Table 3.

Summary of themes, subthemes and main codes mapped to Theoretical Domains Framework (TDF) domains^18,30 and corresponding COM-B Model of behaviour factors.¹⁶

COM-B model	TDF domains [adapted from18, 30]	Themes (no. meaning units)	Subthemes (if applicable)	Codes (non-exhaustive list)	Quotes (see Additional File 4)
Capability
Psychological	Knowledge	Personal health literacy (185)	Health-related knowledge	Awareness, lack of knowledge/understanding, lack of information, misinformation	“[…] not sure how I could adopt the part of the Code that talks about radiation derived from high levels of (unnoticeable), not least because I don't really understand what that would mean, how that kind of radiation could come. And I think in general I don't know how you could adopt that measure” (Portugal, Male, 18–30, HE)
	Cognitive and interpersonal skills; and memory, attention and decision processes		Health-related skills	Ability to find professional help	“I don't know, maybe such coaches would be useful? Who would somehow support with recommendations. Who could be approached online or by phone, or even somewhere on site? (Poland, Female, 31–45, HE)
				Risk perception/risk assessment, balance benefits and risks	“I'm going to do a little thing on point 11, with the vaccination. It is really to be convinced that there are more advantages than disadvantages. But after that, I'm still in favour.” (France, Female, 46–65, ME)
	Behavioural regulation	Psychological resources (57)		Burden/required effort, mental health, psychological maturity, being consistent, personal experience	“I think just the older you're getting, you're just more aware of things that can happen in life. And more so than when you're trying, you don't have to worry about anything.” (Ireland, Female, 31–45, HE)
	Behavioural regulation, beliefs about capabilities, and reinforcement	Perceived internal influences (168)	Behavioural reaction	Factors outside of one's control, resistance to change, temptation, finding balance	“The only disadvantages I see are those that do not directly involve the possible risk of being a patient. And that's what they are, the environmental ones, the ones that don't depend on you. Exposure to areas where there might be some kind of, well, as it says here, radiation, or even exposure to the sun's rays.” (Spain, Male, 31–45, HE)
			Cognitive abilities	Being committed, being concerned, lack of interest, lack of trust	“I think the most difficult ones are related to screening. I don't know … I have a reluctance to go to the doctor; I couldn't exactly explain why, but I don't go with an open heart. I keep postponing it.” (Romania, Female, 31–45, HE)
			Emotional responses	Pleasure, dislike, discomfort	“For colon cancer, I don't know what is done, is it a colonoscopy? Who would think of doing a colonoscopy … plus, it's under general anaesthesia and it's not very good to do it like that. Problems with the colon for years and sometimes when there is pain I worry that there might not be another problem, but now it does not work to say give me a colonoscopy to constantly undergo this.” (Bulgaria, Female, 46–65, HE)
			Personal traits	Self-control, willpower, perseverance	“Yes, I can imagine that. It may be difficult in some cases, but with a strong will it is possible. So of course, the head plays a big role in pushing it through.” (Germany, Male, 46–65, HE)
Physical	Physical skills and beliefs about capabilities	Physical abilities (68)	Biological factors	Age, preexisting health conditions, physical inability to take action	“[…] I started following some of them due to getting older. When I saw that … I don't know. Physical limitations have appeared, actually. I noticed that I get tired more quickly, that I start to feel various pains … In my back, kidneys. And well! That convinced me; otherwise, I don't think I would … I don't know.” (Romania, Female, 31–45, HE)
			Psychological factors	Having an addiction, cravings	“Well, because some people have addictions. We were talking about smoking, well, they can't help themselves. So, they're bound to do it anyway. So, they're going to, they're going to [inaudible] health or whatever.” (France, Female, 18–30, ME)
		Physical skills (44)		Difficulty or perceived inability to act	“Because it's already a habit and you'd have to do a lot of … you'd have to do a lot of thinking. I know it's bad for you, very bad indeed, one day later I really want to quit smoking, but because of the stress of everyday life and all that stuff, I don't want to stop now. It's not wanting to; it's not being able to.” (Portugal, Female, 18–30, ME)
Opportunity
Social	Social influences, social/professional role and identity, environmental context, and beliefs about consequences	Social, cultural, and interpersonal influences (243)	Cultural factors	Celebrations/rituals, customs, taboos	“[…] it's never affected me. But again, I just knowing from talking to people or in hearing it in general, some people are sitting breastfeeding, and they feel conscious, or they get told can they go to another area or something and that's a natural way to feed a newborn. So, I just think that needs to be promoted and told a little bit clear about that this is really natural and it's not someone getting stripping in public.” (Ireland, Female, 31–45, HE)
			Societal factors	Social acceptance of harmful behaviours, social pressures, public awareness, social support, having a supportive environment, media	“It's very deeply rooted in society right now. You meet someone for a beer, sometimes a coffee, but mostly something alcoholic. If you go out at night you often end up having a drink.” (Spain, Male, 18–30, HE)
	Social influences		Family-related factors	Parent responsibilities, role model, family support, family dynamics	“Oh my. For my children, for my close family, I want to pass on to them good habits in relation to healthy eating for example or not smoking or not drinking too much, doing things on foot. So yes for my family, for the planet too. I don't really know what to say.” (France, Female, 31–45, HE)
			Peer-related factor	Peer pressure, peer support, shared habits/goals, health promotion peer encouragement	“[…] Mm, yes. I have a group of friends who are very much urging me to quit smoking. They shout at me a lot when I go to smoke a cigarette so … I think they would motivate me to do it.” (Poland, Male, 46–65, ME)
Physical	Environmental context	Environmental factors (105)		Geographical limitations, modern convenient lifestyle, environmental factors, place of residence, rural vs. urban environment, seasonal aspects	“I also find it a bit difficult sometimes to adopt the measure of screening, because in the area where I live it's not exactly a common thing. Sometimes you have to travel a few kilometres to go for a screening, and this makes it more difficult for people like me, who live in those areas, to have a screening. Even if sometimes they want to, it is difficult to do it because of the distance.” (Portugal, Male, 18–30, HE)
		Personal circumstances (121)		Time constraints, time management, work-life balance	“[…] the consequence of today's life, too much sitting, too much work, too many obligations. I think that maybe sometimes it's not, as you would say, within some limits of our capabilities. If I watch, say, starting with myself, who have a desire for 100 things, cycling, running with hiking. Sometimes people don't have time for that. So, you work all day, you come home with a bunch of obligations, so I think it's more of a problem of some kind of hectic lifestyle.” (Croatia, Male, 31–45, HE)
		Systemic and policy-level determinants (72)		Conflict of interest, availability of programmes, prevention campaigns, regulations, taxation, governmental intervention, universal healthcare coverage, adequate provision of healthcare services/workforce, infrastructure	“A major insurmountable obstacle is the existence of strong financial interests in the sale of high-calorie drinks, alcohol, canned meats and other highly processed foods” (Bulgaria, Male, 46–65, HE)
		Workplace-related factors (64)		Type of job, employees' benefits, workplace culture, employers' responsibilities, workplace safety	“Well, when I'm in a workplace like that. I go into the sun both in the morning and in the afternoon. And to work from work, the sun is both in the face and in the lap, chest.” (Croatia, Male, 46–65, ME)
	Resources	Access to resources (120)		Access to healthcare services, access to cancer screening tests/programmes, access to vaccination programmes, access to green spaces, access to sport facilities, access to healthy food/quality products, access to information	“What also facilitates physical activity is to have spaces, parks, etc. In Lyon, this is very limited. In Lyon, it's very difficult. But to have spaces too … Maybe smaller green spaces. It's true that they are now trying to include this in the projects, but these are things that could facilitate physical activity.” (France, Male, 31–45, HE)
		Economic factors (73)		Affordability, cost of living, financial constraints, household budget	“Well, some of the major disadvantages we have, I believe, are the conditions. With not having a very good financial situation in Romania, it is difficult to go to the gym because memberships are quite expensive, and it's hard to have a more active lifestyle, although you can certainly do that outdoors.” (Romania, Male, 18–30, ME)
		Healthcare accessibility (53)		Difficulty to set an appointment, lack of follow up, out-of-pocket payment services, disregard importance of cancer prevention, health insurance	“The only problem I was a bit kind of wary of at that it was at least a month before the next appointment. So, if you've got something you're worried about, I'd say that seems quite long.” (Ireland, Female, 31–45, HE)
Motivation
Automatic	Emotions and beliefs about consequences	Emotional responses (91)		Concerns about medical procedure, fear of cancer, seeing other people suffer, closes cases of cancer diagnosis family/loved ones, feeling better, feeling healthier, parental protective instinct, happiness, well-being	“Well, the main reason is the fear that some malignant disease might eventually happen to me. Fear of, in the future, that something will happen to me.” (Croatia, Female, 46–65, HE) “The main reason is my health and that of my loved ones. It is important to follow the recommendations if we want to be healthy for ourselves and our loved ones.” (Bulgaria, Female, 31–45, HE)
	Reinforcement	Habits and personal empowerment (41)		Having a routine, habit formation, being motivated	“For me, it is important that a person is motivated, to implement the recommendations that are really achievable.” (Bulgaria, Female, 46–65, HE)
Reflective	Beliefs about consequences	Benefits (25)		Not perceived benefit, health benefits	“Yes, if I chastise myself with it and I'm not convinced that I want to do it, I wouldn't do it either. Why should I subject myself to the torture, now it's a bit exaggerated torture, but really subject myself to an effort, then I'll just live longer with this effort. That doesn't do me any good. I don't know how to explain it.” (Germany, Male, 46–65, LE)
		Self-reflection (16)		Being mindful of one's body image, taking care of one's health, being mindful of others' health	“It clearly helps not to consume alcohol, not to do … It also helps you from … you don't get wrinkles if you don't stay like that, I mean you don't get as many wrinkles if you don't spend so much time in the sun and if you put on SPF and all that.” (Romania, Female, 18–30, ME)
	Beliefs about capabilities (confidence)	Values (21)		Determination	“It depends on the approach. Well, it will come easier for some, it will come harder for others a little bit, no? It's all in the mind. If you decide to do something, if you are determined to do it, then I think … you can achieve it.” (Poland, Female, 31–45, LE)
	Goals and intentions	Plans and goals (84)		Cancer prevention, disease prevention, desire for better health, desire for a better quality of life, desire for longevity, early detection, well-being, weight management, having a healthy lifestyle	“I want to enjoy a healthy life. I want to live my life as best I can (inaudible) any steps I could take to reduce cancer; I'd gladly take on board.” (Ireland, Male, 18–30, HE)
	Social/professional role and identity, and optimism/pessimism	Beliefs (22)		Religion, vaccine hesitancy, conviction	“I used to hesitate when I vaccinated children, had them vaccinated.? I thought then, normal stories, ouch, maybe it could be both harmful and this and that … Then I had such a doubt, but I'm glad they were vaccinated, I'm very glad. And secondly, nothing, it was such a doubt, i had doubts maybe I was wrong, maybe I wasn't … And everything else, I absolutely don't think there are any shortcomings.” (Croatia, Female, 46–65, ME)

TDF: Theoretical Domains Framework. Numbers in brackets indicate the total number of meaning units assigned to each theme, classified as either barriers or facilitators. Educational attainment: HE: High education, ME: Moderate education, LE: Low education.