title: Lifetime shift work exposure: association with anthropometry, body composition, blood pressure, glucose and heart rate variability.
abstract: 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.
authors.affiliation: School of Medicine, Federal University of Ouro Preto, Ouro Preto, Brazil.
authors.forename: Breno Bernardes
authors.initials: BB
authors.lastname: Souza
authors.affiliation: School of Nutrition, Federal University of Ouro Preto, Ouro Preto, Brazil.
authors.forename: Nayara Mussi
authors.initials: NM
authors.lastname: Monteze
authors.affiliation: Department of Statistics, Federal University of Ouro Preto, Ouro Preto, Brazil.
authors.forename: Fernando Luiz Pereira
authors.initials: FL
authors.lastname: de Oliveira
authors.affiliation: Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: José Magalhães
authors.initials: JM
authors.lastname: de Oliveira
authors.affiliation: School of Nutrition, Federal University of Ouro Preto, Ouro Preto, Brazil.
authors.forename: Silvia
authors.initials: S
authors.lastname: de Freitas Nascimento
authors.affiliation: School of Medicine, Federal University of Ouro Preto, Ouro Preto, Brazil.
authors.forename: Raimundo
authors.initials: R
authors.lastname: Marques do Nascimento Neto
authors.affiliation: São Paulo State Cancer Institute, São Paulo, Brazil.
authors.forename: Maria Lilian
authors.initials: ML
authors.lastname: Sales
authors.affiliation: Department of Biological Sciences, Federal University of Ouro Preto, Ouro Preto, Brazil.
authors.forename: Gabriela Guerra Leal
authors.initials: GG
authors.lastname: Souza
mesh_terms: D000328:Adult; D000886:Anthropometry; D001786:Blood Glucose / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D001938:Brazil; D003430:Cross-Sectional Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D014940:Work Schedule Tolerance / Q000502:physiology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose
keywords: cardiac autonomic control; principal component analysis