Response to Gender-Specific Associations of Short Sleep Duration With Prevalent Hypertension
We appreciate the insightful remarks by Stang et al.1 on our recent article examining the associations of self-reported duration of sleep with prevalent and incident hypertension in a representative sample of British men and women.2 We were particularly pleased to learn about the findings of Stang et al1 that corroborate our results showing cross-sectional associations between sleep deprivation (≤5 hours) and prevalent hypertension among women only. The effect size of the German study is compatible with our own when considering its 95% CIs. Unfortunately, the lack of longitudinal findings from the Heinz study does not allow a direct comparison with our prospective analyses, which showed an attenuation of the association between short sleep and incident hypertension after accounting for cardiovascular risk factors and psychiatric comorbidities (odds ratio: 1.31; 95% CI: 0.65 to 2.63). The inconsistency between cross-sectional and prospective analyses was observed in a further analysis between duration of sleep and obesity (prevalent versus incident).3 These findings highlight the possibility that either other factors or comorbid conditions may confound or mediate the associations between duration of sleep and health outcomes or the measure of exposure (ie, sleep duration) at 1 point in time does not capture the impact of sleep “duration” over time on sleep “deprivation,” which is better measured by changes in sleep duration over time, as shown for cardiovascular mortality.4
The first point is well taken and has been corrected at once.2 However, the misprint does not apply to Table 2 of the original article.2 As for the second point, the novel aspect of our article is the dual approach of cross-sectional and prospective analyses. The latter describes the incident risk according to exposure.
Stang A, Moebus S, Möhlenkamp S, Erbel R, Jöckel KH. Gender-specific associations of short sleep duration with prevalent hypertension. Hypertension. 2008; 51: e15–e16.
Cappuccio FP, Stranges S, Kandala N-B, Miller MA, Taggart FM, Kumari M, Ferrie JE, Shipley MJ, Brunner E, Marmot MG. Gender-specific associations of short sleep duration with prevalent and incident hypertension: the Whitehall II study. Hypertension. 2007; 50: 693–700.(Correction. Hypertension. 2007;50:e70).
Stranges S, Cappuccio FP, Kandala N-B, Miller MA, Taggart FM, Kumari M, Ferrie JE, Shipley MJ, Brunner E, Marmot MG. Cross-sectional versus prospective associations of sleep duration with changes in relative weight and body fat distribution: the Whitehall II Study. Am J Epidemiol. 2007; doi: 10.1093/aje/kum302.