Lifetime shift work exposure: association with anthropometry, body composition, blood pressure, glucose and heart rate variability

• Published in: Occupational and environmental medicine (London, England) Vol. 72; no. 3; pp. 208 - 215
• Main Authors: Souza, Breno Bernardes, Monteze, Nayara Mussi, de Oliveira, Fernando Luiz Pereira, de Oliveira, José Magalhães, de Freitas Nascimento, Silvia, Marques do Nascimento Neto, Raimundo, Sales, Maria Lilian, Souza, Gabriela Guerra Leal
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group 01.03.2015; BMJ Publishing Group LTD
• Subjects: Adult; Anthropometry; Blood Glucose - physiology; Blood pressure; Blood Pressure - physiology; Body composition; Body Composition - physiology; Body size (biology); Brazil; Circadian rhythm; Circumferences; Cross-Sectional Studies; Diabetes; Exposure; Heart rate; Heart Rate - physiology; Humans; Hypertension; Hypotheses; Influence; Iron compounds; Male; Mathematical models; Middle Aged; Mortality; Occupational exposure; Physiology; Population; Principal components analysis; Regression Analysis; Risk factors; Shift work; Studies; Variables; Work Schedule Tolerance - physiology; Workers; Working conditions; Working hours; Workplace; Young Adult; Brazil; principal component analysis; cardiac autonomic control
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oemed-2014-102429

Objective To evaluate the association between lifetime exposure to shift work and blood pressure, fasting glucose (FG), anthropometric variables, body composition and heart rate variability (HRV). Methods Male shift workers (N=438) were evaluated using principal component (PC) analysis. The variables used were: weight, body mass index (BMI), waist circumference (WC), neck circumference (NC), hip circumference (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat mass (BFKg), body fat percentage (BF%), visceral fat area (VFA), FG, systolic (SBP) and diastolic blood pressure (DBP), and HRV variables. ECG was performed, extracting heart rate (HR), root mean square of the successive differences (RMSSD), high frequency (HF), low frequency (LF) and the LF/HF ratio. Using linear regression models, the lifetime shift work exposure was associated with each PC. Results Five PCs were obtained, which accounted for 79.6% of the total variation of the data. PC1 (weight, BMI, WC, NC, HC, WHR, WHtR, BFKg, BF% and VFA) was designated as body obesity; PC2 (HF, RMSSD and LF) as good cardiac regulation; PC3 (SBP and DBP) as blood pressure; PC4 (LF/HF ratio and HR) as bad cardiac regulation and PC5 (WHR and FG) as insulin resistance. After age adjustment, the regression analysis showed that lifetime shift work was negatively associated with PC2 and positively associated with PC3. Conclusions The association of lifetime shift work exposure with PC2 and PC3 suggests that shift work promotes unfavourable changes in autonomic cardiac control related to a decrease in parasympathetic modulation and an increase in blood pressure.