title: [The seasonal variation in the plasma fibrinogen concentrations in patients with essential arterial hypertension].
abstract: OBJECTIVE
  To determine whether plasma fibrinogen in hypertense patients varies with the weather.
  
  
  METHODS
  Descriptive study, with two transversal cuts, one in winter and one in summer.
  
  
  METHODS
  Health district in the periphery of the city of Valencia.
  
  
  METHODS
  Patients with essential hypertension selected at random from 2483 in the programme and seen by appointment in January or February and July or August 1997. Sample size was calculated for paired data with an alpha error of 0.05 and a beta error of 20%. The difference in fibrinogen concentration considered relevant was set at 40 mg/dl. Variability was deduced from a sample of 10 cases, and a sample of 28 patients entered the study. The following were recorded: sex, age, size, weight, body mass index (BMI), blood pressure, counts, glucaemia, total cholesterol, HDL-C, LDL-C, uric acid, triglycerides and fibrinogen. Meteorological data were supplied by the Valencia Weather Centre.
  
  
  RESULTS
  Temperature (25.7 degrees vs. 12.7 degrees C), sunshine (9.9 hours a day vs. 5.9) and relative humidity (67% vs. 61.5%) were higher in summer. There were no differences in mean atmospheric pressure (760 mm Hg vs. 760.7). 23 patients (15 women), with an average age of 60, completed the study. The fibrinogen average was higher in winter: 289 (CI 95, 273-306) vs. 247 mg/dl (CI 95, 232-263). We also found significant differences for systolic pressure, diastolic pressure and uric acid, but not for BMI, total cholesterol or triglycerides.
  
  
  CONCLUSIONS
  Seasonal variation in plasma concentrations of fibrinogen was found in the sample studied.
authors.affiliation: Centro de Atención Primaria Pintor Stolz, Valencia. cspstolzmg@meditex.es
authors.forename: J
authors.initials: J
authors.lastname: Murciano Revert
authors.forename: J J
authors.initials: JJ
authors.lastname: Martínez-Lahuerta
authors.forename: L A
authors.initials: LA
authors.lastname: Porcar
mesh_terms: D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D008685:Meteorological Concepts; D008875:Middle Aged; D011897:Random Allocation; D012621:Seasons; D013030:Spain; D018709:Statistics, Nonparametric
chemical_list: D005340:Fibrinogen
vernacular_title: Variación estacional de las concentraciones plasmáticas de fibrinógeno en pacientes con hipertensión arterial esencial.