title: Peak expiratory flow rate shows a gender-specific association with vitamin D deficiency.
abstract: BACKGROUND
  To our knowledge, no previous studies examined the longitudinal relationship between vitamin D status and pulmonary function in a population-based sample of older persons.
  
  
  OBJECTIVE
  Our objective was to examine the cross-sectional as well as the longitudinal relationship between vitamin D status and peak expiratory flow rate (PEFR) in a representative sample of the Dutch older population.
  
  
  METHODS
  Participants included men and women in the Longitudinal Aging Study Amsterdam, an ongoing cohort study in older people.
  
  
  METHODS
  PEFR was measured using the mini-Wright peak flow meter.
  
  
  RESULTS
  Men with serum 25-hydroxyvitamin D (25-OHD) levels below 10 ng/ml (25 nmol/liter) had a significantly lower PEFR in the cross-sectional analyses, and men with serum 25-OHD levels below 20 ng/ml (50 nmol/liter) had a significantly lower PEFR in the longitudinal analyses as compared with men with serum 25-OHD levels above 30 ng/ml (75 nmol/liter) (cross-sectional: β = -47.0, P = 0.01 for serum 25-OHD <10 ng/ml; longitudinal: β = -45.0, P < 0.01 for serum 25-OHD <10 ng/ml; and β = -20.2, P = 0.03 for serum 25-OHD = 10-20 ng/ml in the fully adjusted models). Physical performance (β = -32.5, P = 0.08 for serum 25-OHD <10 ng/ml) and grip strength (β = -40.0, P = 0.03 for serum 25-OHD <10 ng/ml) partly mediated the cross-sectional associations but not the longitudinal associations. In women, statistically significant associations between 25-OHD and PEFR were observed in the cross-sectional analyses after adjustment for age and season of blood collection but not in the fully adjusted models or in the longitudinal analyses.
  
  
  CONCLUSIONS
  A strong relationship between serum 25-OHD and PEFR was observed in older men, both in the cross-sectional as well as longitudinal analyses, but not in older women. The association in men could partly be explained by physical performance and muscle strength.
authors.affiliation: EMGO Institute for Health and Care Research, VU University Medical Center, 1081 BT Amsterdam, The Netherlands. nm.vanschoor@vumc.nl
authors.forename: N M
authors.initials: NM
authors.lastname: van Schoor
authors.forename: R T
authors.initials: RT
authors.lastname: de Jongh
authors.forename: J M A
authors.initials: JM
authors.lastname: Daniels
authors.forename: M W
authors.initials: MW
authors.lastname: Heymans
authors.forename: D J H
authors.initials: DJ
authors.lastname: Deeg
authors.forename: P
authors.initials: P
authors.lastname: Lips
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010366:Peak Expiratory Flow Rate / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D012727:Sex Characteristics; D017678:Sex Distribution; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000503:physiopathology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D