Introduction

Cardiovascular disease is the main cause of mortality and severe disabilities worldwide. In 2019, the disease prevalence increased to 523 million and its mortality is expected to constitute 31.7% of global deaths by 2030 [1]. Increased prevalence of cardiovascular risk factors such as obesity, diabetes, high cholesterol, and hypertension has caused a considerable increase in mortality rates among CVD (Cardiovascular Disease) patients [2]. In addition, some of the modifiable risk factors such as smoking, poor diet, alcohol consumption, and sedentary lifestyle are attributed to the majority of CVD cases and deaths [3, 4]. The role of psychological factors including work stress and job strain has also been investigated in different literatures as potential risk factors for coronary heart diseases [5].

Nurses as the largest group of health care providers should constantly promote their health status due to an intertwining connection between the quality of services rendered by them and their health performance [6–8]. Furthermore, nursing is a stressful job which necessitates nurses to work in long, variable shifts, and expose to a variety of work-related hazards, stress, and burnout leading to various health complications such as cardiovascular diseases [9]. Researchers have investigated that rotating shift workers are associated with a higher prevalence of coronary risk factors including smoking, hypertension, increased serum cholesterol, uric acid, and glucose levels together with depression, obesity, sleep disorders and behavioral changes [10, 11].

On the other hand, heart diseases not only impose several direct and indirect costs to the health system, but also they can result in job burnout, absenteeism, loss of productivity, or job instability among healthcare providers [12]. Given the key role of nurses in the health delivery system, their mental disorders and consequently physical illnesses might have devastating effects on the quality of provided services to patients [13]. Therefore, to develop effective strategies for the prevention of cardiovascular diseases among nurses, it is required to determine and classify associated risk factors, and take necessary actions to prevent complications in at-risk nursing staff [14].

Different literatures on cardiovascular risk factors among nursing staff have shown that a considerable number of nurses are in face of an increased level of risk factors particularly overweight, lack of regular exercise, sleep disorders, smoking and poor diet [8–14]. In a research conducted by Miller et al. findings revealed that 96% of obese nurses mentioned their obesity as a risk factor of heart disease, while nearly 30% of them were not aware of their diabetes, and about 90% were uninformed of having hyperlipidemia [8]. Even though nurses are continuously monitoring the health condition of patients, they rarely pay necessary attention to their health issues. Due to an increasing rate of coronary vascular disease and related deaths worldwide and lack of sufficient evidence dealing with the epidemiology of CVDs and its risk factors among nurses we conducted a systematic review and meta-analysis to describe the overall epidemiology of CVD risk factors in this group of key health care providers globally.

Materials and methods

Data collection

Following the search of electronic databases, 334 articles were identified. After importing the documents to EndNote software, duplicates were removed and finally resulted in 221 articles; of which 76 articles were published in Pub Med, 91 in SCOPUS, 23 in Web of Science and 31 articles were retrieved from EMBASE. Then, title/ abstracts were screened by two independent members of the research team in order to check data relevancy. Studies which reported quantitative data on CVD prevalence among nurses and its risk factors including (SBP(Systolic Blood Pressure) ≥ 140mmHg, DBP(Diastolic Blood Pressure) ≥ 90mmHg, HDL(High‐Density Lipoprotein) <40, LDL(Low-Density Lipoprotein) >100, TC(Total Cholesterol) ≥200, Obesity (BMI≥30), smoking, physical inactivity, alcohol consumption 3 or 4/wk, high blood sugar, having the history of CVD, or family history of CVD) were included for further consideration. References of included articles were examined and conference abstracts were also searched to be included as additional references. After applying inclusion/exclusion criteria, 22 studies were found to be included in the research (Fig 1).

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Fig 1. Flow diagram of our review process (PRISMA).

https://doi.org/10.1371/journal.pone.0286245.g001

Results

This systematic review was reported according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA). Finally, 22 articles with a total number of 117922 nurses were included in this systematic review. The characteristics of included studies are summarized in Table 1.

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Table 1. The characteristics of studies.

https://doi.org/10.1371/journal.pone.0286245.t001

Meta-analysis based on behavioral risk factors

Among all risk factors, sedentary lifestyle and lack of regular physical activity with a prevalence of 46.3% (CI 95%, 26.6–67.2) was regarded as the main prevalent risk factor among nurses. Furthermore, other prevalent risk factors were family history of cardiovascular disease (41.9%; 95% IC: 29.8–55.1%), and being overweight (33.3%; 95% IC: 24.7–43.2%) followed by alcohol consumption (24.6%; 95% IC: 16.4–35.2%). However, smoking had the least prevalence reported among 3.9% (CI 95%, 1.6–9.3) of nurses (Table 2).

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Table 2. The prevalence of cardiovascular risk factors among nurses.

https://doi.org/10.1371/journal.pone.0286245.t002

Meta-analysis based on physical risk factors

The mean systolic blood pressure (SBP) measured in the study population was 121.31 (CI 95%, 114.73–127.90) and the mean diastolic blood pressure (DBP) was 78.08 (CI 95%, 74.90–81.25); nevertheless, 11.2% (CI 95%, 8–15.3) of nurses had SBP above 140 mm Hg and 13.5% (CI 95%, 9.6–18.7) of them had DBP above 90 mm Hg which considered as hypertension (Table 3). The mean Body mass index (BMI) among nurses was estimated at 25.51 (CI 95%, 24.18–26.84) while 33.3% (CI 95%, 24.7–43.2) of nurses with a BMI between 25 and 29.9 were over weighted and 15.3% (CI 95%, 10.7–23.3) of them with BMI> 30 were suffering from obesity (Table 3).

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Table 3. The mean score of cardiovascular risk factors among nurses.

https://doi.org/10.1371/journal.pone.0286245.t003

Meta-analysis based on work shifts

To better understand the effects of working hours on nurses, we divided all participants into two groups of day workers and shift workers. Study results showed that, among nurses with shift works almost all risk factors got higher score representing the worse condition. To cite and example, the mean score of total cholesterol was estimated at 170.36 (10.2) among day workers’ nurses, however, the score among shift workers was reported to be 176.47 (9.6) (Table 4).

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Table 4. Meta-analysis based on work shifts.

Mean (SD).

https://doi.org/10.1371/journal.pone.0286245.t004

Publication bias

According to the analysis regarding the detection of publication bias (shown in Funnel plot in Fig 2), there was no publication bias and the Egger test results were below one (P = 0.68) (Fig 2).

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Fig 2. Funnel plot of publication bias.

https://doi.org/10.1371/journal.pone.0286245.g002

Discussion

In this study, among all risk factors, sedentary lifestyle and lack of regular physical activity with a prevalence of 46.3% (CI 95%, 26.6–67.2) was regarded as the main prevalent risk factor among nurses. Although the prevalence rate for physical inactivity was different in several researches (for example 86.9%, 72.6%, and 40.6% in Faruque et al., Samir et al. and Al-Hazzaa studies respectively), most of them agreed on physical inactivity as the most significant cardiovascular risk factor threatening the health status of nurses [21, 35, 36]. Correspondingly, in a study by AboSaad, physical inactivity was mentioned to be nearly two times more prevalent among healthcare personnel compared to the general population (55.9% compared to 29.8%) [37]. Circadian rhythm disturbances, lack of adequate time to get rest, work strain, fatigue and stress are regarded as the most common barriers to a regular physical activity among health workforce. Meanwhile, having regular exercise helps nurses remain the physical resilience required to overcome stressful situation and hold an adequate level of rigor in their job. It also helps them prevent serious physical disabilities such as heart diseases and other chronic conditions [38]. Furthermore, various studies have confirmed that an increased physical activity could be associated with decreased prevalence of CVD due to its contribution to reduced hypertension, obesity, LDL, and diabetes. In fact, exercise has protective effects to decrease the overall risk of CVD incident [39]. Therefore keeping regular physical activity besides having a healthy diet can play key role in avoiding CVD [40].

Furthermore, our study revealed that the second most prevalent risk factor among nurses was alcohol consumption. Several reports have confirmed the linking between alcohol consumption and increased prevalence of CVD. They also indicated the significant effect of a low alcohol consumption on the reduction of CVD risk [26-28]. Health care workers particularly nurses are greatly prone to hard work, stress, burnout, and sleep disorders which results in different health disorders particularly cardiovascular disease [29]. There is evidence that 42.6% of health workforce in the US had alcohol use disorder due to several stressors encountering in the workplace resulting in burnout and occupational stress [26]. In a study 26.6% of nurses were reported to consume alcohol above the limit, which was considerably higher than that reported in the general population (17% versus 9%) [41]. Similarly, in Nigeria, the prevalence of binge drinking among nurses was higher than the rest of community (9.1% versus 1%) [28]. In countries with limited resources, effective strategies should be considered for the prevention of heart disease through controlling potential risk factors particularly those related to behavioral habits [29, 30]. Thus, lifestyle modifications such as controlling alcohol drinking, stress, negative emotions, and sleep disorders can properly manage and prevent CVD among nurses [42].

Cigarette smoking is another risk factor which contributes to the high prevalence of CVD and has been responsible for nearly 140,000 annual deaths from the disease [32]. Based on our study findings, 3.9% of nurses were current smokers which was higher than that reported in the studies by Faruque; while was less than that reported by Ohida’s study [21, 43]. As it is obvious from different study results, smoking had the lowest prevalence among other risk factors of CVD. For example, Khan et al. reported that only 0.6% of nurses smoked, and Fair et al. estimated the prevalence of smoking among nurses at 3.6% [7, 19]. Despite the low prevalence of this risk factor among nurses with CVD, having adequate knowledge about smoking side effects and being in a position of role modeling smoking cessation seem to act as fundamental barriers for nurses to avoid smoking [35, 36].

The mean SBP measured in the study population was 121.31 and the mean DBP was 78.08; nevertheless, 11.2% of nurses had SBP above 140 mm Hg and 13.5% of them had DBP above 90 mm Hg which considered as hypertension. Our findings also revealed that approximately 47% of coronary heart diseases are attributable to high blood pressure. However, the prevalence of hypertension vary significantly worldwide from 1.5% in Fair’s study to 20% in Gallagher’s [22]. These differences might be due to the variations in the demographic characteristics of study population (including age, gender, family history, work shift, etc.) as well as differences in design, analysis and interpretation of study findings. Evidence has affirmed that nurses working in shifts had a considerable increased level of blood pressure and an augmented cardiovascular risk [44]. A similar study showed that estimated systolic blood pressure was at 122.04 mmHg in shift workers and 115.62mmHg in day workers. Additionally, the diastolic blood pressure was reported to be 81.9 mmHg in shift workers and 79.8 mmHg in day workers. Accordingly, the prevalence of hypertension was almost four times higher among shift workers (20% in shift workers versus 4% in day workers) [45]. Similarly, in another research by Abedini et al. the prevalence of hypertension in shift workers was almost twice the prevalence in day workers. In this study, the mean SBP in shift workers was 141.05 mmHg, which was higher than day workers estimated at 22.45 mmHg; while, the mean DBP of shift workers was reported to be slightly lower than day workers (9.53 mmHg versus 10.46 mmHg) [46]. Other studies also affirmed the findings and agreed on higher prevalence of SBP and DBP in shift workers compared to day workers [47]. Thus, it is recommended that health promotion education, screening programs, and continuous care of nurses should be included in the health and wellbeing programs of nursing staff to control their high blood pressure as a main risk factor for CVD [46].

According to study analysis, the mean Body Mass Index (BMI) among nurses was estimated at 25.51 while 33.3% of them with a BMI between 25 and 29.9 were over weighted and 15.3% with BMI> 30 were suffering from obesity. Relatively, Griep et al. found that a 10 kg higher body weight is related to a 3.0 mm Hg higher systolic and 2.3 mm higher diastolic blood pressure which consequently results in a significant 12% increase in coronary heart disease and 24% augmented risk of stroke [47]. The high rate of obesity signifies an inappropriate lifestyle, raises the risk of CVD by increasing the level of immobilization, and accelerates hyperlipidemia, high blood pressure, and diabetes. All these risk factors emphasize on the need for continuous monitoring and supporting weight management in nurses in order to prevent many of the subsequent physical complications. Comparing these results among shift workers and day workers suggests that the prevalence of overweight and obesity among the former group is significantly higher than the latter one. This conclusion confirms the results of previous studies; for example in a study by Griep a significant association between duration of exposure to night shift works and BMI was approved in nurses [32]. In a review conducted by Van Drongelen et al. the relationship between night shift work and body weight gain was affirmed. However they found that a crude association between shift work and body weight becomes insufficient after controlling for confounders [48]. Thus, in reaching a robust conclusion, several methodological limitations should be considered. Above all, in some of the studies weight and height data was gathered based on self-report techniques which might have brought about some ambiguities in BMI assessment. Additionally, most of the studies used crude data about the work schedule of the nursing staff at the moment of study, which could limit the conclusions regarding underlying relationships between study variables.

Based on study findings, the mean fasting blood sugar was estimated at 85.52 while 3.9% of study participants were at risk of diabetes due to fasting or random blood sugar upper limit of normal. Similarly, the relative risk was 3.8% in Gallagher’s study but it was estimated at 1% in Zhao’s study [22, 49]. However the reported prevalence of hyperglycemia among Bangladeshi nurses was significantly higher in Faruque study (19.4%) [21]. As it can be concluded from existing literature, mean fast blood sugar (FBS) in different studies varies from 71.84 in Hojat et al. research to 102.88 in Donker’s study [50, 51]. Literature has affirmed that both low glucose level and impaired fasting glucose act as risk factors for coronary heart disease (fasting). In fact, CVD was regarded as the main cause of death in people living with diabetes, leading to 2/3 of mortalities in patients with type 2 diabetes [52].

Study results showed that, among nurses with shift works almost all risk factors got higher score representing the worse condition. Similar findings were observed in different studies conducted to compare the prevalence of FBS among shift workers and those working only day shifts as a nurse. It was concluded that shift workers encountered with an increased risk of diabetes. Correspondingly, Pietroiusti’s study found that 5% of night-shift workers suffered from high blood glucose, while only 3.9% of daytime workers experienced a similar condition [52]. Likewise, Hansen confirmed statistically significant increased risks of diabetes in nurses who worked night (1.58; 1.25 to 1.99) or evening shifts (1.29; 1.04 to 1.59) compared to those working in day shifts [30]. As the appropriateness of blood sugar level and controlling of inflammatory factors can play an important role in improving the platelet function and reduce the incidence of coronary syndromes it is recommended to develop preventive programs to control nurses’ blood sugar and continuously monitor their well-being.

Analyzing nurses’ lipid profiles in our study showed that their mean total cholesterol, LDL and HDL were 174.24, 91.54 and 48.1, respectively. Furthermore, 9.3% of nurses had hypercholesterolemia (TC≥200); 12.3% of them had LDL≥ 100 and 19.4% (CI 95%, 7.2–42.5) had HDL<40, which are associated with an increased risk of cardiovascular diseases. Literature affirmed that patients with increased cholesterol level were at higher risk of CVD. With high cholesterol, fatty deposits will develop in blood vessels, making it difficult for blood to flow through the arteries, causing a process called atherosclerosis, which potentially might lead to the rupture of clots and cause a heart attack or stroke [53]. Kazemi et al. affirmed that among different aspects of dyslipidemia (cholesterol >200mg/dl, HDL) low HDL (41.28%) and high LDL (35.54%) were the most prevalent. Low HDL and high TG are connected to increased levels of LDL, which consequently enhance the risk of having atherosclerosis. Furthermore, decreased cholesterol levels through statin medication or lifestyle intervention were associated with lower CVD risk [55]. Comparing the results based on work shifts total cholesterol as well as low-density lipoprotein (LDL) in shift workers were significantly higher compared to day workers [54]. Regarding the work schedule, the prevalence of fixed night-time shifts has been proven to be associated with sleep deficit, high cardiovascular risk, and association with coronary heart disease [55]. According to Solymanzadeh’s study, a significant difference between total cholesterol and shift work was approved (p ≤0.001) and about 20% of shift workers were found to have hypercholesterolemia [17]. Furthermore, findings revealed no significant difference between high-density lipoprotein (HDL) and shift work (p = 0.77). In fact, only a small percentage (8.33%) of study population had low levels of HDL. Findings also revealed that night shift nurses had a significantly higher percentage of abnormal serum Triglyceride (59.3%) compared to day shift nurses (31.2%). In addition, the proportion of night shift nurses with abnormal LDL was significantly higher than the corresponding proportion among day shift nurses. These results emphasize that night shift nurses are at risk of abnormal lipid profile more than day workers [56]. On the contrary, no statistical significant relationship between lipid profile of nurses and their work shift was found (P = 0.051) [37]. This variation in obtained results might be due to different diets, amount and type of physical activity, and perhaps racial and ecological varieties in study populations. However, as a general approach standard preventive and treatment strategies such as diet control, aerobic exercise, and drug therapy are proposed to decrease serum cholesterol, alleviate plasma dyslipidemia and accordingly prevent heart disease among nurses.

To our knowledge, this is the first systematic review and meta-analysis conducted to investigate the prevalence of CVD risk factors among nurses reported in published studies between 2000 and 2022 using a wide range of search terms to retrieve all documents in English using strict criteria.

Conclusion

As study results revealed, sedentary lifestyle was regarded as the main prevalent risk factor among nurses followed by family history of cardiovascular disease, being overweight and alcohol consumption. Furthermore, among nurses with shift works almost all risk factors got higher score representing the worse condition in comparison with day workers’ nurses. In fact, the current study enables learning the associated risk factors of CVD among nurses to facilitate interventional programs with a view to reduce the exposure of nursing staff particularly those who work in shifts to cardiovascular risk factors. This information can comprise essential tools for health human resource management contributing to advance nursing.

Supporting information