Trends and determinant factors for population blood pressure with 25 years of follow-up: results from the Copenhagen City Heart Study

Secular trends in risk of stroke according to body mass index and blood pressure, 1976–2017

Objective

To test the hypothesis that the associations of body mass index (BMI) and BMI-related risk factors with risk of stroke have attenuated over time using cohorts recruited from the general population over 4 decades.

Methods

We undertook prospective studies of 2 cohorts enrolled in 1976 to 1978 (13,567 participants from the Copenhagen City Heart Study) and 2003 to 2015 (107,040 participants from the Copenhagen General Population Study). Each cohort was recruited randomly from the Danish general population 20 to 100 years of age. Participants were followed up from the date of examination to date of emigration, death, or stroke event, whichever occurred first. Follow-up ended in March 2017. We did not lose track of any individual. BMI and blood pressure were modeled with splines and in categories. Main outcome was incident stroke, including ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage.

Results

The crude incidence of stroke declined in extreme categories of BMI and blood pressure from 1977 to 2017. The multivariable-adjusted hazard ratios for stroke in participants with BMI ≥30 vs 18.5 to 24.9 kg/m2 were 1.4 (95% confidence interval 1.2–1.6) in the 1976–1978 cohort and 1.1 (1.0–1.2) in the 2003–2015 cohort (p = 0.008 for 1976–1978 vs 2003–2015). The corresponding hazard ratios (confidence intervals) in participants with blood pressure ≥160/100 vs <140/90 mm Hg were 2.1 (1.9–2.3) and 1.5 (1.4–1.7), respectively (p < 0.001). Similar secular trends were observed for diabetes mellitus but were not obvious for other risk factors.

Conclusion

The associations of high BMI and high blood pressure with higher risk of stroke were attenuated across 2 Danish cohorts enrolled from 1976 through 2015.

Worldwide trends in blood pressure from 1975 to 2015: a pooled analysis of 1479 population-based measurement studies with 19·1 million participants

BACKGROUND

Raised blood pressure is an important risk factor for cardiovascular diseases and chronic kidney disease. We estimated worldwide trends in mean systolic and mean diastolic blood pressure, and the prevalence of, and number of people with, raised blood pressure, defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher.

METHODS

For this analysis, we pooled national, subnational, or community population-based studies that had measured blood pressure in adults aged 18 years and older. We used a Bayesian hierarchical model to estimate trends from 1975 to 2015 in mean systolic and mean diastolic blood pressure, and the prevalence of raised blood pressure for 200 countries. We calculated the contributions of changes in prevalence versus population growth and ageing to the increase in the number of adults with raised blood pressure.

FINDINGS

We pooled 1479 studies that had measured the blood pressures of 19·1 million adults. Global age-standardised mean systolic blood pressure in 2015 was 127·0 mm Hg (95% credible interval 125·7-128·3) in men and 122·3 mm Hg (121·0-123·6) in women; age-standardised mean diastolic blood pressure was 78·7 mm Hg (77·9-79·5) for men and 76·7 mm Hg (75·9-77·6) for women. Global age-standardised prevalence of raised blood pressure was 24·1% (21·4-27·1) in men and 20·1% (17·8-22·5) in women in 2015. Mean systolic and mean diastolic blood pressure decreased substantially from 1975 to 2015 in high-income western and Asia Pacific countries, moving these countries from having some of the highest worldwide blood pressure in 1975 to the lowest in 2015. Mean blood pressure also decreased in women in central and eastern Europe, Latin America and the Caribbean, and, more recently, central Asia, Middle East, and north Africa, but the estimated trends in these super-regions had larger uncertainty than in high-income super-regions. By contrast, mean blood pressure might have increased in east and southeast Asia, south Asia, Oceania, and sub-Saharan Africa. In 2015, central and eastern Europe, sub-Saharan Africa, and south Asia had the highest blood pressure levels. Prevalence of raised blood pressure decreased in high-income and some middle-income countries; it remained unchanged elsewhere. The number of adults with raised blood pressure increased from 594 million in 1975 to 1·13 billion in 2015, with the increase largely in low-income and middle-income countries. The global increase in the number of adults with raised blood pressure is a net effect of increase due to population growth and ageing, and decrease due to declining age-specific prevalence.

INTERPRETATION

During the past four decades, the highest worldwide blood pressure levels have shifted from high-income countries to low-income countries in south Asia and sub-Saharan Africa due to opposite trends, while blood pressure has been persistently high in central and eastern Europe.

FUNDING

Wellcome Trust.

Contributions of risk factors and medical care to cardiovascular mortality trends

Ischaemic heart disease, stroke, and other cardiovascular diseases (CVDs) lead to 17.5 million deaths worldwide per year. Taking into account population ageing, CVD death rates are decreasing steadily both in regions with reliable trend data and globally. The declines in high-income countries and some Latin American countries have been ongoing for decades without slowing. These positive trends have broadly coincided with, and benefited from, declines in smoking and physiological risk factors, such as blood pressure and serum cholesterol levels. These declines have also coincided with, and benefited from, improvements in medical care, including primary prevention, diagnosis, and treatment of acute CVDs, as well as post-hospital care, especially in the past 40 years. These variables, however, explain neither why the decline began when it did, nor the similarities and differences in the start time and rate of the decline between countries and sexes. In Russia and some other former Soviet countries, changes in volume and patterns of alcohol consumption have caused sharp rises in CVD mortality since the early 1990s. An important challenge in reaching firm conclusions about the drivers of these remarkable international trends is the paucity of time-trend data on CVD incidence, risk factors throughout the life-course, and clinical care.

Biomarkers of healthy ageing: expectations and validation

The challenge of devising a set of biomarkers capable of measuring the ageing rate in human subjects was articulated long ago. In recent years, progress in the basic biology of ageing suggests the realistic possibility of preventive or restaurative interventions that may extend healthy lifespan in mammals including human subjects. Specifically, frailty is being increasingly recognised as a clinically relevant syndrome that may be therapeutically addressed. This greatly enhances the need for sensitive and specific biomarkers of healthy ageing that are validated in both experimental animals and, importantly, in human subjects over the whole age range. Here, we will discuss the present challenges and requirements for biomarker validation in human subjects. We propose the central requirements for a validated biomarker of healthy ageing as: (i) better predictive power than chronological age for multiple dimensions of ageing; (ii) identification of the age range in which the marker is informative; (iii) establishment of sensitivity/specificity as indicators of its predictive power at the level of the individual; (iv) minimisation of methodological variation between laboratories.

Trends in self-reported arterial hypertension in Brazilian adults: an analysis of data from the Brazilian National Household Sample Survey, 1998-2008

This study investigated the time trend in self-reported arterial hypertension from 1998 to 2008 in individuals older than 20 years in Brazil. Data were analyzed on prevalence of hypertension from the National Household Sample Survey (PNAD) for the years 1998, 2003, and 2008. The analysis considered the sampling complexity and included 203,419, 238,591, and 257,816 individuals in the years 1998, 2003, and 2008, respectively. The time trend in hypertension was analyzed by sex, family income, geographic regions of Brazil, and area of residence (urban versus rural), and the prevalence rates were adjusted for age. Prevalence of self-reported hypertension was 12.5% in 1998, 13% in 2003, and 13.9% in 2008, with an annual increase of 1.07%. The highest increases occurred in the Southeast Region (1.41%), in men (1.82%), and in urban areas (1.15%). The study showed a rise in the prevalence of self-reported hypertension in all income brackets and with increasing age. Knowledge of the prevalence of hypertension is essential for backing activities to prevent and control the problem, especially among the more vulnerable subgroups.

Gender difference and economic gradients in the secular trend of population systolic blood pressure

To a large extent population blood pressure (PBP) affects morbidity and mortality in the society. Reports indicated that PBP decreased in many western countries. The associations between the main cardiovascular risk factors and the changing PBP have been described. The aim of this study was to investigate association between income factors and trends in population BP and hypertension. Copenhagen City Heart Study is a prospective longitudinal epidemiological study on almost 20000 individuals through four surveys from 1976 to 2003. The BP measurement was fully standardised. Questionnaires on household income and CV risk factors were completed by the participants. After adjustment for cardiovascular risk factors there were no significant differences in systolic BP (SBP) trend associated to income among men. Among women, however, there was a reverse relationship between SBP and income. In addition, there was a trend towards a lowering of risk-factor adjusted SBP in the high income women with time. The mechanism that lies behind the associations between trend in SBP and income is not known but data suggest that poor lifestyle may explain some of the differences. The treated hypertensives are treated without income associated treatment differences.

IN CONCLUSION

Women in higher income groups have lower SBP than women in low-income groups and the gap between SBP in high-income women and low-income women increased with time. There were no significant differences in SBP-trend associated to income among men. Results in treating hypertension did not differ between the income groups.

Trends of blood pressure levels and management in Västerbotten County, Sweden, during 1990-2010

Background

Availability of longitudinal data on hypertension and blood pressure levels are important to assess changes over time at the population level. Moreover, detailed information in different population sub-groups is important to understand inequity and social determinants of blood pressure distribution in the population.

Objectives

The objectives of this study are to: (1) describe the trends of population blood pressure levels in men and women between different educational levels and geographic areas in Sweden during 1990–2010; (2) identify prevalences of hypertension, awareness, treatment, and control in the population; and (3) assess the 10-year risk of developing hypertension among individuals with normal and high normal blood pressures.

Methods

This study is based on data from the Västerbotten Intervention Program (VIP) in Västerbotten County, Sweden. The cross-sectional analysis includes 133,082 VIP health examinations among individuals aged 30, 40, 50, and 60 years from 1990 to 2010. The panel analysis includes 34,868 individuals who were re-examined 10 years after the baseline examination. Individuals completed a self-administered health questionnaire that covers demographic and socio-economic information, self-reported health, and lifestyle behaviours. Blood pressure measurement was obtained prior to the questionnaire. In the cross-sectional analysis, trends of blood pressure by sex, and between educational groups and geographic areas are presented. In the panel analysis, the 10-year risk of developing hypertension is estimated using the predicted probability from logistic regression analysis for each sex, controlling for age and educational level.

Results

The prevalence of hypertension decreased from 1990 to 2010; from 43.8 to 36.0% (p < 0.001) among men, and 37.6 to 27.5% among women (p < 0.001). Individuals with basic education had a significantly higher prevalence of hypertension compared to those with medium or high education. Although the decreases were observed in all geographic areas, individuals in rural inland areas had a much higher prevalence compared to those who lived in Umeå City. The proportion of hypertensive women who were aware of their hypertension (61.7%) was significantly higher than men (51.6%). About 34% of men and 42% of women with hypertension reported taking blood pressure medication. Over time, awareness and control of hypertension improved (from 46.5% in 1990 to 69% in 2010 and from 30 to 65%, respectively). The gaps between educational groups diminished. This study shows a significantly higher risk of developing hypertension for men and women with high normal blood pressure compared to those with normal blood pressure at baseline in all age cohorts and educational groups. The average risks of developing hypertension among men with high normal blood pressure were 21.5, 45.8, and 56.3% in the 30, 40, and 50-year cohorts, respectively. Corresponding numbers for women were 22.6, 47.4, and 57.9%.

Conclusions

Levels of blood pressure and hypertension decreased significantly among the Västerbotten population in the last 21 years. Hypertension management has improved and there is increased awareness, treatment, and control of blood pressure. Despite these achievements, the persisting social gaps in blood pressure levels and management demand further investigation and action from policy makers. Future research should attempt to identify and address the root causes of these health inequities to ensure better and equal health for the whole population.

Blood pressure variations and low blood pressure values at home after hospital discharge in older hypertensives

Background: Blood pressure (BP) variations occurring after hospital discharge in a population of older hypertensives have not been previously investigated.

Design: elderly (≥65 years) hypertensives admitted to the geriatric acute ward of a university-teaching hospital were enrolled in this prospective observational study.

Methods: Exclusion criteria were terminal illness, discharge to institution, and changes in antihypertensive regimen. BP was recorded in the emergency room, at ward admission, daily during hospital stay, and at discharge. Home self blood pressure measurement was performed after discharge.

Results: The study population included 106 patients. There was a significant decrease in systolic BP (SBP) and diastolic BP (DBP) throughout the study time points. SBP and DBP decreased after discharge (from 135.1 ± 15.0 to 131.5 ± 16.1 mmHg and from 77.2 ± 8.4 to 71.6 ± 8.7 mmHg, respectively), the difference being significant only for DBP ( p = 0.000). We further observed higher prevalence of critically low BP values (SBP <120 mmHg and DBP <70 mmHg) at home (23.6% and 48.1%, respectively) compared to discharge (8.5% and 9.4%, p = 0.006 and p = 0.000, respectively).

Conclusions: We observed a decrease in BP values, and particularly DBP values, after hospital discharge, in a sample of older hypertensives. Critically low BP values were observed at home in a high proportion of subjects, suggesting wise use of antihypertensive therapy at discharge and early monitoring of BP values at home.

Twenty-year trends in cardiovascular risk factors in India and influence of educational status

BACKGROUND

Urban middle-socioeconomic status (SES) subjects have high burden of cardiovascular risk factors in low-income countries. To determine secular trends in risk factors among this population and to correlate risks with educational status we performed epidemiological studies in India.

METHODS

Five cross-sectional studies were performed in middle-SES urban locations in Jaipur, India from years 1992 to 2010. Cluster sampling was performed. Subjects (men, women) aged 20-59 years evaluated were 712 (459, 253) in 1992-94, 558 (286, 272) in 1999-2001, 374 (179, 195) in 2002-03, 887 (414, 473) in 2004-05, and 530 (324, 206) in 2009-10. Data were obtained by history, anthropometry, and fasting blood glucose and lipids estimation. Response rates varied from 55 to 75%. Mean values and risk factor prevalence were determined. Secular trends were identified using quadratic and log-linear regression and chi-squared for trend.

RESULTS

Across the studies, there was high prevalence of overweight, hypertension, and lipid abnormalities. Age- and sex-adjusted trends showed significant increases in mean body mass index (BMI), fasting glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides (quadratic and log-linear regression, p < 0.001). Systolic blood pressure (BP) decreased while insignificant changes were observed for waist-hip ratio and low-density lipoprotein (LDL) cholesterol. Categorical trends showed increase in overweight and decrease in smoking (p < 0.05); insignificant changes were observed in truncal obesity, hypertension, hypercholesterolaemia, and diabetes. Adjustment for educational status attenuated linear trends in BMI and total and LDL cholesterol and accentuated trends in systolic BP, glucose, and HDL cholesterol. There was significant association of an increase in education with decline in smoking and an increase in overweight (two-line regression p < 0.05).

CONCLUSION

In Indian urban middle-SES subjects there is high prevalence of cardiovascular risk factors. Over a 20-year period BMI and overweight increased, smoking and systolic BP decreased, and truncal obesity, hypercholesterolaemia, and diabetes remained stable. Increasing educational status attenuated trends for systolic BP, glucose and HDL cholesterol, and BMI.