‘Gout was like the boss’. A qualitative study exploring the impact of gout on employment

Abstract

Objective

Previous research has identified that gout impacts various domains of daily life. However, there have been no qualitative studies focusing on employment. This study aimed to understand the impact of gout on employment.

Methods

Semistructured interviews were conducted in Spain and Aotearoa/New Zealand, in people with gout (according to the 2015 American College of Rheumatology/European Alliance of Associations for Rheumatology criteria) who had experienced a gout flare during their employment. The interviews were guided by questions exploring the impact on employment, job changes, disclosure and co-workers’ reactions. Data were analysed thematically.

Results

Eighteen participants were interviewed (89% male, mean age 52.9 years). Six themes were identified. The characteristics of the disease (pain intensity, tophi and joints affected) and the job itself (including physical job requirement and workplace flexibility) determined the experience of working with gout. The experiences were divided into physical (from total incapacity to working despite pain), emotional (feeling responsible, embarrassment, guilt and depression) and social (including disclosure responses and financial impact). Gout management strategies including rapid gout flare management and urate-lowering therapy reduced the number of flares and the intensity of pain, and allowed work attendance and participation.

Conclusion

Both gout and work characteristics influence the employment experience for people with gout. Effective management of gout led to improved work experiences in all its domains.

WHAT IS ALREADY KNOWN ON THIS TOPIC.

WHAT THIS STUDY ADDS

• Job demands and gout severity influence the experience of working with gout that impacts work impairment. Physically demanding roles exacerbate the impact, particularly in severe gout cases.

• Gout impacts employment across multiple domains.

• Early treatment of gout flares and effective urate-lowering therapy improve the employment experience for patients.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY:

• Health providers should ask people with gout about how the disease impacts their employment.

Introduction

Gout is the most common form of inflammatory arthritis globally.^{1 2} It is a debilitating disease associated with severe pain, inflammation and swelling around the affected joints, and diminished health-related quality of life.³ People with gout report that the disease influences many dimensions of their daily functioning, including mobility, work, social relationships and engagement in recreation and leisure activities.⁴ When asked to identify and rank areas of life affected by gout, patients reported four aspects to be the most important: pain, loss of joint motion, work loss, and joint inflammation and swelling.⁵

The impact of disease on employment has been studied in other types of inflammatory arthritis.^{6 7} In a previous study, people with a recent diagnosis of arthritis reported that pain and stiffness caused physical restrictions that impacted their capacity to manage work.⁶ Patients also prioritised paid work over other life roles, particularly when they were the primary earner for the family. Some also felt guilty and stressed about their ability to do their job and quit without disclosing their disease. A key issue was the ‘disclosure effect’, where some patients were concerned that disclosing their diagnosis could lead to negative results, including being terminated from their jobs.^{6 7} Some strategies to improve the working environment have also been developed and promoted, including the use of ergonomic workstations, flexible scheduling, policies to build awareness of invisible disabilities and national legislation and financial incentives to encourage employment and retention of vulnerable workers.⁸

Some people with gout experience shame, embarrassment and social stigma due to cultural narratives that gout is a self-inflicted disease of dietary excess.^{9 10} These characteristics may cause people with gout to have unique experiences and challenges within the workplace. Although prior qualitative studies have identified the impact of gout on various domains, there have been no prior qualitative studies designed to specifically examine the impact of gout on employment. This study aims to understand the impact of gout on paid work.

Methods

Study design and participants

People with gout completed semistructured interviews on their experiences in paid work. Ethics approval was obtained from the Auckland Health Research Ethics Committee (AH26019) and from the Comité d’ètica en Investigació Fundació Jordi Gol (23/106P). The study was performed in accordance with the ethical standards of the Declaration of Helsinki, and all participants provided informed consent (written or recorded verbal consent). The research team consisted of rheumatologists, a health psychologist and two medical doctors (working in research and primary care). The two interviewers did not have existing relationships with the participants, which helped to minimise bias.

All participants met the 2015 American College of Rheumatology (ACR) and European Alliance of Associations for Rheumatology (EULAR) classification criteria¹¹ for gout and had at least one flare during their employment. Participants were aged ≥18 years and were English, Spanish or Catalan speaking. Participants were excluded if they had a cognitive impairment that would preclude completion of the interview or other forms of inflammatory arthritis.

Data collection

Data collection began on 9 June 2023 and ended on 18 August 2023. Semistructured interviews were conducted by a rheumatologist (CD-T) and a general practitioner (MAP) who were not involved in the medical care of the participants. The interviews took place remotely (over Zoom), or in person at the Clinical Research Centre, University of Auckland, Aotearoa/New Zealand, or at the Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.

Participants were recruited through existing databases of people with gout who had volunteered for research and through public advertising at the Clinical Research Centre, University of Auckland, Aotearoa/New Zealand, and through databases from Primary Care and Rheumatology Centres from Barcelona, Spain. Purposive sampling was used to ensure a broad and diverse representation of demographic variables (age, ethnicity, gender), work characteristics (sedentary and physical jobs, self-employed or working for another) and gout disease characteristics (disease duration, presence of tophi, flare frequency and control of the disease). The final sample size was based on the concept of ‘information power’.¹² Information power suggests that the more information that is held by a sample, the fewer participants are needed. As such, the final sample size was determined when no new themes were generated from the data and when a diverse sample was established.

During the interview, participants were asked to share their experience with gout and its impact on employment. An interview schedule containing open-ended questions and probes was used to encourage conversation (see online supplemental file 1). These questions included: ‘Can you tell me about how you were diagnosed with gout?’ ‘How did gout affect your work when you were first diagnosed?’ ‘Can you tell me how gout has affected your work since then?’ ‘If you changed your job, how did having gout affect your decisions about a new job?’ ‘Did you tell your boss or workmates about your gout?’ and ‘How have your boss or workmates reacted to you having gout?’ The questions and probes were developed from a systematic review that examined the work experiences of employees with arthritis and similar studies.^{6 8 13}

Demographic information (age, gender, ethnicity), work (current employment, hours of work, days off work due to gout in the preceding year, and income) and clinical data (disease duration, number of flares, presence of subcutaneous tophi and use of urate-lowering therapy) were reported by participants before the interview. Each interview was audiorecorded, transcribed verbatim and anonymised to ensure confidentiality. Participants had the opportunity to review the transcripts to check for completeness and representativeness.

Data analysis

Data collection and analysis occurred simultaneously, and initial data informed successive sampling as themes were generated. Interviews continued until no new themes were generated from the data and purposive sampling was completed. Data were analysed using a reflexive thematic approach.¹⁴ Transcripts from the interviews were read and reread to immerse the researchers in the data. The themes identified from the transcripts were initially coded and categorised by two researchers (MAP and CD-T) using NVivo software, V.14 (QSR International Property). The codes were then grouped into potential themes and subthemes through meeting with the researchers, with repeated iterations. The researchers met regularly to discuss the data throughout the analysis stage, and the final themes were defined, named and agreed on by all authors. Illustrative quotes from transcripts were selected to provide evidence for each theme and subtheme.

The study meets the Consolidative Criteria for Reporting Qualitative Research (COREQ).¹⁵

Results

Study participants

Eighteen participants with gout were interviewed. Interviews lasted between 15 and 40 min. Participants were between 29 and 74 years (mean age 53 years) and were mostly male (89%). Twelve interviews were in person and six remote. Three participants were retired at the time of the interview, and seven had taken days off in the last year. Paid work roles included teachers, engineers, government officers, architects and factory maintenance work. There was diversity across age, gender, ethnicity, body mass index, employment characteristics and clinical features of gout (table 1 and online supplemental table 1).

Table 1. Demographic, clinic and employment characteristics of the participants.

Participant number	Sex	Age (years)	Gout duration (years)	Tophi	Ethnicity	Work roles	Time off work due to gout in the last year
1	M	62	41	Yes	NZ European	Wharf worker/ hospitality /retail	No
2	M	41	8	No	Asian (NZ)	Manager	No
3	M	56	12	No	NZ European	Architect	No
4	M	54	2	No	NZ European	Computer programmer	No
5	M	74	14	Yes	NZ European	Factory maintenance	Retired
6	M	57	3	Yes	NZ European	Chemist engineer	No
7	M	48	8	No	Māori (NZ)	University teacher	No
8	M	53	9	No	Asian (NZ)	Storeman	Yes
9	M	60	30	Yes	Māori (NZ)	Government officer	Yes
10	M	59	12	No	Asian (NZ)	Engineer/hospitality	Yes
11	M	49	9	No	NZ European	Engineer	No
12	M	36	1	No	Māori (NZ)	Project supervisor	Yes
13	F	36	18	Yes	Pacific peoples (NZ)	Senior administrator	Yes
14	F	33	10	No	Pacific peoples (NZ)	Service consultant	Yes
15	M	29	13	Yes	Pacific peoples (NZ)	Storeman/psychologist	Yes
16	M	42	8	No	European (Spain)	Teacher	No
17	M	66	37	No	European (Spain)	Factory worker/commercial	Retired
18	M	67	7	No	European (Spain)	Teacher	Retired

Themes

Six main themes were identified from the interviews. A thematic map describing the themes and their relationships is shown in figure 1. The characteristics of the disease and the job itself influenced the experience of working with gout. The experiences were divided into physical, emotional and social. Effective gout management improved participants’ employment experience.

Figure 1. Thematic map describing the main themes and their relationship with work experiences for people with gout.

Gout factors

Pain intensity at the time of gout flares, presence of tophi and the joints affected by the flare were gout factors that influenced the experience of work. Illustrative quotes are shown in table 2. Participants reported that severe flares made work virtually impossible, whereas mild flares were considered to be inconvenient. Most of the participants explained that they rested when the pain was intense. When the pain decreased, they would return to work, sometimes even before the flare completely ended. Tophi and chronic gouty arthritis created more difficulties in physical jobs (such as manual labour). The location of the joint affected by a gout flare also determined limitation in work; when flares occurred in the lower extremities, participants could not move or go to their job, but they could do sedentary work. A gout flare affecting the wrist or fingers caused difficulties typing or doing office work.

Table 2. Gout factors influencing the experience of work.

Gout factors	Quotes
Pain intensity at the time of gout flares	‘If it wasn’t above 6 or 7 I could actually do most of the work I needed to do, just by the compartmentalising the pain, but in the first flare when it was up at 9 or 10, there was no way you could actually remove the pain from about it to do your day-to-day work’. (Participant 11)‘There were times where I would have a minor flare and I would still go to work. Just limp a little bit’. (Participant 6)‘Gout dictated a lot of that. Gout was like the boss. He says: you have gout, if it is a little gout, you go to work. If it’s a big gout, well, you can’t, even no matter how bad you want to go, you sometimes can't’. (Participant 9)
Tophi	‘And then tophi appeared. And my hands were like claws…, so I started struggling, climbing, climbing the ladder, because my hands were like claws…’ (Participant 1)
Joints affected	‘Because I type…. I couldn't move my arm, like if I just moved one little bit, like, I couldn't do anything. Yeah, so I think I must have worked, but I told my team leader that, you know, I might be a bit slow today because my arm is sore’. (Participant 14)‘Put it this way. Some days you could work with gout. Some days, you can’t. You know if I have gout in my elbow. For instance, I can still use my fingers. So, depending where I had the gout was depending on what I could actually do. Like if it is affecting my knee, you can’t walk around’. (Participant 1)

Work factors

Physical requirements of the work, flexibility of the workplace and sick leave availability were key work factors. Illustrative quotes are shown in table 3. The physical requirements of the work (such as walking, lifting or climbing stairs) impacted employment experiences; having a sedentary job was different from a physical one, particularly during a gout flare. Overuse of a joint at work could also trigger a gout flare the following day. Some participants explained that they had problems at work or could not attend work as putting on shoes or boots were too painful during a gout flare. Participants with an office job considered that they were lucky because it would have been impossible to work during a gout flare if they had a physical job.

Table 3. Work factors influencing the experience of working with gout.

Work factors	Quotes
Physical work	‘I am lifting boxes about 20 to 30 kilos every day. And it affected me because I couldn't walk. I couldn't carry out my duties… Because my job is labour intensive, I was unable to carry out my duties to the best of my ability due to the pain I had in my foot’. (Participant 8)‘…a lot of jobs required physical labour…so those jobs they would be affected by gout. If I had gout, I wouldn't, I wouldn't be able to turn up’. (Participant 12)‘You are using hammers and you’re using different stuff and sometimes if I overdid it, next thing, I’d have gout in my wrist…’ (Participant 1)
Footwear requirements	‘…some days I couldn’t even put my shoe on. If I could put my shoe on and stand up, I would go to work but if I couldn’t put my shoe on and I couldn’t stand up I wouldn’t go to work’. (Participant 15)‘Well, the worst thing was, because I normally wear jandals, so gout was alright. But when I had to go to work, I had to put on the big boots and that was the hardest thing to get your foot into a boot’. (Participant 5)
Sedentary work	‘Because it’s office work, there is not a high demand for walking. But if it required walking, you know, there was no way in hell with the flare, even with all of the flares, pretty much, you were near bed-bound’. (Participant 11)‘I went to work just the same because I was sitting down, so there was no problem’. (Participant 17)
Flexibility of workplace	‘I work in the office, so I don’t need to be out or physically active. But when I do see clients, I would revert to virtual calls if I couldn’t get out’. (Participant 2)‘When I have the flare I cannot go to the office and at that time we could not work from home. So I had to take some days off’. (Participant 10)
Sick leave availability	‘I didn’t have the sick leave for many days either. I was there for 4 days. And that’s it. I went back to work. And it bothered me a bit, but not much’. (Participant 16)‘When I run out of sick leave and if I don't go to work, I don't get paid’. (Participant 8)
Self-employment	‘I worked for my own little company, so I was never prone to, you know, have a day off. But if I worked for somebody else, I probably would've. But as I worked for myself, I would go to work… but if I worked for somebody else, I would've probably said, hey, I'm not coming in, I'm too sick’. (Participant 5)‘I might have had the odd day off if I was in paid employment, but because you are self-employed you know you are not going to get paid, so you just carry on’. (Participant 3)

Flexibility in the workplace also determined whether employees with gout could work. The possibility of working remotely reduced the impact of gout on their job. The ability to change meeting dates or stay in the office instead of moving out (eg, to a building site) was beneficial.

The ability to take time off work or take sick leave was another important work factor. Participants reported differences in their experiences of leave based on availability of sick leave and whether they were employees or self-employed. Participants who were self-employed could not take days off and had to go to work with pain.

Physical experiences

Participants reported a variety of experiences with how gout had a physical impact on their employment. Illustrative quotes are shown in table 4. This ranged from the complete inability to work to working despite pain. Participants explained that it was impossible to work when pain was very severe, and they needed to time off work until the pain improved. The experience of working despite pain was common. Gout flares caused difficulty getting to the workplace. Gout also diminished the physical capacity to work, making tasks slower or limiting the achievement of goals. One participant described that ‘you go with your pain and do what you can’. Many participants went to work despite pain, mostly because they felt that even if they were less productive, they could still be useful, especially when the flare was ending and the pain was not so intense. Others went to work because they held positions of responsibility and felt that they could not be replaced. Finally, some went to work because they had run out of sick days and had no other choice.

Table 4. Physical, emotional and social experiences of employment for people with gout.

Physical experiences	Quotes
Time off work during gout flares	‘I needed time off, I needed to go and get a sick note from the doctor because I was in pain, as simple as that’. (Participant 18)‘If we looked at it as an annual average, I would say approximately on month a year, during this time I was affected by gout disrupting my employment’. (Participant 9)
Working despite pain	‘You just went with your pain and did what you could’. (Participant 15)‘I have to plan my day, I have to manage my day around my pain’. (Participant 2)‘I had to perform duty even under, less efficient and a lot of pain, but my presence was still required. So I just had to do it’. (Participant 9)
Diminished work capacity	‘… I still had pain so during the day you weren’t really giving 100%. You were pretty much just attending, trying to do your best and probably running at about 60%’. (Participant 11)‘How much work I did was probably less, because I was slower to walk, you know, to go to get something or do whatever I was doing. So I would have been slower for sure’. (Participant 5)‘I couldn’t meet some of my deadlines’. (Participant 7)
Difficulty getting to work	‘… when I had this attack, I needed time off because I couldn’t really walk. And then after a few days I was taking a taxi to work and then finally after a week I started taking public transport as before’. (Participant 18)‘… it became difficult if I had to walk a long way. Like if I was having a bad gout attack, it became very difficult to walk from the car park to my desk at work’. (Participant 4)‘If I was to get a flare, that would affect my role because I needed to drive to work. Unfortunately, it’s always my driving foot, that would have the flare’.(Participant 13)
Difficulty concentrating	‘No, my productivity, my concentration, my focus, all affected’. (Participant 15)‘And then when I'm sitting at my desk at work, it becomes very difficult to concentrate on my work because I've got such a sore foot basically’. (Participant 4)
Difficulty sleeping due to pain	‘… the only another thing with gout is you’d be awake through the night…you’d wake up a lot of times through the night. … not having a good night’s sleep. Would be tired.’ (Participant 5)‘To be honest, I probably should not have gone to work. Not 100% because I’m not resting… So when I go to work, still tired, still have a little pain, and I just couldn’t do my job properly’. (Participant 8)

Pain affected the ability to concentrate at work. If the flare was intense, participants simply could not concentrate and only focused on the pain. Participants also reported poor sleep during a gout flare, which impacted their work the following day.

Emotional experiences

Emotional responses included feeling responsible, embarrassed, guilty or depressed. Illustrative quotes are shown in table 4. Feeling responsible for missing work, being less efficient or needing help were common. Participants explained that this was the reason they came back to work before the gout flare resolved. Some did not want to leave their work for their colleagues, and others wanted to feel useful. Some participants (particularly women and younger participants) felt embarrassed and tried to hide their disease.

Participants also described feeling guilty. Some blamed themselves for having gout, and felt they were responsible for the days off work, working less efficiently and asking for help. Others felt guilty because they considered they had triggered flares after dietary transgressions and could not go to work. Lastly, a participant with severe gout reported becoming depressed as he could no longer do the things he used to.

Social experiences

Social impacts included experiences within the workplace and in other aspects of the person’s life outside the workplace. Illustrative quotes are shown in table 4. Disclosure responses were variable. Some participants were afraid of disclosing their gout diagnosis in the work environment, to avoid judgmental comments about their age, diet or lifestyle. However, many experienced empathetic support and help from coworkers. In general, participants disliked having to ‘bother’ their work colleagues for help.

Another important experience was the feeling that ‘work comes first.’ Some participants arrived home exhausted after working with gout, and had to give up their usual family roles in order to keep their work.

The consequences of gout had a personal financial impact. Some participants lost income because they could not work or were paid less when they had no sick leave. Some participants had changed their job because of gout or had to look for jobs that were ‘gout friendly.’ Patients described three main points as ‘gout friendly’ work: not physical, flexible (meaning that during the flare less physical tasks could be prioritised, leaving the more demanding work until the flare had ended) and could be done from home. For example, one patient decided to return to study to train for a ‘gout friendly’ job.

The positive impact of effective gout management

Effective gout management improved experiences with employment. Understanding their disease was important, knowing how to control gout flares with anti-inflammatory medications and the impact of committing to long-term urate-lowering therapy. Illustrative quotes are shown in table 5. Some participants reported that by learning to treat gout flares early, they avoided more severe flares or reduced the intensity of the pain so that they could go to work. Regular urate-lowering therapy meant that gout flares diminished or disappeared so that the person no longer had to take time off work. Some participants, especially those who were older or had severe disease, described that nobody had explained the disease properly. The intermittent clinical presentation made it difficult to understand gout as a chronic disease. This led to ineffective management, experiencing more gout flares, with worse experiences at work. By understanding the disease and its treatment, the symptoms improved, and there were fewer problems with gout at work.

Table 5. Positive impact of effective gout management.

	Quotes
Flare management—taking medications to work	‘When I started with more pain I could work because I very quickly was able to control the pain with colchicine, so It didn’t stop me’. (Participant 18)‘There were times where I would go to work, but I would work from my car until the pain relief would work’. (Participant 12)‘… it caused discomfort which required me to change my work pattern, but it didn't stop me working and I would deal the occasional flares by taking anti-inflammatories or some painkiller’. (Participant 6)
Long-term urate-lowering therapy	‘The allopurinol is helping me, every day I take it. And if it wasn't for my medication, I wouldn't be able to work’. (Participant 12)‘… being on regular medication now, I don't have as many flares. Work is a little bit easier now because I'm feeling a little bit healthier’. (Participant 1)
Understanding gout	‘I do not know why I was not educated so earlier in this disease. Why did it take two decades to start educating me? Why wasn't at the beginning as a person, a young person with gout, I made fully aware of the consequences on the long-term fact that your body has gout’. (Participant 9)‘So that was kind of the uneducated version of taking drugs for the sake of pain killing, but not understanding the root problem of gout… that pain and discomfort that I had from gout was inhibiting. I couldn't do anything. I couldn't physically walk. So, it made me realise that something needed to change. And so that was the main point that made me decide to seek treatment and knowledge on gout’. (Participant 2)

Discussion

This qualitative study has examined the impact of gout on employment. The possibility of losing work is an important issue for people with gout.⁵ The burden of inflammatory diseases on employment has been studied in other rheumatic diseases.68 13 16,19 This study has shown that both the characteristics of the disease and the job determined experiences with employment. Working with gout had physical, emotional and social impacts. Lastly, effective gout management improved experiences in the workplace.

It is important to note that gout has some clinical differences from other types of inflammatory arthritis, such as rheumatoid or psoriatic arthritis. Its intermittent presentation with complete resolution between flares, preference for joints in the feet and stigma about the cause may lead to unique experiences. Although gout may be considered less severe than other chronic inflammatory arthritis, there are some people with early onset or a severe presentation, where the disease can limit or prevent the ability to work. It has also been demonstrated that patients’ limitations and impact of foot and ankle symptoms are similar for different types of inflammatory arthritis.²⁰ In our study, participants described that the clinical intermittent presentation of gout made it difficult to understand gout as a chronic disease that required continuous treatment. Understanding the disease led to improved disease management with urate-lowering treatment which in turn improved experiences in employment.

The stigma of gout impacted some participants’ experiences with employment. Some were embarrassed and did not disclose their disease to their colleagues or clients. While some research has shown that people with gout are afraid of losing their employment and income,^{6 13} study participants also feared ridicule or judgmental comments (such as about diet). Others felt guilty because they considered themselves responsible for having the disease or provoking flares. These findings may inform community education strategies to dispel common myths about the causes of gout, particularly focusing on the importance of the biological factors including genetic risk.

In daily practice, rheumatologists do not usually undertake detailed occupational assessment or management plans.²¹ However, this study has identified several issues that could improve employment experiences for people with gout. Some can be addressed in clinical practice within the doctor–patient relationship, particularly building disease understanding and optimising anti-inflammatory and long-term urate-lowering therapy. Other issues go beyond clinical practice and depend on employment regulations and legislation, which may differ in different countries. For example, in Aotearoa/New Zealand, the number of sick leave days for workers is variable based on employment contracts but is often limited on a per annum basis, whereas, in Spain, sick leave is managed by a general practitioner and covers the entire duration of the illness. More flexible work conditions could also be encouraged. The COVID-19 pandemic and related lockdowns demonstrated that flexible work arrangements, such as remote work, can help patients to better adapt to their disease conditions.²²

This study has some strengths and limitations. The sampling method ensured that participants represented most of the demographic and clinical features of people with gout of employment age. This ensured a diverse range of experiences. Although there were only three participants from Spain, the recruitment of participants from two countries is also a strength. After interviewing the Aotearoa/New Zealand participants and three Spanish participants, we concluded that it was unnecessary to continue recruitment of Spanish participants due to data saturation in the context of the sampling framework. A further strength was the inclusion of Māori and Pacific peoples with gout; in Aotearoa/New Zealand, these groups experience early-onset disease and severe impact of gout, and are therefore likely to experience gout during their working age.²³ Participants were mostly men, and although this reflects the sex differences in gout prevalence, this could reduce the generalisability of the findings to women with gout. Another limitation is that our centres are located in urban areas, so we had no participants working in a manual rural environment. Most participants were on urate-lowering therapy and had good serum urate control and the study findings may not be generalisable to people with gout who are not taking urate-lowering therapy. At the time of recruitment, most of the participants were working in office or administrative jobs, although some had changed from physical to sedentary jobs. Though we have a relatively small sample size, we achieved data saturation in the context of our purposeful sampling framework, guided by information power, which ensured that there was a comprehensive understanding of the patient experience and perspective of work.¹²

In conclusion, this qualitative study identified different factors that determined the physical, emotional, and social experience of gout on employment. In addition, we found that effective gout management positively impacted on the overall experience of gout on paid work.

Data availability statement

Data are available upon reasonable request.