In recent decades modern society has undergone a complex and dynamic series of changes in eating habits and in demographic, socioeconomic and epidemiological patterns, which have led to significant alterations in the panorama of chronic diseases, particularly cardiovascular disease.1

Metabolic syndrome (MS) is the most common metabolic disorder in the modern world and is responsible for most cardiovascular events2 and a significant rise in cardiovascular mortality.3 The clinical importance of MS lies in identifying individuals at risk of cardiovascular disease and type 2 diabetes, enabling preventive lifestyle interventions.4 Obesity contributes to hypertension, high total cholesterol (TC), low high-density lipoprotein cholesterol (HDL-C) and hyperglycemia, which are associated with greater cardiovascular risk.5

The working population represents a large proportion of the general population. Most individuals in employment spend a large part of their day at the workplace. Enterprises are affected by the reduced productivity and increased costs caused by chronic diseases among their workforce and the resulting absenteeism due to illness. Obese workers suffer from physical work limitations, hypertension, type 2 diabetes, dyslipidemia and MS.6 The workplace is thus an important environment for screening of chronic diseases and provides the opportunity for prevention programs based on the availability of occupational medical services.

Hospitals are an ideal environment to collect and disseminate information on quality of life and cardiovascular risk factors. Hospital workers are influenced by their work environment and also have a role as educators.

There are few data on the prevalence of MS among hospital workers. The aim of this study was to determine the prevalence of MS in this population and to identify related variables.

Table 1 shows the characteristics of the study population, consisting of 740 individuals, 72.4% female, mean age 34.9 years. Most were white (80.1%) and had finished high school or college (86.6%). In terms of work shift, 27.8% worked the morning shift, 20.3% the afternoon shift, 34.1% office hours, and 17.8% the night shift. Regarding type of work, most were classified as healthcare workers. As for period of employment, 16.2% had worked ≤1 year, 27% 1–3 years, 13.1% 3–5 years, 21.2% 5–10 years and 22.4% >10 years. On the basis of BMI, 50.1% of the sample were overweight. In terms of lifestyle habits, 66.6% reported consuming alcohol, only 10% smoked and 64.7% took no regular exercise.

More men (50%) worked office hours than any other shift and more women (30.2%) worked the morning shift than any other shift. Regarding type of work, 43.1% of men were auxiliary workers and 68.7% of women were healthcare workers. In terms of BMI, 69.3% of men were overweight or obese and 53.4% of women were normal weight.

Figure 2 describes the components of MS by gender. The diagnosis of MS was confirmed in 95 individuals (12.8%), 16.2% of the men and 11.6% of the women (p=0.121). Waist circumference was high in slightly over half the population (55.4%), with a female predominance (63.1% vs. 35.3%; p<0.001). Low HDL-C was the second most common component (23.8%), and fasting plasma glucose was high in 5.4% of the population.

Figure 2.

Association of gender with components of the metabolic syndrome. BP: raised systolic and/or diastolic blood pressure; FG: raised fasting glucose; HDL-C: low high-density lipoprotein cholesterol; MS: metabolic syndrome; TG: raised triglycerides; WC: high waist circumference. *p<0.001.

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Table 2 shows the results of univariate analysis, which demonstrated a statistically significant association between MS and age (from age 41 onwards) and elementary educational level. The office hours shift was most strongly associated with MS and absence of MS most strongly with the afternoon shift. Other associations were with the auxiliary worker group, length of employment >5 years, overweight and ex-smokers. However, the factors that were independently associated with MS after controlling for confounding factors were age, elementary educational level, office hours work shift, and length of employment >10 years (Table 3). There was no association between MS and the auxiliary worker group (p=0.461). When analyzed as continuous variables, each year of age increased the probability of presenting MS by 5% (odds ratio [OR] 1.05; 95% confidence interval [CI] 1.01–2.08; p=0.006) and each year of employment increased it by 1% (OR=1.01; 95% CI 1.00–1.01; p=0.010).

In this study, the prevalence of MS in hospital workers was 12.8%. After adjusted analysis of risk factors, age, elementary educational level, office hours work shift and length of employment were statistically associated with MS.

Using the IDF definition of MS, the prevalence of MS in the overall population was 12.8%, with no significant difference between the sexes (16.2% in men and 11.6% in women). A study in the USA14 of 3601 individuals aged between 20 and 70 found a prevalence of 34.5% (33.7% in men and 35.4% in women), using the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) definition and 39% with the IDF definition (39.9% in men and 38.1% in women). In Portugal15, a study of 16 856 individuals showed a prevalence of 27.5% (28.7% in women and 26.0% in men) using the NCEP-ATP III criteria.

A study of healthcare workers in Turkey16 revealed a prevalence of 5.2% in women and 12.7% in men using the NCEP-ATP III definition. In a study of workers in a university hospital in the Brazilian city of Florianopolis17, the prevalence of MS using the IDF definition was 21.9% in women and 19.4% in men, while in 7256 workers aged between 20 and 60 at an automobile plant in Spain18 it was 10.2% (8.7% in men and 3% in women) on the NCEP-ATP III criteria. A 2008 study of 992 railway employees aged 30–60 in India found a prevalence of MS by the NCEP-ATP III criteria of 27.03% (27.3% in women and 26.7% in men), and in a German study20 of workers in a chemical company, using the IDF definition, MS was present in 23.5% of workers, with a higher proportion of men (30% vs. 9.7%). There is thus considerable variation in the literature concerning MS prevalence in the workforce, probably due to differences in the populations studied and in the definition of MS used.

In our study population, age and length of employment >10 years were significantly associated with greater risk for MS. Prevalence was 27.4% in the 41–50 age-group and 26.3% in those aged over 50. Among US adults the prevalence was 23.7% in the 20–69 age-group and 6.7% in the 20–29 age-group, increasing progressively up to 43.5% in the 60–69 age-group10. A population study in the Brazilian city of Vitoria21 showed increasing MS prevalence with age, with a prevalence of 48.3% in those aged 55–64. In the above-cited study in Florianopolis17, the prevalence was 67.5% in the 40–49 age-group, while in the Indian railway employees19 MS was strongly associated with age over 45. In a study of municipal workers in Izmir, Turkey22, there was a significant association between MS and over 10 years’ employment (p=0.009). Increasing age and length of employment, together with the more modern lifestyles of these populations, lead to changes in eating habits and greater access to labor-saving goods and hence reductions in the physical effort required to perform tasks at home and at work; the result is energy imbalances and weight gain.

In this study a lower educational level (elementary education only) was significantly associated with MS. A study of professional and office workers in Bangkok, Thailand23, showed a higher MS prevalence in those with only a high-school educational level. A higher educational level, giving better access to information including newspapers and magazines and educational programs, can influence eating habits and improve lifestyle choices.

In the present study a significant association was found between MS and office hours work shift, and a greater tendency for MS in those working the night shift. A study in a factory in Buenos Aires24 analyzed MS prevalence in those working the day shift (8hours/day) and those on a rotating work shift (2 days of night shift followed by 3 days’ rest). MS was more common in those on the rotating shift (17.2% vs. 10.7%; p<0.005). In a prospective study of 1529 workers in Belgian companies24, MS was more prevalent in those working rotating shifts than in those on day shifts (32.7% vs. 21.6%); those who spend more of their day at work tend to consume high energy but nutritionally poor foods, and longer working hours often imply greater sedentarism.

We found that a diagnosis of MS in hospital workers was affected by age, educational level, work shift, and prolonged period of employment. Hospital workers need stimuli to make preventive changes to their behavior to modify cardiovascular risk factors.