The American Journal of Medicine
Volume 120, Issue 11 , Pages 960-967, November 2007

Predictors of Significant Short-Term Increases in Blood Pressure in a Community-Based Population

  • Aryan N. Aiyer, MD

      Affiliations

    • The Cardiovascular Institute, University of Pittsburgh, Pittsburgh, Pa
    • Corresponding Author InformationRequests for reprints should be addressed to Aryan N. Aiyer, MD, Cardiovascular Institute, University of Pittsburgh, University Center, Suite 302, 120 Lytton Avenue, Pittsburgh, PA 15213.
    • ,
  • Kevin E. Kip, PhD

      Affiliations

    • Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pa
    • ,
  • Suresh R. Mulukutla, MD

      Affiliations

    • The Cardiovascular Institute, University of Pittsburgh, Pittsburgh, Pa
    • ,
  • Oscar C. Marroquin, MD

      Affiliations

    • The Cardiovascular Institute, University of Pittsburgh, Pittsburgh, Pa
    • ,
  • Lee Hipps Jr, BA

      Affiliations

    • The Urban League of Pittsburgh, Pittsburgh, Pa
    • ,
  • Steven E. Reis, MD

      Affiliations

    • The Cardiovascular Institute, University of Pittsburgh, Pittsburgh, Pa

Article Outline

Abstract 

Background

Blood pressure predicts the risk of cardiovascular disease events in a linear, graded manner. Factors associated with significant short-term increases in blood pressure are not well established. We aimed to identify predictors of a significant increase in blood pressure over a 1-year period among nonhypertensive, community-dwelling adults.

Methods

From the community-based Heart Strategies Concentrating on Risk Evaluation study, 509 nonhypertensive adults (mean age 58 years; 68% were female; 24% were black) had baseline and 1-year assessments of blood pressure. Demographics, medical history, anthropometrics, lipids/lipoproteins, physical activity, and psychologic status were measured at both intervals. A “significant” increase in blood pressure was defined as an increase in systolic blood pressure of greater than 20 mm Hg, diastolic blood pressure of greater than 10 mm Hg, or initiation of antihypertensive medication.

Results

At 1 year, 22% of participants had a significant increase in blood pressure. In multivariable analysis, baseline body mass index (BMI) and a greater than 5% increase in weight or waist circumference were associated with a significant increase in blood pressure (adjusted relative risk 2.09; 95% confidence interval, 1.35-3.21). The adverse effect of an increase in weight and waist circumference on blood pressure was evident in subgroup analyses by age, race, baseline BMI, and regular exercise.

Conclusions

Baseline BMI and a greater than 5% increase in weight or waist circumference over 1 year are associated with a significant increase in blood pressure. These data emphasize the need for weight maintenance. They also serve to stratify individuals who may benefit from close clinical observation and preventive intervention.

Keywords: Cardiovascular diseases, Epidemiology, Hypertension, Obesity, Prehypertension, Prevention

 

Hypertension affects more than 50 million people in the United States and is an independent risk factor for cardiovascular disease.1 It is well established that there exists a graded and continuous relationship between blood pressure and cardiovascular disease risk.2 Therefore, determination of predictors of increasing blood pressure over time in nonhypertensive individuals may identify a subgroup that is at high risk for progression to hypertension and the development of cardiovascular disease. The present study investigates the factors that are associated with clinically significant increases in systolic and diastolic blood pressure over a 1-year period in a community sample of nonhypertensive individuals who are enrolled in the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) study.

Clinical Significance

 


•A significant increase in blood pressure developed in a large number of nonhypertensive, community-dwelling individuals (22%) within only 1 year.

•Baseline BMI and increases in weight or waist circumference independently predict a significant increase in blood pressure within 1 year among nonhypertensive individuals.

•These independent predictors are clinically useful measures to the practicing internist to identify at-risk individuals who may benefit from close observation and preventive intervention.

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Methods and Materials 

Source Population 

The source population consists of 2000 participants enrolled in the Heart SCORE study. Heart SCORE is an ongoing single-center, prospective, community-based participatory research cohort study. Baseline enrollment began on June 16, 2003 and was completed on October 11, 2006. Eligibility criteria include age 45 to 75 years, residence in the greater Pittsburgh metropolitan area, ability to undergo baseline and annual follow-up visits, and absence of known comorbidities expected to limit life expectancy to less than 5 years (eg, metastatic cancer, end-stage heart failure). Within this full cohort, the mean age at study entry was 59.1 years, 65% were female, 54% were white, 43% were black, 61% were married, and 81% had at least some college education beyond a high school diploma. The institutional review board at the University of Pittsburgh approved the study protocol, and all study subjects provided written informed consent. Data collection included demographics, medical history, lipids/lipoproteins, physical activity, and psychologic status as previously described.3 Body mass index (BMI) was calculated as kilograms/meters squared.

Study Population 

Of the 2000 Heart SCORE participants, 1349 (67%) were enrolled in the study for at least 1 year and had 1-year follow-up data, including blood pressure measurement and current medication use. Of these 1349 participants, 509 (38%) were categorized as being nonhypertensive (ie, normal blood pressure or prehypertension) in accordance with criteria established by the Seventh Report of the Joint National Commission on High Blood Pressure.1 Specifically, these participants had a baseline systolic blood pressure of less than 140 mm Hg, diastolic blood pressure of less than 90 mm Hg, and no current use of antihypertensive medications, thereby constituting the study population. Prehypertension was defined as a systolic blood pressure of 120 to 139 mm Hg or a diastolic blood pressure of 80 to 89 mm Hg.1 The mean age of the 509 study participants at entry was 57.8 years, 68% were female, 73% were white, 24% were black, 66% were married, and 86% had at least some college education.

Blood Pressure Measurement 

Under the supervision of study investigators, experienced cardiovascular research coordinators measured blood pressure by using a manual sphygmomanometer and an appropriately sized cuff. Subjects rested for 5 minutes in a seated position before the initial blood pressure measurement, and 2 separate readings were obtained during the study visit. Routine calibration and, if necessary, replacement of blood pressure equipment were performed. This protocol is similar to those of larger epidemiologic studies.4

Primary Outcome 

The primary outcome was a clinically “significant” increase in blood pressure from baseline to 1-year follow-up, defined as any of the following changes: increase in systolic blood pressure of greater than 20 mm Hg, increase in diastolic blood pressure of greater than 10 mm Hg, or use of antihypertensive medication at the 1-year visit. For sensitivity analyses, 2 alternate definitions were constructed: the conservative definition—same as the primary outcome except diastolic blood pressure of greater than 15 mm Hg rather than greater than 10 mm Hg; the liberal definition—same as the primary outcome except systolic blood pressure of greater than 15 mm Hg rather than greater than 20 mm Hg.

Statistical Analysis 

Factors at baseline and changes in participant factors from baseline to 1 year were compared among participants with and without a “significant” increase in blood pressure (as previously defined) by chi-square tests for categoric variables and Student t tests and Wilcoxon tests (based on distributional properties) for continuous variables. To assess factors independently associated with a significant increase in blood pressure, relative risks (RRs) and 95% confidence intervals (CIs) were estimated by log binomial regression. Separate models were fit for the primary and alternative outcome definitions, with the baseline variables systolic blood pressure, diastolic blood pressure, age, and gender forced into all models, and stepwise selection used to identify additional predictors. All analyses were performed using the Statistical Analysis System software, version 9.1.3 (SAS Inc, Cary, NC).

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Results 

At baseline, 202 of the 509 study participants (39.7%) had normal blood pressure and the remaining 307 participants (60.3%) were prehypertensive. By using the primary outcome definition, 114 of the 509 participants (22.4%) experienced a clinically “significant” increase in blood pressure from the baseline to 1-year assessment. This included 18 participants (3.5%) with an increase in systolic blood pressure of greater than 20 mm Hg, 56 participants (11.0%) with an increase in diastolic blood pressure of greater than 10 mm Hg, 15 participants (2.9%) initiating antihypertensive medication, and 25 participants (4.9%) meeting multiple criteria. By using the conservative and liberal definitions (as defined in “Methods and Materials”), 75 (14.7%) and 125 (24.6%) of all participants, respectively, experienced a significant increase in blood pressure.

Changes in blood pressure also were evaluated in subgroups of participants with normal blood pressure and prehypertension. Some 61 of 202 baseline normotensive participants (30%) experienced a significant increase in blood pressure at 1 year. Of these 61 participants, 8 (13%) remained within the normal blood pressure category, 40 (66%) progressed to the prehypertension category, and the remaining 13 (21%) progressed to the hypertension category. Some 53 of 307 baseline prehypertensive participants (17%) experienced a significant increase in blood pressure at 1 year. Of these 53 participants, 24 (45%) remained within the prehypertension category and the remaining 29 (55%) progressed to the hypertension category. Thus, the study definition of a significant increase in blood pressure usually led to participants being classified in a higher blood pressure category.

Distribution of Change in Blood Pressure 

At 1-year follow-up, 10.8% of all participants had a systolic blood pressure of 140 mm Hg or higher, exceeding the baseline inclusion criterion of less than 140 mm Hg. However, the mean change in systolic blood pressure from baseline to 1 year in the entire study cohort increased only nominally from 120.8±10.4 to 121.9±13.8. Similarly, average diastolic blood pressure was essentially unchanged from baseline to 1 year (74.4±7.5 to 74.5±8.5). Only 3.9% of all participants at 1 year had a diastolic blood pressure of 90 mm Hg or higher, exceeding the baseline inclusion criterion of less than 90 mm Hg. However, these observed differences in the distribution of blood pressure between baseline and 1-year measurements do not account for the 2.9% of participants who began taking antihypertensive medications between baseline and 1-year visits.

Baseline Characteristics Associated with Significant Increase in Blood Pressure 

Age, gender, and race were not associated with a significant increase in blood pressure (Table 1). In contrast, compared with participants without an increase, those with a significant increase in blood pressure had higher baseline mean BMI, cynicism scores, and level of education.

Table 1. Baseline Characteristics by Significant Increase in Blood Pressure
Baseline CharacteristicNo Increase (N=395)Increase (N=114)P Value
Age (y), mean, SD57.7,7.357.9,7.7.79
Race, % .39
White74.466.7
Black21.832.5
Other3.80.9
Female, %67.870.2.73
Education; Bachelors degree or higher, %60.048.3.03
Current smoker, %10.45.3.10
BMI, mean, SD27.3,4.828.6,5.2.01
Systolic blood pressure, mean, SD121.6,10.4118.1,9.9.002
Diastolic blood pressure, mean, SD75.2,7.271.4,7.7<.001
Resting pulse (per minute), mean, SD62.0,9.163.3,10.5.24
Total cholesterol (mg/dL), mean, SD219.2,40.9221.9,48.7.51
LDL cholesterol (mg/dL), mean, SD146.2,35.1148.0,37.9.54
HDL cholesterol (mg/dL), mean, SD59.9,15.960.7,16.4.74
Triglycerides (mg/dL), mean, SD116.9,70.9114.0,67.2.48
Glucose (mg/dL), mean, SD92.7,19.696.1,41.5.98
Metabolic status (ATP-3), %
Normal83.086.0.39
Metabolic syndrome11.97.5
Diabetes5.16.5
Psychosocial measures
Depression (CESD score≥16), %12.59.9.74
CMHI Cynicism scale score, mean, SD3.1,2.73.8,2.8.01
CMHI Hostility scale score, mean, SD1.3,1.21.3,1.3.97
CMHI Aggressive scale score, mean, SD2.9,1.52.8,1.6.53
STAI Anxiety scale score, mean, SD6.6,4.76.2,4.4.44
STAI Anger scale score, mean, SD5.6,3.64.9,3.5.05
Cohen Stress score, mean, SD4.4,3.04.3,3.0.86

SD=standard deviation; BMI=body mass index; LDL=low-density lipoprotein; HDL=high-density lipoprotein; ATP-3=Adult Treatment Panel 3; CESD=Center for Epidemiologic Studies Depression Scale; CMHI=Cook-Medley Hostility Inventory; STAI=State-Trait Anxiety Inventory.

Baseline to 1-Year Change Measures Associated with Significant Increase in Blood Pressure 

Compared with participants without an increase in blood pressure, those with a significant increase in blood pressure over 1 year were more likely to have exhibited an increase in body weight of more than 5% (22% vs 10%) and an increase in waist circumference of greater than 5% (33% vs 17%) over 1 year as shown in Table 2. There also was a nonsignificant trend for an increase in total cholesterol of more than 10% (26% vs 17%) to be associated with a significant increase in blood pressure, whereas changes in physical activity and depressive symptoms were not associated with significant increases in blood pressure.

Table 2. Baseline to 1-Year Change Measure by Significant Increase in Blood Pressure
Baseline to 1-Year ChangeNo Increase (N=395)Increase (N=114)P Value
Change in weight (kg), mean, SD0.2,6.31.0,3.5<.001
Change in weight≥5%⁎ (%) .007
Decrease9.87.9
Same79.870.2
Increase10.421.9
Change in waist circumference (cm), mean, SD−0.4,5.92.4,7.9.002
Change in waist circumference≥5%⁎ (%) <.001
Decrease21.412.4
Same61.254.3
Increase17.333.3
Change in total cholesterol≥10%⁎ (%)
Decrease26.820.8.06
Same56.253.5
Increase17.025.7
Change in LDL cholesterol≥10%⁎ (%)
Decrease31.525.7.19
Same46.046.5
Increase22.527.7
Change in HDL cholesterol≥10%⁎ (%)
Decrease19.621.8.58
Same62.053.5
Increase18.524.8
Change in triglycerides≥20%⁎ (%)
Decrease30.133.7.52
Same44.242.6
Increase25.723.8
Current smoking, %
Baseline=no; Year 1=no89.994.5.51
Baseline=yes; Year 1=no2.10.9
Baseline=no; Year 1=yes0.30.0
Baseline=yes; Year 1=yes7.84.6
Regularly engage in strenuous activity, %
Baseline=no; Year 1=no53.658.3.21
Baseline=yes; Year 1=no8.513.0
Baseline=no; Year 1=yes15.09.3
Baseline=yes; Year 1=yes22.819.4
Depression (CESD score≥16), %
Baseline=no; Year 1=no82.485.2.88
Baseline=yes; Year 1=no7.06.5
Baseline=no; Year 1=yes5.24.6
Baseline=yes; Year 1=yes5.43.7

SD=standard deviation; LDL=low-density lipoprotein; HDL=high-density lipoprotein; CESD=Center for Epidemiologic Studies Depression Scale.

Missing cases exist for some variables.

⁎Mantel-Haenszel chi-square test of trend.

Independent Predictors of Significant Increase in Blood Pressure 

In multivariable analysis, several baseline factors and changes in factors over 1 year were independently associated with a significant increase in blood pressure (Table 3). At baseline, a higher BMI was associated with a significant increase in blood pressure (adjusted RR=1.34 per increase of 5 kg/m2; 95% CI, 1.14-1.57). At 1 year, it was observed that an increase in body weight of more than 5% (adjusted RR=1.61; 95% CI, 1.18-2.19) and an increase in waist circumference (adjusted RR=1.19 per 5 cm; 95% CI, 1.08-1.30) were each independent predictors of a significant increase in blood pressure.

Table 3. Independent Predictors of Significant Increase in Blood Pressure
PredictorPrimary Definition (n=458)Conservative Definition (n=435)Liberal Definition (n=435)
Adjusted RR95% CIAdjusted RR95% CIAdjusted RR95% CI
Baseline variables
Systolic blood pressure (per 5 mm Hg)0.970.88-1.070.900.78-1.030.920.83-1.03
Diastolic blood pressure (per 5 mm Hg)0.76‡0.66-0.880.890.73-1.080.83⁎0.71-0.96
Age (per 5 y)1.080.95-1.221.24⁎1.05-1.471.070.94-1.22
Female gender0.810.57-1.160.890.55-1.420.860.59-1.27
BMI (per 5 kg/m2)1.34‡1.14-1.571.32†1.09-1.621.26†1.08-1.47
Lipid-lowering agent0.610.35-1.05————
STAI Anger scale score (per 1 unit)0.95⁎0.90-1.00————
Baseline to 1-y change variables
Weight increase≥5%1.61†1.18-2.191.95†1.19-3.191.430.97-2.13
Change waist circumference (per 5 cm)1.19‡1.08-1.301.18†1.04-1.341.18†1.06-1.30

RR=relative risk; CI=confidence interval; BMI=body mass index; STAI=State-Trait Anxiety Inventory.

Adjusted RR also adjusted for alcohol use.

⁎P<.05.

†P<.01.

‡P<.001.

For the alternate conservative definition, older age (adjusted RR=1.24 per 5 years; 95% CI, 1.05-1.47), higher baseline BMI (adjusted RR=1.32 per increase of 5 kg/m2; 95% CI, 1.09-1.62), increase in body weight of more than 5% (adjusted RR=1.95; 95% CI, 1.19-3.19), and increase in waist circumference (adjusted RR=1.18 per 5 cm; 95% CI, 1.04-1.34) were independently associated with a significant increase in blood pressure. For the liberal definition, a higher baseline BMI (adjusted RR=1.26 per increase of 5 kg/m2; 95% CI, 1.08-1.47) and an increase in waist circumference (adjusted RR=1.18 per 5 cm; 95% CI, 1.06-1.30) were independently associated with a significant increase in blood pressure. Thus, in aggregate, the most consistent independent predictors of a significant increase in blood pressure included higher baseline BMI, an increase in body weight of more than 5%, and an increase in waist circumference of 5 cm.

Examination of 1-Year Change in Weight and Waist Circumference 

On the basis of the results of multivariable analysis, the relationship between a significant increase in blood pressure and 1-year change in weight and/or waist circumference was further examined. As seen in Figure 1, increases of more than 5% in weight and/or waist circumference over 1 year were associated with a significant increase in blood pressure (P <.001), with no appreciable difference in the effects of these 2 anthropometric measures on increases in blood pressure. This observation is demonstrated by analyses indicating that 36% of participants who experienced a greater than 5% increase in weight and/or waist circumference had a significant increase in blood pressure compared with 17% among participants without a greater than 5% increase in weight and/or waist circumference (Figure 1, right).

  • View full-size image.
  • Figure 1. 

    Incidence of a significant increase in blood pressure from baseline to 1 year by whether or not participants experienced a more than 5% increase in body weight and/or waist circumference from baseline to 1 year.

After statistical adjustment, a more than 5% increase in weight and/or waist circumference was associated with a 2-fold risk of a significant increase in blood pressure (adjusted RR=2.09; 95% CI, 1.35-3.21) (Table 4). This approximate 2-fold risk was consistently evident in subgroup analyses by age, race, BMI at study entry, and regular exercise. There was an indication that a more than 5% increase in weight and/or waist circumference exerted a greater effect on the risk of a significant increase in blood pressure in females (adjusted RR=2.44) compared with males (adjusted RR=1.47); however, a formal test of interaction (differential effect) did not achieve statistical significance (P=.08).

Table 4. Relative Risk of a Significant Increase in Blood Pressure Attributed to 1-Year Increase in Weight and/or Waist Circumference of 5% or More
SubgroupNIncidence of BP IncreaseRRAdjusted RR⁎95% CIP Value
Weight/Waist Δ <5%Weight/Waist Δ ≥5%
All participants46616.8%36.0%2.142.091.35-3.21.001
Age at study entry
45-55 y18819.3%34.0%1.761.710.76-3.83.19
56-65 y20214.5%34.4%2.371.961.21-3.16.006
66-75 y7616.7%45.5%2.732.620.42-16.17.30
Gender
Male14220.5%26.7%1.301.470.75-2.92.26
Female32414.9%38.5%2.592.441.39-4.27.002
Race
White34015.4%31.1%2.021.901.02-3.54.04
Black11321.7%56.7%2.612.311.39-3.82.001
BMI at study entry
<3035614.3%32.4%2.262.251.27-4.00.006
≥3011025.0%47.1%1.881.610.96-2.71.07
Exercise/labor≥3 times/wk
No15019.6%35.4%1.812.101.22-3.63.007
Yes31115.3%37.1%2.422.251.19-4.23.01

BP=blood pressure; RR=relative risk; CI=confidence interval; BMI=body mass index.

⁎Adjusted for baseline systolic and diastolic blood pressure, age, gender, alcohol, body mass index, and Anger scale.

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Discussion 

Our results indicate that in a diverse community cohort of nonhypertensive individuals, baseline BMI and changes in weight and/or waist circumference over a 1-year period are independent predictors of a significant increase in blood pressure. These findings extend previous associations between weight and blood pressure5, 6 because they indicate that regardless of baseline BMI, increases in weight and/or waist circumference are independent predictors of increases in blood pressure over 1 year.

Hypertension, Prehypertension, and Cardiovascular Disease Risk 

Several longitudinal studies have demonstrated that people with high normal blood pressure are susceptible to developing hypertension, a primary risk factor in cardiovascular disease.4, 7, 8 On the basis of these observations, blood pressure classification was revised in 2003 creating a prehypertension category, defined as a systolic blood pressure between 120 and 139 mm Hg or a diastolic blood pressure between 80 and 89 mm Hg.1 This category includes people who were previously considered as having normal blood pressure under Joint National Committee VI criteria.9

Individuals with prehypertension tend to be older and have higher prevalences of anthropometric indices of obesity, such as higher BMI, increased waist circumference, and increased waist-hip ratio, compared with those with normal blood pressure.10, 11 Individuals with prehypertension also have a higher prevalence of diabetes, impaired fasting glucose, and less favorable lipid profiles, suggesting that insulin resistance is a common feature in this group.12, 13 Individuals with prehypertension have elevations in inflammatory markers such as C-reactive protein, serum amyloid-A, tumor necrosis factor-alpha, and fibrinogen compared with normotensive subjects.14, 15 Individuals with prehypertension have evidence of subclinical atherosclerosis,16, 17, 18 increased left ventricular mass,16, 19 and left ventricular diastolic dysfunction.19, 20 These observations support the concept that prehypertension is a pathologic state in the blood pressure continuum and suggest that studies should consider blood pressure as a continuous variable rather than a measured categoric value.

Predictors of Clinically Significant Increases in Blood Pressure 

Our study indicates that baseline BMI and 1-year changes in weight and/or waist circumference are independent predictors of clinically significant increases in systolic or diastolic blood pressure among individuals with normal blood pressure or prehypertension. Our definition of an increase in blood pressure over 1 year is clinically relevant because patients who exhibit this degree of blood pressure change will move from normal to prehypertension or from prehypertension to hypertension categories unless their initial blood pressure is less than 100/70 mm Hg. Previous studies have indicated epidemiologic long-term associations between obesity and hypertension.5, 6 Our results confirm these findings and demonstrate that high BMI is a short-term predictor of a significant increase in blood pressure. Our results indicate that small increases in weight and/or waist circumference are significant predictors of 1-year increases in blood pressure independently of baseline BMI, weight, or waist circumference. Therefore, these results suggest that increases in weight and/or waist circumferences are risk factors for blood pressure increases in individuals across the continuum of normal weight to obesity.

Our study did find that lower baseline systolic and diastolic blood pressures were associated with a higher incidence of a significant increase in blood pressure. An individual’s true blood pressure may reflect the mean of a series of longitudinal blood pressure measurements. Therefore, an individual with a lower baseline blood pressure measurement on a single occasion may regress to the mean with a higher blood pressure measurement later.

Clinical Implications of Weight Gain and Increases in Blood Pressure 

The Joint National Committee VII guidelines identify a group of individuals susceptible to developing hypertension who would benefit from lifestyle modification. The PREMIER trial demonstrated that a behavioral interventional program directed at patients with prehypertension or stage 1 hypertension can improve control of blood pressure and achieve weight loss.21 The successful interventions in the PREMIER trial included intensive counseling on weight loss, increase in moderate-intense physical activity of at least 180 minutes per week, reduction in dietary sodium, limitations in alcohol consumption, and adherence to the Dietary Approaches to Stop Hypertension diet.22 Our study serves to provide a mechanism to risk stratify individuals who may benefit from these types of interventions by simple measurement of baseline BMI and recent changes in weight or waist circumference. Moreover, our results also indicate that similar studies should be conducted to assess the effectiveness of behavioral modification strategies in nonhypertensive and nonobese individuals with recent changes in weight or waist circumference to prevent increases in blood pressure.

Limitations 

Our study’s sample size is smaller than that of previous studies on prehypertension and hypertension. Therefore, we may not have had sufficient power to detect other risk factors for smaller and less clinically relevant changes in blood pressure. Second, referral and volunteer biases may have enrolled a study cohort inherently interested in cardiovascular health, a possibility indicated by the low prevalence of smokers in our population. However, it should be noted that a high proportion of our “healthy volunteers” developed a clinically significant increase in blood pressure after only 1 year. Third, we did not use ambulatory blood pressure monitoring, which may be a more useful measure of blood pressure.23 However, most clinicians do not use this tool. Thus, our method of measuring blood pressure more closely resembles common clinical practice. Fourth, biological variability (eg, circadian variation) and potential error measurement in baseline to 1-year assessments of blood pressure may have occurred, with the most likely net consequence of underestimation of the true magnitude of associations. Finally, we can only comment on those variables that predict blood pressure increase over 1 year. Longer follow-up of the Heart SCORE cohort may reveal other variables associated with significant long-term blood pressure increases.

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Conclusion 

Our results demonstrate that baseline BMI and 1-year changes in weight and waist circumference are independent predictors of a clinically significant increase in blood pressure over 1 year among individuals without hypertension. Moreover, these variables remain predictive across race, gender, and all classes of BMI. These findings serve to stratify individuals who may benefit from close clinical observation and preventive intervention as published in previously conducted trials.21, 22

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 The authors have no conflict of interests to report.This project is funded in part by a grant with the Pennsylvania Department of Health (Contract ME-02-384). The department specifically disclaims responsibility for any analyses, interpretations, or conclusions.

PII: S0002-9343(07)00674-2

doi:10.1016/j.amjmed.2007.06.021

The American Journal of Medicine
Volume 120, Issue 11 , Pages 960-967, November 2007

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