Prevalence of Sleep Apnea in Women
Condition: Lung Diseases; Sleep Apnea Syndromes
MeSH terms: Apnea; Sleep Apnea Syndromes; Lung Diseases
Study type: Observational

Summary: 
      To identify the prevalence of sleep apnea (SA) in women and its relationship to age; to
      predict those women at risk for sleep apnea; and to define the natural history of those with
      sleep apnea.
    

Detailed description: 
      BACKGROUND:

      Often sleep apnea is accompanied by considerable morbidity; the associated excessive daytime
      sleepiness, cardiovascular abnormalities and cognitive impairment impact greatly on daytime
      functioning. The obese, hypertensives, elderly and postmenopausal women are reported to be at
      increased risk for sleep apnea. The investigators published on the prevalence of sleep apnea
      in several special populations: elderly subjects without sleep complaints and insomniac,
      narcoleptic, hypertensive and obese patients. They established the prevalence of sleep apnea
      in men based on the sleep laboratory evaluation of approximately 1,000 men randomly selected
      from a randomly generated telephone sample of 4,364 men from the general population. Their
      preliminary estimate of prevalence was that about 2.2 percent of the adult male population
      have clinically diagnosable sleep apnea. Further, in the male sample, the age distribution
      was not linearly related to age. Rather, it peaked at approximately age 55. Finally, the
      major risk factors appeared to be obesity and snoring. The differences in the male/female
      ratio in clinical and selected populations ranged from 10.0:1 to 1.9:1. One recent study
      suggested that the prevalence of sleep apnea in women was about two-fold less than in men.
      However, this study did not sample the general population and used only a restricted age
      range (30 to 60 years) which did not allow the assessment of the influence of menopause.
      Thus, the prevalence of sleep apnea in women in the general population remained largely
      undetermined.

      DESIGN NARRATIVE:

      In order to establish the prevalence in women with reasonable precision, the prevalence study
      employed a two-stage sample modified from the prevalence study in men in the following two
      ways: an expanded telephone sample (N=12,219 women) selected randomly from the general
      population was evaluated, for clinically relevant risk factors for sleep apnea; and 2) a
      second sample (N=1,000) selected randomly from the first sample based on higher risk for
      sleep apnea (including the additional risk factor of menopause) was evaluated in the sleep
      laboratory to determine the presence of sleep apnea. This strategy yielded an adequate power
      in order to establish the prevalence of sleep apnea requiring treatment and sleep disordered
      breathing in women in the general population as well as result in a large enough sample to
      establish the association between risk factors and sleep apnea in women. In order to perform
      gender analyses, the study compared previously published data from a total of 4,364 men
      interviewed in an expanded telephone sample and 741men evaluated in the sleep laboratory.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Stratified random sample following initial phone survey