Factors Associated With Elevated Blood Pressure in Nursing Workers

Abstract Introduction Nurses from the night shift are exposed to sleep deprivation, which is associated with circadian rhythm alteration, lifestyle changes, psychosocial stress, and, consequently, increased risk of blood pressure (BP) deregulation and hypertension. Objective To analyze risk factors associated with elevated BP levels in nursing workers. Methods A transversal, quantitative study was conducted with 172 nursing professionals of a large hospital in the state of Minas Gerais, Brazil. The following data were collected: anthropometric and BP measurements, sociodemographic characteristics, clinical variables, and lifestyle habits. Results were evaluated by bivariate analysis and logistic regression. The level of significance adopted in the statistical analysis was 5%. Results Participants’ average age was 42.7 ± 9.6 years old; 86.6% (n = 149) were female, and 20.3% (n = 35) had previous diagnosis of hypertension. Overweight and obesity (odds ratio [OR]: 2.187, 95% confidence interval [CI]: 1.060 – 4.509) and night shift (OR: 2.100, CI 95%: 1.061 – 4.158) were statistically significant (p < 0.05) for increased risk of elevated BP level. Conclusion Excessive weight and night shift were significant factors for increased BP in nursing workers.

capacity and 50 g sensibility.Height was measured using a non-extensible measuring tape against a 90º wall with no baseboard, with the participant standing in the proper position for this measurement.The body mass index (BMI) was calculated with the following formula: BMI = weight (kg) / height (m). 2 BMI classes were: normal (BMI between 18.5 and 24.9 kg/m 2 ), overweight (BMI between 25 and 29.9 kg/m 2 ), and obese (BMI ≥ 30 kg/m 2 ). 5 BP was measured following the Brazilian Guidelines for Arterial Hypertension. 9,10P (systolic/diastolic) was checked 3 times for each participant, with an interval of 1 to 2 minutes, with a digital sphygmomanometer (Omron HEM-7113) on the right arm, in sitting position after a 5-minute rest.The value considered was the average of the last 2 consecutive measurements.Elevated BP values were considered according to the measurement obtained on the evaluation day, i.e., systolic BP > 120 mmHg and/or diastolic BP > 80 mmHg. 10rticipants who informed that they were not involved in any physical activity more than twice a week were considered sedentary.Alcohol consumers were those who informed drinking, regardless of drink type, amount, or frequency.Smokers were those who smoked at least one cigarette per day.Diabetes was considered as previous diabetes mellitus history using oral hypoglycemic medicine or insulin.Dyslipidemia was considered as use of lipid-lowering medicine.

Data analysis
Data collected were entered in the Statistical Package for the Social Sciences for Windows (SPSS) ® software, version 22.0.
The normal distribution of quantitative variables was confirmed using the Kolmogorov-Smirnov test.Categorical variables were presented as absolute and percent frequency distribution, while quantitative variables were presented as central tendency measures (average) and variability (standard deviation).Bivariate analysis was used to confirm the association of sociodemographic characteristics, clinical variables, and lifestyle habits with BP level variables, including measures of association in contingency tables (relative risk, odds ratios, and respective confidence intervals), followed by logistic regression, adjusting the other potentially relevant variables.The level of significance adopted in the statistical analyses was 5%.responsible for alterations in the circadian rhythm, lifestyle, and psychosocial stress, in addition to being associated with an increased risk of SAH, this study analyzed the risk factors associated with elevated BP levels in nursing workers. 8

Trial design and location
This observational, transversal, and quantitative study was conducted in the sectors of clinical medicine, emergency room, and intensive care units of a large hospital, with 526 beds distributed in diverse specialties, in the state of Minas Gerais, Brazil.

Participants and inclusion criteria
The sample size was calculated considering the following parameters: 32.5% prevalence of SAH, 9 5% accuracy, and 95% confidence interval, for a finite population of 500 nursing professionals, resulting in a total of 202 participants (formula: n = Z 2 α / 2 p(1-p) / E 2 ).The recruitment process was non-probabilistic.
Permanent staff nurses and nursing technicians who had been employed for at least 1 year, were over 18 years old, regardless of gender, were included, from July 2018 to January 2019.Professionals from the day shift working night shifts were excluded.

Data collection
Data collection was conducted at the beginning of each shift without interfering with the professionals' work starting time in their sectors.Participants responded to a data collection instrument elaborated by the authors, with sociodemographic characteristics, clinical variables, and lifestyle habits (gender, age, self-declared color, comorbidities [SAH, diabetes, obesity, dyslipidemia], smoking, sedentary behavior, alcohol consumption, physical activity practice, and personal background).Anthropometric data (weight, height, BP, and heart rate) were also measured.
Shifts were categorized into day and night shifts.Workers considered exposed were from the night shift, that is, those who initiated their workday at 18:30/19:00.Workers considered non-exposed were from the day shift, with workdays starting at 6:30/7:00 or 12:30/13:00.For anthropometric data measurement, an electronic digital scale was used (model Omron HBF-214), with 150 kg

Results
From the total number of eligible participants, 30 did not participate because of vacation, refusal, or sick leave during the study period.
The average age of the 172 participants was 42.7 ± 9.6 years; the majority were women (n = 149, 86.6%), and 80 (46.5%) self-identified as white.Participants' sociodemographic characteristics, clinical variables, and lifestyle habits are presented in Table 1 according to shift work.
Statistically significant associations between overweight and night shift and elevated BP values were observed while evaluating predictor variables (risk factors) using logistic regression test at p < 0.05 (Table 2).

Discussion
This transversal study of a representative sample from a nursing team of a high complexity hospital demonstrated that the night shift was associated with elevated BP levels.Overweight, a traditional risk factor, was also associated with elevated BP levels.Contrary to our findings, another transversal study with a nursing team demonstrated that night shift was not associated with BP magnitude (odds ratio [OR]: 1.0, 95% confidence interval [CI]: 0.8 -1.3). 11In contrast, researchers who analyzed the effects of shift work over SAH observed that shift workers were more likely to have SAH than day laborers (OR: 1.31, 95% CI: 0.98 -1.75); furthermore, the risk of SAH was increased in workers with longer time in shift work (OR: 1.51, 95% CI: 1.08 -2.11), even after adjusting for age, BMI, alcohol consumption, exercise habits, and smoker status, which are variables that can interfere with BP. 12 Another longitudinal study that used recorded data of exposure time to night shift suggests that the risk of SAH increases and remains high with increasing exposure to night shift in comparison to day work. 13These findings are in agreement with the present study, which, despite its transversal design, reinforces that night work is associated with BP increase.
It is known that shift work leads to circadian rhythm desynchronization, influencing dipper BP variation to non-dipper, increasing the risk of hypertension in night workers. 14Moreover, researchers have observed that night workers have less control of SAH (OR: 0.74, 95% CI: 0.68 -0.80) in comparison to day workers regarding this pathology. 15systematic review and meta-analysis demonstrated that 3 in 5 adults over the age of 50 years have elevated BP, with hypertensive proportion increasing gradually between 2005 and 2018, which can be explained by the increased obesity proportion observed in this population. 16Obesity mechanisms related to hypertension are complex and are centered around a greater activation of the sympathetic nervous system, leading to increased reabsorption of renal tubular sodium, induction of kidney disease development, increased vascular oxidative stress, adipokine deregulation, and increased insulin resistance. 17In 2020, Tiruneh et al. observed that the probability of developing hypertension among people who are obese or overweight was 3 times greater than in people with normal weight (OR: 3.34, 95% CI: 2.12 -5.26). 18These data corroborate with our findings, where overweight exhibited a 2-fold greater risk of elevated BP levels.

Limitations
One limitation of this study is its small sample size.As a transversal study, the lack of establishing cause-effect relation between risk factors and elevated BP levels is acknowledged.Another limitation of this study is the inclusion of hypertensive workers, which is considered as a bias that can negatively affect the outcomes.

Conclusion
The altered variables, BMI and night shift, were statistically significant, representing expressive risk factors for elevated BP levels in the nursing team.We indicate the need to provide regular occupational health services, including screening of cardiovascular disease risk factors for all night shift workers.

Author contributions
Conception and design of the research, acquisition of data, analysis and interpretation of the data, statistical

Table 1 -Sociodemographic characteristics, clinical variables, and lifestyle habits of day (n = 102) and night (n = 70) shift participants. Uberlândia, Minas Gerais, Brazil, 2019 Day shift Night shift p
Data expressed in absolute and relative (percentage) values or average ± standard deviation.SBP: systolic blood pressure; DBP: diastolic blood pressure; mmHg: millimeters of mercury; HR: heart rate; bpm: beats per minute; BMI: body mass index.

Table 2 -Bivariate analysis and logistic regression for participants' BP levels, sociodemographic variables, and lifestyle habits. Uberlândia, Minas Gerais, Brazil, 2019
BMI: body mass index; CI: confidence interval; OR A : gross or non-adjusted odds ratio; OR B : adjusted odds ratio; BP: blood pressure.Significance level (p < 0.05).p value is attributed to OR B .