Our results confirm that the ORMDL3 locus is a risk factor for asthma in ethnically diverse populations. However, inconsistent SNP-level results suggest that further studies will be needed to determine the mechanism by which ORMDL3 predisposes to asthma.

Genetic association studies in admixed populations may be biased if individual ancestry varies within the population and the phenotype of interest is associated with ancestry. However, recently admixed populations also offer potential benefits in association studies since markers informative for ancestry may be in linkage disequilibrium across large distances. In particular, the enhanced LD in admixed populations may be used to identify alleles that underlie a genetically determined difference in a phenotype between two ancestral populations. Asthma is known to have different prevalence and severity among ancestrally distinct populations. We investigated several asthma-related phenotypes in two ancestrally admixed populations: Mexican Americans and Puerto Ricans. We used ancestry informative markers to estimate the individual ancestry of 181 Mexican American asthmatics and 181 Puerto Rican asthmatics and tested whether individual ancestry is associated with any of these phenotypes independently of known environmental factors. We found an association between higher European ancestry and more severe asthma as measured by both forced expiratory volume at 1 second (r=-0.21, p=0.005) and by a clinical assessment of severity among Mexican Americans (OR: 1.55; 95% CI 1.25 to 1.93). We found no significant associations between ancestry and severity or drug responsiveness among Puerto Ricans. These results suggest that asthma severity may be influenced by genetic factors differentiating Europeans and Native Americans in Mexican Americans, although differing results for Puerto Ricans require further investigation.

In these preliminary results, the prevalence of OS in our population is similar to that previously reported. Daytime hypercapnia correlated with the more severe sleep-disordered breathing (SDB) and worse nocturnal hypoxemia in all subjects. Severity of obstructive ventilatory impairment is associated with worse SDB during REM sleep. Randomized trials to determine if PSGs are indicated in all patients with severe COPD should be considered. This is an ongoing study.

Sleep complaints are very common among the general population and are usually accompanied by significant medical, psychological and social disturbances (Redline S, Strohl K, Otolaryngol Clin North Am, 132:303, 1999). A higher prevalence of sleep complaints has been described in the elderly (Vgontzas AN, Kales A, Annu Rev Med, 50:387-400, 1999). It is manifested by breathing disturbances during sleep, loud snoring, difficulties maintaining sleep, fatigue, daytime sleepiness, mood effects and impairment of daily activities (Lugaresi E, Cirignotta F, Zucconi M et al., Good and poor sleepers: an epidemiological survey of the San Marino population, Raven, New York, pp 1-12, 1983; Kales A, Soldatos CR, Kales JD, Am Fam Physician, 22:101-108, 1980). It has been associated with cardiovascular, endocrine and neurocognitive manifestations. Growing interest in early diagnosis and treatment has been noted in recent years based on emerging knowledge about the potential health consequences when the disease goes untreated (Nanen AM, Dunagan DP, Fleisher A et al., Chest, 121:1741, 2002). The veteran population in the mainland has a higher tendency for obesity, high blood pressure (HBP), sleep disorders and chronic alcohol consumption (Mustafa M, Erokwu N, Ebose I, Strohl K, Sleep Breath, 9:57-63, 2005). The Hispanic veteran population has never been studied in detail for sleep disorders and related conditions. We used previously validated screening tools for sleep disturbance breathing. Two hundred and forty-five questionnaires were administered. We found a higher prevalence of Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) in our population compared with data from the mainland (USA). The mean age was 64 years (+/-11). Ninety seven per cent were males. The mean body mass index was 25 kg/cm(2); mean Epworth Sleepiness Scale score was 8. Thirty-four per cent met high-risk criteria for sleep apnea, 53% for insomnia, 13% for symptoms suggestive of narcolepsy and 13% for those suggestive of restless leg syndrome. There were high incidences of alcohol consumption (37.6%), diabetes (32.7%), hypercholesterolemia (31.8%), depression (31.8%), hypertension (39.6%) and post-traumatic stress disorder (PTSD) (9.8%).

We conducted a survey to determine parent-reported asthma prevalence, morbidity, and healthcare utilization among 3527 children attending public schools (n = 2849) and private schools (n = 678) in San Juan, Puerto Rico. Schools were randomly selected from each of 12 geographic regions of the San Juan metropolitan area. Parents of children age 4-7 years old completed a 12-item questionnaire on asthma diagnosis, respiratory symptoms and morbidity, and healthcare utilization. Parents of children in public schools and private schools reported similar rates of a physician having previously diagnosed asthma in their children (43.2% vs. 39.4%); however, significantly more children in public schools were reported to still have asthma at the time of the survey (32.6% vs. 23.7%). Children attending public schools vs. private schools were reported to have missed significantly more school and to have had more hospitalizations and emergency department visits. Among children reported to still have asthma, significantly more children visited an emergency department, were hospitalized, and missed more school days due to respiratory symptoms in the past year. The high prevalence of parent-reported asthma, respiratory symptoms, and healthcare utilization among Puerto Rican children in San Juan calls for further studies using objective methods for ascertaining asthma and asthma-related morbidity. Differences in healthcare utilization between children attending public vs. private schools suggest that socioeconomic factors play a role in asthma management in Puerto Rico.