Office Blood Pressure and Cardiovascular Disease

Association between short-term daily temperature variability and blood pressure in the Chinese population: From the China hypertension survey

BACKGROUND

We aimed to evaluate the impacts of short-term daily temperature variability (DTV) on blood pressure (BP) among participants with normotension, prehypertension, and hypertension, respectively, and explore the effects in different climate zones and seasons.

METHODS

A representative population sample (n = 397,173) covering the subtropical, temperate continental, and temperate monsoon zones was obtained from the China Hypertension Survey. DTV was calculated as the standard deviation of daily minimum and maximum temperatures during the exposure days. The linear mixed effect regression model was used to estimate the associations between DTV exposure and BP among normotension, prehypertension, and hypertension, respectively, and further stratified analysis was performed by climate zones and seasons.

RESULTS

After adjustment for confounders, per interquartile range (IQR) increase in DTV (2.28 °C) at 0-6 days of exposure was associated with an increase of 0.41 mmHg (95 % confidence interval [CI]: 0.07, 0.75) in systolic BP (SBP) and 0.41 mmHg (95 % CI: 0.09, 0.72) in pulse pressure (PP) among hypertensive participants in the subtropical zone. Similarly, DTV exposure was associated with an increase of 0.31 mmHg (95 % CI: 0.06, 0.55) in SBP and 0.59 mmHg (95 % CI: 0.24, 0.94) in PP among prehypertensive participants in the temperate continental zone. Additionally, during the warm season, DTV was positively associated with SBP among populations with prehypertension and hypertension, and with PP among all three populations.

CONCLUSION

Short-term DTV exposure was associated with an increase in SBP and PP among hypertensive and prehypertensive participants in the subtropical zone and the temperate continental zone. In addition, positive associations of DTV with SBP and PP were observed among participants with prehypertension and hypertension in the warm season. Comprehensive health education and effective intervention strategies should be implemented to mitigate the effects of temperature variations on BP, particularly among prehypertensive and hypertensive populations.

Nighttime mean arterial pressure is associated with left ventricular hypertrophy in white‐coat hypertension

White‐coat hypertension (WCH) is associated with increased cardiovascular risks. To investigate the relationship between WCH and left ventricular hypertrophy (LVH), the authors recruited 706 participants who underwent anthropometric measurements, blood laboratory analysis, 24h ambulatory blood pressure monitoring (ABPM), and echocardiography. The authors defined WCH as elevated office BP but normal ABPM over 24h, daytime, and nighttime periods. The authors compared the proportion of LVH between the true normotension (NT) and the WCH population, and further assessed the associations between BP indexes and LVH in the two groups, respectively. The proportion of LVH was significantly higher in the WCH group than in NT participants (19.70% vs. 13.12%, P = .036). In the NT group, 24h SBP, 24h PP, daytime SBP, daytime PP and SD of nighttime SBP were associated with LVH after adjustment for demographic and blood biochemical data (all P < .05). In the WCH population, LVH was associated with 24h SBP, nighttime SBP, nighttime MAP, and office SBP after adjustment (all P < .05). However, on forward logistic regression analysis with all the BP indexes listed above, only 24h SBP (OR = 1.057, 1.017–1.098, P < .001) in the NT group, and nighttime MAP (OR = 1.114, 1.005–1.235, P < .05) and office SBP (OR = 1.067, 1.019–1.117, P < .001) in the WCH group were still significantly associated with LVH. Our study suggests that the proportion of LVH is higher in WCH patients than in the NT population. Furthermore, elevated nighttime MAP and office SBP may play critical roles in the development of LVH in the WCH population.

Early cardiovascular structural and functional abnormalities as a guide to future morbid events

Aims

Our aim was to evaluate the predictive value of a battery of 10 non-invasive tests of cardiovascular structural and functional health on the future risk of cardiovascular morbid events.

Methods and Results

A total of 1900 asymptomatic adults concerned about their risk for cardiovascular disease underwent non-invasive assessment with 10 tests of vascular and cardiac structure and function. A disease score (DS) was calculated for each individual based on these 10 tests. Follow-up (mean 9.2 years) for cardiovascular morbidity and mortality was available for 1442 individuals (mean age 53.2 years, 48.2% women). Those in the lowest DS tertile (0–2) experienced 0.16 cardiovascular events per 100 patient-years (PY), those in the middle tertile (3–5) experienced 0.86 events per 100 PY, and those in the highest tertile (6+) experienced 1.3 events per 100 PY (p &lt; .001). Sensitivity analysis, assuming a neutral effect of DS on projected events in subjects not followed, did not alter statistical significance. Risk assessment using the Framingham risk score (FRS) also predicted morbid events but the two methods differed in identifying individuals at high risk. The net reclassification index was improved by 0.11 (p = 0.01) when DS was added to FRS.

Conclusions

Assessing the biological disease process in the arteries and heart of asymptomatic adults provides a guide to the risk of a future cardiovascular morbid event. Larger and longer studies are needed to determine whether risk factor algorithms, the severity of the biological process or some combination is the optimal method for identifying individuals in need of intervention to delay morbid events.