title: Association of plasma homocysteine with self-reported sleep apnea is confounded by age: results from the national health and nutrition examination survey 2005-2006.
abstract: High levels of plasma homocysteine are implicated in the pathogenesis of cardiovascular diseases especially if accompanied by sleep apnea, but a direct pathogenetic link between plasma homocysteine levels and obstructive sleep apnea is debatable. This association can have far-reaching public health implications considering the inverse association between folate and plasma homocysteine. We used data from the 2005-2006 cycle of the National Health and Nutrition Examination Survey (NHANES) to test the hypothesized associations. Of the 4490 subjects included in analysis, 177 reported sleep apnea. Age-standardized and design-effect-corrected prevalence rates were differential across gender, plasma homocysteine, and red cell folate status. Plasma homocysteine was positively correlated with age (r = 0.38, P < 0.0001). Multivariate analyses using sociodemographic and clinical covariates demonstrated that plasma homocysteine levels retained their respective associations with self-reported sleep apnea in all models except when age was included as a covariate. Our results demonstrate that the claimed association of plasma homocysteine with sleep apnea may be confounded by age.
authors.affiliation: Lata Medical Research Foundation, Nagpur, 440022, India ; Cleveland Clinic Sleep Disorders Center, Cleveland, OH 44195, USA.
authors.forename: Tushar P
authors.initials: TP
authors.lastname: Thakre
authors.forename: Manju
authors.initials: M
authors.lastname: Mamtani
authors.forename: Shweta
authors.initials: S
authors.lastname: Ujaoney
authors.forename: Hemant
authors.initials: H
authors.lastname: Kulkarni