title: Prevalence of asymptomatic and symptomatic meibomian gland dysfunction in the general population of Spain.
abstract: OBJECTIVE
  To describe epidemiologic characteristics of asymptomatic and symptomatic meibomian gland dysfunction (MGD) in a general adult population in northwestern Spain.
  
  
  METHODS
  A total of 1155 subjects aged 40 years and older were selected by an age-stratified random sample procedure in O Salnés, Spain. A standardized symptoms questionnaire was administered and a comprehensive ophthalmic evaluation, which included ocular surface tests, was carried out. Absent, viscous, or waxy white secretion upon digital expression, lid margin telangiectasia or plugging of the meibomian gland orifices was considered evidence of MGD. The prevalence and associations of asymptomatic and symptomatic MGD, and their effects on the ocular surface, were investigated.
  
  
  RESULTS
  From 937 eligible subjects, 619 (66.1%) participated (mean age [SD], 63.4 [14.5] years; range, 40-96; 37.0% males). The prevalence of asymptomatic MGD was 21.9% (95% confidence interval [CI], 18.8-25.3). This prevalence increased with age (P = 0.000) and was higher in males than in females (P = 0.003). The prevalence of symptomatic MGD was 8.6% (95% CI, 6.7-10.9). This prevalence also increased with age (P = 0.000) but was not associated with sex. Abnormal tear breakup time and fluorescein staining prevalence estimates were higher among asymptomatic subjects. After controlling for age and sex, asymptomatic MGD was associated with diabetes (adjusted odds ratio [OR(a)] 2.23) and cardiovascular disease (OR(a) 1.80), and symptomatic MGD with rosacea (OR(a) 3.50) and rheumatoid arthritis (OR(a) 16.50).
  
  
  CONCLUSIONS
  Asymptomatic MGD is more common than symptomatic MGD. Symptomatology is not associated with secondary damage to the ocular surface. Some systemic diseases may lower whereas others may raise the risk of developing symptoms. Symptom-based approaches do not seem appropriate for MGD estimation.
authors.affiliation: Servicio de Oftalmología, Complexo Hospitalario de Pontevedra, Spain. evo@mundo-r.com
authors.forename: Eloy
authors.initials: E
authors.lastname: Viso
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Rodríguez-Ares
authors.forename: Dolores
authors.initials: D
authors.lastname: Abelenda
authors.forename: Benjamín
authors.initials: B
authors.lastname: Oubiña
authors.forename: Francisco
authors.initials: F
authors.lastname: Gude
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D003430:Cross-Sectional Studies; D005141:Eyelid Diseases / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008537:Meibomian Glands / Q000473:pathology*; D008875:Middle Aged; D015995:Prevalence; D017678:Sex Distribution; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires