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Novel Risk Factors for Coronary Disease:
Plasma Serum Homocysteine and its relationship with classical risk factors for Coronary
Disease in scholarships. La Pintana Municipality. Metropolitan Region. Chile. 1999.
Szot-Meza Jorge, Berríos Ximena
Department of Public Health
School of Medicine
Santiago de Chile.
Materials and Methods
Introduction: Serum homocysteine levels (SHL) would be an independent
Risk Factor (RF) for Coronary Heart Disease (CHD) in adults. Little information exists on
homocysteine levels in children.
Objectives: To describe the distribution of SHL and its relationship with
classic RF for CHD.
Materials and Methods: 112 schoolchildren both sexes, mean age: 10.1
years-old (DS+-1.03). Data collection was done at schools by trained field personnel
measuring Height and Weight, Systolic Blood Pressure and Diastolic Blood Pressure
according international recommendations.
Fasting Total cholesterol, HDL-cholesterol ,tryglicerides, and SHL were assessed as well.
Conventional laboratory methods were used. Criteria to state Prevalence (P) of RF is
according to international recomendations. For High SHL (HSHL) value: ³
8.96m mol/lt. SMK was assessed by a self-administered
questionnaire and defined as current conssumption. In the entire population were assessed
SES through Graffar method, and sexual maturity (SM).
Results: 47.3% boys, and 52.7% girls. 79.7% in low-middle social class.
47.5% boys are at first Tanner degree. 57.1% girls are at 2nd and 3rd Tanner
degree. The mean of SHL is 5.74 m mol/lt.(DS+-1.67 CI
95%5.42-6.05)for all children. In boys 6.02 m mol/lt (DS+-1.93,
CI 95%5.49-6.56) and girls: 5.48 m mol/lt.(DS+-1.36 CI
95%5.12-5.83)respectively. (p-value=.005). There are not differences in SHL levels
according to sexual maturity.
The SHL means in children do not exhibit any association with other RF. Global prevalence
for HSHL is 6.3%: 9.3% in boys and 3.4% in girls.
Conclusions: The SHL mean values are coincident with reports published in
the international litarature. The mean of SHL is lower in children than in adults, and in
girls than in boys. No significant association with other RF assessed here was founded.
The importance of this study is to have a baseline of a novel RF which allows follow up to
detect changes during childhood and adolescence.
Introduction: Risk Factors
(RF) for Coronary Heart Disease (CHD), as High Blood Pressure (HBP), Obesity (OB),
abnormal Lipid Profile (LP) and Smoking (SMK) could be present at early stages during
life. These have been considered "classic" RF. Since the late 80´s "new
risk factors" (NRF) for CHD have been added. These have been assessed mainly in
adulthood. Among these NRF its important to mention: the Plasmatic Fibrinogen, C-reactive
Protein (CRP), Lipoproteins A, B and LpA and the Serum Homocysteine high level (SHHL). The
first signal that SHHL could become a coronary risk appeared in the 60´s: Carson found
that homocysteinuric children were keen to atherosclerosis. In fact, prospective studies
have demonstrated that elevations in the concentration of the Plasmatic Homocysteine (PH)
could precede the developing of the CHD. The SHHL is related to adults ´s Systolic
Hypertension (SH) and the effect increases when people smoke. The PH is produced by the
metionine´s demetilation, and can be removed by two enzymes, which must have B-12 vitamin
and folic acid as a cofactor. The explanation of damage produced by SHHL is well known:
This substance can inhibit the anticoagulant mechanism and to favor the LDL´s oxidation.
On despite of this great amount of information about homocysteine (H), most of it has been
produced through research in adult population. There isn't enough information about H in
The purpose of this communication is to provide information about the
presence of H in school population.
To describe the distribution of PH and its association with classical RF for CHD: OB,
HBP, LP and SMK in a schoolchildren population.
Materials and Methods: The study population is a
non-random sample of 112 schoolchildren both sexes, mean age: 10.1 years old (DS+-1.03) of
4th and 5th grade at schools of La Pintana Municipality. (Located in
the southeast area of Santiago, the capital city).
The data collection was done according to international
recommendations, during September and October of 1998. A self-administered questionnaire
to collect information about current SMK and either biological measurements such as
weight, height, blood pressure, classical lipid profile, and PH were performed by trained
field personnel. Informed written consent was asked to the children's parents. All blood
samples to assess lipid profile and PH were studied at the Central Laboratory of the
Faculty of Medicine at Catholic University.
The risk criteria were: for OB: Body Mass Index (BMI)³ 85th percentile distributed by sex and age; for HBP:
Systolic or diastolic blood pressure ³ 95th
percentile distributed by sex and age; for LP: total cholesterol (TC)³
180 mg/dl, HDL-cholesterol (HDL)£ 35 mg/dl, LDL-cholesterol
(LDL)³ 130 mg/dl, triglicerides (TG)³
200 mg/dl, and index TC/HDL ³ 4. For PH two cut points were
considered: 1). 8.99 m mol/lt of PH corresponding to
+2SD(standard deviations) of the distribution in a large North American schoolchildren
population (n=3524), and 2). 8.5m mol/lt corresponding to the
value of 95th percentile of the distribution of the same population.
Socioeconomic Situation (SES) was assessed through Graffar method, and Sexual Maturity
(SM) through Tanner Index.
The statistics analysis was done using the SPSS for Windows 95 Program
and processed at the Public Health Department of the Catholic University of Chile.
- Study population was: 47.3% boys (CI 95% 38.0-56.5) (n=53) and 52.7% (CI 95% 43.6-61.9)
- Mean age: 10.1 years old (SD+-1.03). Sexual Maturity: 47.5% pre-puberal stage in boys
and 23.8% in girls respectively.
- SES: 79.7% belongs to low-middle SES. (CI95%: 70.9-88.5).
- The distribution of the PH mean in all children is: 5.74 m
mol/lt (SD +-1.67. CI95%: 5.42-6.05). Range: 2.5 through 10.20 m
- The mean in boys is 6.02 m mol/lt (SD+-1.93 CI95% 5.49-6.56)
in girls 5.48 m mol/lt (SD+- 1.36 CI95% 5.12-5.83) (p-value:
.005). Values are depicted in graphics N°1 and N°2.
- Regarding association between PH means in children neither with nor without classical RF
in the entire population there was no difference.
- Regarding prevalences: High PH global Prevalence is 6.3% according to the first cut
point as criterion (9.4% in boys and 3.4% in girls) and 8.0% according to the second cut
point as criterion (13.2% in boys and 3.4% in girls) respectively.
- There was no difference at the prevalence of HHSL in children neither with nor without
classical RF in the entire population.
- There was a weak correlation between children age and PH distribution: r=0.202
This study shows how the PH is distributed in a group of healthy Chilean scholarships at
the Metropolitan Region of Chile. This area accounts for the 42% of the Chilean
population. General characteristics of the study population are quite homogenous: 67%
children are 9-10 years-old, 40% of them have incipient signs of sexual maturity, and near
80% are living in low-middle SES.
Differences between PH concentrations among boys (higher) and girls, and PH values lower
in children than in adults were found agree with the international reports
There was no difference in the PH levels in children according to his/her sexual
maturity, which differs from the other risk factors distributions, like OB or abnormal LP.
PH values in the study population were not as closer to the Hispanics American
population as it was expected.
It would be important to increase the sample size in order to obtain more general
There is a preliminary approach to the characteristics of the PH distribution in
children. The small sample size avoids to make projection to general population.
Nevertheless we have a basic information about this important NRF and about the method to
assess its magnitude, which imply a relevant issue for future research.
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