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New study shows no link between insomnia, incident hypertension in older adults

Tuesday, February 17 2009 | Comments

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What's This? New data do not support the notion that insomnia increases the risk of developing hypertension in older adults. In fact, findings from the study actually showed a reduced risk of incident hypertension among nonblack men who reported difficulty initiating sleep at baseline.

The study researchers hypothesized that insomnia complaints would predict the development of hypertension, particularly among black individuals. They cited a longitudinal analysis that revealed a link between short sleep and hypertension, as well as additional research indicating that objectively measured sleep durations are generally shorter among black individuals than among white individuals. The association between short sleep and hypertension, they suggested, could account for the increased prevalence of hypertension among black individuals.

In the current study, the investigators evaluated data for 1,419 older adults (mean age at baseline, 73.5 yrs) who participated in the community-based Cardiovascular Health Study and were free of hypertension at baseline. The analysis included 6 years of follow-up data for 150 black participants (10.6% of the cohort), 1,264 white participants, and 5 participants of American Indian/Alaskan, Asian/Pacific Islander, or other race.

Potential predictors of hypertension included difficulty initiating sleep, sleep continuity disturbance, early morning awakening, and difficulty initiating sleep combined with one or both of the other sleep complaints.

In a model that adjusted for age and education, early morning awakenings were associated with an increased risk of incident hypertension during follow-up among black men (relative risk [RR], 2.03; 0.99-4.16; P=.05), but this association was attenuated after additional adjustment for income, body mass index, smoking status, alcohol intake, forced expiratory volume (FEV1), coronary heart disease, diabetes stage, and height (RR, 1.89; 95% CI, 0.83-4.32; P=.13). None of the other sleep complaints was associated with hypertension in this group.

Among nonblack men, difficulty initiating sleep was actually associated with a reduced risk of hypertension in the fully adjusted model (RR, 0.47; 95% CI, 0.25-0.87). A similarly reduced risk of hypertension was observed among nonblack men who reported a combination of difficulty initiating sleep and sleep continuity disturbance and among nonblack men reporting all 3 insomnia symptoms.

Further adjustment for depression changed these estimates only slightly, the authors noted.

Among the women, none of the sleep complaints was significantly associated with hypertension in either race, although the researchers observed a trend toward an increased risk of hypertension among nonblack women who reported difficulty initiating sleep at baseline (fully adjusted RR, 1.23; 95% CI, 0.98-1.54; P=.08).

"The lack of convincing correlation between insomnia complaints and incident hypertension contrasts with the consistent association between short sleep and hypertension and highlights the important distinction between insomnia and sleep restriction," the authors commented.

"There remains little strong evidence that insomnia is associated with any adverse outcome except for depression," they concluded. (Phillips B, et al. Sleep 2009;32:65-72.)

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