Co-occurrence of lifestyle risk behaviors

To the best of my knowledge, this thesis is the first to assess relationships between a lifestyle risk index score, work ability and sick leave in a general working population over time. In all three papers included in this thesis, we found higher odds of low work ability by higher lifestyle risk score (see e.g. Figure 7). A similar association was also observed in relation to sick leave at follow-up. The association between lifestyle risk score and work outcomes may be important for public health policy-making in terms of providing new information on the co-occurrence of unhealthy behaviours and the potential consequences of this. Such lifestyle risk factors are theoretically modifiable. Several studies have investigated the relationship between individual lifestyle risk factors and work outcomes (9, 10, 13, 71, 129), but the effects of co-occurring lifestyle factors are less well-known.

In large epidemiological studies, a lifestyle risk index can be helpful when investigating how the co-occurrence of lifestyle risk factors relates to public health challenges (i.e.

work outcomes). There are indications that lifestyle risk factors can accumulate, and that they are linked to mortality (CVD) (7). It can be hypothesised that altering a lifestyle risk factor in a positive direction will have a positive effect on other factors. Findings from a recent study among young adults indicate that increasing physical activity may raise awareness of a healthy diet (130). However, these interactions are complex and a Norwegian cohort study found that those who increased their BMI were more likely to be less physical active, but this did not occur bidirectional (131). Despite the observation of a positive association between lifestyle risk index and work outcomes, the thesis

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results do not indicate which lifestyle risk factors need to be adjusted to achieve the greatest impact on work outcomes. Nevertheless, our results may support future meta-analysis and systematic reviews investigating lifestyle risk factor co-occurrence and work outcomes.

The lifestyle risk index score used in the three papers represents a simplification of a multifactorial concept. It is likely that the results would have differed if different lifestyle risk factors had been included. For example, the lifestyle risk index does not include important factors suggested by others (7, 108), such as alcohol, sedentary behaviour and lack of social participation. These studies reported associations between sedentary behaviour and all-cause mortality (7, 108). At the same time, inconsistent associations with all-cause mortality have been found for diet (108) and alcohol consumption (7).

Nevertheless, we acknowledge that including these lifestyle risk factors – and particularly additional socioeconomic factors – could have produced different results.

There is evidence that lifestyle risk factors often co-occur (17, 18). The three papers making up this thesis did not investigate the clustering of different lifestyle risk patterns in relation to the outcomes. However, Paper III found that individual lifestyle risk factors were correlated. Individuals who reported a low level of physical activity were more likely to have an unhealthy diet (χ2 = 83.86, p<0.05) than individuals who reported recommended (or higher) levels of physical activity. In addition, persons who reported a low level of physical activity were more likely to smoke (χ2 = 70.91, p<0.05). Despite the observation that some of the individual lifestyle risk factors are inter-related, the results do not allow a conclusion as to the underlying mechanism or direction of these relationships. Additional studies are needed to explore these complex relationships.

In our study population, 51% of the subjects in the study population were categorised as overweight or obese at baseline (BMI ≥25 kg/m²) (2013). This in line with the findings from the recent National Public Health Survey in Norway (2020) showing that 59% of men and 47% of women had a BMI ≥25 kg/m² (16). Together with other Norwegian cohort studies, the Telemark Study will continue to expand the knowledge base regarding changes in BMI at the general population level.

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Efforts to tackle obesity at the individual level are numerous, but often difficult to implement. Societal efforts are also needed to reduce obesogenic factors in the environment (132). Examples of such factors include less physical demanding work tasks, reduced physical activity during leisure time and the easy availability of processed and high-calorie foods with little nutritional value (15). Moreover, a recent narrative review examining contextual factors in the prevention of obesity (acceptability, costs and equity) found that policies such as front-of-pack nutrition labelling, sweetened beverage taxes and restrictions on advertising targeting children are all potentially effective population-based measures for preventing high BMI (133). The review also acknowledged the need for more research in the field of health promotion policy, for example to examine the effect of marketing on integrated digital platforms (blogs and vlogs, social media, etc.) (133). Interestingly, a recent Norwegian study investigating the impact of an abrupt increase in taxes on sugar and chocolate products and non-alcoholic beverages (implemented in November 2017: an 80% increase in taxes on sugar and chocolate products and a 40% increase in taxes on non-alcoholic beverages) found no decrease in sales of these products (134). The study may indicate that the taxes were still too low to have an impact on sales (134). Norway had a period of taxation on sugar back to 1922, but this tax was levied as of 1.january 2021 (135, 136). Today, the tax system differentiates between sugar and artificial sweeteners, and is regarded as a response to health concerns about high-sugar beverages (137).

A Norwegian study from 2015 has identified socioeconomic differences in consumption patterns for fish and vegetables (138). The same study also found that barriers to the consumption of these food items included perceived quality and knowledge (e.g. of preparation) and – to a lesser degree – price, and that these factors were linked to socioeconomic group (138). It is likely that the debate on public health food policies, including taxation of less healthy dietary components, will continue.

The workplace is a large and important part of a person’s life, but is also important for society at large. Workplace measures therefore have a potential reach beyond the individual employee (139). An important factor in health promotion at the workplace may

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be the substantial amount of time spent there, as this may make health promotion easier to integrate than elsewhere. Nevertheless, only a limited number of studies have identified effective health-promotion activities for reducing sick leave and enhancing work ability. The evidence in this area is therefore weak (36, 140-142). There are indications that the adult population is spending increasing amounts of time on sedentary activities (15), and further studies are needed. The results of this thesis indicate that efforts to increase physical activity in general may be important. The workplace is one of many potential arenas for increased physical activity both during and after office hours.

A recent randomised, controlled trial among persons with obesity and sedentary occupations in Germany found a statistically significant increase in work ability after 12 weeks of low-volume, high-intensity interval training (total session time of 14 minutes), combined with dietary advice, compared to a control group (143). Although this was not a workplace intervention, the findings suggest that short, intense physical activity may increase work ability and motivate facilitation of such activity at work (143). On the other hand, while physical activity is recognised as positive for health (144) the negative effects of ‘exercise as medicine’ have scarcely been debated in large epidemiological studies.

Such effects may include sport-induced injuries (145) or precautions that should be made in regards to specific diseases (144).

Norway has seen positive results of tobacco-control and health-promotion policies (146), and it can be speculated that some of these successes could be replicated by policies focusing on healthy diet, healthy BMI and increased physical activity, thereby improving general population health. A number of considerations arise in this regard. Firstly, these policies took many years to agree and implement (>40 years). Secondly, new technology (like mobile applications – apps) may allow individuals to be reached on a more personal level, and a vast potential remains to be explored in terms of utilising technological advances in both primary and secondary prevention of poor health (147). However, it is important to note that health-promotion campaigns and policies may lead to ‘victim blaming’ as people experience stigmatisation because of their health choices (148). Public health strategies that concentrate on empowerment rather than behavioural change may therefore achieve higher compliance (148). In this context, ‘empowerment’ refers

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to giving people the ability and freedom to make choices in their own lives. These choices may not always coincide with health-promotion measures (148), but it is also important to respect individual freedom. Moreover, the question of whether there is a linear relationship between changes in lifestyle behaviours and better health-related quality of life remains unanswered. For example, no consistent relationship has been found between weight loss and increased health-related quality of life (149).

Although the three papers included in this thesis did not investigate health-promotion interventions at the workplace, it appears important for future research to measure the effectiveness of these types of interventions due to their potential to reach large populations. This is in line with the World Health Organization’s emphasis on the workplace as pivotal in health-promotion activities in the 21st century (150, 151).

Norway’s Public Health Act was implemented in 2012. It incorporates five principles:

reduce social inequality, ‘health in all policies’, sustainable development, the precautionary approach and participation (152, 153). Health-promotion activities, especially from the `health in all policies’ perspective, should focus on prevention of unhealthy behaviours while simultaneously encouraging healthy lifestyle changes (147, 154). Further, the ‘health in all policies’ perspective also suggests that health-promotion activities both at and outside the workplace should not target individual lifestyle risk behaviours but rather aim to promote a range of healthy behaviours (147).

Interestingly, a Dutch study has explored moral issues linked to health promotion in a working environment. The study found that most employees viewed such activities positively, with younger participants being the most positive (139). It has also been suggested that building a better understanding of complex health and work outcomes may require the inclusion of qualitative approaches in future intervention and cohort studies (155), such as sub-sample in-depth interviews or focus group discussions. This would make a valuable contribution to an improved understanding of the complexity of lifestyle behaviours and work outcomes.

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