title: Seasonal variations of systemic lupus erythematosus flares in southern France.
abstract: OBJECTIVE
  Exposure to sunlight is one of the environmental factors involved in the pathogenesis of systemic lupus erythematosus. We investigated whether there is seasonal variation in the incidence of cutaneous and noncutaneous severe lupus flares in southern France.
  
  
  METHODS
  We retrospectively reviewed clinical and biological data from all SLE patients hospitalized for a flare of the disease during a two year period in our centre and collected corresponding meteorological data from the official website of MeteoFrance.
  
  
  RESULTS
  Forty one patients, mean age 36.7 ± 13.8 years, were included. Twenty-six patients (63.4%) had kidney biopsy performed, showing in all cases proliferative nephritis, associated with membranous nephritis in 9 (22%). We found a clear seasonal pattern for overall lupus flares with 39% of flares occurred in Spring. Among patients without any cutaneous involvement, this seasonal pattern was still observed (p=0.024). Patients under antimalarials presented flares significantly later in the sunny season than those without (respectively median in July versus May, p=0.044). There were strong positive correlations between occurrence of lupus flares and maximum temperature increase (ρ=0.87, p<0.001), minimum temperature increase (ρ=0.87, p<0.001), and duration of sunshine increase (ρ=0.78, p=0.003). These correlations were also observed in patients with renal flares.
  
  
  CONCLUSIONS
  We confirmed a seasonal pattern for lupus flares among patients living in Southern France, with most flares in spring, in correlation with an increase in temperature and duration of sunshine. A similar seasonal pattern was observed in patients with no cutaneous involvement and with visceral involvement.
authors.affiliation: Department of Internal Medicine, Hôpital de la Conception, Marseille, France. laurent.chiche@ap-hm.fr
authors.forename: Laurent
authors.initials: L
authors.lastname: Chiche
authors.forename: Noémie
authors.initials: N
authors.lastname: Jourde
authors.forename: Claire
authors.initials: C
authors.lastname: Ulmann
authors.forename: Julien
authors.initials: J
authors.lastname: Mancini
authors.forename: Albert
authors.initials: A
authors.lastname: Darque
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bardin
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Dicostanzo
authors.forename: Guillemette
authors.initials: G
authors.lastname: Thomas
authors.forename: Jean-Robert
authors.initials: JR
authors.lastname: Harlé
authors.forename: Julien
authors.initials: J
authors.lastname: Vienne
authors.forename: Harilaos
authors.initials: H
authors.lastname: Loukos
authors.forename: Charleric
authors.initials: C
authors.lastname: Bornet
mesh_terms: D000293:Adolescent; D000328:Adult; D002980:Climate; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D015994:Incidence; D008178:Lupus Erythematosus, Cutaneous / Q000188:drug therapy / Q000453:epidemiology*; D008180:Lupus Erythematosus, Systemic / Q000188:drug therapy / Q000453:epidemiology*; D008181:Lupus Nephritis / Q000188:drug therapy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012621:Seasons; D055815:Young Adult
chemical_list: D007166:Immunosuppressive Agents