHeS surveys use a question that asks if participants have drunk alcohol at all in the past 12 months.

It is, however, important to note that surveys consistently obtain lower consumption estimates than those implied by alcohol sales or tax revenue data. This discrepancy can largely be explained by participants’ under-reporting of consumption, due in part to a lack of accounting for atypical/special occasion drinking^[17], and there is also some evidence that survey non-responders are more likely than responders to engage in hazardous alcohol use among other risky health behaviours^{[18],[19],[20]}.

While self-reported survey estimates of consumption are typically lower than estimates based on sales data, surveys provide valuable information about the social patterning of individuals' alcohol consumption.

Calculating alcohol consumption in the SHeS 2020 telephone survey

The guidelines on lower risk drinking are expressed in terms of units of alcohol consumed. As discussed above, detailed information on the volume of alcohol drunk on the heaviest drinking day in the week preceding the survey was collected from participants. The volumes reported were not validated. In the UK, a standard unit of alcohol is 10 millilitres or around 8 grams of ethanol. In this report, alcohol consumption is reported in terms of units of alcohol.

Questions on the quantity of wine drunk were revised in 2008. Since then, participants reporting drinking any wine have been asked what size of glass they drank from: large (250ml), medium (175ml) and small (125ml). To help participants make more accurate judgements, details regarding the quantities in a small, medium and large glass were included in the question text (unlike the face-to-face survey where participants are shown a showcard depicting glasses with 125ml, 175ml and 250ml of liquid). Participants also had the option of specifying the quantity of wine drunk in bottles or fractions of a bottle; with a bottle treated as the equivalent of six small (125ml) glasses.

There are numerous challenges associated with calculating units at a population level, not least of which are the variability of alcohol strengths and the fact that these have changed over time. Table 5 below overleaf outlines how the volumes of alcohol reported in the survey were converted into units (the 2008 report provides full information about how this process has changed over time)^[21]. Those who drank bottled or canned beer, lager, stout or cider were asked in detail about what they drank, and this information was used to estimate the amount in pints.

Table 5: Alcohol unit conversion factors

Type of drink	Volume reported	Unit conversion factor
Normal strength beer, lager, stout, cider, shandy (less than 6% ABV)	Half pint	1.0
	Can or bottle	Amount in pints multiplied by 2.5
	Small can (size unknown)	1.5
	Large can/bottle (size unknown)	2.0
Strong beer, lager, stout, cider, shandy (6% ABV or more)	Half pint	2.0
	Can or bottle	Amount in pints multiplied by 4
	Small can (size unknown)	2.0
	Large can / bottle (size unknown)	3.0
Wine (including champagne and prosecco)	250ml glass	3.0
	175ml glass	2.0
	125ml glass	1.5
	750ml bottle	1.5 x 6
Sherry, vermouth and other fortified wines	Glass	1.0
Spirits	Glass (single measure)	1.0
Alcopops	Small can or bottle	1.5
	Large (700ml) bottle	3.5

Daily alcohol consumption

Participants were asked about drinking in the week preceding the interview, with actual consumption on the heaviest drinking day in that week then examined in more detail^[22]. Non-drinkers were defined in this survey as those who reported that they did not drink alcohol 'nowadays' whereas the face-to-face SHeS surveys use a question that asks if participants have drunk alcohol at all in the past 12 months. Details on the amounts consumed for each of the six types of drink listed in Table 5 above were collected and converted into units of alcohol consumed.

The UK Chief Medical Officers alcohol guidelines consist of three recommendations:

• A weekly guideline on regular drinking;
• Advice on single episodes of drinking; and
• A guideline on pregnancy and drinking.

According to the weekly guideline, adults are safest not to regularly drink more than 14 units per week, to keep health risks from drinking alcohol to a low level. If you do drink as much as 14 units a week, it is best to spread this evenly over three days or more. On a single episode of drinking, advice is to limit the total amount drunk on any occasion, drink more slowly, drink with food and alternate with water. The guideline on drinking and pregnancy, or planning a pregnancy, advises that the safest approach is not to drink alcohol at all^[23].

Consumption of more than three units (women) or four units (men) on a single day is also reported in this chapter, although these daily amounts of alcohol are no longer included in the most recent guidance from the UK Chief Medical Officers. Consumption of double this amount (six units for women and eight for men) is also reported.

It should be noted that these questions are asked of all aged 16 or 17 and the majority of those aged 18 or 19 using a paper self-completion questionnaire for the face-to-face SHeS surveys (asked by interviewers for older adults), but were asked by interviewers for all aged 16 and above in the 2020 telephone survey.

1.9.8 Chapter 7: Smoking

Cigarette smoking status

Smoking status categories reported here are:

• current cigarette smoker
• ex-regular cigarette smoker
• never regular cigarette smoker
• never smoked cigarettes at all

In previous SHeS surveys, ex-smokers were defined as those who used to smoke cigarettes regularly. Frequency of previous smoking among ex-smokers was not asked in the 2020 telephone survey with all who reported ever having smoked cigarettes, regardless of frequency or length of time, as ex-smokers.

Electronic cigarettes

Electronic cigarettes or e-cigarettes are battery-powered handheld devices which heat a liquid that delivers a vapour. The vapour is then inhaled by the user, which is known as ‘vaping’. E-cigarettes typically consist of a battery, an atomiser and a cartridge containing the liquid. Earlier models, often referred to as ‘cigalikes’, were designed to closely resemble cigarettes but there is now a wide variety of product types on the market. The liquid is usually flavoured and may not contain nicotine, although in most cases e-cigarettes are used with nicotine. Unlike conventional or traditional cigarettes, they do not contain tobacco and do not involve combustion (i.e. they are not lit). The questions about e-cigarettes were amended in 2016 to include the term ‘vaping devices’.

Exposure to second-hand smoke (adults)

Exposure to second-hand smoke in adults was measured by asking participants to self-report where they have been exposed to second-hand smoke.

It should be noted that these questions are asked of all aged 16 or 17 and the majority of those aged 18 or 19 using a paper self-completion questionnaire for the face-to-face SHeS surveys (asked by interviewers for older adults), but were asked by interviewers for all aged 16 and above in the 2020 telephone survey.

Table List

Table 1.1 Detailed fieldwork outcomes

Table 1.2 Household and individual response, by Health Board

Table 1.3 Household and individual response, by Local Authority

Table 1.4 Household and individual response, by SIMD (2020)

Table 1.5 Age distribution of responding adult sample compared with 2019 mid-year population estimates for Scotland by sex

Table 1.6a True standard errors and 95% confidence intervals for general health variables

Table 1.6b True standard errors and 95% confidence intervals for cardiovascular conditions, diabetes and high blood pressure variables

Table 1.6c True standard errors and 95% confidence intervals for respiratory conditions and treatment variables

Table 1.6d True standard errors and 95% confidence intervals for caring prevalence variable

Table 1.7 True standard errors and 95% confidence intervals for mental wellbeing variables

Table 1.8 True standard errors and 95% confidence intervals for social capital and loneliness variables

Table 1.9a True standard errors and 95% confidence intervals for diet variables

Table 1.9b True standard errors and 95% confidence intervals for obesity variables

Table 1.9c True standard errors and 95% confidence intervals for food insecurity variables

Table 1.10 True standard errors and 95% confidence intervals for physical activity variables

Table 1.11 True standard errors and 95% confidence intervals for alcohol consumption variables

Table 1.12 True standard errors and 95% confidence intervals for smoking variables

Table 1.13 True standard errors and 95% confidence intervals for dental health variables

The tables can be found in the technical report page under supporting documents.