2012 Fiscal Year Final Research Report
Cross-sectional Study about the Association between Morning Blood Pressure Surge and Indoor Room Temperature
| Project/Area Number |
22790567
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Public health/Health science
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| Research Institution | Nara Medical University |
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Principal Investigator |
SAEKI Keigo 奈良県立医科大学, 医学部, 助教 (60364056)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 疫学 / 室温 / 血圧モーニングサージ / 自由行動下血圧測定 / 入浴 / 夜間血圧 |
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| Research Abstract |
Background: Higher morning BP surge is a risk factor for cardiovascular disease independent of 24-h mean BP. Although low outdoor temperatures are associated with higher morning BP surges, the influence of indoor temperature and ambient temperatures (temperature while indoors or temperature while outdoors) on morning BP surges remains unclear. Such information may help prevent excess winter mortality.Methods and Results: We simultaneously measured indoor temperatures (living room and bedroom), ambulatory BP, and physical activity for 768 person-days during winter and spring/fall in 192 participants (mean age, 69.9 years). We found a decreased correlation between indoor and outdoor temperatures in lower outdoor temperature than its median value. (r=0.28 in -3.37°C to 9.73°C) compared with warmer situation (r=0.84 in 9.82 to 27.7°C). In univariate and multivariate analyses, models that included the ambient temperature showed a better fit (lower AIC) than those including only indoor or outdoor temperature. A multivariate linear mixed -effect regression model showed that a 1°C decrease in the ambient temperature was significantly associated with a 0.44-mm Hg increase in the sleep-trough morning BP surge and a 0.52-mm Hg increase in the prewaking BP surge. This was independent of potential confounders, including physical activity. Conclusion: Lower ambient temperatures were independently associated with higher morning BP surges.
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