High Occupational Physical Activity and cardiovascular risk factors in employees: a cross-sectional study

Background The impact of occupational physical activity (OPA) intensity, considering adults work many hours a day, on health is unknown. The present study aims to evaluate the association between the high intensity of OPA and cardiovascular risk factors of employees. Methods A cross-sectional study was carried out in the “Fomento de Construcciones y Contratas S.A. Company” (FCC S.A. Delegation) in 2017, Spain. The intensity of OPA of each employee was classied by work categories in low ( ≤ 3 METs) or high (> 3 METs). Health and lifestyle data of employees were collected on medical consultation in the workplace. Results Associations were analyzed between the high intensity of OPA and cardiovascular risk factors of employees. 751 employees, 55.5% (n = 417) with high intensity of OPA. An 82.2% (n = 245) of employees with low intensity of OPA presented overweight/obesity compared with 69.0% (n = 171) with high intensity of OPA employees (p < 0.001). In men, high intensity of OPA is negatively associated with Body Mass Index (BMI) (B: -0.042, p = 0.003), waist circumference (B: -0.027, p < 0.001) waist-hip ratio (B: -5.484, p < 0.001), cholesterol (B: -0.007, p = 0.001) and triglycerides (B= -0.003, p = 0.025). In women, high intensity of OPA was positively associated with blood pressure (BP) (systolic BP: B = 0.036, p = 0.005 and diastolic BP: B = 0.040, p = 0.021). In conclusion, the high intensity of OPA is associated with less cardiovascular risk factors in men, whereas women are associated with high levels of blood pressure, suggesting an inuence of gender and work categories.


Data collection
In FCC S.A. Delegation Medical Examination Service, the physician did a check-up of all employees every year and recruited the information of employees in the workplace such as age, gender, anthropometric, biochemical, and lifestyle.
This medical visit consisted of the recruitment of anthropometric, biochemical and lifestyle data.
Anthropometric data Anthropometric data were weight (kg), height (m) and waist circumference (WC) measured above the iliac crest and hip circumference (HP) (cm) using the Lohman manual [16].Diagnoses of abdominal obesity were assessed (WC ≥ 102 cm in men and ≥ 88 cm in women) [17,18]. The waist-hip ratio was calculated by dividing WC by HC (considered high waist-hip ratio for men > 1 and women > 0.9031) [17]. Moreover, body mass index (BMI) (kg/m 2 ) was calculated, and it was categorized using the World Health Organization (WHO) thresholds (BMI ≥ 25 kg/m 2 overweight or ≥ 30 kg/m 2 obesity).
Systolic and diastolic blood pressure were collected (mmHg) using the OMRON® arterial pressure monitor. The employees were sitting in at rest for about 10 minutes with the arterial pressure monitor in the arm, the physician measured three times the arterial pressure and the mean of three measurements were used. The hypertensive employees were registered in the medical record and were register for the prescribed medication for hypertension by family physicians for obtaining more information about the employee.

Biochemical data
Biochemical data were parameters related to cardiovascular diseases: cholesterol, triglycerides, and glucose collected in blood samples. Employees with hypercholesterolemia (cholesterol ≥ 200 mg/dL), hypertriglyceridemia (triglycerides ≥ 150 mg/dL), and diabetes mellitus (glucose ≥ 126 mg/dL) were derived from a family physician, to obtain better health management of the employee.

Lifestyle data
Focusing on lifestyle, alcohol risky consumption was considered if the employed referred an alcohol consumption > 28 standard drink units (SDUs) /week in males and 17 SDUs/week in females. Tobacco consumption was registered if the employee is an active smoker. Physical activity outside of work hours (named as leisure-time physical activity, LTPA) were collected by International Physical Activity Questionnaire [19] and classi ed by ≥ 30 minutes/day of LTPA as high LTPA or < 30 minutes/day of LTPA as low LTPA. From this questionnaire [19], it was only considered LTPA, but other variables such as transport used, household domain and working hours were dismissed.
Employees OPA and socioeconomic characteristics Employees were classi ed by different work categories based on the International Labour Organization [20], and linked with socioeconomic level evaluated [21,22], into: a) Managers: administrative and commercial managers/production and specialized service managers (high socioeconomic levels: directors and managers), Moreover, the intensity of OPA was registered from the Compendium of Physical Activities [23] and work categories by the International Labour Organization [20]. The OPA intensity was the physical activity developed in the workplace, and this is assessed by physical activity intensity done during work hours using METs, depending on the type of work. Employees who spent ≤ 3 METs in their work hours per day were categorized as the low intensity of OPA, and employees who spent > 3 METs in their work hours per day were categorized as the high intensity of OPA.

Additional data
The Metabolic Syndrome of employees has considered if they present these three factors: diabetes mellitus, hypercholesterolemia, obesity and/or hypertension and its association with OPA intensity [24].

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The principal outcome was the association of OPA intensity calculated by the physical activity of the category work of each employee and cardiovascular risk factors. The secondary outcome was considered the association of OPA intensity and cardiovascular risk factors segregated by gender.
Continuous variables were presented as the means ± standard deviations (SD), and categorical variables are presented as percentages. ANOVA test was used to compare continuous variables and Chi-square to compare categorical variables. Analyses were conducted segregating the population by OPA intensity and gender. Logistic regression models were used to analyze the associations between OPA and cardiovascular risk factors. Logistic regression multivariate analysis was used to calculate the associations with high intensity of OPA and anthropometric or biochemical parameters, whereas for categorical variables such as lifestyle parameters (tobacco and alcohol consumption, it used binary regression logistic analysis to calculate the association with high intensity of OPA).
All data were analyzed using SPSS V.25.0 for Windows (SPSS Inc., Chicago, Illinois, USA). The level of statistical signi cance was set to p < 0.05.

Results
All of the employees, 751 employees from the FCC S.A. Delegation were included in the present cross-sectional study. Table 1 showed the characteristics of the FCC S.A. Delegation, consisted mainly of males (72.7% (n = 546 /751)). The age mean ± (SD) of the total population was 45.2 ± 9.8 years. A 98.8% (n = 742) of the FCC S.A. Delegation employees had a low or very low socioeconomic level according to the work categories of employees; highlighting that a 51.7% of employees were non-quali ed workers (categorized as very low socioeconomic employees). The results were expressed as mean and ± SD: Standard Deviation Table 2 shows the characteristics of employees depending on their intensity OPA, high OPA or low OPA. Almost half of the employees, 44.5% (n = 334) were categorized as low OPA. A 54.6% (n = 298) of males had a low OPA compared with only 17.5% (n = 36) of females. OPA: Occupational physical activity -According to Compendium of Physical Activities [23] Professional category: to the International Labour Organization [20]   In lifestyle parameters, only tobacco consumption was signi cantly positively associated with the high intensity of OPA in male employees (B = 0.394, p = 0.024). Other lifestyles such as LTPA or alcohol, consumption were not associated with the intensity of OPA.  Table 3 are reinforced in additional le 2, where males carried out the high intensity of OPA presented lower levels of BMI, WC, WHR, cholesterol, and higher consumption of tobacco, compared to employees carried out the low intensity of OPA. On the other hand, females carried out the high intensity of OPA presented higher levels of SBP and DBP compared to the low intensity of OPA females (additional le 2), results supported by association analysis presented in Table 3. Also, additional le 2 showed lower levels of OW and OB prevalence in the high intensity of OPA (69%; n = 171) compared to the low intensity of OPA (82.2%; n = 245), p < 0.001. Moreover, considering females and males together, employees carried out the high intensity of OPA presented lower percentages of diabetes mellitus (3.5%, n = 15 vs. 7.5%, n = 25; p = 0.022) and metabolic syndrome (1.7%, n = 7 vs. 4.2%, n = 14; p = 0.045), compared with employees carried out the low intensity of OPA. In lifestyle parameters, speci cally in high LTPA, there are no signi cant differences between low intensity of OPA vs high intensity of OPA (14.4%, n = 48 vs. 9.8%, n = 41; p = 0.069).
In a Spanish cross-sectional study, conducted with 259,014 workers, aimed to associate metabolic syndrome with occupation and gender, demonstrated that metabolic syndrome was higher in blue collars females, such as cleaners than white collars such as administrative occupation [30]. These results were aligned with our results, due to our high OPA female population, majority cleaners (blue collar), presented higher blood pressure, one of the criteria of metabolic syndrome, than low OPA female population. While cross-sectional of Sanchez-Chaparro et al associated metabolic syndrome with occupational category, our present cross-sectional had one-step further because associated with the intensity of OPA related to the occupational category. Moreover, focus on the low intensity of OPA employees, the prevalence of overweight and obesity was higher than Spanish National data (18-65y) in 2017 [31]. Spanish working population presented a prevalence of overweight plus obesity of 56% in males and 39% in females, lower than 82.2% and 55.6% showed in the present cross-sectional study, respectively. So, workplace weight management programs could increase the engagement of employees [32]. However, from all results, one important aspect to consider is to design and implement different workplace interventions depending on the OPA intensity levels and gender of employees, to achieve a signi cant effect.
On the other hand, focusing on lifestyles, male employees with high OPA intensity presented a signi cantly higher prevalence and signi cant association of tobacco consumption compared to low OPA intensity employees. Most of the high intensity of OPA male employees of FCC S.A. Delegation developed tasks of their work outdoors, as street cleaners probably they have more access to smoke than the low OPA intensity employees.
Thus, not only to avoid smoking, a major cardiovascular risk factor, the intensity of OPA, type of job developed by employee and gender could be considered as key indicators to contemplate in the design of workplace programs to improve the cardiovascular health of employees.
Whereas for employees with low intensity of OPA, taking into account this activity could be considered as a sedentary lifestyle, acting as a major modi able risk factor for cardiovascular disease [7,33].The interventions to improve cardiovascular risk factors for males with high intensity of OPA should be tested because the evidence suggests that high OPA employees may not be a bene t for LTPA supporting caution should be in recommending exercise in the high intensity of OPA employees [34]. However, in workplace interventions directed to females with high intensity of OPA, it is suggested the effectiveness of lowering SBP by a single session per day in cleaners' females [35].
Therefore, from the evidence of the cardiovascular risk factors of employees, it could carry on actions to prevent cardiovascular disease at the workplace.
Supporting the interventions, the workplace is a good environment to improve physical activity behaviors [36][37][38].
The present cross-sectional study had some limitations. Firstly, the study population included only one Delegation of one company, the FCC workers in Tarragona, whereas more participants of other FCC Delegations around all Spain could provide more information. Secondly, physical activity during the working time was assessed by International Physical Activity Questionnaire [19], and it was not calculated by an Actical accelerometer considered as the gold standard tool to evaluate physical activity [19,39,40] due to implying higher costs for the company. Thirdly, disease variables such as percentage of employees with hypertension and cholesterol were based on the diagnosis of the family physician, and workers were medicated, for this reason, the mean of variables related to medicated employees (mean of blood pressure and mean of blood cholesterol) was misleading. Fourthly, OW and OB prevalence could act as a confounder because it is associated with high cardiovascular risk factors, and males with high OPA intensity levels showed a low percentage of OW and OB and less cardiovascular risk factors than males with low intensity of OPA. Fifthly, although this study had the appropriate sample size, it would be more interesting to include different companies to obtain a sample size with a higher diversity of employees, to be possible to improve the generalizability of the results obtained. Besides, males represented the huge part, the generalizability of our ndings to female is limited, and it should include a higher percentage of females in future researches.
Furthermore, the study had some strengths, it included a huge sample size of employees with different OPA intensity categories. Moreover, the data obtained related to cardiovascular risk factors assessed in the workplace, are based on blood analysis, anthropometric measures, and validated questionnaires. The present cross-sectional study is the rst study that investigated the workplace population categorizing the intensity levels of the OPA in Spain.

Conclusion
High intensity of OPA is associated with less cardiovascular risk factors in men, whereas women are associated with high levels of blood pressure, suggesting an in uence of gender and work categories.

List Of Abbreviations
Occupational Physical Activity (OPA)

AVAILABILITY OF DATA AND MATERIAL
The technical appendix, statistical code, and dataset are available from the corresponding authors upon request: elisabet.llaurado@urv.cat and lucia.tarro@urv.cat.

COMPETING INTERESTS
Authors declare no con icts of interest.

ACKNOWLEDGMENTS
This study was supported by the FCC S.A. Delegation. We would like to express our gratitude to the staff and employers and the FCC S.A. Delegation.

FUNDING DETAILS
No funding was received for this study.