TwinsUK COVID-19 personal experience questionnaire (CoPE): wave 1 data capture April-May 2020 [version 1; peer review: awaiting peer review]

TwinsUK is a population-based study which consists of 14,575 adult twins at present (55% monozygotic and 43% dizygotic) who are between 18 to 101 years of age from around the United Kingdom (UK). In response to the coronavirus disease 2019 (COVID-19) pandemic and the resulting UK ‘lockdown’ restrictions, our team developed the TwinsUK COVID-19 personal experience (CoPE) questionnaire. To date the CoPE questionnaire has been implemented three times, once during the first lockdown (April-May 2020), once as the restrictions eased (July-August 2020) and another when we entered the second wave of the pandemic and stricter restrictions were put into place (October-November 2020). This data note details the sample characteristics, and response rates of the data collected during the initial lockdown phase (wave 1) using the CoPE questionnaire. This questionnaire was designed to capture a variety of social, behavioural, psychological, environmental and health factors. It includes both measures that have been collected previously in TwinsUK as well as new measures. This data can be combined with pre-pandemic TwinsUK data and biological and genetic data. TwinsUK will also soon be complemented with the availability of linked health records. All TwinsUK data is available upon request and details are provided on how to access the data below.


Introduction
The global coronavirus disease 2019 (COVID-19) pandemic resulting from the spread of severe acute respiratory syndrome coronavirus 2 has triggered differing responses from governments around the world in attempts to safeguard their populations. In the United Kingdom (UK), a national 'lockdown' was instigated ordering all citizens to 'stay at home', with regulations coming into effect on 23 rd March 2020. Whilst negative impacts of social isolation and loneliness on health and wellbeing are well-documented [1][2][3][4][5] , little is known about the impacts in the context of health policy promoting widespread isolation as a mitigation to the outbreak.
As the largest adult twin registry in the UK, with extensive biological and baseline phenotypic measures, TwinsUK 6 are well placed to collect data that capture the experiences of individuals during this time and importantly present analytical opportunities to utilise the powerful twin design to understand the influence of lockdown regulations without genetic confounding 7 . The 'COVID-19 personal experience study (CoPE)' collected questionnaire data on a number of measures that focused on capturing mental health, social isolation, loneliness and key risk factors. The CoPE study collected data at three waves throughout 2020, with many measures repeated at each time point to allow longitudinal assessment.
Here, we present the questions asked as part of the first round of CoPE (April 2020), and highlight key measures of interest to researchers. All data is available upon request (see 'data availability' section below) and can be linked to other cohort data (including biological and genetic) and soon health records data. Furthermore, as members of the Wellcome Trust's Covid-19 Questionnaire steering group we have where possible harmonised our data collection with other cohorts.

Sample
The UK Adult Twin Registry (or TwinsUK) is a cohort of volunteer adult twins which consists of 14,575 adult twins at present (55% monozygotic and 43% dizygotic) who are between 18 to 101 years of age from around the United Kingdom. The registry was set up in 1992 via media campaigns which aimed to recruit middle-aged women to study osteoporosis and osteoarthritis. The success of these studies drove the growth of the registry, with the scope broadening to include both male, female and mixed twins with a spectrum of clinical and behavioural phenotypes in addition to genotyping data.
The Department of Twin Research and Genetic Epidemiology at St. Thomas' Hospital, King's College London accommodates the registry. The leading focus of the TwinsUK study is the genetic foundation of complex diseases (cardiovascular, metabolic, musculoskeletal, and ophthalmologic diseases) and healthy ageing processes. Data in the registry, which include longitudinal measures, are collected on a rolling basis through clinical visits, yearly questionnaires, and various project-led studies.

Study design
The COVID-19 personal experience study (CoPE) commenced data collection in April 2020. The questionnaire was around 100 questions long and took around 30 minutes for the twins to complete online, or about 20 minutes over the phone by TwinsUK administrative staff. This questionnaire was implemented three times. The first questionnaire was sent out in April 2020 (at the beginning of the first UK lockdown), the second was sent out in July 2020 (towards the end of the COVID-19 outbreak when the government eased isolation and distancing measures), and the third was sent out in October 2020 (further detail can be found here: https://time.graphics/line/ 4c88cc0482538f247bcb58b299463ca2) For the subsequent two rounds of data collection, questions viewed as time variant were repeated. Additional questions capturing COVID-19 symptoms and long-term fatigue were added as part of a synergistic study outside the scope of this data presentation. Round 2 was collected during a period of broadly lighter restrictions in the UK (July-August 2020), although local lockdowns remained in force. Round 3 was collected during fluctuating restrictions as the pandemic approached a 'second wave'.

Participants and questionnaire methods
For the first wave of data collection, a total of 3901 twins completed the questionnaire. Figure 1 presents a flow diagram of the selection process. Twins were eligible to take part in the study if they were over the age of 18 years, lived in the UK, were members of the TwinsUK registry, and had previously taken part in at least one prior questionnaire (indicating them as engaged participants).
Based on this eligibility criteria, 5666 twins were contacted via email and 404 twins were contacted via post and telephone.
To aid recruitment, a follow up e-mail was sent to those completing the questionnaire online, encouraging them to take part or thanking them for their participation.
For those completing the questionnaire via the telephone, priority twins were contacted first via telephone to ensure representation in case resource limitations meant the whole call list could not be contacted by the administrative team. Priority twins were flagged as those who live in more deprived areas (captured by Index of Multiple Deprivation), were from Black, Asian or minority ethnic backgrounds, or those who had lower educational attainment (no formal education beyond age 16).

Questionnaire content
The questions included were designed to capture a number of social, behavioural psychological, environmental and health factors. This questionnaire included both measures that had been previously collected in the TwinsUK cohort as well as new measures. Efforts were also made to utilize measures from the Longitudinal Population Studies (LPS) Wellcome Trust's Covid-19 Questionnaire, in order to harmonize with other UK national cohorts.
The questionnaire included 5 sections, and captured information on the following: • Section D: Questions about the household location and environment, including nature relatedness and environmental health of the home, and financial challenges due to COVID-19.
• Section E: Demographic questions, including capture of key worker status.
All questions listed in full (supplementary Table 2 8 ), and a detailed breakdown of the responses by question can be found as extended data 8 .

Results
Overall response rate (waves 1-3) Table 1 presents the number of twins who took part in each data collection wave and the number of twins who took part in all data collection waves.
Response rate by measure (wave 1) Supplementary Table 2 presents the counts and percentages of valid and missing data for each measure included in wave 1 8 . Summary of key characteristics for those who responded (wave 1) Selected responses (wave 1) Tables 3 to Table 10 highlight key measures from wave 1 of COPE. Presented measures were selected following consultation with members of the calling team, as a qualitative assessment of questions of interest (gauged by perceived interest of participants, and potential interest to researchers); we additionally present the validated questionnaires. The remaining response summaries can be viewed in Supplementary File S1. Table 3 presents the responses to question 6-8 of COPE. These measures aimed to assess participants' understanding, knowledge and institutional trust in the context of COVID-19. These measures may be of interest to researchers in particular who are interested in understanding individuals' psychology in relation to health behaviour. Table 4 presents the responses to: In the past week, have any of the following aspects of your life changed? For this measure (and affiliated section of the questionnaire), behavioural change was assessed over the first UK 'lockdown' period.

Behaviour change
Self-reported loneliness in TwinsUK during the COVID-19 pandemic Loneliness was assessed using four items from the UCLA Loneliness Scale. A very similar short form of the UCLA Loneliness Scale has previously been developed for use in large-scale surveys and correlates strongly with the full 20-item version 9 . Participants were asked to fill out the UCLA loneliness scale twice; once in relation to how they felt prior to the COVID-19 pandemic and once in relation to how they feel at time of response. Table 5- Table 6 present responses to the UCLA Loneliness Scale (4 item version).   Common mental health in TwinsUK during the COVID-19 pandemic Anxiety and depressive symptoms were measured using the Hospital Anxiety and Depression Scale (HADS) 10 , the Patient Health Questionnaire (PHQ-2) 11 and the Generalised Anxiety Disorder (GAD-2). Table 7 presents responses to the PHQ-2 and the GAD-2.
Self-reported resilience in TwinsUK during the COVID-19 pandemic Resilience was measured using the Brief Resilience Scale (BRS-R). Table 8 presents responses to the BRS.
Self-reported general health in TwinsUK during the COVID-19 pandemic General health was measured through asking twins 'In general would you say your health is': poor (0), fair (1), good (2), very good (3), excellent (4). Table 9 and Table 10 present responses to general health.

Ethical approval and consent
The data which has been generated and provided in the report have been collected via questionnaires that had received ethical approval associated with TwinsUK Biobank (19/NW/0187), Twins UK (EC04/015) or Healthy Ageing Twin

Data availability
Underlying data TwinsUK promotes and encourages data to be shared within the scientific community to help assist and generate further scientific research. Researchers who would like access to the datasets which have been presented in this data note in addition to other TwinsUK data can follow the steps provided below.
1. Please use the TwinsUK Phenotype spreadsheet containing a list of all TwinsUK phenotypes to search for the specific phenotype required. If requesting data from this study, if phenotypes are not listed in the above spreadsheet, please submit the question numbers in Table 2 and refer to the study as the 'CoPE study'.
2. Please read through the TwinsUK Data Access Policy document which explains how to access the data and samples in addition to the costs. There are a limited number of grants available to waive any costs to any researcher whose research scope can be considered 'social science'.
3. Please send your Proposal Form to the TwinsUK Resource Executive Committee (TREC) for it to be considered. You will receive a notification about the conclusion of the review within three weeks of submitting and then be advised on the next step of the process.
The data and/or samples required including individual variables should be specified on the proposal form with an appropriate reason outlining the aims/hypothesis of the project for which the data is needed. If further information is required, it can be found on the TwinsUK website (www.twinsuk.ac.uk/ data-access