Combined Association of Cardiorespiratory Fitness and Family History of Hypertension on the Incidence of Hypertension

Abstract

Family history of hypertension (FH) is a non-modifiable risk factor of hypertension. However, cardiorespiratory fitness (CRF) is a modifiable risk factor and may be important for preventing hypertension for both people with and without FH. PURPOSE: The purpose of this study was to investigate the combined association of CRF and FH on the incidence of hypertension in male Japanese workers. METHODS: A total of 6890 male workers, who were free from hypertension, were included in this study. CRF was determined using a submaximal exercise test, with a cycle ergometer. A self-reported questionnaire was used to determine FH. Six groups were established, combining the 2 groups with and without FH (Yes, No) and the 3 groups based on age-specific tertiles of CRF (Low, Moderate, High). The incidence of hypertension, defined as systolic blood pressure of ≥140 mmHg or diastolic blood pressure of ≥90 mmHg, or self-reported physician-diagnosed hypertension, was evaluated. Cox proportional hazards regression analysis was performed with incidence of hypertension as the dependent variable and the 6 groups as independent variables. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated after adjustment for age and potential confounding factors (BMI, cigarette smoking, and alcohol intake). RESULTS: During the observation period of 101,212 man-years of observation (median 17 years, minimum 1 year, maximum 23 years), 2210 workers developed hypertension. There were 3860 participants who had a FH (56%). As compared with the Yes-Low group, the HRs for hypertension were 66% lower in No-High (HR 0.34 [95%CI, 0.28-0.40]), 47% lower in No-Low (HR 0.53 [95%CI, 0.46-0.61]), and 24% lower in Yes-High (HR 0.76 [95%CI, 0.67-0.86]). FH and CRF did not show a significant interaction (p for interaction = 0.181). CONCLUSIONS: The combination of FH and CRF showed a clear association with the risk of hypertension, and even participants with FH showed a lower risk of hypertension when the level of CRF was high. FH and CRF did not show a significant interaction. Therefore, these findings suggest that CRF might be equally beneficial for preventing hypertension in both people with and without FH.