title: Seasonal variations in fatigue in persons with rheumatoid arthritis: a longitudinal study.
abstract: BACKGROUND
  Fatigue is a prominent symptom in persons with rheumatoid arthritis (RA). Although this symptom has been described to vary in duration and frequency little is known about fluctuations in fatigue over time and season. The aim of this study was to describe monthly and seasonal variations in fatigue, in persons with RA of working age.
  
  
  METHODS
  Sixty-five participants diagnosed with RA and aged 20-65 years were recruited from a rheumatology clinic in Sweden. The participants provided self-assessments of their fatigue at seven time points during the four seasons using a 0-100 mm visual analogue scale (VAS) and the Bristol Rheumatoid Arthritis Fatigue Multidimensional Questionnaire (BRAF-MDQ). Multiple regression analysis using mixed models was used to analyze changes in fatigue over time.
  
  
  RESULTS
  The mean ± SD of fatigue rated on the VAS was 51 ± 13, indicating substantial fatigue. Analysis of monthly variation showed statistically significant variation in fatigue ratings concerning VAS fatigue score (p < 0.01) as well as the BRAF-MDQ total score and Living, Cognition (p < 0.001), and Physical (p < 0.05) sub-scores, but not the BRAF-MDQ Emotional sub-score. The greatest variations were seen from January to September, with higher fatigue ratings in January. The changes in VAS fatigue scores over time were considered to be of clinical importance. Analysis of seasonal variation revealed a statistically significant seasonal variation in fatigue levels, with higher fatigue values during the winter as measured by VAS fatigue score (p < 0.01) as well as BRAF-MDQ total score (p < 0.01) and Physical and Living sub-scores (both p < 0.01). The greatest variation was seen between winter and autumn for VAS fatigue and between winter and summer for BRAF-MDQ total score and Physical and Living sub-scores. There were no statistical differences in fatigue levels, monthly or seasonal, between sexes or age groups.
  
  
  CONCLUSIONS
  The majority of rating scales used in this study showed fluctuations in fatigue, general and physical fatigue being significantly greater during the winter. As fatigue is a substantial symptom in many persons with RA, this information is important for rheumatology professionals when dealing with persons with RA in routine care.
authors: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. caroline.feldthusen@vgregion.se.|The University of Gothenburg Centre for Person-Centred Care (GPCC), Gothenburg, Sweden. caroline.feldthusen@vgregion.se.
authors: Caroline
authors: C
authors: Feldthusen
authors: Department of Public Health and Community Medicine, Sahlgrenska Academy and University Hospital, University of Gothenburg, Gothenburg, Sweden.
authors: Anna
authors: A
authors: Grimby-Ekman
authors: Department of Public Health and Clinical Medicine, Rheumatology, Umeå University, Umeå, Sweden.
authors: Helena
authors: H
authors: Forsblad-d'Elia
authors: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Lennart
authors: L
authors: Jacobsson
authors: The University of Gothenburg Centre for Person-Centred Care (GPCC), Gothenburg, Sweden.|Section of Physiotherapy, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Kaisa
authors: K
authors: Mannerkorpi
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000453:epidemiology*; D005221:Fatigue / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods / Q000639:trends*; D012621:Seasons; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult