Key words: Metabolic syndrome, adults, Kuwait
.........................................................................................................................

INTRODUCTION

Metabolic syndrome is the disease of the new millennium; its prevalence is increasing dramatically because of the rising number of people who are obese and inactive. [1]

To date there is no global consensus on a definition of metabolic syndrome.[2] In 1998 the World Health Organization (WHO) proposed a formal definition of metabolic syndrome, and three years later, the National Cholesterol Education Program - Adult Treatment Panel III (NCEP - ATP III) proposed its definition. The European Group for the study of Insulin Resistance (EGIR) also developed a definition. The attention brought by the report of the NCEP - ATP III to the metabolic syndrome has ignited an intense interest, as evidenced by the numerous publications and meetings concerning the metabolic syndrome. [3,4]

"The whole is greater than the sum of its parts" such axiom is the case with metabolic syndrome.[4] The major characteristics of metabolic syndrome include insulin resistance, abdominal obesity, elevated blood pressure (BP) and lipid abnormalities in the form of elevated levels of triglycerides and low levels of high density lipoprotein cholesterol (HDL-C).[3]

To have a mechanistic view of how metabolic syndrome develops, it is necessary that obesity viewed as a contributory factor to insulin resistance/hyperinsulinaemia rather than a consequence of the defect in insulin action. It is to be emphasized that obesity increases the likelihood that an individual will be insulin resistant but the reverse is not true.[5]

Metabolic syndrome has piqued the interest and concern of physicians. It represents a co-mingling of several conditions and risk factors and links accelerated cardiovascular disease (CVD) with insulin resistance.[6] This cluster of risk factors is responsible for much of the excess CVD morbidity among overweight and obese patients and those persons with type 2 diabetes.[3] By the time a diagnosis of diabetes type 2 is made, about 70 to 90% of patients have metabolic syndrome irrespective of ethnicity or definition used.[2,3]

Currently the metabolic syndrome is viewed as the phenotypic confluence of central obesity, atherogenic dyslipidaemia, hypertension, and insulin resistance (with or without type 2 diabetes) resulting from deregulated gene expression and lifestyle behaviors. [7]

Kuwait showed rapid progress within the span of one generation. The economic and social development brought sedentary lifestyle changes to the Kuwaiti population. Accordingly, the prevalence of obesity in Kuwait is increasing gradually and may be the highest among the Gulf countries [8]. It turns out to be a major public health problem as 79.7% of the adult males and 81.2% of adult females are overweight and obese. [9] In view of that, the aim of the present study was to estimate the prevalence of metabolic syndrome and the high-risk aspects contributing to it among healthy Kuwaiti adults attending two primary health care centers in Kuwait.

METHODS

A cross sectional study was carried out on subjects attending Quortuba and Abdulla Al-Salem primary health care centers for routine examination. The inclusion criteria were Kuwaiti nationals aged from 20-44 years who were attending the health center for routine check up and who were not suffering from or have ever been diagnosed with any chronic illness such as diabetes, hypertension, heart problems or dyslipidaemia. Pregnant females were excluded.

A convenience sample of 434 subjects was invited to participate in the study after having an individual verbal consent for involvement. A relevant history, physical examination and laboratory investigations were performed as part of routine check up.

Data collected included personal data: age, gender and some lifestyle behaviors such as current smoking status and level of regular aerobic physical activity such as brisk walking at least 30 minutes per day, most days of the week, according to the recommendation of lifestyle modification, Seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High blood Pressure [10]. The NCEP-ATP III criteria of metabolic syndrome were used, and it dictates that the aggregation of three or more of the following: [2]

Blood samples were collected in the lab, following the usual procedures. FBG (after 6-8 hours of fasting) and lipids profile -HDL-C and triglycerides- (after 12-14 hours of fasting) were assessed.

Blood pressure was measured with a standard mercury sphygmomanometer on the left arm after at least 10 minutes of rest. Mean values were determined from two independent measurements.
Waist circumference was measured to the nearest cm while subjects were fasting overnight and wearing only underwear. Subjects' weight (to the nearest half kg) and height (to the nearest cm) were measured using the Detecto-Scale. Calibration was done every morning before use. Body mass index (BMI) was calculated. Subjects with BMI equal to or greater than 30.0 Kg/m2 were classified as obese, and those with BMI 25-29.9 Kg/m2 were categorized as overweight and 18.5-24.9 Kg/m2 were normal. [11,12]

RESULTS

The study was carried out among 434 Kuwaiti adults; the majority were males (62.2%). The mean age and standard deviation (SD) was 29.2 (6.5) years where females were significantly older than males (30.3 and 28.6 years respectively).

Only about one third (35.7%) of the participants had normal BMI, while overweight (27%) and obesity (37.3%) showed no significant gender differences (31.1% & 39.6% of females respectively) and 24.4% & 36% of males respectively. The mean BMI was 28.4 (6.9) and ANOVA analysis showed significant gradual increase by age. It increased from almost 27 during the 20s to about 30 in the 30s to 32.3 in the 40s (p<0.0001).

Males significantly dominated females regarding smoking (61.5% vs. 2.4% respectively, p<0.0001) and exercising regularly (47.4% vs 21.3% respectively, p<0.0001).

The prevalence of the five biochemical indices for diagnosing metabolic syndrome according to NCEP-ATP III criteria is illustrated in Table 1 Low HDL-C showed the highest prevalence (50.7%), followed by central obesity that was prevalent among more than one third of the sample (34.6%) and was significantly more prevalent among females than males (45.7% vs 27.8% respectively). High TG was prevalent among 19% and followed an opposing gender pattern where males rated significantly higher than double females (28.9% vs 14.1% respectively). About 17% of the sample were suffering from high blood pressure and impaired fasting blood glucose.

Table 2 revealed that almost 18% of the healthy Kuwaiti adults included in the study with almost equal prevalence among males and females were suffering from metabolic syndrome. Also about another quarter (23%) was at high potential risk of developing metabolic syndrome (diagnosed with 2 criteria of the NCEP-ATP III) Multivariate binary logistic regression analysis was performed to eliminate the effect of potential confounders. Metabolic syndrome was the dependent variable (0=subjects with no metabolic syndrome, 1=subjects with metabolic syndrome). The classification matrix overall prediction accuracy showed that 79.7% of the subjects were correctly identified by the model. Four factors (age, gender, smoking status and practicing exercise) represented the independent variables. Age was the only significant predictor for metabolic syndrome as getting older gradually raised the risk of developing metabolic syndrome from 2.4 times (risk) in the early 30s to 3.5 times (hazard) in the late 30s to 4.4 times (vulnerability) in the early 40s compared to early 20s as illustrated in Table 3.

DISCUSSION

The prevalence of metabolic syndrome (18%) among healthy adults is remarkably alarming. Our study focused on apparently healthy young individuals who were not treated for any chronic illness, and who can be easily missed being recognized as harboring a CVD risk when they visit their clinicians for any other reason. Many of them could be considered free of, although according to the criteria of ATP - III they are diagnosed as having metabolic syndrome.

This study can be considered the only one done in Kuwait and maybe in the Gulf area, estimating the prevalence of metabolic syndrome among healthy adults. The results of this study although lower than the prevalence of metabolic syndrome (34%) using the ATP-III, among a group of hypertensive Kuwaiti adults above 40 years, but more hazardous. Those people were unaware about the towering risk factors that threatened their lives and made them more prone to suffer from CVD at any point of time [13]. This finding also is in concordance with the study performed among US adults using ATP-III criteria and reported prevalence of metabolic syndrome of 21.8%.[14] Moreover, the presence of about one quarter having two criteria of ATP-III are at risk of developing metabolic syndrome in a few years when get older, and add to the seriousness of the situation. This echoes the increasing morbidity and mortality rates from developing CVD and diabetes mellitus type 2 in early ages.[15,16] As a construct that denotes risk factor clustering, the metabolic syndrome has been a useful paradigm. That is, it draws attention to the fact that some CVD risk factors tend to cluster in patients so predisposed. The teaching point implied by the term, and explicitly stated by the NCEP - ATP III, is that the identification of one of the risk variables in a patient should prompt a search for others.[17]

Understanding the prevalence of metabolic syndrome is critical in helping define the public health burden. The lack of a standard definition has impeded greatly the efforts to determine the prevalence. Efforts by the WHO, NCEP-ATP III, and the EGIR to develop standard definitions have been critical in trying to determine the prevalence of metabolic syndrome. [4] The actual prevalence of metabolic syndrome varies greatly by definition used, and in population groups, studied.[2]
All reports on the definition of metabolic syndrome have mainly emphasized lifestyle interventions as first-line management.[18] Lifestyle modification is an essential part of weight loss for people with or at risk of metabolic syndrome. Maintaining a healthy diet and weight, performing 30 to 60 minutes of moderately intense exercise every day and quitting smoking can all help reduce a person's chances of developing heart disease.[1] This was not analogous with the finding that almost two thirds of the healthy Kuwaiti adults were not practicing exercise regularly.

Getting older was the only predictor for metabolic syndrome in the present study and this reflects the further sedentary lifestyle and lack of healthy habits by the aged in the studied population. This is in agreement with a consistent finding in several studies using different definitions and that is the observation that the prevalence is highly age-dependent.[19]

Sedentary lifestyle, inadequate nutrition and physical inactivity are the roots of the syndrome and it has been strongly recommended that a healthy lifestyle that holds optimum body weight and increased physical activity should be adopted. Consequently, the non-pharmacological therapy of the metabolic syndrome should be emphasized. The most important treatment is the reduction of body weight in the presence of obesity, which is relevant for almost 90% of the patients. Body weight can rapidly be diminished by hypocaloric diets. Increased physical activity also lowers weight or prevents relapsing. Both methods, reducing diet and physical training, act on various factors related to insulin resistance. For example, hypocaloric diets activate thyroxine kinase of the insulin receptor and reduce glucose and insulin in plasma. Physical training reduces not only insulin and glucose in plasma but also frees fatty acids and increases capillary density in skeletal muscle. [20] As obesity is a major public health problem in Kuwait, hence further studies are recommended to identify the syndrome in the general population.

The largest public health benefits will be in preventing the development and progress of metabolic syndrome. The challenge is to transform attitudes and change behaviour. Long-lasting changes in lifestyle are essential in order to achieve health enhancement. Therefore, programs on individual or social basis are required in order to improve nutrition and increase physical activity.

CONCLUSION

Prevalence of metabolic syndrome among healthy adults attending the referred primary health care centers in Kuwait is high and echoes rapid intervention. Lifestyle behaviour programs should be considered to help people to adapt effectively to a healthy way of living. Family physicians are recommended to use ATP-III criteria for early detection of high risk subjects.

Table 1. Distribution of NCEP-ATP III criteria for diagnosis of metabolic syndrome

Variables	Total n=434	Males n=270	Females n=164	p value*
Central obesity     Not obese     Obese	65.4 34.6	72.2 27.8	54.3 45.7	0.0001
TG     Normal     High	81.1 18.9	78.1 28.9	85.9 14.1	0.04
HDL-C levels     Desirable     Low	49.3 50.7	51.5 48.5	45.7 54.3	0.25
Blood pressure     Normal     High	83.4 16.6	83.0 17.0	84.1 15.9	0.75
FBG     Normal     Impaired	82.9 17.1	81.1 18.9	86.0 14.0	0.19

 *Chi square test

back to text

Table 2: Prevalence of metabolic syndrome in healthy Kuwaiti adults

Variables*	Total n=434 (%)	Males n=270 (%)	Females n=164 (%)
No metabolic syndrome	28.3	30.4	25
At potential risk for metabolic syndrome:    1 symptom    2 symptoms	30.9 22.8	28.9 22.6	34.1 23.2
Metabolic syndrome:    (3 symptoms)	18.0	18.1	17.7

Chi square test , *p>0.05

back to text

Table 3. Binary logistic regression of significant predictors for metabolic syndrome

Variables	ß	Adjusted OR	95% CI	p value
Age (years):    20 – 24 (RG)    25 – 29    30 – 34    35 – 39    40 – 44	-0.614 0.868 1.265 1.480	0.541 2.37 3.54 4.39	0.24 – 1.25 1.18 – 4.76 1.75 – 7.16 1.97 – 9.79	0.15 0.02 <0.0001 <0.0001

The adjusted variables were: age, gender, smoking, physical exercise
RG: Reference group

back to text

REFERENCES