Longitudinal association of sleep-disordered breathing and nondipping of nocturnal blood pressure in the Wisconsin Sleep Cohort Study

Sleep. 2008 Jun;31(6):795-800. doi: 10.1093/sleep/31.6.795.


Study objectives: The association of sleep-disordered breathing (SDB) and blunting of normal nocturnal lowering of blood pressure (BP) (nondipping) has only been examined cross-sectionally. The purpose of this study is to investigate whether SDB is prospectively associated with nondipping.

Methods: The longitudinal association between SDB and incident nondipping was examined in a subsample of 328 adults enrolled in the Wisconsin Sleep Cohort Study who completed 2 or more 24-hour ambulatory BP studies over an average of 7.2 years of follow-up. SDB identified by baseline in-laboratory polysomnography was defined by apnea-hypopnea index (AHI) categories. Systolic and diastolic nondipping was defined by systolic and diastolic sleep-wake BP ratios > 0.9. All models were adjusted for age, sex, body mass index at baseline and follow-up, smoking, alcohol consumption, hypertension, sleep time, length of follow-up time, and antihypertensive medication use.

Results: There was a dose-response increased odds of developing systolic nondipping in participants with SDB. The adjusted odds ratios (95% confidence interval) of incident systolic nondipping for baseline AHI 5 to < 15 and AHI > or = 15, versus AHI < 5, were 3.1 (1.3-7.7) and 4.4 (1.2-16.3), respectively (P trend = 0.006). The adjusted odds ratios (95% confidence interval) of incident diastolic nondipping for corresponding SDB categories were not statistically significant: 2.0 (0.8-5.6) and 1.3 (0.2-7.1).

Conclusions: Our longitudinal findings of a dose-response increase in development of systolic nondipping of BP with severity of SDB at baseline in a population-based sample provide evidence consistent with a causal link. Nocturnal systolic nondipping may be a mechanism by which SDB contributes to increased cardiovascular disease.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Body Mass Index
  • Cohort Studies
  • Comorbidity
  • Cross-Sectional Studies
  • Female
  • Follow-Up Studies
  • Humans
  • Hypertension / diagnosis
  • Hypertension / epidemiology*
  • Male
  • Middle Aged
  • Polysomnography
  • Sleep Apnea Syndromes / diagnosis
  • Sleep Apnea Syndromes / epidemiology*
  • Smoking / epidemiology