Relationship of 30-year changes in obesity to sleep-disordered breathing in the Western Collaborative Group Study

Obesity is an important etiologic factor in sleep-disordered breathing (SDB), but the extent to which changes in obesity across adult life contribute independently to SDB in old age has not been studied. In this study, we examined the association between changes in obesity from midlife to late adulthood and overnight recording of respiration during sleep.

Subjects in this study are from the Western Collaborative Group Study, a longitudinal cardiovascular epidemiological study that began in 1960 through 1961. Overnight sleep recordings were obtained from 281 male participants in the 1995 through 1996 follow-up of the Western Collaborative Group Study. Subjects were 75 to 91 years old when assessed for SDB as indexed by the respiratory disturbance index and an oxygen desaturation index (O2DI). Long-term changes in anthropometrics were evaluated and examined in relation to SDB severity.

Over the 30 years of follow-up, body mass index and waist circumference increased significantly for this sample and were associated with SDB severity as indexed by respiratory disturbance index and O2DI. Waist circumference at baseline and gain in waist circumference over the 30 years of follow-up (both p = 0.01) were significantly and independently associated with SDB severity as assessed by O2DI. However, percentage of variance as accounted for by waist circumference was modest.

This study supports the hypothesis that gain in waist circumference over adult life is significantly associated with SDB severity in older men.