The metabolic syndrome is characterized by a clustering of. The Increasing Prevalence of Metabolic Syndrome among Finnish Men and Women over a Decade

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1 ORIGINAL Endocrine ARTICLE Care The Increasing Prevalence of Metabolic Syndrome among Finnish Men and Women over a Decade Gang Hu, Jaana Lindström, Pekka Jousilahti, Markku Peltonen, Lena Sjöberg, Risto Kaaja, Jouko Sundvall, and Jaakko Tuomilehto Departments of Health Promotion and Chronic Diseases Prevention (G.H., J.L., P.J., M.P., J.T.) and Health and Functional Capacity (J.S.), National Public Health Institute, FIN Helsinki, Finland; Department of Public Health (G.H., L.S., J.T.), University of Helsinki, FIN Helsinki, Finland; Department of Obstetrics and Gynaecology (R.K.), Helsinki University Hospital, FIN Helsinki, Finland; and South Ostrobothnia Central Hospital (J.T.), Seinäjoki, Finland Objective: Our objective was to assess a 10-yr change in the prevalence of the metabolic syndrome defined by the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) among Finnish men and women. Design and Subjects: Two cross-sectional population surveys were performed in Finland in 1992 and A total of 3495 participants aged yr were included in the analysis. Results: In both years the metabolic syndrome was more common among men than women. In men the prevalence of the metabolic syndrome tended to increase slightly between 1992 and 2002, from % (P 0.139) based on the NCEP definition, and from % based on the IDF definition (P 0.102). In women the prevalence of the metabolic syndrome increased significantly from % based on the NCEP definition (P 0.003), and from % based on the IDF definition (P 0.002). In both sexes the prevalence of high blood pressure decreased, but the abnormalities in glucose metabolism increased between 1992 and The prevalence of central obesity increased in women between 1992 and Conclusions: In Finland the prevalence of the metabolic syndrome, based both on the NCEP and IDF definitions, is higher in men than women. However, the increase in the prevalence of the metabolic syndrome, from , was significant only among women. (J Clin Endocrinol Metab 93: , 2008) The metabolic syndrome is characterized by a clustering of several cardiovascular risk factors, including impaired glucose regulation, hyperinsulinemia, elevated triglycerides, decreased high-density lipoprotein (HDL) cholesterol, increased blood pressure (BP), and obesity and its central distribution. The pathogenesis of the syndrome is complex and so far incompletely understood, but obesity, sedentary lifestyle, dietary factors, and genetic factors are known to contribute and interact in its development (1, 2). The strongest dimension of the metabolic syndrome is its association with the risk of the development of type 2 diabetes (3 6), but ultimately it is advocated as a tool to predict cardiovascular disease (CVD) (7 10). In the past few years, several expert groups have developed simple diagnostic criteria to be used in clinical practice to identify subjects with the metabolic syndrome. Until very recently, the World Health Organization Consultation for diabetes and its complications (11) and the National Cholesterol Education Program (NCEP) Expert Panel (12) have formulated definitions for the metabolic syndrome. In 2005, the International Diabetes Federation (IDF) published new criteria for identifying subjects with the metabolic syndrome (13), and the American Heart Association and the National Heart, Lung, and Blood Institute proposed minor modifications to the NCEP definition (14). The prevalence of the metabolic syndrome reported from different studies has varied widely, mainly because of differences in the definitions of the syndrome and in part because of differences in the X/08/$15.00/0 Printed in U.S.A. Copyright 2008 by The Endocrine Society doi: /jc Received August 22, Accepted December 3, First Published Online December 11, 2007 Abbreviations: BP, Blood pressure; CVD, cardiovascular disease; HDL, high-density lipoprotein; IDF, International Diabetes Federation; NCEP, National Cholesterol Education Program; NHANES, National Health and Nutrition Examination Survey. 832 jcem.endojournals.org J Clin Endocrinol Metab. March 2008, 93(3):

2 J Clin Endocrinol Metab, March 2008, 93(3): jcem.endojournals.org 833 characteristics of the populations studied (8, 15 19). Only a few studies have reported trends in the prevalence of the metabolic syndrome by any criteria thus far (20 23). Information regarding trend in the prevalence of the metabolic syndrome outside the United States is largely unknown. The aim of this study was to assess the trend during in the prevalence of the metabolic syndrome defined by the NECP and IDF among Finnish adults. Subjects and Methods Subjects As part of the national cardiovascular risk factor monitoring studies, baseline surveys were performed in two Eastern Finnish provinces, North Karelia and Kuopio, in the Turku-Loimaa region in Southwestern Finland, and in the Helsinki capital area in 1992 and The sample included subjects who were yr of age. The original sample was sampled at random after stratification by sex and four equally large 10-yr age groups according to the World Health Organization MONItoring trends and determinants in CArdiovascular disease protocol (24). A subsample (45 64 yr old) comprising 3201 subjects in 1992 and 1851 subjects in 2002 was invited to receive the fasting glucose test at baseline. The participation rates were 67% in 1992 and 74% in After excluding 15 subjects due to incomplete data on any variables required, the present analysis comprises 2120 participants in 1992 and 1375 participants in The participants gave an informed consent (verbal 1992 and signed 2002). These surveys were conducted according to the ethical rules of the National Public Health Institute, and the investigations were performed in accordance with the Declaration of Helsinki. Measurements A self-administered questionnaire was mailed to the participants to be completed at home. The questionnaire included questions on medical history, use of antihypertensive and antidiabetic drugs, smoking habits, physical activity, and dietary habits. Based on the responses, the participants were classified as never, ex-, and current smokers. Physical activity included occupational, commuting, and leisure time physical activity. A detailed description of the questions has been presented elsewhere (25 27). The participants reported their occupational physical activity according to the following three categories: low, moderate, and high. The daily commuting return journey to work was grouped into three categories: 1) using motorized transportation, or not working outside of home (0-min walking or cycling); 2) walking or bicycling 1 29 min; and 3) walking or bicycling for more than 30 min. Self-reported leisure time physical activity was classified into three categories: low, moderate, and high. Alcohol consumption was categorized into three groups: none, 1 100, and more than 100 g/wk. At the study site, specially trained research nurses measured the height, weight, waist, and hip circumferences, as well as BP using a standardized protocol (24). Body weight of the participants wearing usual light indoor clothing without shoes was measured with a 0.1-kg precision. Height was measured to the nearest 0.5 cm. Body mass index was calculated as weight in kilograms divided by the square of the height in meters. Waist circumference was measured midway between the lower rib margin and iliac crest. Hip circumference was measured at the level of widest circumference over greater trochanters. BP was measured with a standard sphygmomanometer from the right arm of the participant who was seated for 5 min before the measurement. Blood samples were collected after an overnight fast and mailed to a central laboratory. Glucose concentration was determined with the glucose dehydrogenase method (Hoffmann-La Roche, Basel, Switzerland) in 1992 and the glucose dehydrogenase method (ABX Diagnostics, Montpellier, France) in HDL-cholesterol levels were measured in 1992 using the enzymatic cholesterol method (CHOD-PAP; Boehringer Mannheim, Mannheim, Germany) after precipitation of apo -containing lipoproteins with dextran sulfate (Pharmacia, Uppsala, Sweden) and magnesium chloride(merck, Darmstadt, Germany), andin2002usingthedirecthdlassay, polyethylene glycol-modified enzyme (Thermo Electron Corp., Vantaa, Finland). Enzymatic methods were used to determine triglyceride levels (glycerol phosphate oxidase-p-aminophenazone; Boehringer Mannheim) in 1992 and (Thermo Electron Corp.) 2002 (28). All samples were analyzed in the same laboratory at the National Public Health Institute. According to the External Quality Assessment program organized by Labquality (Helsinki, Finland), the systematic error (bias) was 5.7% (n 5, SD 1.5) for HDL-cholesterol, 2.3% (n 5, SD 1.1) for triglycerides, and 2.8% (n 12, SD 2.5) for glucose in 1992, and 1.7% (n 5, SD 3.3) for HDL-cholesterol, 0.9% (n 5, SD 1.4) for triglycerides, and 0.5% (n 12, SD 3.0) for glucose in The assay conditions such as collecting of the blood samples, experimental methods, technicians, laboratory, and instruments in the two surveys were identical. Definition of the metabolic syndrome In this study we used two proposed definitions of the metabolic syndrome. According to the updated NCEP definition of the metabolic syndrome (14), an individual has the metabolic syndrome if he or she met at least three of the following criteria: elevated waist circumference ( 102 cm in men or 88 cm in women); elevated triglyceride level ( 1.7 mmol/liter), reduced HDL-cholesterol level ( 1.04 mmol/liter in men or 1.29 mmol/liter in women), and elevated BP ( 130/85 mm Hg or treatment with antihypertensive medications); and elevated fasting glucose value ( 5.6 mmol/liter or drug treatment for elevated glucose). The IDF definition considers the metabolic syndrome to be present in individuals who have central obesity defined as waist circumference more than or equal to 94 cm in men, or more than or equal to 80 cm in women for Europids, in addition to at least two of the four following criteria: fasting glucose more than or equal to 5.6 mmol/liter or previously diagnosed type 2 diabetes; systolic BP more than or equal to 130 mm Hg and/or diastolic BP more than or equal to 85 mm Hg or current use of antihypertensive drugs; HDL-cholesterol less than 1.04 mmol/liter in men or less than 1.29 mmol/liter in women or a specific treatment for lipid abnormalities; and triglycerides more than or equal to 1.7 mmol/ liter or a specific treatment for lipid abnormalities (13). Statistical analyses Differences of the mean values of baseline characteristics and prevalence of the metabolic syndrome and its individual components of the metabolic syndrome between the two study time points were tested by independent-samples t test analysis for continuous variables and the 2 test for categorical variables. The statistical package SPSS for Windows (version 15.0; SPSS, Inc., Chicago, IL) was used for statistical analysis. Results From , mean BP and triglyceride levels, and the prevalence of high BP significantly decreased, whereas the prevalence of glucose abnormalities (high fasting glucose or previously diagnosed diabetes) increased significantly in both genders (all P 0.001) (Table 1). The mean waist circumference and the prevalence of central obesity increased significantly in women (P 0.001), but not in men. The prevalence of the metabolic syndrome was higher in men than women, both in 1992 and 2002, but the increase in the prevalence during was significant in women only (Table 2). In women the prevalence of the metabolic syndrome increased from % based on the NCEP definition (P 0.003), and from % based on the IDF definition (P 0.002). The increase in the prevalence, based on both NCEP and IDF definitions, was significant in the age groups of and yr. In men the

3 834 Hu et al. in Prevalence of Metabolic Syndrome J Clin Endocrinol Metab, March 2008, 93(3): TABLE 1. Background factors and the prevalence of individual components of the metabolic syndrome by sex in 1992 and 2002 and their changes prevalence of the metabolic syndrome increased only slightly but nonsignificantly between 1992 and 2002, from %, based on the NCEP definition, and from % based on the IDF definition (all P 0.1). In men the prevalence of the metabolic syndrome did not change in the younger age group, whereas a statistically significant increase in the prevalence was found in the age group of yr (P 0.041) by the IDF definition, but not by the NCEP definition. When we performed some additional analyses excluding participants with diabetes (n 326), the same trend was found (Table 2). During , the prevalence of the metabolic syndrome did not change in men. However, in women the prevalence of the metabolic syndrome increased from % based on the NCEP definition (P 0.002), and from % based on the IDF definition (P 0.001). TABLE 2. Prevalence of the metabolic syndrome among nondiabetic subjects according to the NCEP and IDF definitions by age and sex in 1992 and 2002 and their changes Men Men Women Women n BMI (kg/m 2 ) Waist circumference (cm) Systolic BP (mm Hg) Diastolic BP (mm Hg) HDL-cholesterol (mmol/liter) Triglycerides (mmol/liter) Central obesity, waist circumference cm in men or 88 cm in women (%) Central obesity, waist circumference cm in men or 80 cm in women (%) BP 130/85 or use medication (%) HDL-cholesterol 1.04 mmol/liter in men or mmol/liter in women (%) Triglycerides 1.7 mmol/liter (%) Fasting plasma glucose 5.6 mmol/liter or previously diagnosed type 2 diabetes (%) Data are mean or percentage. BMI, Body mass index. Total sample NCEP definition Total IDF definition Total Excluding diabetic patients NCEP definition Total IDF definition Total

4 J Clin Endocrinol Metab, March 2008, 93(3): jcem.endojournals.org 835 Discussion Between 1992 and 2002, the prevalence of the metabolic syndrome based on the NCEP and IDF definitions has increased significantly among middle-aged Finnish women, but not among middle-aged Finnish men. Increases in the prevalence of abdominal obesity and abnormalities in glucose metabolism accounted for the increase in the prevalence of the metabolic syndrome in women. Nevertheless, even in 2002 the prevalence of the metabolic syndrome was higher in men than women. Only a few studies have examined the trend in the prevalence of the metabolic syndrome, and the results are inconsistent (20 23). Ford et al. (20) have reported that the ageadjusted prevalence of the metabolic syndrome increased from 27.0% in National Health and Nutrition Examination Survey (NHANES) III to 32.9% in NHANES (P 0.014) based on revised NCEP definition in U.S. women, however, it did not change in U.S. men (from %; P 0.866). Moreover, there was no gender difference in the prevalence of the metabolic syndrome in either NHANES III (P 0.610) or NHANES (P 0.177). In the San Antonio Heart Study, an increase in the prevalence of the metabolic syndrome is present in men and women, in Mexican Americans and non-hispanic whites, and in diabetic and nondiabetic individuals (22). However, two other studies, the Mexico City Diabetes Study (21) and the Korean National Health and Nutrition Survey (23), show no increase trend in the prevalence of the metabolic syndrome. Women had a higher prevalence of the metabolic syndrome than men in the Mexico City Diabetes Study (21) and the Korean National Health and Nutrition Survey (23). In the present study, the prevalence of the metabolic syndrome based on the NCEP and IDF definitions has increased significantly among Finnish women but not among Finnish men from Nevertheless, the prevalence of the metabolic syndrome was higher in men than women in both 1992 and Different study populations and different changes in individual components of the metabolic syndrome can explain the different change trend of the prevalence of the metabolic syndrome in these studies. Nevertheless, it is worth noting that the gender difference in trend in the prevalence in the United States was in keeping with our results. Another issue is that the prevalence of the metabolic syndrome in Finnish men and women was clearly higher than that in the United States. This is most likely due to the high prevalence of high BP in Finland (29), even though BP levels have decreased in Finland during the last decades. During the last decades, Finland has achieved great success in prevention and control of CVD and several CVD risk factors by the community based intervention program, including promotion of more healthy diets, reorganization of hypertension care, etc. (30 32). In the present study, we found that during , mean BP and serum triglyceride levels, and the prevalence of high BP significantly decreased, and the mean HDL-cholesterol level significantly increased in both genders, whereas the prevalence of glucose abnormalities in both genders and central obesity in women significantly increased. The aforementioned changes may account for much of the increase in the prevalence of the metabolic syndrome, particularly among women. Physical inactivity, dietary factors, smoking, and alcohol consumption are known to contribute to the development of the components of the metabolic syndrome. Unfortunately, we do not have detailed data on the changes in diet and physical activity that could explain the increasing trend. A slight increase in the prevalence of past/current smokers and alcohol drinkers in women during was observed (data not shown) and may be associated with the increase in the prevalence of the metabolic syndrome. BP and waist circumference in our two surveys were measured using similar methods. The assays for glucose, HDL-cholesterol, and triglycerides changed between the two surveys. The difference between methods can be verified by the systematic error. However, the systematic error had only a minor effect on estimating and interpreting changes in fasting glucose, serum HDLcholesterol, and serum triglycerides in our population surveys (28). The results from clinical trials conducted in China, Finland, the United States, and India have demonstrated that lifestyle intervention (reduction of obesity, increased physical activity, and dietary changes) reduces the risk of progression from impaired glucose tolerance to type 2 diabetes (33 37). The majority of the participants in the Finnish and U.S. prevention trials had the metabolic syndrome (37, 38). Lifestyle intervention also improved several CVD risk factors and the components of the metabolic syndrome (33 37). Recently, an American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement has provided a summary of clinical management for the metabolic syndrome (14). In addition, the recent European guideline on diabetes, prediabetes, and CVD has summarized the management of the metabolic syndrome (39). The prime emphasis in management of the metabolic syndrome per se is to mitigate the modifiable, underlying risk factors (obesity, physical inactivity, and atherogenic diet) through lifestyle changes. Effective lifestyle change will reduce all of the metabolic risk factors. In conclusion, the present study demonstrates that the prevalence of the metabolic syndrome in Finland is high in international comparison. Based on both the NCEP and IDF definitions, it is higher in men than women in Finland. During , the prevalence of the metabolic syndrome has significantly increased only among women, but not in men. Acknowledgments Address all correspondence and requests for reprints to: Gang Hu, M.D., Ph.D., Department of Health Promotion and Chronic Diseases Prevention, National Public Health Institute, Mannerheimintie 166, FIN Helsinki, Finland. hu.gang@ktl.fi. This study was supported by the Finnish Academy (Grant ) and the Finnish Foundation for Cardiovascular Research. Disclosure Statement: The authors have nothing to disclose.

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