Winter morning surge in blood pressure after the Great East Japan Earthquake

Abstract

The great earthquake triggered a powerful tsunami, which provoked catastrophic damage, especially in coastal regions. Almost all buildings were completely destroyed, and thousands of residents in the affected areas were forced to move from their own homes or apartments to temporary housing. Even today, more than 7 years after the disaster, many of the displaced victims continued to live in temporary housing. The quality of life in such housing may affect the health of evacuees, since temporary housing tends to be simpler, less spacious, and less comfortable than occupant-owned housing.Blood pressure (BP), including 24-hour ambulatory BP, fluctuates with the seasons and is generally higher in winter and lower in summer. [1][2][3][4][5][6][7] Previous studies have also demonstrated that seasonal BP variations are more highly associated with indoor temperature than outdoor temperature 8,9 and that indoor temperature is mainly determined by the temperature or permanent nature of residential housing. 4,10 Therefore, housing conditions may be one of the greatest determinants of the seasonal BP variations. However, there have been no studies investigating the association between seasonal BP variations and the nature of the residential housing in areas damaged by the Great East Japan Earthquake.Elderly individuals show more highly exaggerated BP variability than younger people, mainly due to the autonomic nervous dysfunction in the former. [11][12][13][14] The elderly also show higher BP levels in the winter than in the summer, while younger individuals do not exhibit this seasonal BP difference. [15][16][17] Therefore, compared to the BP levels of young people, those of the elderly would be more likely to be changed due to differences in housing conditions; however, information is limited regarding the association between seasonal BP variations and housing conditions in the elderly.To investigate this association, we used data from the Minamisanriku study, a prospective observational study of outpatients of the Minamisanriku hospital who experienced changes in their housing status, to test our hypothesis that seasonal BP variations would be associated with housing conditions (especially This study investigated the association between winter morning surge in systolic blood pressure (SBP) as measured by ambulatory BP monitoring and the housing conditions of subjects in an area damaged by the Great East Japan Earthquake. In 2013, 2 years after disaster, hypertensives who lived in homes that they had purchased before the disaster (n = 299, 74.6 ± 8.1 years) showed significant winter morning surge in SBP (+5.0 ± 20.8 mmHg, P < 0.001), while those who lived in temporary housing (n = 113, 76.2 ± 7.6 years) did not. When we divided the winter morning surge in SBP into quintiles, the factors of age ≥75 years and occupant-owned housing were significant determinants for the highest quintile (≥20 mmHg) after adjustment for covariates. The hypertensives aged ≥75 years who lived in their own homes showed a significant risk for the hi...

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“…Another factor that needs to be considered is the housing conditions, which are especially important for elderly hypertensive patients. A study by Nishizawa et al analyzed the winter morning surge according to the housing conditions after the Great East Japanese earthquake and found that hypertensive patients aged ≥75 years who lived in self‐owned older homes showed a significantly higher risk for being in the highest quintile (≥20 mm Hg) of the morning BP surge (odds ratio 5.21; 95% confidence interval, 1.49‐18.22; P = .010) compared to that for individuals who lived in better insulated temporary housing provided by the government . The results from this study show the importance of adequate indoor insulation and heating to minimize the winter morning BP surge, especially in elderly individuals.…”

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“…The times and places at which the surge BP is generated would be the most risky times/places for an individual's cardiovascular event onset. Even among well‐controlled hypertensive patients, the morning BP surge remains significant in the winter . Anticipation medicine for cardiovascular diseases—which both anticipates pathological surge BP based on the previous time series of individual BP data and avoids the generation of surge BP—is an ideal future practical direction to take in order to decrease the gap between the guidelines and individualized medicine in the era of ICT‐based “real‐world” big data analysis and feedback systems.…”

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“…There is also significant seasonal variation in BP. Both BP and BPV are increased in the winter, and inverse and exaggerated seasonal BP variation increased the risk of CVD . Pathological thresholds are ≥180 mm Hg for maximum SBP, ≥20 mm Hg for SD of visit‐to‐visit systolic BPV, ≥20 mm Hg for orthostatic SBP change (increase or decrease by ≥20 mm Hg), and <0 mm Hg or ≥20 mm Hg for winter increase in SBP (SBP in winter minus SBP in summer; seasonal variation).…”