Response to Letter by Walsh et al
We would like to thank Drs Walsh, Donnelly, and Lyons for their interest in our article. We have read their comments with interest. They raised the possibility that the sex difference of relation between height and stroke mortality observed in our study1 might be explained by pulse pressure (PP).
In our study,1 we used systolic blood pressure (BP) as one of the covariates of the multiple adjusted model testing the relation because several previous studies showed that PP was less useful in predicting long-term stroke risk than systolic BP in Asia.2,3 However, as Walsh et al pointed out, PP might be a better marker of vessel stiffness. Thus, we additionally analyzed the relation of height and stroke mortality adjusted for PP instead of systolic BP. The results showed that multiple adjusted relative hazards (RH) for stroke mortality per 5-cm increment of height were 0.75 (95% CI: 0.63 to 0.90) for women and 0.92 (95% CI: 0.78 to 1.07) for men. This result was almost identical to our previous report (RHs per 5-cm increment of height were 0.77 for women and 0.92 for men).1 Thus, their hypothesis that PP can explain the sex difference of relation between height and stroke mortality was declined in our case. However, although we could not assess in this cohort, considering hemodynamic factors that influence PP, such as aortic pulse wave velocity (stiffness) and pulse wave analysis (wave reflectance), could attenuate the sex difference might be of interest in future.
Hozawa A, Murakami Y, Okamura T, Kadowaki T, Nakamura K, Hayakawa T, Kita Y, Nakamura Y, Okayama A, Ueshima H; the NIPPON DATA80 Research Group. Relation of adult height with stroke mortality in Japan: NIPPON DATA80. Stroke. 2007; 38: 22–26.
Miura K, Soyama Y, Morikawa Y, Nishijo M, Nakanishi Y, Naruse Y, Yoshita K, Kagamimori S, Nakagawa H. Comparison of four blood pressure indexes for the prediction of 10-year stroke risk in middle-aged and older Asians. Hypertension. 2004; 44: 715–720.
Asia Pacific Cohort Studies Collaboration. Blood pressure indices and cardiovascular disease in the Asia Pacific region: a pooled analysis. Hypertension. 2003; 42: 69–75.