Lifestyle intervention in workers with obesity and sedentary behavior: A pilot study for the “OTTiMo LavorO” project

1 Introduction

Obesity represents a global epidemic problem [1] not only because it contributes to the onset of numerous chronic diseases [2], but also because it itself constitutes a serious debilitating condition [3]. It is an increasingly widespread also among workers. Initially linked mainly to shift work, which can cause the onset of pathologies or at least alteration of physical and mental well-being, today it is widespread in numerous professional activities, which over the years have been characterized by longer sedentary periods, with an inevitable negative impact on health. Obesity reduces life expectancy [4] and is associated with several medical conditions, such as type 2 diabetes, and cardiovascular disease [5]. It also has serious consequences in terms of economic burden, because people with obesity have a greater need for medical care (up to 3.66 times [6] than people with normal weight [7, 8], causing more absences from work (from 1.1 to 1.7 extra days annually missed respect to normal weight worker) [9] or even preventing them from having a job [10, 11]. Van Nuys et al. showed how the likelihood of short-term disability, compensation claims, absenteeism, and employer costs increased with a body mass index (BMI) >25 kg/m² [12]. In particular, employees suffering from obesity costs on average $8067 per year compared to $3830 for normal weight workers [12].

According to the US Diabetes Prevention Program, the promotion of weight loss through healthy behaviors, such as increased physical activity (PA) and healthy eating, can reduce the development of type 2 diabetes [13] and metabolic syndrome (MetS) [11, 13]. Nowadays, MetS prevalence is estimated to be aroud 25% worldwide [14].

Many factors, including incorrect dietary behavior, low level of PA, or sedentary lifestyle, contribute to overweight and obesity in adult [15]. An adequate level of PA should always be incorporated into any treatment plan for individuals affected by obesity [16]. The 2010 World Health Organization guidelines for reducing the chances of developing chronic conditions, recommend at least 150–300 minutes of moderate-intensity PA weekly [17]. Otherwise, 75-150 minutes of vigorous-intensity, or an equivalent weekly combination of moderate-intensity and vigorous-intensity aerobic PA, may also be helpful [17]. Despite this, for many workers who spend around 40 hours per week at work, eat at least one daily meals outside the home [18], and, in indoor jobs, spend many hours sitting, adopting healthy behaviors is complex. The risk of obesity and mortality inevitably increases [19, 20]. For this reason, it is necessary to encourage interventions aimed at promoting healthy lifestyles [21, 22].

Increasing PA among employees improves their health, productivity, and sleep quality, as well as reduces healthcare costs, sick leaves, and absenteeism [23–30]. It also has positive effects on mental health [31–34].

The work environment constitutes an excellent terrain for introducing behavioral interventions [35–41], which take into account both the individual preferences and characteristics of the worker and real situation of the company [30, 42–44].

These lifestyle interventions, which require a multidisciplinary approach to be implemented [29, 46], should focus, on one hand, on the reduction of a sedentary behavior at work, and on the other, on the introduction of a structured program of daily exercises [19].

The aim of this pilot study, in a real working context, was to evaluate the effects of diet and a self-monitoring PA protocol in workers with overweight or obesity in order to promote greater PA and the improvement of healthy and active lifestyles by educational programs.

2 Materials and methods

The OTTiMo LavorO (OTtimizzare il Trattamento Multidisciplinare del Lavoratore con Obesità) is an on-working project with the aim of optimizing the multidisciplinary treatment for workers with obesity in workplace health promotion campaigns. The study was conducted according to the Good Clinical Practice guidelines and approved by the Human Ethic Committee of the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico (Registration number: 852) and written informed consent was collected for each participant at enrollment.

This study was performed between September 2019 and February 2020 at Obesity and Work Center of the Occupational Health Unit, IRCCS Ca’ Granda – Ospedale Maggiore Policlinico Foundation in collaboration with the University of Milan. In particular, participants were enrolled from September until the end of December 2019 (baseline, T0). During this period, patients were evaluated as eligible after the compilation of two questionnaires and the administration of the six-minute walking test (6MWT). After enrollment, participants could begin PA for one to three months (end of the treatment, T1), depending on the date of recruitment. In fact, follow-up visits were carried out in January and February 2020 in order to verify the effects of the protocol.

The study included workers who had been referred to our centre for a health promotion program, with special attention to nutritional and behavioral aspects. Eligibility criteria were: to be active worker, BMI > 25 kg/m² (overweight or grade I or II obesity); age > 18 years; inactive or minimal active subjects (measured with the Global Physical Activity Questionnaire, GPAQ). The exclusion criteria were: cardio-respiratory pathologies, neurological diseases, psychiatric illness, uncontrolled hypertension, neoplasms with bone metastases, uncontrolled vertebral fractures, spondylolisthesis/spondylolysis, low-density lipoprotein-cholesterol (LDL-C) ≥190 mg/dL. Regarding medications, if in use at the time of recruitment, participants continued treatment for the entire duration of the study.

During the two clinical visits (at T0 and T1), a skilled dietitian used a wall-mounted stadiometer and scale (ISECA) to measure participants’ height and weight. The measurements were taken while participants were wearing light clothing. BMI was then calculated by dividing the weight in kilograms by the square of the height in meters. The waist circumference by directly measuring the midpoint between the lowest rib and the iliac crest on the participant’s skin was also measured. Participants were prescribed a low-calorie Mediterranean diet therapy for weight loss [47]. Considering each individual’s food intake and PA, a 600 kcal-calorie reduction based on the Harris Benedict equation [48] was recommended. To calculate daily heat production of each participant, the observed body weight for both males and females was used.

The diet included 50% carbohydrates, 30% lipids, and 20% proteins, divided into 5 meals per day, and recommended eating fish at least 3 times a week (Online Supplement Table S1). Adherence to the meal plan was monitored by checking the diary that participants were invited to fill out.

Measurement of PA performance, functional limitation degree, and quality of life were performed with 6MWT [49], Short Form-36 Health Survey (SF-36) [50–52], and GPAQ [53, 54]. The employed tests are described in Table 1. Since the aim of the intervention was to introduce/increase daily PA according to the examples provided during the first visit, PA was not associated with a calorie target to burn.

We used, and we encourage scientific literature to do it, people-first language (according to the recommendation of the Italian Dietetic Association-ADI, and the European Association for Study of Obesity-EASO) to reduce bias associated with the term “obesity” and to stop stigma that labels patients by their condition [55].

3 Results

For this study, 39 worker participants were recruited, divided into 14 males and 25 females.

Baseline characteristics of the analyzed population are shown in Table 2, while Tables 3 and 4 indicate the variation between T0 and T1 in PA performance, in the degree of functional limitation, and in the quality of life recorded through SF-36, 6MWT, and GPAQ. Physical functioning, limitations due to physical conditions, energy/fatigue, emotional well-being, and general health had significantly improved after the intervention, as shown by the results of the SF-36 (Table 3). Similarly, as shown by GPAQ, participants significantly increased time spent in leisure activities (from 30 [0–120] min/week to 150 [150–200] min/week, p < 0.001) and reduced sedentary time (from 7 [4–8.5] hours/day to 6 [4–8.5] hours/day, p < 0.001) (Table 4).

Finally, the 6MWT showed a significant increase of the distance that subjects were able to walk from 462.5 [421.5–500] m at T0 to 500 [462.5–550] m at T1 (p < 0.001) (Table 4).

Table 5 shows the participants’ anthropometric parameters before and after intervention. Weight and BMI showed a significant reduction, as well as basal metabolic rate (from 1530 [1403–1841] kcal/m²/h to 1496 [1440–1738] kcal/m²/h, p < 0.001), as expected in a low-calorie diet.

A multiple linear regression analysis was performed to investigate the impact of selected covariates (PA, body weight reduction, and sedentary time) on the 6MWT outcomes after the intervention, but none of them were statistically noteworthy. Adjusting the analysis for gender, the improvement in PA was statistically significant in men.

The aim of the study was to evaluate the effects of a self-monitoring diet and PA protocol in workers with obesity and sedentary behavior, with intervention on their lifestyles.

The protocol and diet formulated for study participants improved overall physical performance, quality and lifestyle.

The Mediterranean diet is considered one of the healthiest eating patterns and its multiple benefits on physical and mental health are supported by a wide range of evidence [58]. In this study, however, the focus was mainly on PA. The workplace can play a pivotal role in promoting a healthy lifestyle and, in this specific case, in preventing the complications of obesity. It would therefore be advantageous to introduce lifestyle assessment programs, even from a prevention perspective, which would benefit not only the individual, but also the company itself [34].

The diary, which constitutes a sort of personal monitoring system, could be the optimal tool for achieving objectives that must become habits, such as diet, PA, and weight loss program. In our study, we recorded a statistically evident weight loss from T0 to T1, together, obviously, with the reduction in BMI. Weight reduction certainly influenced the results of the 6MWT, which, combined with the results of GPAQ, indicate an overall improvement in the lifestyle of participants after the intervention.

Regular PA has a beneficial impact on lifestyle and should also be encouraged in the workplace to combat the spread of obesity [59–61]. This line of studies has demonstrated the correlation between obesity/overweight, sedentary work, time spent in the working environment or type of employment [62]. Obviously, according to our program, tailored interventions for different professional groups may be necessary.

In a recent study by Andersen et al. [63], in some workplaces, micro-exercises have been implemented, such as simple and short strengthening exercises, to act on the main muscles used during work activities. These exercises can be comfortably performed with elastic resistance bands, together with colleagues at their usual workstations, for only 10 minutes, three times a week and without the need to change clothes, go to the gym or shower afterwards. Engaging in micro-exercises at work has the ability to reduce the likelihood of extended sick leave due to illness [63].

Health interventions should be part of company policy to improve health and well-being of workers and promote healthy lifestyle behaviors under the supervision of competent health specialist.

PA has been shown to reduce inflammatory markers and improve clinical outcomes in individuals with obesity or Mets [64]. Different exercise modalities (aerobic, resistance, and combined training), have different impacts on MetS parameters. Combined exercise, for example, compared to aerobic or resistance exercise alone, has a greater beneficial effect on weight [65, 66], waist circumference [65], lipid- [65, 66], glycemic- [65, 66] and blood pressure- [65] profile. Similar results have also been reported with only aerobic exercise [67, 68], but not following resistance exercise [69]. Regardless of the type, exercise has thus pleiotropic effects on nutrients, metabolism, mitochondrial function, inflammation markers, and MetS features [70]. PA also reduces serum uric acid level [71], a cardiovascular risk markers in patients affected by obesity, especially in those with MetS [72].

Prevention of obesity requires sufficient levels of moderate to vigorous PA, but light PA also contributes to daily energy expenditure [73].

The benefits of a healthy lifestyle, and in particular of PA, are not limited to the prevention/management of chronic diseases [74], but are also related to the improved work performance [63]. This is confirmed by the results deriving from several programs that have been applied in different working environments [38, 75–80].

Finally, comparison of the SF-36 items identified at T0 and at T1 showed that physical functioning, energy/fatigue, emotional well-being, and general health were all significantly improved after the intervention. However, regarding the psychological assessment, some considerations can be made taking into account the limitations of this study linked both to the small number of subjects enrolled and to the short period of follow-up. Psychological examination of the enrolled participants confirmed the beneficial effect of our self-monitoring PA protocol and diet on mood, symptoms of anxiety and depression, as well as psychological well-being.

Some limitations of our study must be acknowledged. We only investigated concurrent short-term changes in diet, well-being, leisure PA behaviors, and BMI. We had no information on changes in body composition, which may limit the broader applicability of our findings. Furthermore, the sample size of our study was relatively small due to the difficult to implementing effective and long-lasting Workplace Health Promotion interventions in the real world of work. Conducting randomized controlled trials in a work environment presents several challenges, such as the difficulty of building the sample itself (work may prevent you from following the program).

Shift schedules do not allow enough workers to be involved to draw solid conclusions. Moreover, all interventions are carried out on a voluntary basis and worker participation is often low because they do not recognize their effectiveness. However, despite these limitations, an important aspect of this our study was a complex approach involving different professionals (physicians, physiotherapists, dietitians and psychologists).

In conclusion, our study suggests that a self-monitoring PA protocol and diet are a sustainable tool and an important component of an improved weight loss lifestyle. Consequently, an adequate amount of PA must become an integral part of any clinical intervention and any treatment plan for weight control. The role of physical exercise in promoting well-being and healthy aging, together with the prevention of many chronic non-communicable diseases and stressful conditions, is now indisputable. However, it is very difficult to change lifestyles by introducing PA into daily life. Therefore, the decrease in hours/day of sedentary activities is a very encouraging finding. In the workplace, for example, simple posters displayed or the involvement of the occupational physician could be the first means to try to promote PA in sedentary workers. The intervention that we have proposed in this study also represents a practical, simple, and sustainable model, in which, even if under the guidance of a specialist, the subjects themselves define specific objectives that can be autonomously modulated and increased over time.

Supplementary data

Table S1: Dietary protocols followed by study participants, divided between women and men.