Relationship between obstructive sleep apnea and diurnal leptin rhythms.
OBJECTIVE
Several studies have reported an association between obstructive sleep apnea and leptin, a hormone that influences satiety and body weight. We evaluated the relationship of leptin levels and the overnight change in levels with sleep apnea.


METHODS
Cross-sectional analysis of data from a prospective cohort study.


METHODS
Case Western Reserve University General Clinical Research Center.


METHODS
A total of 138 individuals participating in the Cleveland Family Study--59% women, 45% African-American, with mean apnea-hypopnea index (AHI) of 6.9 (range 0-106)--were studied.


METHODS
None.


RESULTS
Serum leptin was measured at 10:00 pm to 11:00 pm and at 7:00 am to 8:00 am. Leptin levels in both the morning and evening were positively correlated with apnea-hypopnea index (AHI) in age-, sex-, and race-adjusted analyses (P < .0001) but not after additional adjustment for body mass index. The evening/morning leptin ratio, however, was associated with AHI independent of age, sex, race, body mass index, and waist-hip ratio (P = .03). Conversely, AHI was an independent predictor of the leptin ratio (P = .001) and more predictive than arousal index, oxygenation indices, time asleep, or sleep-stage distribution. An AHI > 15 was associated with a 23% increase in leptin ratio.


CONCLUSIONS
These findings suggest that sleep apnea may suppress secretion of leptin in the morning. Alternatively, the relative elevation in evening leptin may influence apnea pathogenesis.
Patel
Sanjay R
SR
Rainbow Babies and Children's Hospital, Cleveland, OH, USA. spatel@partners.org
Palmer
Lyle J
LJ
Larkin
Emma K
EK
Jenny
Nancy S
NS
White
David P
DP
Redline
Susan
S
D000293:Adolescent; D000328:Adult; D001143:Arousal / Q000502:physiology; D015992:Body Mass Index; D002940:Circadian Rhythm; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D020738:Leptin / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000378:metabolism; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000378:metabolism*
D020738:Leptin