Background: Fast heart rate and high blood pressure (BP) at rest may raise risk for the development of type-2 diabetes mellitus (DM). We therefore investigated dose-response and interactive effects of resting heart rate and BP on the incidence of DM in a Japanese population.
Methods: A follow-up study was conducted for 16 828 men and 8368 women aged 30-59 years and apparently healthy at baseline. Incident DM was identified by 'fasting serum glucose > or =7.00 mmol/l (126 mg/dl)' or/and 'under medical treatment for DM'. Using Cox proportional hazard models, hazard ratio (HR) for incident DM were estimated according to the quartiles of heart rate, systolic or diastolic BP (SBP, DBP), and its linear trends were checked by computing the three indices as continuous variables. Subsequently, interactive effects of slow/fast heart rate (dichotomized by the median) and low/high SBP or DBP (dichotomized by the median) on HR were examined. Baseline age, body mass index, smoking, drinking, exercise and education were computed as conventional confounders.
Results: During the follow-up of 125 106 person-years for men and 59 616 person-years for women, 869 men and 224 women developed DM. The multivariate-adjusted HR for incident DM increased across quartiles of heart rate, SBP and DBP in both sexes (linear trend P<0.001 for all). Neither sex showed any significant interactive effects of heart rate and SBP or DBP on HR.
Conclusions: Resting heart rate and BP proportionally raise the risk for DM in middle-aged healthy men and women. Moreover, the adverse effects of fast heart rate and high BP are independent of each other as well as of the influences of conventional confounders.