Population heterogeneity in trajectories of midlife blood pressure

Blood Pressure Trajectories and Outcomes for Veterans Presenting at VA Medical Centers with a Stroke or Transient Ischemic Attack

BACKGROUND

Blood pressure control has been shown to reduce risk of vascular events and mortality after an ischemic stroke or transient ischemic attack (TIA). Yet, questions remain about effectiveness, timing, and targeted blood pressure reduction.

METHODS

We analyzed data from a retrospective cohort of 18,837 veterans cared for 12 months prior and up to 12 months after an emergency department visit or inpatient admission for stroke or TIA. Latent class growth analysis was used to classify patients into systolic blood pressure trajectories. With Cox proportional hazard models, we examined relationships between blood pressure trajectories, intensification of antihypertensive medication, and stroke (fatal or non-fatal) and all-cause mortality in 12 months following the index event.

RESULTS

The cohort was classified into 4 systolic blood pressure trajectories: 19% with a low systolic blood pressure trajectory (mean systolic blood pressure = 116 mm Hg); 65% with a medium systolic blood pressure trajectory (mean systolic blood pressure = 136 mm Hg); 15% with a high systolic blood pressure trajectory (mean systolic blood pressure = 158 mm Hg), and 1% with a very high trajectory (mean systolic blood pressure = 183 mm Hg). After the stroke or TIA, individuals in the high and very high systolic blood pressure trajectories experienced a substantial decrease in systolic blood pressure that coincided with intensification of antihypertensive medication. Patients with very low and very high systolic blood pressure trajectories had a significantly greater (P < .05) hazard of mortality, while medication intensification was related significantly (P < .05) to lower hazard of mortality.

CONCLUSIONS

These findings point to the importance of monitoring blood pressure over multiple time points and of instituting enhanced hypertension management after stroke or TIA, particularly for individuals with high or very high blood pressure trajectories.

Association of age and blood pressure among 3.3 million adults: insights from China PEACE million persons project

OBJECTIVE

To assess the association between blood pressure (BP) with age and its heterogeneity across various sociodemographic subgroups in China.

METHODS

In this cross-sectional study, we analysed the data from nearly 3.3 million individuals aged 35-75 years from all 31 provinces in mainland China collected from September 2014 through August 2019. On the basis of possible combinations of eight characteristics and antihypertensive status, subgroups of at least 10 000 individuals were created and the age--blood pressure relationship was determined for each group.

RESULTS

The study included 3 291 058 participants (59.6% women), with a mean age of 55.8 ± 9.8 years. The prevalence of hypertension was 47.6%, of which 30.0% were taking antihypertensive medications. The mean SBP was 135.9 ± 20.2 mmHg. SBP increased at a mean unadjusted rate of 0.639 ± 0.001 mmHg/year. For 95% of the 25 145 subgroups, the SBP increased by 0.28--0.85 mmHg/year. The most common characteristics in the subgroups with the steepest association were female sex, rural area, low education, low-income family, Tibet region, and farmer occupation. The increase in SBP ranged from 0.13 to 0.41 mmHg/year for 95% of the treated subgroups and from 0.33 to 0.82 mmHg/year for 95% of the untreated subgroups.

CONCLUSION

Blood pressure is positively associated with age in this study, with almost three-fold variation across subgroups, indicating subgroup differences in biology, behaviour, or exposures. Antihypertension strongly blunts the association of age and blood pressure and diminishes the variation.

Life-course blood pressure trajectories and cardiovascular diseases: A population-based cohort study in China

BACKGROUND

The patterns of blood pressure trajectory (i.e., change over time) over life-course remain to be explored. In this study, we aim to determine the trajectories of systolic blood pressure (SBP) from adulthood to late life and to assess its impact on the risk of cardiovascular diseases (CVDs).

METHODS

Based on the China Health and Nutrition Survey, a total of 3566 participants aged 20-50 years at baseline (1989) with at least three SBP measurements during 1989-2011 were included. SBP was measured through physical examination, and socio-demographic factors, lifestyles, medications, and CVDs were based on self-reported questionnaire. Latent class growth modeling was performed to examine SBP trajectory. Odds ratio (OR) and 95% confidence interval (CI) from logistic regression was used to determine the association between SBP trajectory and CVDs.

RESULTS

Five trajectory groups of SBP were identified: Class 1: rapid increase (n = 113, 3.2%); Class 2: slight increase (n = 1958, 54.9%); Class 3: stable (n = 614, 17.2%); Class 4: increase (n = 800, 22.4%); Class 5: fluctuant (n = 81, 2.3%). After adjustment of demographic factors, baseline SBP, and lifestyles, compared with the "slight increase" group, the OR (95% CI) of CVDs was 0.65 (0.32, 1.28) for "stable" group, 2.24 (1.40, 3.58) for "increase" group, 3.95 (1.81, 8.62) for "rapid increase" group, and 4.32 (1.76, 10.57) for "fluctuant" group. After stratified by use of antihypertensive drugs, the association was only significant for "rapid increase" group among those using antihypertensive drugs with OR (95% CI) of 2.81 (1.01, 7.77).

CONCLUSIONS

Having a rapidly increasing SBP over life-course is associated with a higher risk of CVDs. This implies the importance of monitoring lifetime change of blood pressure for the prevention of CVDs.

Role of Vascular Adaptation in Determining Systolic Blood Pressure in Young Adults

Background

Two individuals can have a similar pulse pressure (PP) but different levels of systolic blood pressure (SBP), although the underlying mechanisms have not been described. We hypothesized that, for a given level of PP, differences in SBP relate to peripheral vascular resistance (PVR); and we tested this hypothesis in a large cohort of healthy young adults.

Methods and Results

Demographic, biochemical, and hemodynamic data from 3103 subjects were available for the current analyses. In both men and women, for a given level of PP, higher SBP was associated with significantly higher body weight, body mass index, heart rate, and PVR (P<0.05 versus those with lower BP for all comparisons). Moreover, stratifying individuals by quartiles of PP and PVR revealed a stepwise increase in SBP from the lowest to highest quartile for each variable, with the highest SBP occurring in those in the highest quartile of both PP and PVR (P<0.001 for overall trend for both sexes). PVR was also increased with increasing tertile of minimum forearm vascular resistance, in both men (P=0.002) and women (P=0.03).

Conclusions

Increased PVR, mediated in part through altered resistance vessel structure, strongly associates with the elevation of SBP for a given level of PP in young adults. An impaired ability to adapt PVR appropriately to a given level of PP may be an important mechanism underlying elevated SBP in young adults.

Short- and long-term systolic blood pressure changes have different impacts on major adverse cardiovascular events: Results from a 12.5 years follow-up study

BACKGROUND

Systolic blood pressure increased in middle-aged person contributes significantly to the risk of major adverse cardiovascular events (MACE). Meanwhile, different patterns (short- or long-term change) of SBP increase may result in differential risk and lead to differences in predictive ability.

METHODS

A total of 19,544 and 22,610 participants in the Fuxin Cardiovascular Cohort Study underwent measurement of SBP at 2 examinations for short- and long-term change study population. Cox proportional hazards models were used to relate future clinical outcomes with change in SBP.

RESULTS

During a median follow-up period of 12.5 years, 1064 (772 stroke, 247 myocardial infarction, 528 CVD deaths) and 1316 (958 stroke, 301 myocardial infarction, 660 CVD deaths) MACE were identified during short- and long-terms SBP change, respectively. For SBP increased participants, short-term change in SBP was associated with future MACE (hazard ratio [HR]: 1.241 per 1-SD increase; 95% confidence interval [CI]: 1.146-1.344; P < 0.001), long-term change in SBP (HR: 1.218; 95% CI: 1.123-1.322; P < 0.001). For prehypertension participants, long-term changes conferred a strong impact than short-term. For hypertensive participants, short-term changes conferred a strong impact than long-term.

CONCLUSIONS

Having a SBP rise in short- or long-term both confer an increased risk of MACE and its subgroups. Furthermore, short- and long-term SBP increase patterns adds different additional information beyond one single baseline examination. Change in SBP may be a prognostic surrogate marker and future studies are needed to clarify the possible mechanism for predicting MACE.

Isolated systolic hypertension in the young: a position paper endorsed by the European Society of Hypertension

: Whether isolated systolic hypertension in the young (ISHY) implies a worse outcome and needs antihypertensive treatment is still a matter for dispute. ISHY is thought to have different mechanisms than systolic hypertension in the elderly. However, findings from previous studies have provided inconsistent results. From the analysis of the literature, two main lines of research and conceptualization have emerged. Simultaneous assessment of peripheral and central blood pressure led to the identification of a condition called pseudo or spurious hypertension, which was considered an innocent condition. However, an increase in pulse wave velocity has been found by some authors in about 20% of the individuals with ISHY. In addition, obesity and metabolic disturbances have often been documented to be associated with ISHY both in children and young adults. The first aspect to consider whenever evaluating a person with ISHY is the possible presence of white-coat hypertension, which has been frequently found in this condition. In addition, assessment of central blood pressure is useful for identifying ISHY patients whose central blood pressure is normal. ISHY is infrequently mentioned in the guidelines on diagnosis and treatment of hypertension. According to the 2013 European Guidelines on the management of hypertension, people with ISHY should be followed carefully, modifying risk factors by lifestyle changes and avoiding antihypertensive drugs. Only future clinical trials will elucidate if a benefit can be achieved with pharmacological treatment in some subgroups of ISHY patients with associated risk factors and/or high central blood pressure.

Long-Term Exposure to Elevated Systolic Blood Pressure in Predicting Incident Cardiovascular Disease: Evidence From Large-Scale Routine Electronic Health Records

Background

How measures of long‐term exposure to elevated blood pressure might add to the performance of “current” blood pressure in predicting future cardiovascular disease is unclear. We compared incident cardiovascular disease risk prediction using past, current, and usual systolic blood pressure alone or in combination.

Methods and Results

Using data from UK primary care linked electronic health records, we applied a landmark cohort study design and identified 80 964 people, aged 50 years (derivation cohort=64 772; validation cohort=16 192), who, at study entry, had recorded blood pressure, no prior cardiovascular disease, and no previous antihypertensive or lipid‐lowering prescriptions. We used systolic blood pressure recorded up to 10 years before baseline to estimate past systolic blood pressure (mean, time‐weighted mean, and variability) and usual systolic blood pressure (correcting current values for past time‐dependent blood pressure fluctuations) and examined their prospective relation with incident cardiovascular disease (first hospitalization for or death from coronary heart disease or stroke/transient ischemic attack). We used Cox regression to estimate hazard ratios and applied Bayesian analysis within a machine learning framework in model development and validation. Predictive performance of models was assessed using discrimination (area under the receiver operating characteristic curve) and calibration metrics. We found that elevated past, current, and usual systolic blood pressure values were separately and independently associated with increased incident cardiovascular disease risk. When used alone, the hazard ratio (95% credible interval) per 20–mm Hg increase in current systolic blood pressure was 1.22 (1.18–1.30), but associations were stronger for past systolic blood pressure (mean and time‐weighted mean) and usual systolic blood pressure (hazard ratio ranging from 1.39–1.45). The area under the receiver operating characteristic curve for a model that included current systolic blood pressure, sex, smoking, deprivation, diabetes mellitus, and lipid profile was 0.747 (95% credible interval, 0.722–0.811). The addition of past systolic blood pressure mean, time‐weighted mean, or variability to this model increased the area under the receiver operating characteristic curve (95% credible interval) to 0.750 (0.727–0.811), 0.750 (0.726–0.811), and 0.748 (0.723–0.811), respectively, with all models showing good calibration. Similar small improvements in area under the receiver operating characteristic curve were observed when testing models on the validation cohort, in sex‐stratified analyses, or by using different landmark ages (40 or 60 years).

Conclusions

Using multiple blood pressure recordings from patients’ electronic health records showed stronger associations with incident cardiovascular disease than a single blood pressure measurement, but their addition to multivariate risk prediction models had negligible effects on model performance.

See Editorial Ahmad and Oparil

Blood Pressure Trajectories From Childhood to Young Adulthood Associated With Cardiovascular Risk: Results From the 23-Year Longitudinal Georgia Stress and Heart Study

The purpose of this study is to identify subgroups of individuals with similar trajectories in blood pressure (BP) from childhood to young adulthood and to determine the relationship of BP trajectories with carotid intima-media thickness (IMT) and left ventricular mass index (LVMI). BP was measured ≤16 times during a 23-year period in 683 participants from childhood to young adulthood. IMT and LVMI were measured in 551 participants and 546 participants, respectively. Using latent class models, 3 trajectory groups in BP from childhood to young adulthood were identified, including high-increasing, moderate-increasing, and low-increasing groups. We found that trajectory of systolic BP was a significant predictor of both IMT and LVMI with increased rate of growth in systolic BP associated with higher levels of IMT and LVMI (P_{for trend} <0.001). Similar to the BP trajectory groups from childhood to young adulthood, 3 trajectory groups in BP during childhood (≤18 years) were identified, and participants in the high-increasing group had thicker IMT (P<0.001) and increased LVMI (P=0.043) in comparison with those in the low-increasing group. Results were similar for mid-BP trajectories but not for diastolic BP trajectories. Our results suggested that different BP trajectories exist from childhood to young adulthood, and the trajectories were independently associated with IMT and LVMI. We, for the first time, reported the association between systolic BP trajectories derived from childhood with subclinical cardiovascular risk in young adulthood, indicating that monitoring trajectories of BP from childhood may help identify a high cardiovascular risk population in early life.

A statistical model to describe longitudinal and correlated metabolic risk factors: the Whitehall II prospective study

Background

Novel epidemiology models are required to link correlated variables over time, especially haemoglobin A1c (HbA1c) and body mass index (BMI) for diabetes prevention policy analysis. This article develops an epidemiology model to correlate metabolic risk factor trajectories.

Method

BMI, fasting plasma glucose, 2-h glucose, HbA1c, systolic blood pressure, total cholesterol and high density lipoprotein (HDL) cholesterol were analysed over 16 years from 8150 participants of the Whitehall II prospective cohort study. Latent growth curve modelling was employed to simultaneously estimate trajectories for multiple metabolic risk factors allowing for variation between individuals. A simulation model compared simulated outcomes with the observed data.

Results

The model identified that the change in BMI was associated with changes in glycaemia, total cholesterol and systolic blood pressure. The statistical analysis quantified associations among the longitudinal risk factor trajectories. Growth in latent glycaemia was positively correlated with systolic blood pressure and negatively correlated with HDL cholesterol. The goodness-of-fit analysis indicates reasonable fit to the data.

Conclusions

This is the first statistical model that estimates trajectories of metabolic risk factors simultaneously for diabetes to predict joint correlated risk factor trajectories. This can inform comparisons of the effectiveness and cost-effectiveness of preventive interventions, which aim to modify metabolic risk factors.

Association Between Early Life Growth and Blood Pressure Trajectories in Black South African Children

Early growth is associated with blood pressure measured on one occasion, but whether early life growth patterns are associated with longitudinal blood pressure trajectories is under-researched. Therefore, we sought to examine the association between early growth and blood pressure trajectories from childhood to adulthood. Blood pressure was measured on 7 occasions between ages 5 and 18 years in the Birth to Twenty cohort study, and conditional variables for growth in infancy and mid-childhood were computed from anthropometric measures (n=1937, 52% girls). We used a group-based trajectory modeling approach to identify distinct height-adjusted blood pressure trajectories and then tested their association with growth between birth and mid-childhood adjusting for several covariates. Three trajectory groups were identified for systolic and diastolic blood pressure: lower, middle, and upper in boys and girls, separately. In boys, predictors of the middle or upper systolic blood pressure trajectories versus the lower trajectory were in birth weight (odds ratio 0.75 [95% confidence interval 0.58-0.96] per SD) and relative weight gain in infancy (4.11 [1.25-13.51] per SD). In girls, greater relative weight gain and linear growth in both infancy and mid-childhood were consistently associated with an almost 2-fold higher likelihood of being in the upper versus lower systolic blood pressure trajectory. The associations for the diastolic blood pressure trajectories were inconsistent. These findings emphasize the importance of identifying children at risk of progression to high blood pressure. Accelerated growth in infancy and mid-childhood may be a key target for early life intervention in prevention of elevated blood pressure progression.

Prehypertension During Normotensive Pregnancy and Postpartum Clustering of Cardiometabolic Risk Factors: A Prospective Cohort Study

The nonstratification of blood pressure (BP) levels may underestimate future cardiovascular risk in pregnant women who present with BP levels in the range of prehypertension (120-139/80-89 mm Hg). We prospectively evaluated the relationship between multiple antepartum BP measurements (from 11(+0) to 13(+6) weeks' gestation to term) and the occurrence of postpartum metabolic syndrome in 507 normotensive pregnant women after a live birth. By using latent class growth modeling, we identified the following 3 distinctive diastolic BP (DBP) trajectory groups: the low-J-shaped group (34.2%; DBP from 62.5±5.8 to 65.0±6.8 mm Hg), the moderate-U-shaped group (52.6%; DBP from 71.0±5.9 to 69.8±6.2 mm Hg), and the elevated-J-shaped group (13.2%; DBP from 76.2±6.7 to 81.8±4.8 mm Hg). Notably, the elevated-J-shaped trajectory group had mean DBP and systolic BP levels within the range of prehypertension from 37(+0) and 26(+0) weeks of pregnancy, respectively. Among the 309 women who completed the ≈1.6 years of postpartum follow-up, the women in the elevated-J-shaped group had greater odds of developing postpartum metabolic syndrome (adjusted odds ratio, 6.55; 95% confidence interval, 1.79-23.92; P=0.004) than the low-J-shaped group. Moreover, a parsimonious model incorporating DBP (membership in the elevated-J-shaped group but not in the DBP prehypertension group as identified by a single measurement) and elevated levels of fasting glucose (>4.99 mmol/L) and triglycerides (>3.14 mmol/L) at term was developed, with good discrimination and calibration for postpartum metabolic syndrome (c-statistic, 0.764; 95% confidence interval, 0.674-0.855; P<0.001). Therefore, prehypertension identified by DBP trajectories throughout pregnancy is an independent risk factor for predicting postpartum metabolic syndrome in normotensive pregnant women.

Longitudinal Patterns of Change in Systolic Blood Pressure and Incidence of Cardiovascular Disease: The Atherosclerosis Risk in Communities Study

Elevated blood pressure in midlife contributes significantly to the risk of cardiovascular disease. However, patterns of blood pressure increase may differ among individuals and may result in differential risk. Our goal was to examine the contribution of longitudinal patterns of blood pressure change to incidence of heart failure, coronary heart disease, stroke, and cardiovascular disease mortality. Latent class growth models were used to identify patterns of change in blood pressure across 4 clinical examinations (1987-1998) among 9845 Atherosclerosis Risk in Communities (ARIC) cohort participants (mean age, 53.7 [SD 5.7] years). Patterns of change in systolic blood pressure included slowly and steeply increasing, a decreasing and a sustained elevated blood pressure. Changes in diastolic and mid-blood pressure (½ systolic+½ diastolic) were less pronounced. The association of blood pressure pattern group membership with incidence of clinical outcomes was examined in follow-up from the fourth clinical examination (1996-1998) to December 31, 2011, using Poisson regression models adjusted for demographic and metabolic characteristics, and hypertension medication use. A gradient of rates of all events was observed across the identified patterns. Associations were attenuated after adjustment for covariates. Cumulative systolic blood pressure load, rather than the temporal pattern of change in systolic blood pressure itself, plays a role in determining the risk of cardiovascular disease, in particular, of heart failure and cardiovascular disease mortality, independent of blood pressure level measured at one point in time.

Childhood to Early-Midlife Systolic Blood Pressure Trajectories: Early-Life Predictors, Effect Modifiers, and Adult Cardiovascular Outcomes

Previous studies examining blood pressure change over time have modeled an average population trajectory. Recent research among older adults suggests there may be subgroups with different blood pressure trajectories. Identifying subgroups at risk of developing adult hypertension early in life can inform effective risk reduction efforts. We sought to identify different systolic blood pressure trajectories from childhood, their correlated risk factors, and early-midlife cardiovascular outcomes. Blood pressure data at ages 7, 11, 18, 26, 32, and 38 years from a longitudinal, representative birth cohort study (n=975) were used to identify 4 distinct trajectory groups via group-based trajectory modeling: normal (21.8%), high-normal (43.3%), prehypertensive (31.6%), and hypertensive (4.2%). The categories refer to blood pressure beginning at the age of 7 years and most recently measured at the age of 38 years. Family history of high blood pressure (odds ratio [OR], 43.23; 95% confidence interval [CI], 5.27-354.65), male sex (OR, 109.48; 95% CI, 26.82-446.96), being first born (OR, 2.5; 95% CI, 1.00-8.69) and low birth weight (OR, 2.79; 95% CI, 2.49-3.09) were associated with hypertensive group membership (compared with the normal group). Higher body mass index and cigarette smoking resulted in increasing blood pressure across trajectories, particularly for the higher blood pressure groups. Prehypertensive and hypertensive trajectory groups had worse cardiovascular outcomes by early midlife. Harmful blood pressure trajectories are identifiable in childhood, associated with both antecedent and modifiable risk factors over time, and predict adult cardiovascular disease risk. Early detection and subsequent targeted prevention and intervention may reduce the lifecourse burden associated with higher blood pressure.

Using Web-Based Questionnaires and Obstetric Records to Assess General Health Characteristics Among Pregnant Women: A Validation Study

Background

Self-reported medical history information is included in many studies. However, data on the validity of Web-based questionnaires assessing medical history are scarce. If proven to be valid, Web-based questionnaires may provide researchers with an efficient means to collect data on this parameter in large populations.

Objective

The aim of this study was to assess the validity of a Web-based questionnaire on chronic medical conditions, allergies, and blood pressure readings against obstetric records and data from general practitioners.

Methods

Self-reported questionnaire data were compared with obstetric records for 519 pregnant women participating in the Dutch PRegnancy and Infant DEvelopment (PRIDE) Study from July 2011 through November 2012. These women completed Web-based questionnaires around their first prenatal care visit and in gestational weeks 17 and 34. We calculated kappa statistics (κ) and the observed proportions of positive and negative agreement between the baseline questionnaire and obstetric records for chronic conditions and allergies. In case of inconsistencies between these 2 data sources, medical records from the woman’s general practitioner were consulted as the reference standard. For systolic and diastolic blood pressure, intraclass correlation coefficients (ICCs) were calculated for multiple data points.

Results

Agreement between the baseline questionnaire and the obstetric record was substantial (κ=.61) for any chronic condition and moderate for any allergy (κ=.51). For specific conditions, we found high observed proportions of negative agreement (range 0.88-1.00) and on average moderate observed proportions of positive agreement with a wide range (range 0.19-0.90). Using the reference standard, the sensitivity of the Web-based questionnaire for chronic conditions and allergies was comparable to or even better than the sensitivity of the obstetric records, in particular for migraine (0.90 vs 0.40, P=.02), asthma (0.86 vs 0.61, P=.04), inhalation allergies (0.92 vs 0.74, P=.003), hay fever (0.90 vs 0.64, P=.001), and allergies to animals (0.89 vs 0.53, P=.01). However, some overreporting of allergies was observed in the questionnaire and for some nonsomatic conditions sensitivity of both measurement instruments was low. The ICCs for blood pressure readings ranged between 0.72 and 0.92 with very small mean differences between the 2 methods of data collection.

Conclusions

Web-based questionnaires can be used to validly collect data on many chronic disorders, allergies, and blood pressure readings among pregnant women.

Effects of cardiorespiratory fitness on blood pressure trajectory with aging in a cohort of healthy men

BACKGROUND

Although the trajectory of blood pressure (BP) with aging is well known, there is a lack of data on how cardiorespiratory fitness (hereafter referred to as fitness) affects age-associated changes in BP.

OBJECTIVES

The objective of the study was to investigate whether fitness alters the aging-BP trajectory.

METHODS

A cohort from the Aerobics Center Longitudinal Study totaling 13,953 men between 20 and 90 years of age who did not have hypertension, cardiovascular disease, or cancer completed 3 to 28 (mean of 3.8) follow-up medical examinations between 1970 and 2006. Fitness was measured by a maximal treadmill exercise test. Longitudinal data were analyzed using linear mixed models.

RESULTS

Diastolic blood pressure (DBP) tended to increase until nearly 60 years of age, when a decrease was observed. Systolic blood pressure (SBP) tended to increase over all age periods. On multivariate analysis, average SBP increased by 0.30 mm Hg (95% confidence interval: 0.29 to 0.31) with 1-year age increment after adjusting for body fat percent, fitness, resting heart rate, glucose level, triglyceride level, cholesterol level, current smoking, heavy alcohol consumption, and parental history of hypertension. DBP had a yearly increase of 0.14 mm Hg (95% confidence interval: 0.13 to 0.15) before age 60 years. Overall, abnormal SBP (>120 mm Hg) began to occur at approximately 50 years of age and abnormal DBP (>80 mm Hg) began to occur at 60 years of age. Men with higher fitness levels experienced abnormal SBP later than those with low fitness levels.

CONCLUSIONS

Our findings underscore the potential modifying effect of fitness on BP trajectory with aging over the male adult life span. Improving fitness levels might extend the normal SBP and DBP ranges, delaying the development of hypertension.

Preventing vascular effects on brain injury and cognition late in life: knowns and unknowns

For some researchers, the relationship between prevalent cardiovascular risk factors and late-life cognitive decline is not worthy of further study. It is already known that effective treatment of vascular risk factors lowers risk of such major outcomes as stroke and heart attack, the argument goes; thus, any new information about the relationship between vascular risk factors and another major outcome--late-life cognitive decline--is unlikely to have an impact on clinical practice. The purpose of this review is to probe the logic of this argument by focusing on what is known, and what is not known, about the relationship between vascular risk factors and late-life cognitive decline. The unknowns are substantial: in particular, there is relatively little evidence that current vascular risk factor treatment protocols are adequate to prevent late-life cognitive decline or the clinically silent brain injury that precedes it. In addition, there is relatively little understanding of which factors lead to differential vulnerability or resilience to the effects of vascular risk factors on silent brain injury. Differential effects of different classes of treatments are similarly unclear. Finally, there is limited understanding of the impact of clinically-silent neurodegenerative disease processes on cerebrovascular processes. Further study of the relationships among vascular risk factors, brain injury, and late-life cognitive decline could have a major impact on development of new vascular therapies and on clinical management of vascular risk factors, and there are promising avenues for future research in this direction.

Blood pressure and incidence of twelve cardiovascular diseases: lifetime risks, healthy life-years lost, and age-specific associations in 1·25 million people

BACKGROUND

The associations of blood pressure with the different manifestations of incident cardiovascular disease in a contemporary population have not been compared. In this study, we aimed to analyse the associations of blood pressure with 12 different presentations of cardiovascular disease.

METHODS

We used linked electronic health records from 1997 to 2010 in the CALIBER (CArdiovascular research using LInked Bespoke studies and Electronic health Records) programme to assemble a cohort of 1·25 million patients, 30 years of age or older and initially free from cardiovascular disease, a fifth of whom received blood pressure-lowering treatments. We studied the heterogeneity in the age-specific associations of clinically measured blood pressure with 12 acute and chronic cardiovascular diseases, and estimated the lifetime risks (up to 95 years of age) and cardiovascular disease-free life-years lost adjusted for other risk factors at index ages 30, 60, and 80 years. This study is registered at ClinicalTrials.gov, number NCT01164371.

FINDINGS

During 5·2 years median follow-up, we recorded 83,098 initial cardiovascular disease presentations. In each age group, the lowest risk for cardiovascular disease was in people with systolic blood pressure of 90-114 mm Hg and diastolic blood pressure of 60-74 mm Hg, with no evidence of a J-shaped increased risk at lower blood pressures. The effect of high blood pressure varied by cardiovascular disease endpoint, from strongly positive to no effect. Associations with high systolic blood pressure were strongest for intracerebral haemorrhage (hazard ratio 1·44 [95% CI 1·32-1·58]), subarachnoid haemorrhage (1·43 [1·25-1·63]), and stable angina (1·41 [1·36-1·46]), and weakest for abdominal aortic aneurysm (1·08 [1·00-1·17]). Compared with diastolic blood pressure, raised systolic blood pressure had a greater effect on angina, myocardial infarction, and peripheral arterial disease, whereas raised diastolic blood pressure had a greater effect on abdominal aortic aneurysm than did raised systolic pressure. Pulse pressure associations were inverse for abdominal aortic aneurysm (HR per 10 mm Hg 0·91 [95% CI 0·86-0·98]) and strongest for peripheral arterial disease (1·23 [1·20-1·27]). People with hypertension (blood pressure ≥140/90 mm Hg or those receiving blood pressure-lowering drugs) had a lifetime risk of overall cardiovascular disease at 30 years of age of 63·3% (95% CI 62·9-63·8) compared with 46·1% (45·5-46·8) for those with normal blood pressure, and developed cardiovascular disease 5·0 years earlier (95% CI 4·8-5·2). Stable and unstable angina accounted for most (43%) of the cardiovascular disease-free years of life lost associated with hypertension from index age 30 years, whereas heart failure and stable angina accounted for the largest proportion (19% each) of years of life lost from index age 80 years.

INTERPRETATION

The widely held assumptions that blood pressure has strong associations with the occurrence of all cardiovascular diseases across a wide age range, and that diastolic and systolic associations are concordant, are not supported by the findings of this high-resolution study. Despite modern treatments, the lifetime burden of hypertension is substantial. These findings emphasise the need for new blood pressure-lowering strategies, and will help to inform the design of randomised trials to assess them.

FUNDING

Medical Research Council, National Institute for Health Research, and Wellcome Trust.

Blood pressure trajectories in early adulthood and subclinical atherosclerosis in middle age

IMPORTANCE

Single measures of blood pressure (BP) levels are associated with the development of atherosclerosis; however, long-term patterns in BP and their effect on cardiovascular disease risk are poorly characterized.

OBJECTIVES

To identify common BP trajectories throughout early adulthood and to determine their association with presence of coronary artery calcification (CAC) during middle age.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort data from 4681 participants in the CARDIA study, who were black and white men and women aged 18 to 30 years at baseline in 1985-1986 at 4 urban US sites, collected through 25 years of follow-up (2010-2011). We examined systolic BP, diastolic BP, and mid-BP (calculated as [SBP+DBP]/2, an important marker of coronary heart disease risk among younger populations) at baseline and years 2, 5, 7, 10, 15, 20, and 25. Latent mixture modeling was used to identify trajectories in systolic, diastolic, and mid-BP over time.

MAIN OUTCOMES AND MEASURES

Coronary artery calcification greater than or equal to Agatston score of 100 Hounsfield units (HU) at year 25.

RESULTS

We identified 5 distinct mid-BP trajectories: low-stable (21.8%; 95% CI, 19.9%-23.7%; n=987), moderate-stable (42.3%; 40.3%-44.3%; n=2085), moderate-increasing (12.2%; 10.4%-14.0%; n=489), elevated-stable (19.0%; 17.1%-20.0%; n=903), and elevated-increasing (4.8%; 4.0%-5.5%; n=217). Compared with the low-stable group, trajectories with elevated BP levels had greater odds of having a CAC score of 100 HU or greater. Adjusted odds ratios were 1.44 (95% CI, 0.83-2.49) for moderate-stable, 1.86 (95% CI, 0.91-3.82) for moderate-increasing, 2.28 (95% CI, 1.24-4.18), for elevated-stable, and 3.70 (95% CI, 1.66-8.20) for elevated-increasing groups. The adjusted prevalence of a CAC score of 100 HU or higher was 5.8% in the low-stable group. These odds ratios represent an absolute increase of 2.7%, 5%, 6.3%, and 12.9% for the prevalence of a CAC score of 100 HU or higher for the moderate-stable, moderate-increasing, elevated-stable and elevated-increasing groups, respectively, compared with the low-stable group. Associations were not altered after adjustment for baseline and year 25 BP. Findings were similar for trajectories of isolated systolic BP trajectories but were attenuated for diastolic BP trajectories.

CONCLUSIONS AND RELEVANCE

Blood pressure trajectories throughout young adulthood vary, and higher BP trajectories were associated with an increased risk of CAC in middle age. Long-term trajectories in BP may assist in more accurate identification of individuals with subclinical atherosclerosis.

Cognitive and kidney function: results from a British birth cohort reaching retirement age

BACKGROUND

Previous studies have found associations between cognitive function and chronic kidney disease. We aimed to explore possible explanations for this association in the Medical Research Council National Survey of Health and Development, a prospective birth cohort representative of the general British population.

METHODS

Cognitive function at age 60-64 years was quantified using five measures (verbal memory, letter search speed and accuracy, simple and choice reaction times) and glomerular filtration rate (eGFR) at the same age was estimated using cystatin C. The cross-sectional association between cognitive function and eGFR was adjusted for background confounding factors (socioeconomic position, educational attainment), prior cognition, and potential explanations for any remaining association (smoking, diabetes, hypertension, inflammation, obesity).

RESULTS

Data on all the analysis variables were available for 1306-1320 study members (depending on cognitive measure). Verbal memory and simple and choice reaction times were strongly associated with eGFR. For example, the lowest quartile of verbal memory corresponded to a 4.1 (95% confidence interval 2.0, 6.2) ml/min/1.73 m(2) lower eGFR relative to the highest quartile. Some of this association was explained by confounding due to socioeconomic factors, but very little of it by prior cognition. Smoking, diabetes, hypertension, inflammation and obesity explained some but not all of the remaining association.

CONCLUSIONS

These analyses support the notion of a shared pathophysiology of impaired cognitive and kidney function at older age, which precedes clinical disease. The implications of these findings for clinical care and research are important and under-recognised, though further confirmatory studies are required.

Early-life overweight trajectory and CKD in the 1946 British birth cohort study

BACKGROUND

Few studies have examined the impact of childhood obesity on later kidney disease, and consequently, our understanding is very limited.

STUDY DESIGN

Longitudinal population-based cohort.

SETTING & PARTICIPANTS

The Medical Research Council National Survey of Health and Development, a socially stratified sample of 5,362 singletons born in 1 week in March 1946 in England, Scotland, and Wales, of which 4,340 were analyzed.

PREDICTOR

Early-life overweight latent classes (never, prepubertal only, pubertal onset, or always), derived from repeated measurements of body mass index between ages 2 and 20 years.

OUTCOMES & MEASUREMENTS

The primary outcome was chronic kidney disease (CKD), defined as creatinine- or cystatin C-based estimated glomerular filtration rate (eGFRcr and eGFRcys, respectively) <60 mL/min/1.73 m² or urine albumin-creatinine ratio (UACR) ≥3.5 mg/mmol measured at age 60-64 years. Associations were explored through regression analysis, with adjustment for socioeconomic position, smoking, physical activity level, diabetes, hypertension, and overweight at ages 36 and 53 years.

RESULTS

2.3% of study participants had eGFRcr <60 mL/min/1.73 m², 1.7% had eGFRcys <60 mL/min/1.73 m², and 2.9% had UACR ≥3.5 mg/mmol. Relative to being in the never-overweight latent class, being in the pubertal-onset- or always-overweight latent classes was associated with eGFRcys-defined CKD (OR, 2.04; 95% CI, 1.09-3.82). Associations with CKD defined by eGFRcr (OR, 1.27; 95% CI, 0.71-2.29) and UACR (OR, 1.33; 95% CI, 0.70-2.54) were less marked, but in the same direction. Adjustment for lifestyle and health factors had little impact on effect estimates.

LIMITATIONS

A low prevalence of CKD resulted in low statistical power. No documentation of chronicity for outcomes. All-white study population restricts generalizability.

CONCLUSIONS

Being overweight in early life was found to be associated with eGFRcys-defined CKD in later life. The associations with CKD defined by eGFRcr and UACR were less marked, but in the same direction. Reducing or preventing overweight in the early years of life may significantly reduce the burden of CKD in the population.

Low birth weight, later renal function, and the roles of adulthood blood pressure, diabetes, and obesity in a British birth cohort

Low birth weight has been shown to be associated with later renal function, but it is unclear to what extent this is explained by other established kidney disease risk factors. Here we investigate the roles of diabetes, hypertension, and obesity using data from the Medical Research Council National Survey of Health and Development, a socially stratified sample of 5362 children born in March 1946 in England, Scotland, and Wales, and followed since. The birth weight of 2192 study members with complete data was related to three markers of renal function at age 60-64 (estimated glomerular filtration rate (eGFR) calculated using cystatin C (eGFRcys), eGFR calculated using creatinine and cystatin C (eGFRcr-cys), and the urine albumin-creatinine ratio) using linear regression. Each 1 kg lower birth weight was associated with a 2.25 ml/min per 1.73 m(2) (95% confidence interval 0.80-3.71) lower eGFRcys and a 2.13 ml/min per 1.73 m(2) (0.69-3.58) lower eGFRcr-cys. There was no evidence of an association with urine albumin-creatinine ratio. These associations with eGFR were not confounded by socioeconomic position and were not explained by diabetes or hypertension, but there was some evidence that they were stronger in study members who were overweight in adulthood. Thus, our findings highlight the role of lower birth weight in renal disease and suggest that in those born with lower birth weight particular emphasis should be placed on avoiding becoming overweight.

Association between younger age when first overweight and increased risk for CKD

There is little information on how the duration of overweight or obesity during life affects the risk for CKD. To investigate whether prolonged exposure to overweight during adult life increases the risk of later CKD in a cumulative manner, we analyzed data from the Medical Research Council National Survey of Health and Development, a socially stratified sample of 5362 singleton children born in 1 week in March 1946 in England, Scotland, and Wales. Multiple imputation expanded the analysis sample from the initial 1794 participants with complete data to 4584. This study collected self-reported body mass index (BMI) at ages 20 and 26 years and measured BMI at ages 36, 43, 53, and 60-64 years. The outcome of interest was CKD at age 60-64 years, suggested by estimated GFR (eGFR) <60 ml/min per 1.73 m(2) and/or urine albumin-to-creatinine ratio (UACR) ≥ 3.5 mg/mmol. In analyses adjusted for childhood and adulthood social class, first becoming overweight at younger ages was associated with higher odds of developing CKD by age 60-64 years. Compared with those who first became overweight at age 60-64 years or never became overweight, those first overweight at age 26 or 36 years had approximately double the odds of developing CKD. The strength of this association decreased with increasing age when first overweight (P for trend <0.001). These associations were consistent for creatinine-based eGFR, cystatin C-based eGFR, and UACR. Taken together, these results suggest that preventing overweight in early adulthood may have a considerable effect on the prevalence of CKD in the population.