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Impact of multiple risk factor clustering on the elevation of blood pressure
Masahiko Tozawa1, Kunitoshi Iseki, Chiho Iseki
1Third Department of Internal Medicine and Dialysis Unit, University of the Ryukyus, Okinawa General Health Maintenance Association, Okinawa, Japan. mtozawa@eb.mbn.or.jp
Insights
Clustering of hypertension risk factors like obesity and diabetes significantly increases blood pressure elevation risk. More combined risk factors lead to a substantially higher likelihood of developing hypertension.
Area of Science:
- Cardiovascular Medicine
- Public Health
- Epidemiology
Background:
- Hypertension is a major cardiovascular risk factor.
- Family history of hypertension, obesity, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia are individually associated with hypertension risk.
Purpose of the Study:
- To investigate the impact of clustering of five common risk factors on blood pressure elevation in normotensive individuals.
- To determine the relative risk of developing hypertension based on the number of co-existing risk factors.
Main Methods:
- Retrospective longitudinal study of 4,857 normotensive subjects (1997-1999).
- Analysis of blood pressure changes and incidence of hypertension.
- Multiple logistic and regression analyses adjusted for age, sex, and baseline blood pressure.
Main Results:
- The incidence of hypertension was 37 per 1,000 person-years.
- Relative risk of BP elevation increased with the number of risk factors: 1.49 (1 factor), 1.65 (2 factors), 4.86 (4+ factors).
- Number of risk factors positively correlated with increased systolic (β=0.51, p=0.001) and diastolic BP (β=0.31, p=0.008).
Conclusions:
- Clustering of hypertension risk factors significantly predicts the development of hypertension.
- The presence of multiple risk factors amplifies the risk of blood pressure elevation and hypertension onset.
Abstract:
A family history of hypertension, obesity, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia have all been associated with risk of hypertension. We retrospectively conducted a longitudinal study in a large screened cohort to explore the effect of the clustering of these five risk factors on the elevation of blood pressure (BP) in normotensive subjects at baseline. The study group comprised 4,857 normotensive subjects not treated with antihypertensive drugs (systolic BP < 140 mmHg, diastolic BP < 90 mmHg, 3,111 men and 1,746 women) who were followed up from 1997 to 1999. By 1999, 360 subjects had BP at the hypertensive level (systolic BP > or = 140 mmHg or diastolic BP > or = 90 mmHg). The incidence of subjects whose BP became hypertensive was 37 per 1,000 person-years. After adjusting for age, sex, systolic BP and other clinical factors, multiple logistic analysis showed that the relative risk of BP elevation was 1.49 (95% Cl: 1.09 to 2.05) in subjects with one risk factor; 1.65 (95% Cl: 1.15 to 2.27) in those with two risk factors; 1.42 (95% Cl: 0.91 to 2.32) in those with three; and 4.86 (95% Cl: 2.58 to 9.16) in those with four or more when compared with subjects with no risk factors. Multiple regression analysis showed that the number of risk factors was positively correlated with an increase in BP from 1997 to 1999; the regression coefficient was 0.51 (p = 0.001) for increase in systolic BP, and 0.31 (p = 0.008) for increase in diastolic BP after adjusting for age and sex. In conclusion, clustering of risk factors significantly predicted the development of hypertension.