PURPOSE: A population based study was undertaken to know the prevalence of Obstructive Sleep Apnea Syndrome (OSAS) in Delhi.
METHODS: 32 municipal wards out of a total of 134 wards were selected by cluster sampling method. One polling station from each ward was selected by simple random method and households from each polling station were then selected by systematic sampling to obtain a sample of 225 to 250 people from each polling station. The Investigators made house-to-house visits and interviewed all adult members of over 18 years residing in the house. There were fifteen multiple choice questions in the validated questionnaire and each question was scored according to the severity of symptoms by the use of a five-point scale. The respondents were classified as having sleep-related symptoms if they had loud snoring (scores 4 or 5) and/or excessive daytime sleepiness (scores 4 or 5). Overnight polysomnograms were done in a random sample of at least 10% subjects found to have sleep-related symptoms. Obstructive Sleep apnea (OSA) was defined as apnea-hypopnea index of more than 5/ hour and OSAS was defined as OSA with excessive daytime sleepiness.
RESULTS: A total of 7975 subjects aged 18 to 103 years were studied. There were 4050 males and 3925 females. Sleep-related symptoms were present in 411 (5.1%) subjects [262 (6.5%) males and 149 (3.8%) females]. 47 (11.4%) of these 411 subjects were randomly selected for full overnight polysomnograhy of which 32 were males and 15 females. OSA was observed in 22 of 32 males and 10 of 15 females and OSAS was seen in 12 of 32 males and 4 of 15 females. The estimated prevalence of OSA was 4.4% (95%Confidence Interval(CI) 3.8%-5.1%)in males and 2.5%(95% CI 2%-3%) in females and OSAS in 2.4% [95%CI 1.9%-2.9%]in males and 1% (95%CI 0.08%-1.1%)in females.
CONCLUSION: The estimated prevalence of OSAS is 2.4% in males and 1% in females.
CLINICAL IMPLICATIONS: This study from India highlights the problem of sleep-related disorders in the community.
DISCLOSURE: V.K. Vijayan, None.