Rotating shift work time is directly associated with excess body adiposity.

OBJECTIVE: To analyze the association between changes in body adiposity and length of service on a schedule of rotating shifts. METHODS: The study was a cross-sectional investigation conducted during the years 2012, 2015, and 2018, involving individuals engaged in rotating shifts at a company involved in iron ore extraction situated within the Iron Quadrangle region of Minas Gerais and the southeastern region of Pará, Brazil. Sociodemographic and behavioral data were collected along with anthropometric parameters in order to calculate body mass index (BMI) and the waist-to-height ratio (WHtR). For data analysis, a multivariate logistic regression was employed to explore potential associations between indicators of body adiposity and the duration of shift work, employing a hierarchical determination model. RESULTS: The findings showed that in the multivariate model, controlling for confounding factors, workers with 5 to 10, 10 to 15, and more than 15 years of shift work had 41 to 96% greater odds of being overweight (BMI > 25.0 kg/m2), 71 to 82% of having altered neck circumference (> 40 cm), 33 to 120% of altered WC (>102 cm), and 57 to 214% of having altered WHtR (> 0.5 cm). CONCLUSION: The findings suggest that time spent in work has a significant effect on anthropometric indicators of body adiposity, especially if the worker has a previously established comorbidity such as dyslipidemia or hypertension and is frequently exposed to night work.

Rotating shift workers with vitamin D deficiency have a higher risk of obstructive sleep apnea.

OBJECTIVES: The study aimed to evaluate the association between obstructive sleep apnea (OSA) and vitamin D deficiency (VDD) in shift workers. METHODS: This cross-sectional study included male rotating shift workers in an iron ore extraction company. Participants were classified as VDD when 25(OH)D < 20 ng/mL for a healthy population and 25(OH)D < 30 ng/mL for groups at risk for VDD. Risk of developing OSA was classified by Berlin questionnaire (BQ) and NoSAS score. Data were compared using chi-square analysis with Cramer's V as effect size, and Bonferroni correction. Multivariate logistic regression analysis was performed to investigate whether or not VDD was associated with OSA risk assessment. RESULTS: Among 1423 male workers, mostly younger, aged 30 to 39 years (53%), worked shifts for more than 5 years (76%). The prevalence of high risk of OSA by BQ was 16%, and 33% by NoSAS score. Additionally, 29% had VDD. In multivariate analysis, controlled for confounding factors, workers with VDD had a 52% increased chance of OSA by BQ (OR 1.52; CI95% 1.06-2.18) and a 64% increased chance of OSA by NoSAS score (OR 1.64; CI95% 1.09-2.48). After subgroup analyses, similar results were not observed in workers aged 20-29 and 30-39 years. CONCLUSION: Rotating shift workers with vitamin D deficiency are more likely to have obstructive sleep apnea, assessed by the Berlin questionnaire and NoSAS score.

Diagnostic accuracy of the Berlin questionnaire and the NoSAS score in detecting risk for obstructive sleep apnea in rotating shift workers.

BACKGROUND: Data on the validity of tools for sleep apnea risk detection in rotating shift workers are limited. The aim was to evaluate the Berlin questionnaire (BQ) and the Neck, Obesity, Snoring, Age, Sex (NoSAS) score for the detection of obstructive sleep apnea risk in shift workers. METHODS: This cross-sectional study included male rotating shift workers, drivers of heavy off-road machinery in an iron ore extraction company. Polysomnography was the gold standard for evaluation. Obstructive sleep apnea (OSA) was defined as an apnea-hypopnea index (AHI) of ≥ 5 events/h. The Shapiro-Wilk test verified the data distribution and comparative analysis was conducted using the chi-square analyses and U Mann-Whitney with Bonferroni correction. Receiver operating characteristic curve analysis, sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and accuracy were used for evaluate BQ and NoSAS with OSA diagnosis by polysomnograph. RESULTS: Among 119 male shift workers, ages 24 to 57 years, polysomnography showed that 84% had obstructive sleep apnea (AHI ≥ 5), and 46% had moderate to severe sleep apnea (AHI ≥ 15). For AHI ≥ 5, the NoSAS score had higher sensitivity and specificity than the BQ. For AHI ≥ 15 and AHI ≥ 30, the NoSAS score had a sensitivity higher than 70% while BQ was 60% and 58%, respectively. The accuracy of the NoSAS score was higher for all OSA criteria than that of BQ. CONCLUSION: In rotating shift workers, drivers of heavy off-road machinery, the NoSAS score showed higher accuracy in identifying patients at risk for sleep apnea than the BQ.

Body fat indicators for cardiometabolic risk screening among shift workers.

BACKGROUND: In view of the costly methods currently available for the assessment of body adiposity, anthropometric obesity indicators have proven effective in predicting cardiovascular risk. OBJECTIVE: To investigate the discriminatory power of body fat indicators for cardiovascular risk screening among shift workers. METHODS: Cross-sectional study with male employees of an iron ore extraction company. The predictive power of body fat indicators relative to cardiovascular risk was analyzed based on the Framingham risk score and metabolic syndrome by means of receiver operating characteristic curves, sensitivity, specificity, positive and negative predictive values, area under the receiver operating characteristic curve and Youden's index. RESULTS: The prevalence of cardiovascular risk was 14.2% in the metabolic syndrome risk model. According to the Framingham score, 95.0%, 4.1% and 0.9% of the participants exhibited low, moderate and high risk, respectively. All the analyzed body fat indicators exhibited satisfactory discriminatory power for the tested cardiovascular risk models. CONCLUSION: Waist-height ratio exhibited the highest ability to predict cardiometabolic risk in both risk models.

Effects of vitamin D supplementation on cardiovascular risk factors in shift workers: Study protocol for randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVE: The present clinical study aims to describe protocol to evaluate the effects of vitamin D3 supplementation on the cardiovascular risk factors in a population of rotating shift workers. DESIGN: A randomized, double-blind, placebo-controlled, parallel group clinical trial testing 2 oral dosages of cholecalciferol (14,000 IU and 28,000 IU per week) for 12 months. SETTING: The primary outcome for evaluation is an 18% reduction in hypertriglyceridemia (≥150 mg/dL) between pre and postintervention measurements. Baseline characteristics of the study population will be summarized separately within each randomized group, and will use tests for continuous and categorical variables. For all tests, a P < .05 will be considered significant. The analysis of primary and secondary outcomes will use an intention-to-treat population and a per-protocol population. The primary and secondary outcomes will be compared separately between each treatment group and placebo, using binary logistic regression or regressão de Poisson for proportions (for binary outcomes) and using linear regression for differences in means (for continuous endpoints), with 95% confidence intervals. PARTICIPANTS: Rotating shift workers, adults aged between 18 and 60 years, with hypovitaminosis D and alterations in at least 1 of the following parameters: fasting glucose, high-density lipoprotein cholesterol, triglycerides, low-density lipoprotein cholesterol, blood pressure, and waist circumference. CONCLUSION: This clinical trial aims to contribute to the gap in knowledge about the potential, dose, and time of vitamin D supplementation to generate beneficial effects on triglycerides in a population at increased risk for hypertriglyceridemia and vitamin D deficiency.

Heart rate variability in shift workers: responses to orthostatism and relationships with anthropometry, body composition, and blood pressure.

In order to investigate the response of heart rate variability (HRV) components to postural change and their association with cardiovascular risk factors in shift workers, a cross-sectional study with 438 Brazilian males rotating shift workers was done. Anthropometric, body composition, and clinical measures were collected. Electrocardiogram was recorded for 3 minutes, in the supine and orthostatic position, and HRV components were extracted. Descriptive analyses showed that mean values of body mass index, waist circumference (WC), waist-to-height ratio, visceral fat area (VFA), and blood pressure (BP) were higher than the reference values. In the regression model, age, WC, VFA, and systolic BP showed negative association with HRV components. These findings suggest the need for determining effective strategies for the evaluation and promotion of health among shift workers focused on the altered variables.

Lipoprotein(a) as a risk factor associated with ischemic heart disease: Ouro Preto Study.

Evidences suggest that lipoprotein(a) [Lp(a)] is an important risk factor for cardiovascular disease. However, literature has been controversial in confirming its role as an independent risk factor for cardiovascular disease. The objective of the present study is to evaluate the association between serum levels of Lp(a) and ischemic heart disease as well as other cardiovascular risk factors in a population-based study conducted on a local cohort of the Brazilian population. Lp(a) serum levels were measured in 400 individuals selected from a larger sample of a populational survey carried out in Ouro Preto, a city in the southeast of Brazil. Lipid profile, fasting blood glucose, anthropometric and clinical parameters were analyzed. Lp(a) levels were significantly associated with the presence of ischemic heart disease. In relation to other cardiovascular risk factors, it was verified that Lp(a) levels were statistically associated with age, total cholesterol, LDL-cholesterol and percentage of body fat determined by bioelectric impedance. Lp(a) was also highly associated with the Framingham risk score (p=0.003). In a multivariate analysis two significant interactions were revealed; one involving ischemic heart disease, sex and age and other associating ischemic heart disease, age and total cholesterol. In summary, in the present analysis Lp(a) serum levels were correlated with the occurrence of ischemic heart disease and other cardiovascular risk factors.