Prevalence of metabolic syndrome in Brazilian adults: A systematic review

Article (PDF Available)inBMC Public Health 13(1):1198 · December 2013with55 Reads
DOI: 10.1186/1471-2458-13-1198 · Source: PubMed
Abstract
The metabolic syndrome (MS) is a complex of risk factors for cardiovascular disease. This syndrome increases the risk of diabetes, cardiovascular disease and all-cause mortality. It has been demonstrated that the prevalence of MS is increasing worldwide. Despite the importance of MS in the context of metabolic and cardiovascular disease, few studies have described the prevalence of MS and its determinants in Latin America. The present study aims to assess studies describing the prevalence of MS in Brazil in order to determine the global prevalence of the syndrome and its components. Systematic review. Searches were carried out in PubMed and Scielo from the earliest available online indexing year through May 2013. There were no restrictions on language. The search terms used to describe MS were taken from the PubMed (MeSH) dictionary: "metabolic syndrome x", "prevalence" and "Brazil". Studies were included if they were cross-sectional, described the prevalence of MS and were conducted in apparently healthy subjects, from the general population, 19-64 years old (adult and middle aged) of both genders. The titles and abstracts of all the articles identified were screened for eligibility. Ten cross-sectional studies were selected. The weighted mean for general prevalence of MS in Brazil was 29.6% (range: 14.9%-65.3%). Half of the studies used the criteria for clinical diagnosis of MS proposed by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) (2001). The highest prevalence of MS (65.3%) was found in a study conducted in an indigenous population, whereas the lowest prevalence of MS (14.9%) was reported in a rural area. The most frequent MS components were low HDL-cholesterol (59.3%) and hypertension (52.5%). Despite methodological differences among the studies selected, our findings suggested a high prevalence of MS in the Brazilian adult population.

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RES E AR C H A R T I C L E Open Access
Prevalence of metabolic syndrome in Brazilian
adults: a systematic review
Fernanda de Carvalho Vidigal
1
, Josefina Bressan
1
, Nancy Babio
2,3
and Jordi Salas-Salvadó
2,3*
Abstract
Background: The metabolic syndrome (MS) is a complex of risk factors for cardiovascular disease. This syndrome
increases the risk of diabetes, cardiovascular disease and all-cause mortality. It has been demonstrated that the
prevalence of MS is increasing worldwide. Despite the importance of MS in the context of metabolic and
cardiovascular disease, few studies have described the prevalence of MS and its determinants in Latin America. The
present study aims to assess studies describing the prevalence of MS in Brazil in order to determine the global
prevalence of the syndrome and its components.
Methods: Systematic review. Searches were carried out in PubMed and Scielo from the earliest available online
indexing year through May 2013. There were no restrictions on language. The search terms used to describe MS
were taken from the PubMed (MeSH) dictionary: metabolic syndrome x, prevalence and Brazil. Studies were
included if they were cross-sectional, described the prevalence of MS and were conducted in apparently healthy
subjects, from the general population, 19-64 years old (adult and middle aged) of both genders. The titles and
abstracts of all the articles identified were screened for eligibility.
Results: Ten cross-sectional studies were selected. The weighted mean for general prevalence of MS in Brazil was
29.6% (range: 14.9%-65.3%). Half of the studies used the criteria for clinical diagnosis of MS proposed by the
National Ch olesterol Education Program Adult Treatment Panel III (NCEP-ATP III) (2001). The highest prevalence of
MS (65.3%) was found in a study conducted in an indigenous population, whereas the lowest prevalence of MS
(14.9%) was reported in a rural area. The most frequent MS components were low HDL-cholesterol (59.3%) and
hypertension (52.5%).
Conclusions: Despite methodological differences among the studies selected, our findings suggested a high
prevalence of MS in the Brazilian adult population.
Keywords: Metabolic syndrome, Prevalence, Brazil
Background
The metabolic syndrome (MS) is a complex of interrelated
risk factors for cardiovascular disease and diabetes. These
factors include hyperglycemia, hypertension, high triacyl-
glycerol levels, low HDL-cholesterol (HDL-c) levels, and
abdominal obesity [1]. Separately the MS component s
increase the risk of diabetes , cardiovascular disease and
all-cause mortality, but t he full syndrome is a ssociated
with risk increases that are greater than the sum of the
risk of each feature [2]. It has been reported that the
association of MS with cardiova scula r disea se increases
total mortality 1.5 times and cardiova scular death 2.5
times [3]. Pe ople with M S also have a 5-fold higher risk
of developing type 2 diabetes [4].
The underlying cause of MS continues to challenge
the experts. However, insulin resistance and abdominal
obesity are postulated to be the key components. Genetic
predisposition, physical inactivity, smoking, an unhealthy
dietary pattern, ageing , proinflammatory state and hor-
monal changes may also have a ca usal eff e ct. Their role,
however, may depend on ethnic group [3-5]. The origin
* Correspondence: jordi.salas@urv.cat
2
Human Nutrition Unit, Department of Biochemistry and Biotechnology,
University Hospital Sant Joan de Reus, IISPV, Faculty of Medicine and Health
Sciences, Rovira i Virgili University, Reus, Spain
3
CIBERobn Physiopathology of Obesity and Nutrition, Institute of Health
Carlos III, Madrid, Spain
Full list of author information is available at the end of the article
© 2013 de Carvalho Vidigal et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of
the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public
Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this
article, unless otherwise stated.
de Carvalho Vidigal et al. BMC Public Health 2013, 13:1198
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of all those metabolic disorders can be explained by a
proinflammatory state derived from excessive caloric
intake and overnutrition, and, perhaps, other chronic
inflammatory conditions. This hypothesis asserts that
this proinflammatory state, being characterized by an
increase in inflammatory mediators, induce insulin re-
sistance and leads to oxidative stress, with the potential
to impair several biological pathways inducing insulin
resistance. Therefore, insulin resistance could act as the
common link among all the component s of MS [6].
It has been demonstrated that the prevalence of MS is
increasing worldwide, and for the adult population is esti-
mated to be about 20 to 25%, largely the result of greater
obesity and sedentary lifestyles [1,4]. In the United States
of America, the prevalence of MS estimated in adults from
the National Health and Nutrition Examination Survey
(NHANES) decreased from 25.5% in 1999/2000 to 22.9%
in 2009/2010 [7]. Studies conducted in Latin American
populations from Chile, Colombia , Mexico, Peru and
Venezuela revealed a high prevale nce of MS which
ranged from 12.3% to 42.7% depending on the criteria
for clinical diagnosis and the characteristics of the study
population [8-12].
Despite of the importance of MS in the context of meta-
bolic and cardiovascular disease, in Brazil, few studies have
described the prevalence of MS and its determinants,
hence restricting the quality of information available on
the magnitude of this problem in the country. Therefore,
to help provide a clearer picture of the current situation in
Brazil, we aimed to systematically review the available epi-
demiological data on the prevalence of MS in the Brazilian
adult population.
Methods
Search strategy and eligibility criteria
An ele ctronic bibliographic index (PubMed) and a
multidisciplinary database for Ibero-America (Scielo) were
searched from the earliest available online indexing
year through May 2013, with no language restrictions.
The search terms used to describe MS were taken from
the PubMed (MeSH) dictionary: met abolic syndrome
x [MeSH] AND prevalence [MeSH] AND Brazil
[MeSH] refined by ages (adult: 19-44 years AND middle
aged: 45-64) in All Fields as tag terms. The key words
used in Scielo were the same as those used in PubMed
(MeSH) without filter restrictions.
Studies w ere included if they were cross-sectional,
described the prevalence of MS and were conducted in
Brazilian populations. We restricted this review to studies
on healthy adults and/or on the general population. Stud-
ies were excluded if they were conducted in subjects with
diseases, in pregnant women, in the elderly (65 years) or
in a specific population (Figure 1).
Study selection and data extraction
The title and abstracts of all the articles identified were
screened for eligibility. All potentially relevant titles and
abstracts were selected for full text examination. To be in-
cluded in the review, a study had to: 1) be cross-sectional;
2) focus on MS prevalence; 3) examine a healthy popula-
tion; 4) examine a general adult population (19 to 64 years
old) of both sexes; 5) provide sufficient information to
accomplish the objectives of the present systematic
review. Although the focus of our re view was the adult
population, some of the artic les sele cted included both
adult and elderly subject s , and therefore some subje c ts
were more than 65 years old.
A total of 156 studies containing data on the prevalence
of MS in Brazil were automatically identified by applying
the aforementioned search terms and 1 study was selected
by hand searching. The selection processes for the articles
are shown in Figure 1.
149 studies after duplicates removed
149 potentially eligible studies
identified and screened by title and
abstract
107 studies excluded for not
meeting inclusion or having
exclusion criteria
42 full text articles assessed for
eligibility
26 studies excluded for consisting of
subjects with diseases:
2 climateric/postmenopausal women
4 diabetic or hypertensive patients
3 polycystic ovary syndrome
1 after liver transplantation
1 chronic hepatitis C virus
3 immunologic diseases
3 psychiatric patients
5 clinical outpatients
1 dermatomyositis
2 HIV infected
1 breast cancer
156 studies identified through
database searching
(PubMed= 145 studies and
Scielo= 11 studies)
1 study identified
through hand searching
Initial search
3 studies excluded for consisting of
specific population (employees,
military service and truck drivers)
1 study excluded for consisting of
pregnant women
2 studies excluded for consisting of
elderly subjects
10 studies included in the present
systematic review
Figure 1 Flow chart of articles included in the present systematic
review.
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Of the 145 studies identified in PubMed, 105 were
excluded because they did not meet the inclusion criteria
or had exclusion criteria. Of the 40 articles screened (titles
and abstracts), 31 were excluded for the following reasons:
25 were conducted on subjects with diseases, 3 were car-
ried out on specific populations, 1 comprised pregnant
women and 2 consisted of elderly subjects. Therefore, 9
studies from this database were included in our systematic
review.
Of the 11 studies identified by Scielo, 8 were excluded
because they were duplicates, 2 did not meet the inclusion
criteria or had exclusion criteria, and 1 was conducted
on subject s with disea ses. Therefore, no studies from
this database were included.
One study was selected by hand searching, so a total
of 10 studies were finally selected for the present system-
atic review.
Once the articles had been selected, the following sig-
nificant data were extracted: authors and year of publica-
tion, study location (city, region), number of participants
(W/M), age range, measurements, criteria for diagnosis of
MS, overall prevalence of MS (%), overall prevalence of
individual components of MS (%) and relevant findings/
associations.
Outcome
The weighted mean prevalence observed in the present
systematic review was calculated as follows: sum of the
number of cases in the studies considered ÷ sum of the
number of subjects in all studies considered × 100 [13].
Results of the studies reviewed
We summarize the results of ten cross-sectional studies
selected for the present systematic review (Table 1). The
studies had been published in scientific journals with
impact factors ranging from 0.4 [14,15] to 5.509 [16].
The studies were conducted in several populations,
and various criteria had been used to diagnose MS. Of
the ten cross-sectional studies selected, five had been
carried out in urban populations [5, 15-18], 3 in rural
populations [14,19,20] and 2 in indigenous populations
[21,22]. According to demographic census by 2010 [23],
in Brazil the indigenous population was 817,963 (0.43%)
for a total population of 190,755,799. Therefore, it wa s
important to include the indigenous population in the
present review since they are part of the Brazilian popula-
tion. Five of the ten studies used the criteria for diagnosing
MS proposed by the National Cholesterol Education
Program Adult Treatment Panel III (NCEP-ATP III)
(2001) [5,16,19,20,22]; two the criteria of the International
Diabetes Federation (IDF) [15,21]; one the criteria of the
NCEP-ATP III (2005) [14]; one the harmonized criteria of
the IDF and American Heart Association/National Heart,
Lung, and Blood Institute (AHA/NHLBI) [18]; and one
study used both IDF and NCEP-ATP III (2005) criteria
[17]. Five studies [5,14,16,19,20] used a mercury sphygmo-
manometer; de Oliveira et al. [21] used an aneroid sphyg-
momanometer; whereas Dutra et al. [18] and Gronner
et al. [17] used an automatic instrument (OMRON®) for
measuring blood pressure. The two remaining studies
[15,22] did not mention how blood pressure was mea-
sured. Nine studies reported the number of measurements
carried out (two [5,15,18,20,21] or three [14,16,17,19]).
Seven studies mentioned the measurement site of blood
pressure (right arm [14,19,21,22], left arm [16,20] or non-
dominant arm [5]). Of the ten studies, eight measured the
waist circumference at the midpoint between the iliac
crest and the lowest rib [14-19,21,22]; one at the lower
curvature between the lowest rib and the iliac crest [5];
and one at the umbilical level [20] (Table 1).
Prevalence of metabolic syndrome in Brazil
The studies sele cted [5,14-22] in this systematic review
comprised 8,505 subjects, 60.8% of whom were women
and 39.2% men. Nine studies had more women than
men [5,15-22], whereas one had similar numbers (50.6%
men and 49.4% women) [14].
In nine studies, the general prevalence of MS (unadjusted
for age and/or gender) was reported [5,14-16,18-22]. In
two of these the prevalence was adjusted for age [19,20],
and in one it was adjusted for age and gender [15]. One
study did not report the general prevalence and only
described the prevalence adjusted for age and gender [17].
In the studies that mentioned rates of prevalence, the
weighted mean for general prevalence of MS was 29.6%
[5,14-16,18-22]. In the studies that mentioned rates of
prevalence using the NCEP-ATP III (2001) criterion, the
weighted mean for general prevalence of MS was 28.9%
[5,16,19,20,22]. The weighted mean for age adjusted
prevalence was 22% [19,20] and the weighted mean for
age and gender adjusted prevalence was 41.3% [15,17],
using the NCEP-ATP III (2001) and the IDF criteria, re-
spectively. The weighted mean for general prevalence of
MS according to region was 29.8%, 20.1% and 41.5% in
urban [5,15,16,18], rural [14,19,20], and indigenous [21,22]
populations, respectively. Taking into account that the in-
digenous population represents only 0.43% of the total
Brazilian population, we calculated the weighted mean for
general prevalence of MS excluding the studies [21,22]
conducted in indigenous population. The weighted preva-
lence of MS without taking into account the indigenous
population was 28.3%, only 1.3% lower than those calcu-
lated using the indigenous population studies (29.6%).
MS was most prevalent (65.3%) in a study conducted
in the indigenous population of Rio Grande do Sul,
using the NCEP-ATP III (2001) criterion for diagnosing
MS [22]. The lowest prevalence of MS (14.9%) was re-
ported in Virgem das Graças and Caju, a rural area in the
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Table 1 Characteristics of cross-sectional studies that evaluated the prevalence of metabolic syndrome in the Brazilian adult population
Authors and
publication
year (Ref. no.)
City, region Number of
participants
(W, M)
Age range
(years)
Measurements Criteria for
diagnosis
of MS
Overall
prevalence
of MS (%)
Overall prevalence
of individual
components of
MS (%)
Relevant findings/Associations*
Dutra et al.,
2012 [18]
Brasília, Federal District 2130
(72.5% W,
27.5% M)
18 WC: at the midpoint between the
iliac crest and the lowest rib
IDF and AHA/
NHLBI
harmonized
criteria (2009)
32.0 AO: N/A Logistic regression model adjusted
for age:
Fasting G, TAG and HDL-c
BP: two measurements
High G: N/A Age 25-34 years: female: PR = 2.06;
95% CI 1.13-3.74; male: PR = 3.35;
95% CI 1.27-8.88
HT: N/A Age 35-44 years: female: PR = 3.62;
95% CI 2.04-6.44; male: PR = 4.87;
95% CI 1.94-12.20
High TAG: N/A Age 45-54 years: female: PR = 5.42;
95% CI 3.08-9.55; male: PR = 7.60;
95% CI 3.08-18.70
Low HDL-c: N/A Age 55-64 years: female: PR = 6.57;
95% CI 3.74-11.55; male: PR = 8.95;
95% CI 3.64-22.00
Age 65 years: female: PR = 7.45;
95% CI 4.23-13.11; male: PR = 7.89;
95% CI 3.14-19.80
BMI 25-29 kg/m
2
: female:
PR = 4.29; 95% CI 3.21-5.75; male:
PR = 4.52; 95% CI 2.64-7.74
BMI 30 kg/m
2
: female: PR =7.04;
95% CI 5.32-9.31; male: PR =9.99;
95% CI 5.92-16.90
Schooling 9-11 years: female:
PR = 0.78; 95% CI 0.64-0.96
Schooling 12 years: female:
PR = 0.51; 95% CI 0.37-0.70
de Oliveira
et al., 2011
[21]
Jaguapiru Indigenous
Village, Dourados, Mato
Grosso do Sul
606
(55.8% W,
44.2% M)
18-69 WC: at the midpoint between the
iliac crest and the lowest rib
IDF 35.7 AO: 60.9 N/A
Fasting G, TAG and HDL-c High G: 11.4
BP: two measurements HT: 40.3
High TAG: N/A
Low HDL-c: N/A
Gronner et al.,
2011 [17]
Southeastern region 1116
(64.5% W,
35.5% M)
30-79 WC: at the midpoint between the
iliac crest and the lowest rib
NCEP-ATPIII
(2005) and IDF
NCEP-ATPIII
(2005): 35.9
AO (NCEP-ATPIII
2005): 56.2
Logistic regression model:
Fasting G, TAG and HDL-c IDF: 43.2 AO (IDF): 72.6 Age 40-49 years: OR = 2.15; 95%
CI 1.47-3.16
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Table 1 Characteristics of cross-sectional studies that evaluated the prevalence of metabolic syndrome in the Brazilian adult population (Continued)
BP: three measurements High G: 13.3 Age 50-59 years: OR = 2.68; 95%
CI 1.85-3.89
HT: 59.2 Age 60-69 years: OR = 4.64; 95%
CI 3.06-7.04
High TAG: 16.8 Age 70-79 years: OR = 4.77; 95%
CI 3.11-7.32
Low HDL-c: 76.3 Skin color white: OR = 1.65; 95%
CI 1.28-2.14
Schooling fundamental§:
OR = 2.51; 95% CI 1.58-4.00
BMI 25 kg/m
2
: OR = 5.68;
95% CI 4.30-7.51
Pimenta et al.,
2011 [14]
Virgem das Graças and
Caju, Jequitinhonha
Valley, Minas Gerais
534
(49.4% W,
50.6% M)
18 WC: at the midpoint between the
iliac crest and the lowest rib
NCEP-ATPIII
(2005)
14.9 AO: 11.6 Poisson regression model:
Fasting G, TAG and HDL-c High G: 10.6 Female: PR = 2.20; 95% CI 1.33-3.62
BP: three measurements HT: 59.7 Obesity (BMI 30 kg/m
2
):
PR = 3.03; 95% CI 2.05-4.48
High TAG: 15.2 CRP quartile: PR = 1.56;
95% CI 1.05-2.31
Low HDL-c: 44.1 HOMA-IR quartile: PR = 1.92;
95% CI 1.28-2.88
Age 60 years: PR = 7.06; CI 95%
2.62-19.04
Alcohol consumption (0.1 to 20 g
ethanol/day): PR = 0.26; CI 95%
0.09-0.73
da Rocha
et al., 2011
[22]
Porto Alegre and
Planalto/ Nonoai, Rio
Grande do Sul
150
(55.3% W,
44.7% M)
40-104 WC: at the midpoint between the
iliac crest and the lowest rib
NCEP-ATPIII
(2001)
65.3 AO: 64.7 N/A
Fasting G, TAG and HDL-c High G: 38.0
BP: N/A HT: 64.7
High TAG: 48.7
Low HDL-c: 67.3
Silva et al.,
2011 [15]
São Paulo 287
(74.6% W,
25.4% M)
20-64 WC: at the midpoint between the
iliac crest and the lowest rib
IDF 36.6 AO: N/A Short height adjusted for age and
gender: OR = 1.25; 95% CI 1.12-
1.26
Fasting G, TAG and HDL-c High G: N/A
BP: two measurements HT: N/As
High TAG: N/A
Low HDL-c: N/A
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Table 1 Characteristics of cross-sectional studies that evaluated the prevalence of metabolic syndrome in the Brazilian adult population (Continued)
Marquezine
et al., 2008
[16]
Vitória, Espírito Santo 1561
(54.5% W,
45.5% M)
25-64 WC: at the midpoint between the
iliac crest and the lowest rib
NCEP-ATPIII
(2001)
25.4 AO: 16.3 Logistic regression model adjusted
for age in female:
Fasting G, TAG and HDL-c High G: 21.4 Low social class: OR = 1.64
BP: three measurements HT: 46.6
High TAG: 30.9
Low HDL-c: 54.3
Salaroli et al.,
2007 [5]
Vitória, Espírito Santo 1630
(54.4% W,
45.6% M)
25-64 WC: at the natural waist or the
lower curvature between the
lowest rib and the iliac crest
NCEP-ATPIII
(2001)
29.8 AO: N/A N/A
Fasting G, TAG and HDL-c High G: N/A
BP: two measurements HT: N/A
High TAG: N/A
Low HDL-c: N/A
Velásquez-
Meléndez
et al., 2007
[19]
Virgem das Graças,
Jequitinhonha Valley,
Minas Gerais
251
(53.4% W,
46.6% M)
18-88 WC: at the midpoint between the
iliac crest and the lowest rib
NCEP-ATPIII
(2001)
21.6 AO: 26.7 Logistic regression model adjusted
for BMI, age and schooling:
Fasting G, TAG and HDL-c High G: 6.0 BMI 25 kg/m
2
: OR = 21.14;
95% CI 8.43-50.01
BP: three measurements HT: 62.5 Age 30-42 years: OR = 3.15;
95% CI 1.08-9.18
High TAG: 22.3 Age 43-59 years: OR = 5.18;
95% CI 1.38-19.41
Low HDL-c: 37.1 Age 60-88 years: OR = 17.58;
95% CI 3.45-49.51
de Oliveira
et al., 2006
[20]
Cavunge, Bahia 240
(57.5% W,
42.5% M)
25-87 WC: at the umbilical level NCEP-ATPIII
(2001)
30.0 AO: 31.7 Age 45 years: PR = 2.60; 95% CI
1.61-4.21
Fasting G, TAG and HDL-c High G: 15.8 Age 55 years: PR = 3.00; 95% CI
1.84-4.89
BP: two measurements HT: 57.1
High TAG: 19.6
Low HDL-c: 70.4
Abbreviations: AHA/NHLBI, American Heart Association/National Heart, Lung, and Blood Institute; AO, abdominal obesity; BP, blood pressure; BMI, body mass index; CRP, C-reactive protein; G, glucose; HDL-c,
HDL-cholesterol; high G, hyperglycemia; high TAG, hypertriglyceridemia; HOMA-IR, Homeostasis Model Assessment of Insulin Resistance; HT, hypertension; IDF, International Diabetes Federation; M, men; MS, metabolic
syndrome; N/A, information not available; NCEP-ATP III, National Cholesterol Education Program Adult Treatment Panel III; PR, prevalence ratio; TAG, triacylglycerol; W, women; WC, waist circumference.
*Only statistically significant associations are shown (P < 0.05).
Reference group for age <30 years.
Reference group for non-white skin color.
§Reference group for higher educational level.
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Jequitinhonha Valley (Minas Gerais), using the NCEP-ATP
III (2005) criterion [14].
Nine studies reported the pre valence of MS by gender
[5,14,16-22]. In five studies [14,19-22] the prevalence of
MS was higher in women than in men. In four other
studies [5,16-18] no difference was observed in the
prevalence of MS between genders. The difference in
prevalence between genders ranged between 0.2% [17]
and 44.7% [22].
Nine studies reported the prevalence of MS by age
[5,14,16-22]. In seven of these [5,14,16-20], the prevalence
of MS increased with age, whereas in the other two
[21,22] this was not demonstrated. The pre valence of
MS was highe st verified in subject s more than 50 yea rs
old. In contra st , prevalence was generally lowest in
those under 30, with the exception of th e indigenous
population of Mato Grosso do Sul where the lowest
prevalence (9.6%) was observed in subject s between 60
and 69 [21].
Prevalence of the metabolic syndrome components
The prevalence of the individual components of MS
among the Brazilian population varied considerably be-
tween studies (Table 1). In six studies [14,16,17,19,20,22],
the overall prevalence of individual components of MS
was reported, whereas de Oliveira et al. [21] reported
only the prevalence of abdominal obesity, hypergly-
cemia and hypertension. The overall weighted mean
prevalence (range) by component was as follows: abdom-
inal obesity 38.9% (11.6%[14]-72.6%[17]); hyperglycemia
16% (6%[19]-38%[22]); hypertension 52.5% (40.3%[21]-
64.7%[22]); hypertriglyceridemia 24% (15.2%[14]-48.7%
[22]); low HDL-c 59.3% (37.1%[19]-76.3%[17]).
The prevalence of individual components of MS by gen-
der was reported in three studies [14,19,21]. In addition,
three other studies described the prevalence of MS com-
ponents by age and gender group [16,17,20]. In general,
the prevalence of abdominal obesity and low HDL-c was
higher in females, whereas prevalence of hypertension was
higher in males. Generally, the prevalence of the individual
components was higher in subjects more than 45 years
old, except for the low HDL-c component.
Abdominal obesity
Seven studies reported the prevalence of abdominal
obesity [14,16,17,19-22]. In these seven studies , the
weighted mean prevalence of abdominal obesity wa s
38.9%. The highest prevalence of abdominal obesity
(72.6%) was found in the urban population of São
Paulo using the IDF criterion [17], whereas the lowest
prevalence (11.6%) was obser ved in the rural popula-
tion of Minas Gerais using th e N CEP-ATP III (2005)
criterion [14].
Hyperglycemia
The prevalence of hyperglycemia was mentioned in seven
studies [14,16,17,19-22]. The weighted mean prevalence of
hyperglycemia was 16%. The prevalence (38%) was highest
in the indigenous population of Rio Grande do Sul [22],
and lowest (6%) in the rural population of Minas Gerais
[19]. Both studies used the NCEP-ATP III (2001) criteria.
Hypertension
The prevalence of hypertension was reported in seven
studies [14,16,17,19-22]. The weighted mean prevalence
of hypertension was 52.5%. Hypertension was shown to be
the most prevalent (64.7%) in the indigenous population
of Rio Grande do Sul [22]. The prevalence (40.3%) was
lowest in the indigenous population of Mato Grosso do
Sul [21].
Hypertriglyceridemia
The weighted mean prevalence of hypertriglyceridemia
was 24% in six studies [14,16,17,19,20,22]. Hypertriglyc-
eridemia was most prevalent (48.7%) among the indigen-
ous population of Rio Grande do Sul [ 22], and least
prevalent (15.2%) in the rural population of Mina s
Gerais [14].
Low HDL-cholesterol
Six studies repor ted the prevalence of the low HDL-c
component of the MS [14,16,17,19,20,22]. The weighted
mean prevalence of low HDL-c was 59.3%. The highest
prevalence of this component was 76.3% in the urban
population of São Paulo [17], and the lowest (37.1%) was
found in the rural population of Minas Gerais [19].
Factors associated with metabolic syndrome
The risk of MS increased significantly with age, body
mass index (BMI) and such conditions as having a white
skin color (compared with a non-white skin color), being
female, belonging to a low social class, and belonging to
the highest quartiles of C-reactive protein and Homeosta-
sis Model Assessment of Insulin Resistance levels (Table 1).
The strongest association was found with BMI 25 kg/m
2
(OR = 21.14; 95% CI 8.43-50.01) [19], followed by age with
subjects aged between 60 and 88 years old compared with
those under 30 (OR = 17.58; 95% CI 3.45-49.51) [19].
Two s tudies reported fa ctors that p rotec ted against
the risk of MS. The education level in females [18], and
moderate alcohol consumption (0.1 to 20 g ethanol/day)
in males and females [14] were inversely related to MS
prevalence.
Discussion
The present systema tic review provides data on the
prevalence of MS in the Brazilian adult population. Ac-
cording to this review, the weighted mean for the general
de Carvalho Vidigal et al. BMC Public Health 2013, 13:1198 Page 7 of 10
http://www.biomedcentral.com/1471-2458/13/1198
prevalence of MS was between 28.9 and 29.6% according
to the criteria used to define MS. This observed preva-
lence was slightly higher than the prevalence estimated
around the world (between 20% and 25%) [4]. In fact, the
mean prevalence of MS in Brazil was higher than that
reported in such European countries as Portugal (27.6%)
[24], Spain (26.6%) [25], France (25% in males and 15.3%
in females) [26] and Italy (28% in males and 26% in fe-
males) [27]. It was also higher than in the United States of
America (22.9%) [7] and some Latin American countries:
Mexico (26.6%) [8] and Peru (18.1%) [10]. This mean
prevalence of MS was higher than that observed in the
CARMELA study, conducted in seven Latin American
countries, and with a prevalence ranging from 14% to 27%
[28]. Prevalences similar to the one we reported in Brazil
were found in Chile (29.5%) [12] and North Africa (30%)
[29]. The mean prevalence we found in Brazil, however,
was lower than that reported in Asia-China (33.9%) [30],
Turkey (36.6%) [31], and Iran (30.1% in males and 55% in
females) [32]-and some other Latin American countries:
Colombia (34.8%) [11] and Venezuela (35.3%) [9].
The highest prevalence (65.3%) of MS in Brazil was
reported in the indigenous population [22]. Likewise,
when analyzed by region (urban, rural and indigenous),
the highest weighted mean for general prevalence of MS
was found in the indigenous population (41.5%) [21,22],
which suggests that these individuals are at higher risk
of cardiovascular disease and diabetes. Kuang-Yao Pan
et al. [33] demonstrated that indigenous groups living in
the northern Ecuadorian Amazon had a 30% higher
probability of mortality and a 62% higher incidence rate
of all-cause morbidity than colonists. According to the
First National Survey of Indigenous Peoples Health and
Nutrition, non-pregnant women presente d the following
risk factors: overweight (30.3%), obesity (15.8%) and
hypertension (13.2%) [34 ].
It is evident that substantial socioeconomic and demo-
graphic changes have occurred in the Brazilian population
over the past decades and the transition from a rural to an
urban lifestyle has been associated with a deterioration in
the metabolic profile because of adverse changes in life-
style habits [19]. Observed disparities in health indicators
underscore that basic healthcare and sanitation services
are not yet as widely available in Brazils indigenous com-
munities as they are in the rest of the country [34].
In the present review, the most frequent MS component
was low HDL-c (59.3%). The same results were found in
Venezuela (65.3%) [9], Colombia (96.1%) [11] and Peru
(females = 60.9%) [10]. In other studies, the most frequent
MS component was abdominal obesity: United States of
America (56.1%) and Chile (41.1%) [12]. In contrast, the
least frequent MS component in Brazil was hyperglycemia
(16%). This was also the rarest MS component observed
in studies conducted in Colombia (3.9%) [11], the United
States of America (19.9%) [7] and Peru (5% in females and
5.4% in males) [10]. In the Chinese population, the least
frequent MS component was low HDL-c (5% in females
and 12.9% in males) [30].
The general prevalence of MS in Brazil, according to
this review, ranged from 14.9% [14] to 65.3% [22], the
differences in MS prevalence being as high as 50.4%. The
differences were also notable in terms of the prevalence of
MS components with the abdominal obesity component
showing the highest difference (61%). The study of MS
has been hampered by the lack of consensus on its defin-
ition, the cutoff points used for its respective components,
and how waist circumference and blood pressure should
be determined. This has an impact on clinical practice and
health policy [3]. Barbosa et al. [35] conducted a cross-
sectional study in a population subgroup of 1439 adults in
the city of Salvador in Brazil, and showed that the cutoff
points for waist circumference proposed by NCEP-ATP
III [36] were inappropriate and underestimated the preva-
lence of MS in the population studied, particularly in men.
Different cutoff points for the waist circumference and the
measurement site of waist circumference make it difficult
to compare studies. Our results showed that in most stud-
ies [14-19,21,22] waist circumference was measured at the
midpoint between the iliac crest and the lowest rib. How-
ever, Salaroli et al. [5] took measurements at the natural
waist or the lower curvature between the lowest rib and
the iliac crest, and de Oliveira et al. [20] at the umbilical
level. Moreover, different techniques and instruments
were also used to measure blood pressure. Another factor
that limits the comparability between studies is the differ-
ent source and type of population studied. For instance,
five of the studies selected were conducted in urban popu-
lations [5,15-18], three in rural populations [14,19,20] and
two in indigenous populations [21,22]. Nevertheless, we
selected only studies that evaluated apparently healthy
adults from the general population in order to make it
possible to compare studies, despite the variability in the
populations studied. Nine studies had more women than
men [5,15-22], whereas one had similar numbers of men
and women [14].
In order to diagnose MS, half of studies [5,16,19,20,22]
used the NCEP-ATP III (2001) criterion. There is no
consensus about the best criterion for diagnosing MS in
clinical practice. Recently, IDF and AHA/NHLBI repre-
sentatives have held discussions in an attempt to resolve
the remaining differences between MS definitions and
they have recognised that the risk associated with a par-
ticular waist circumference mea surement will depend
on the population. The harmonized criterion proposed
by IDF a nd AHA/NHLBI will enable countries to be
compared in the future and should be used as a unifying
worldwide consen sus defin ition for MS [1]. Apart from
the methodological differences between studies, the
de Carvalho Vidigal et al. BMC Public Health 2013, 13:1198 Page 8 of 10
http://www.biomedcentral.com/1471-2458/13/1198
variability in the prevalence of MS observed in our re-
view between populations could be explained by demo-
graphic, epidemiological and nutritional transitions, a s
well as environmental and social influences, and ethnic
differences [18].
Like other reviews, this study has some limitations, so
its findings should be interpre ted with caution. The
multicultural characteristics and the demographic and
epidemiological variability in the Brazilian population
make it difficult to generalize the findings of this study
in Brazil. Further limitations are the different criteria
used to diagnose MS, the different measurement sites
and cutoff point s for waist circumference and the cutoff
points for hyperglycemia. Hence, the need for more
specific and structured research on the prevalence of
MS and its determinant s in Brazil are imperative.
Conclusions
To our knowledge, this is the first published systematic
review assessing studies on the prevalence of MS and its
determinant s in the Brazilian adult population. Despite
the methodological differences and the lack of consensus
on criteria for MS diagnosis, our systematic re view indi-
cates a high prevalence of MS in the healthy Brazilian
adult population. Criteria for MS diagnosis need to be
standardized and suitable cutoff points for individual
MS components in Brazil defined if the precise scope of
this public health problem in Brazil is to be determined.
Information about how the clinical MS components are
distributed and how they are related could provide
greater insight into MS and contribute to the planning
and implementation of public health strategies. Therefore,
primary preventive care could be used to reduce its preva-
lence and impact on human health.
Abbreviations
AHA/NHLBI: American Heart Association/National Heart, Lung, and Blood
Institute; BMI: Body mass index; HDL-c: HDL-cholesterol; IDF: International
Diabetes Federation; MS: Metabolic syndrome; NCEP-ATP III: National
Cholesterol Education Program Adult Treatment Panel III; NHANES: National
Health and Nutrition Exam ination Survey.
Competing interests
The authors declare that they have no competing interests.
Authors contributions
JB and JSS directed the present study. All the authors contributed to the
study concept and design. FCV helped with article searches, review and
selection. All the authors contributed to the analysis and interpretation of
data and drafting of the manuscript. JSS and NB worked as methodological
advisors. All authors read and approved the final manuscript.
Acknowledgements
We thank the CAPES Foundation, Ministry of Education of Brazil (BrasíliaDF
70040-020, Brazil) for providing FCV with a research grant (process
3928-13-6) and the CNPq Foundation, Brazil, for financial support. This study
was funded, in part, by the Spanish Ministry of Health (ISCIII), PI1001407,
Thematic Network G03/140, RD06/0045, FEDER (Fondo Europeo de
Desarrollo Regional), and the Centre Català de la Nutrició de lInstitut
dEstudis Catalans. None of the funding sources played a role in the design,
collection, analysis or interpretation of the data or in the decision to submit
the manuscript for publication. The authors would like to thank the professors
of the Federal University of Viçosa Luciana Ferreira da Rocha SantAna and Silvia
Eloiza Priore for their collaboration and RIBESMET (Red Iberoamericana para el
Estudio del Síndrome Metabólico, http://www.ribesmet.org/) Thematic Network.
Ethical approval not required.
Author details
1
Postgraduate Program in Nutrition Science, Department of Nutrition and
Health, Federal University of Viçosa, Viçosa, Brazil.
2
Human Nutrition Unit,
Department of Biochemistry and Biotechnology, University Hospital Sant
Joan de Reus, IISPV, Faculty of Medicine and Health Sciences, Rovira i Virgili
University, Reus, Spain.
3
CIBERobn Physiopathology of Obesity and Nutrition,
Institute of Health Carlos III, Madrid, Spain.
Received: 10 September 2013 Accepted: 11 December 2013
Published: 18 December 2013
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doi:10.1186/1471-2458-13-1198
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    • "The prevalence of MS has recently increased in developing countries . Several studies have reported a high prevalence of MS in Malaysia (27.5 %), India (28.2 %), Philippines (19.7 %), Nigeria (28.1 %), Brazil (29.6 %), Turkey (44.0 %), and Iran (36.9 %)19202122232425 . As the largest developing country, China is experiencing an emerging epidemic of MS, which might be related to rapid economic development and urbanization [9]. "
    [Show abstract] [Hide abstract] ABSTRACT: Background: Metabolic syndrome (MS) comprises a set of conditions that are risk factors for cardiovascular diseases and diabetes. Numerous epidemiological studies on MS have been conducted, but there has not been a systematic analysis of the prevalence of MS in the Chinese population. Therefore, the aim of this study was to estimate the pooled prevalence of MS among subjects in Mainland China. Methods: We performed a systematic review by searching both English and Chinese literature databases. Random or fixed effects models were used to summarize the prevalence of MS according to statistical tests for heterogeneity. Subgroup, sensitivity, and meta-regression analyses were performed to address heterogeneity. Publication bias was evaluated using Egger's test. Results: Thirty-five papers were included in the meta-analysis, with a total population of 226,653 Chinese subjects. Among subjects aged 15 years and older, the pooled prevalence was 24.5 % (95 % CI: 22.0-26.9 %). By sex, the prevalences were 19.2 % (95 % CI: 16.9-21.6 %) in males and 27.0 % (95 % CI: 23.5-30.5 %) in females. The pooled prevalence of MS increased with age (15-39 years: 13.9 %; 40-59 years: 26.4 %; and ≥60 years: 32.4 %). Individuals living in urban areas (24.9 %, 95 % CI: 18.5-31.3 %) were more likely to suffer from MS than those living in rural areas (19.2 %, 95 % CI: 14.8-23.7 %). Hypertension was the most prevalent component of MS in males (52.8 %), while the most prevalent component of MS for females was central obesity (46.1 %). Conclusions: Our systematic review suggested a high prevalence of MS among subjects in Mainland China, indicating that MS is a serious public health problem. Therefore, more attention should be paid to the prevention and control of MS.
    Full-text · Article · Dec 2016
    • "The MetS can be diagnosed by observation of three of these criteria. In the past several years, the prevalence of MetS increased worldwide [3, 4]; however, in the United States of America, it has declined from 25.5% in 1999/2000 to 22.9% in 2009/2010 [5]. Weiss and colleagues reported that obesity is directly associated with increased prevalence of MetS [6]. "
    [Show abstract] [Hide abstract] ABSTRACT: ABCA1 and ABCG1 genes encode the cholesterol transporter proteins that play a key role in cholesterol and phospholipids homeostasis. This study was aimed at evaluating and comparing ABCA1 and ABCG1 genes expression in metabolic syndrome patients and healthy individuals. This case-control study was performed on 36 patients with metabolic syndrome and the same number of healthy individuals in Hamadan (west of Iran) during 2013-2014. Total RNA was extracted from mononuclear cells and purified using RNeasy Mini Kit column. The expression of ABCA1 and ABCG1 genes was performed by qRT-PCR. Lipid profile and fasting blood glucose were measured using colorimetric procedures. ABCG1 expression in metabolic syndrome patients was significantly lower (about 75%) compared to that of control group, while for ABCA1 expression, there was no significant difference between the two studied groups. Comparison of other parameters such as HDL-C, FBS, BMI, waist circumference, and systolic and diastolic blood pressure between metabolic syndrome patients and healthy individuals showed significant differences ( P < 0.05 ). Decrease in ABCG1 expression in metabolic syndrome patients compared to healthy individuals suggests that hyperglycemia, related metabolites, and hyperlipidemia over the transporter capacity resulted in decreased expression of ABCG1. Absence of a significant change in ABCA1 gene expression between two groups can indicate a different regulation mechanism for ABCA1 expression.
    Full-text · Article · Dec 2015
    • "The agestandardized percentage of obese subjects with MetS ranged from 43% to 78% in men in different European cohorts, with elevated blood pressure the most frequently occurring factor contributing to the prevalence of MetS [80]. The prevalence in population-based surveys for male subjects is 20% in Oman [81], 26% in China [81], 27% in Turkey [81], 29.6% in Brazil [82], 25% in adults in the U.S., with higher rates among racial/ethnic minority groups [83]. A recent meta-analysis showed that the pooled MetS prevalence is 38.7% in individuals with post-traumatic stress disorder (PTSD) [84] . "
    [Show abstract] [Hide abstract] ABSTRACT: Objective: The aim of this longitudinal study was to evaluate the association between occupational stress and metabolic syndrome (MetS) in a rapid response police unit. Method: Work-related stress was continuously monitored during the 5-year period with both the Demand-Control-Support (DCS) and the Effort-Reward Imbalance (ERI) models. Blood pressure, body mass index (BMI), waist circumference, triglycerides, HDL-cholesterol, and fasting blood glucose were measured at baseline in January 2009, and in January 2014. 234 out of 290 police officers (81%) completed the follow-up. Results: The majority of police officers had high stress levels. At follow-up, police officers in the highest quartile of stress had significantly higher mean levels of triglycerides, and lower levels of HDL-cholesterol than their colleagues in the lowest quartile. Police officers with high stress had an increased adjusted risk of developing MetS (aOR = 2.68; CI95% = 1.08-6.70), and hypertriglyceridemia (aOR = 7.86; CI95 = 1.29-48.04). Demand and Effort were significant predictors of MetS. Conclusion: Our study supports the hypothesis that work-related stress induces MetS, particularly through its effects on blood lipids. Future longitudinal studies with continuous monitoring of stress levels will definitively confirm this hypothesis.
    Full-text · Article · Dec 2015
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