The study - the first to examine symptoms of OSA among Caribbean men and women residing in Brooklyn - was recently conducted by the Brooklyn Centre for Health Disparities (BCHD) at State University of New York (SUNY) Downstate Medical Centre and University Hospital of Brooklyn.

Principal authors of the study were Drs Girardin Jean-Louis, associate professor in the Department of Medicine and research core director at BCHD, and Ferdinand Zizi, BCHD associate - two Haitian experts assigned to the centre. The other author was African-American Dr Clinton Brown, BCHD director and clinical associate professor of medicine at the Division of Renal Diseases at SUNY Downstate.

The study found that a significant number of Caribbean nationals report OSA symptoms - snoring and excessive daytime sleepiness - and that a history of heart disease was a "strong predictor of the likelihood of reporting these symptoms".

"The estimate of habitual snoring, the typical symptom of OSA, in our sample (45 per cent) was greater than estimates derived from the general US population or from other ethnic groups, including African-Americans," said the study, dubbed 'Symptoms of Obstructive Sleep Apnoea in a Caribbean Sample'.

It found that excessive daytime sleepiness tended to be more common in a sample of Caribbean-born black men and women, stating that 33 per cent of participants reported this symptom.

In contrast, the authors said 27 per cent was the estimated rate of daytime sleepiness in the 2005 Sleep in America poll.
Comparatively, they said estimates of daytime sleepiness in Sweden, France and the United Kingdom were 16, 20 and 15 per cent, respectively.

"Of particular interest is the observation that rates of daytime sleepiness among Caribbean-born blacks are also higher than that generally observed in blacks (19 per cent), who typically experience more severe daytime sleepiness than do age-matched whites," the study said.

"These findings support the notion that blacks in America do not constitute a homogenous group regarding snoring and daytime sleepiness," it added.

In their analysis, the authors said a history of heart disease is the strongest independent predictor of OSA risk among Caribbean men and women.
They said the odds of reporting OSA symptoms - snoring, daytime sleepiness and sleep fragmentation - are 11 times greater for respondents with a history of heart disease.
At the same time, they said, to a lesser extent, the likelihood of reporting OSA symptoms was also associated with a history of hypertension, reduced satisfaction with sleep, reduced ability to concentrate and inability to stay awake while watching TV.
The authors said that the association of heart disease with OSA "was expected since numerous studies have established that OSA is more prevalent among individuals with cardiovascular disease, congestive heart failure, and arrhythmias".

In addition, they said data from the Sleep Heart Health Study showed that sleep apnoea increased the risk of heart failure by 140 per cent, stroke by 60 per cent and coronary heart disease by 30 per cent.

"However, we were surprised by such a high frequency of OSA symptoms among participants with a history of heart disease," the authors said.

"This is particularly alarming, given the fact that only 10 per cent of patients with OSA have received a diagnosis, which is often attributed to a lack of training among primary care physicians and lack of referrals for sleep assessment when symptoms are detected," the researchers added.

The authors said one implication of the findings was that Caribbean-born patients with a history of heart disease should be a "prime target for interventions that promote adequate screening and timely diagnosis of sleep apnea".
They pointed to a recent chart audit survey, conducted in a sleep clinic serving primarily minority patients in Brooklyn, as revealing that black patients do not routinely adhere to the physician's recommendation to see a sleep specialist.

They, therefore, urged Caribbean nationals, with a history of heart disease, to receive a brief screening for sleep apnoea while attending regular visits in primary care facilities, stating that appropriate referrals for comprehensive sleep assessment must be encouraged.

The authors, however, noted that while Caribbean-born blacks have a higher rate of sleep-related complaints, than previously determined, respondents in the study were recruited in a clinical setting.

They, therefore, warned that estimates in the sample should not be used in a 'head-to-head' match with population-based ones.

The authors also acknowledged some limitations about the study, regarding generalisation of the entire population of Caribbean-born individuals.

"Judging from the geographic location of the participating clinics, most of the patients were from Jamaica, Haiti and Trinidad and Tobago, which, by no means, constituted an accurate sampling of Caribbean people living in Brooklyn," they said.

Additionally, the authors said the sample comprised patients attending regular visits with their physicians, "who, evidently, had medical problems likely affecting their sleep".

Notwithstanding their limitation, they said their data suggest the possibility that Caribbean-born Blacks may be at a greater risk of developing OSA than African-Americans and whites, and that those with a history of heart disease might be particularly vulnerable.

"This suggests that more aggressive effort should be made to increase screening rates for sleep apnoea in that population, thereby increasing the likelihood of early detection and treatment to prevent cardiovascular complications," the authors said.

They recommend that further studies assess sleep patterns among Caribbean nationals, using epidemiologic methodologies.

A total of 554 patients, with an average age of 48, participated in the study; 55 per cent were women.
The purpose of the study was explained to interested patients by a health educator, who also assisted consenting participants in completing questionnaires, which required 15 minutes to complete.