Biochemical Markers and Hypertension in Children
April–July 2019, Vol 21, No 2–3

INTRODUCTION Hypertension is one of the most studied risk factors for cardiovascular disease in adults; in children and adolescents, its global prevalence changes with age, from 1%–3% in children to 3.2% in adolescents. In adults, in addition to hypertension, several biochemical markers of cardiovascular risk have been identified. Confirming an association between these and hypertension in childhood and adolescence would allow for more timely diagnosis and monitoring of cardiovascular disease, since the presence of both the markers and hypertension would imply increased risk.  

OBJECTIVE Confirm an association between biochemical risk markers of cardiovascular disease and hypertension in children aged 8 to 11 years.

METHODS A cross-sectional study of 373 children aged 8–11 years was conducted in 3 primary schools in the city of Santa Clara in central Cuba. The variables examined were age, sex, height, blood pressure, cholesterol, triglycerides, lipoproteins and apolipoproteins. The children were classified as normotensive, prehypertensive or hypertensive, based on blood pressure readings and percentiles for age, sex and height. Descriptive statistics were calculated for quantitative variables. A bivariate analysis, tests of independence for qualitative variables and a means comparison for quantitative variables (ANOVA and its nonparametric alternative, the Kruskal Wallis test) were performed. Fisher’s F-test and its associated probability value were employed.

RESULTS Some 32.2% of the children were prehypertensive and 5.1% hypertensive. Cholesterol and triglyceride values were significantly higher in hypertensive than in normotensive children (p = 0.028 and p = 0.047, respectively). HDL numbers were higher in normotensive children (p =0.001), and LDL numbers and the LDL/HDL ratio were higher in the hypertensive children, with differences between groups (p = 0.001 for both variables). There were differences between the three blood pressure categories for lipoprotein(a) and ApoA (p <0.001 and p = 0.001), for ApoB and for the ApoB/ApoA ratio (p <0.001 for both variables), with lower ApoA values and higher ApoB and ApoB/ApoA values in the hypertensive children.

CONCLUSIONS The biochemical risk markers most strongly associated with hypertension in children are ApoB values, LDL, lipoprotein(a), and LDL/HDL and ApoB/ApoA ratios.

KEYWORDS Adolescent, child, hypertension, apolipoproteins, cardiovascular diseases, risk factors, Cuba

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Development of Hypertension in a Cohort of Cuban Adolescents
January 2015, Vol 17, No 1

INTRODUCTION Primary hypertension has its origins in childhood and is a risk factor for atherosclerosis; it is considered an important health problem because of its high prevalence worldwide.

OBJECTIVE Describe the development of hypertension during adolescence, including some factors that influence its persistence and progression in Cuban adolescents.

METHODS A cohort study was conducted in an intentional sample of 252 apparently healthy adolescents from the catchment area of the Héroes del Moncada Polyclinic in Plaza de la Revolución Municipality, Havana. They were assessed in two cross-sectional studies in 2004 and 2008. Mean age at first assessment was 13.2 years, 17.1 years at the second. Variables were weight, height, body mass index, waist circumference, blood pressure, smoking, family history of hypertension and birth weight. Correlation coefficients and growth curve analyses were applied to assess blood pressure persistence. Risk of developing prehypertension and hypertension was estimated in the second assessment, based on predictors identified in the 2004 cut. Forecasting models with these factors were developed using classification trees as analytical tools.

RESULTS Of the six adolescents categorized as hypertensive in the first assessment, five still showed blood pressure alterations after four years. The main factors related to hypertension in those aged 16–19 were blood pressure itself and a body mass index >90th percentile, followed by low birth weight and abdominal obesity. Prognostic models for predicting this condition at the end of adolescence demonstrated the importance of blood pressure alterations at age 12–15 years.

CONCLUSIONS High rates of persistence and progression of hypertension during adolescence highlights the need for systematic blood pressure screening at the primary health care level and adoption of primary prevention strategies beginning in childhood.

KEYWORDS Atherosclerosis, atherogenesis, high blood pressure, adolescence, hypertension, risk factors, Cuba

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Prevalence of Metabolic Syndrome Risk Factors in Adults in Holguín, Cuba (2004–2013)
January–April 2016, Vol 18, No 1–2

INTRODUCTION High prevalence of metabolic syndrome and its associated risk factors in adults represents both a Cuban and a worldwide public health problem.

OBJECTIVE Determine prevalence of metabolic syndrome’s component risk factors in a representative sample of adults in Holguín Province, Cuba.

METHODS A cross-sectional study was conducted using multistage probability sampling of four Holguín Province municipalities: Holguín, Gibara, Urbano Noris and Banes. We selected a sample of 2085 patients aged ≥20 years during 2004–2013 and measured clinical, anthropometric and biochemical variables. Risk factor prevalence rates were calculated using EPIDAT 3.1.

RESULTS Crude metabolic syndrome prevalence rate was 27.2% (CI 25.3%–29.1%). Crude prevalence rates (with 95% CI) of risk factors were as follows: hypertriglyceridemia 36.1% (34.0%–38.2%); hypercholesterolemia 25.5% (23.6%–27.4%); low HDL cholesterol 26.3% (24.4%–28.2%); high LDL cholesterol 10.1% (8.8%–11.4%); prediabetes 2.2% (1.6%–2.8%); diabetes 14.6% (13.1%–16.1%); prehypertension 3.5% (2.7%–4.3%); hypertension 34.5% (32.5%–36.5%); overweight 23.4% (21.6%–25.2%); obesity 32.0% (30.0%–34.0%) and central obesity 47.3% (45.2%–49.4%). They were significantly higher in women and older adults.

CONCLUSIONS High prevalence of risk factors associated with metabolic syndrome confirms the magnitude of this health problem, particularly in women and older adults.

KEYWORDS Metabolic syndrome, insulin resistance, hypertension, dyslipidemia, type 2 diabetes mellitus, obesity, risk factors, Cuba

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Total Cardiovascular Risk Assessment and Management Using Two Prediction Tools, with and without Blood Cholesterol
October 2013, Vol 15, No 4

INTRODUCTION Over the last decade, total cardiovascular risk assessment and management has been recommended by cardiovascular prevention guidelines in most high-income countries and by WHO. Cardiovascular risk prediction charts have been developed based on multivariate equations of values of some well-known risk factors such as age, sex, smoking, systolic blood pressure and diabetes, including or omitting total blood cholesterol.

OBJECTIVE The objectives of this study were: to determine the distribution of cardiovascular risk in a Cuban population using the WHO/International Society of Hypertension risk prediction charts with and without cholesterol; and to assess applicability of the risk prediction tool without cholesterol in a middle-income country, by evaluating concordance between the two approaches and comparing projected drug requirements resulting from each (at risk thresholds of ≥20% and ≥30%) and for the single-risk-factor approach.

METHODS From April through December 2008, a cross-sectional study was conducted in 1287 persons (85.8% of the sample selected), aged 40–80 years living in a polyclinic catchment area of Havana, Cuba, based on the protocol and data from a WHO multinational study. The study used the two sets of the WHO and the International Society of Hypertension (WHO/ISH) risk prediction charts, with and without cholesterol. Percentages and means were calculated, as well as prevalence (%) of risk factors. The chi-square test was used to compare means (p ≤0.05). Concordance between the two prediction charts was calculated for different risk levels, using the chart with cholesterol as a reference.

RESULTS Using the risk assessment tools with and without cholesterol, 97.1% and 95.4% respectively of the study population were in the ten-year cardiovascular risk category of <20%, while 2.9% and 4.6% respectively were in the category of ≥20%. Risk categories were concordant in 88.1% of the population; overestimation was higher among the nonconcordant (136/153). When risk assessment did not include cholesterol, there was 2.6% (34/1287) overestimation of drug requirements and 0.5% (6/1287) underestimation, compared to estimates including cholesterol.

CONCLUSION Total cardiovascular risk assessment using the WHO/ISH charts without cholesterol could be a useful approach to predict cardiovascular risk in settings where cholesterol cannot be measured. This does not introduce overconsumption of drugs, but does enable better targeting of resources to those who are more likely to develop cardiovascular disease.

KEYWORDS Cardiology, risk assessment, health risk appraisal, hypertension, health policy, cost savings, atherosclerosis, Cuba

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An Efficient Sampling Approach to Surveillance of Non-Communicable Disease Risk Factors in Cienfuegos, Cuba
October 2012, Vol 14, No 4

One of the most common shortcomings in non-communicable disease risk factor surveillance, especially in prevalence studies, is sampling procedures, which can and do compromise accuracy and reliability of derived estimates. Moreover, sampling consumes significant time and resources. Since the early 1990s, risk factor surveys in Cienfuegos province, Cuba have paid particular attention to careful sampling methods. The new survey conducted in 2011 was not only statistically rigorous but introduced an innovative, more efficient method. This article provides a detailed description of the sample design employed to optimize resource use without compromising selection rigor.

KEYWORDS Sampling, descriptive studies, risk factors, non-communicable diseases, hypertension, Cuba

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Dementia and Other Chronic Diseases in Older Adults in Havana and Matanzas: The 10/66 Study in Cuba
October 2011, Vol 13, No 4
INTRODUCTION Chronic non-communicable diseases are the leading cause of death worldwide, except in Sub-Saharan Africa. Nonetheless, one of these conditions, dementia, is the major contributor to disability-adjusted life years in people aged ≥60 years. Few epidemiological studies exist of the prevalence and impact of dementia and selected chronic diseases in older adults in Latin America.
 
OBJECTIVE Describe prevalence of dementia, other chronic vascular diseases and cardiovascular risk factors, as well as resulting disabilities and care needs generated in adults aged ≥65 years in Havana City and Matanzas provinces, Cuba.
 
METHODS The 10/66 study is a prospective longitudinal study involving a cohort of 3015 adults aged ≥65 years in municipalities of Havana City and Matanzas provinces, divided into two phases: a cross-sectional door-to-door study conducted in 2003–2006, and a follow-up and assessment phase in 2007–2010. This article reports findings from the first phase. Hypertension diagnosis was based on criteria from the International Society for Hypertension; diabetes mellitus on American Diabetes Association criteria; stroke according to WHO definitions; and dementia according to criteria of the American Psychiatric Society’s Diagnostic and Statistical Manual of Mental Disorders DSM-IV and the 10/66 International Dementia Research Group. Ischemic heart disease was defined by self-report of previous physician diagnosis. Study variables included age, sex, educational level, substance use (alcohol, tobacco) and dietary habits. A structured physical and neurological exam, including blood pressure measurement, was performed on all participants. Laboratory tests included complete blood count, fasting blood glucose, total cholesterol and lipoprotein fractions, triglycerides and apolipoprotein E genotype. Prevalence and standardized morbidity ratios (crude and adjusted) were calculated for chronic diseases studied with 95% confidence intervals, using a Poisson regression model and indirect standardization.
 
RESULTS The study assessed 2944 older adults (response rate 97.6%) and found high prevalence of vascular risk factors and of chronic non-communicable diseases: hypertension 73.0% (95% CI 71.4–74.7), diabetes mellitus 24.8% (95% CI 22.9–26.5), ischemic heart disease 14.1% (95% CI 12.9–15.4), dementia 10.8% (95% CI 9.7–12.0) and stroke 7.8% (95% CI 6.9–8.8). The majority of participants (85%) had more than one cardiovascular risk factor. The main cause of disability and dependency in the study population was dementia.
 
CONCLUSION The high prevalence of chronic diseases observed in the elderly—with the consequent morbidity, disability and dependency—highlights the need for prevention, early diagnosis and risk factor control, particularly given the demographic and epidemiologic transition faced by Cuba and other developing countries.
 
KEYWORDS Dementia, chronic disease, cardiovascular diseases, heart disease, stroke, diabetes mellitus, disability, hypertension, aging, prevalence, epidemiology, Cuba
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Prevalence of Obesity and its Association with Chronic Kidney Disease, Hypertension and Diabetes Mellitus. Isle of Youth Study (ISYS), Cuba
April 2008, Vol 10, No 2

Introduction Obesity is a social disease constituting a global pandemic. It is present in 90% of diabetic and 65% of hypertensive patients. It is associated with cardiometabolic syndrome and with damaging physiopathological mechanisms, particularly for the vascular system and the kidneys. On Cuba’s Isle of Youth, a community-based epidemiological study of chronic kidney disease (CKD), hypertension (HTN), diabetes mellitus (DM) and cardio-cerebral vascular disease was carried out in total population, including an examination of common risk factors.

Objective Based on the Isle of Youth Study (ISYS) data, determine prevalence of obesity and overweight, and their association with CKD, HTN, DM, and shared risk factors for all these conditions in total population of the Isle of Youth, Cuba.

Methods Phase 1: Population diagnosis (November 2004-April 2006): 96.6% of the Isle of Youth’s total population (80,117) was studied, including all ages and both sexes. Information was offered to the public, and written informed consent obtained. Screening was conducted by participant questionnaire including risk factors, physical measurements (weight, height, blood pressure and body mass index), and a single first-morning urine sample to determine the presence of vascular-renal damage markers – proteinuria and hematuria (Combur 10 Test, Roche), and microalbuminuria (Micral Test, Roche). When results were positive, serum creatinine was determined and glomerular filtration rate (GFR) estimated with Modification of Diet in Renal Disease (MDRD) formula for adults and Schwartz formula for children <15 years. Data obtained were analyzed to determine association of participants’ nutritional status with prevalence of chronic kidney disease, hypertension and diabetes mellitus, as well as a set of common risk factors.

Results Population <20 years: Obesity prevalence 3.2%; positive urine markers in 56.9% of obese and 8.9% of non-obese participants; positive albuminuria in 38% of obese and 3% of non-obese. Obese participants were found to be hyperfiltrating. DM prevalence was 9.5% in obese and 1.1% in non-obese participants. Population ≥20 years: Overweight, 31.3%; obese, 13.4%. Positive markers in normal-weight, overweight and obese individuals were 18.3%, 21.2% and 32.7%, respectively; microalbuminuria values increased with weight. Obese individuals were found to be hyperfiltrating. HTN prevalence in normal-weight, overweight and obese individuals was 18.3%, 31.5%, and 51.0% respectively; DM rates were 2.8%, 5.2% y 11.3%, respectively.

Conclusion In Cuba, obesity poses significant risk for vascular and renal damage and should be the focus of increased prevention efforts.

Keywords Vascular diseases, chronic kidney disease, CKD, chronic kidney insufficiency, hypertension, diabetes mellitus, risk factors, obesity, overweight, body mass index, glomerular filtration rate

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