DOI: 10.2337/diacare.29.02.06.dc05-0724 © 2006 by the American Diabetes Association
Spectrum and Prevalence of Atherogenic Risk Factors in 27,358 Children, Adolescents, and Young Adults With Type 1 DiabetesCross-sectional data from the German diabetes documentation and quality management system (DPV)
1 Department of Pediatrics and Adolescence Medicine, Freiburg University Hospital, Freiburg, Germany Address correspondence and reprint requests to Prof. Dr. K.O. Schwab, MD, Department of Pediatrics and Adolescence Medicine, Freiburg University Hospital, Mathilden Str. 1, D-79106 Freiburg, Germany. E-mail: schwab{at}kikli.ukl.uni-freiburg.de
OBJECTIVEThe aim of this data analysis was to ascertain the type and prevalence rate as well as age and sex distribution of cardiovascular risk factors in type 1 diabetic patients up to 26 years of age. RESEARCH DESIGN AND METHODSCardiovascular risk factors such as obesity, hypertension, dyslipidemia, poor glycemic control, and smoking were analyzed in 27,358 patients who were divided into three groups (prepubertal, pubertal, and adult) using specifically designed diabetes software for prospective disease documentation. RESULTSMore than half of the patients per age-group had at least one cardiovascular risk factor. Two risk factors were age dependently found in 6.221.7% and three or four risk factors in 0.54.7%. Elevated values of HbA1c, total cholesterol, and BMI were found most frequently. Hypertension, smoking, and HDL cholesterol were observed more frequently in males, and elevated BMI, total cholesterol, and LDL cholesterol more often in females. Although 28.6% of the patients had dyslipidemia, merely 0.4% of them received medical treatment, and of the 8.1% of the patients with hypertension, only 2.1% of them were given antihypertensive medication. CONCLUSIONSWith increasing age, a greater number of patients with cardiovascular risk factors were observed. Significant sex differences were seen in the majority of risk factors. Despite the high prevalence of risk factors, only a small minority of patients received antihypertensive or lipid-lowering treatment. Early identification, prevention, and treatment of additional risk factors seem to be necessary, particularly in light of the high incidence of future cardiovascular disease.
Abbreviations: CVD, cardiovascular disease DCCT, Diabetes Control and Complications Trial DPV, diabetes data acquisition system for prospective surveillance PDAY, Pathobiological Determinants of Atherosclerosis in Youth
Type 1 diabetes is increasingly recognized as an independent risk factor for premature cardiovascular disease (CVD) and elevated cardiovascular death rate in patients aged 2039 years (1). Postmortem studies in children and youth who had died an unnatural death also showed that the development of atherosclerotic lesions of the vessel wall starts in childhood and that there is a close relationship to cardiovascular risk factors. In the Bogalusa Heart Study (2) and the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study (3), the evaluation of premortal existing risk factors (glycohemoglobin >8%, increased lipids, hypertension, obesity, and smoking) verified their unfavorable influence on the progression of atherosclerosis. Because childhood and adolescence diabetes is commonly associated with additional risk factors (4,5), we conducted this analysis to obtain reliable data about character and prevalence rate as well as age and sex differences of potential atherogenic risk factors in a large population of German children, adolescents, and young adults with type 1 diabetes.
Based on the continuous diabetes data acquisition system for prospective surveillance (DPV), a cross-sectional analysis was carried out to evaluate associated cardiovascular risk factors in patients with type 1 diabetes. The data documentation DPV started in 1990 and comprises complete demographic characteristics and diabetes-related findings. Anonymous longitudinal data from patients are transmitted for central validation and analyses twice yearly (6,7). Inconsistent data are verified and, if necessary, corrected at the participating centers and reentered in the system. This data analysis considers all type 1 diabetic patients who entered the DPV system by the end of September 2004 and is primarily focused on cardiovascular risk factors. Pathological changes of the following parameters were defined as potential atherogenic risk factors: lipid risk factors: total cholesterol, LDL cholesterol, and HDL cholesterol; nonlipid risk factors: HbA1c (A1C), BMI, blood pressure, and smoking. We additionally performed both multivariate analyses of each cardiovascular risk factor with regard to age, diabetes duration, sex, and overweight and a trend analysis of risk factors (BMI, dyslipidemia, total cholesterol >200 mg/dl [>5.2 mmol/l], systolic and diastolic hypertension, and A1C >9.0%) covering the period from 1994 to 2004. A total of 27,358 patients with type 1 diabetes were consecutively registered at 195 German and Austrian Centers for Pediatrics and Internal Medicine. For reasons of analysis the total number of patients was divided into three age-groups based on the developmental stage: age-group 1 (0.2511 years) covers childhood or prepuberty, age-group 2 (1216 years) covers early adolescence or puberty, and age-group 3 (1726.0 years) covers later adolescence and young adulthood.
Nonlipid risk factors
BMI.
Hypertension.
Smoking.
Lipid risk factors
Total cholesterol.
LDL cholesterol.
HDL cholesterol.
Statistical methods
Assessment of cardiovascular risk factors The prevalence of risk factors showed small changes between 1994 and 2004. There was some increase of BMI but a small decrease in dyslipidemia, total cholesterol >200 mg/dl (>5.2 mmol/l), systolic and diastolic hypertension, and A1C >9.0%. For all patients, the percentages of available data were 71.996.2% for nonlipid variables (A1C, BMI, blood pressure, and smoking) and 41.370.8% for lipid variables (total cholesterol, LDL cholesterol, and HDL cholesterol) (Table 1).
Number of cardiovascular risk factors Apart from the ratio of males to females, all patient characteristics and risk factors mentioned in Table 1 showed statistically significant differences between the age-groups. Overall, 69% of 27,358 subjects investigated had one or more of the risk factors analyzed. The vast majority of patients showed one risk factor (53%), followed with decreasing frequency by patients without any risk factor (31%), two risk factors (14%), and three to four risk factors (2%). Two or more risk factors per patient were found most frequently in patients of age-group 3. All differences among age-groups were statistically significant (P < 0.001). Multivariate analyses showed that overweight (BMI) was most closely related (ß value/estimate = 0.184, P < 0.001) to the number of cardiovascular risk factors, followed by age (ß value/estimate = 0.033, P < 0.001) and diabetes duration (ß value/estimate = 0.012, P < 0.001).
Distribution of cardiovascular risk factors per age-group
Sex distribution of cardiovascular risk factors Nonlipid risk factors. The percentage of elevated A1C values (>7.5%, P < 0.001; >9.0%, P < 0.05) and BMI (90th97th or >97th percentile, P < 0.001, respectively) were higher in female than in male subjects (Fig. 2). Frequency of hypertension and current smoking were significantly higher in males than in females (P < 0.001, respectively).
Lipid risk factors. Total cholesterol and LDL cholesterol levels were higher in female than in male subjects (P < 0.0001, respectively). However, no significant difference of HDL cholesterol was found between female and male subjects.
Frequency of pharmacotherapy
There has been growing awareness during the past few years that type 1 diabetes is an independent risk factor for premature atherosclerotic CVD, which can be accelerated by potentially atherogenic risk factors such as hypertension, dyslipidemia, hyperglycemia, obesity, smoking, albuminuria, or physical inactivity (1,5,16). Our results showed that 69% of the 27,358 subjects investigated had one or more of the cardiovascular risk factors analyzed in this study. Multiple risk factors and their interrelationships but also a family history of premature cardiovascular disease, increasing age, or longer duration of diabetes are discussed in the literature as main determinants of enhanced risk for future CVD (17,18). A detailed profile analysis of our diabetes registry showed that the number of patients at risk, divided into three distinct age-groups, is significantly increasing with age with respect to all risk factors. The most frequently diagnosed risk factor was a raised A1C value. Poor glycemic control is particularly associated with the development of long-term microvascular complications (19), which could be proven impressively by the DCCT (20). In a more recent DCCT publication, an association between glycemia and intima-media thickness, an accepted marker for early atherosclerosis, in patients with type 1 diabetes was demonstrated (21). Further investigations could show that there is a direct relationship between A1C levels and the extent of atherosclerosis. Gerstein et al. (22) found that the intima-media thickness increased 0.026 mm for every 0.9% increase in A1C (P < 0.0001). In another study, A1C levels >7.5% were identified as a strong risk factor for progression of coronary artery calcification in type 1 diabetic patients aged 2250 years (23). The British Diabetic Association Cohort Study investigated 23,752 patients with type 1 diabetes. Compared with the general population, type 1 diabetic patients aged 2039 years had a fivefold higher risk of dying from cardiovascular events (1). Overweight and obesity are thought to be cardiovascular risk factors per se with regard to the development of dyslipidemia, hypertension, type 2 diabetes, and the metabolic syndrome (24,25). If obese children become obese adults, one of the long-term consequences may be early atherosclerosis and increased cardiovascular morbidity (26,27). According to our results, overweight, obesity, and hypertension were found in 3.815.5% of the patients observed. Prevention and treatment of these modifiable risk factors should begin as early as possible because counseling of the patient, lifestyle modification, and pharmacologic therapy are quite promising interventions to retard damage or avoid further harm. The high percentage of smokers in many countries is alarming. The Global Youth Tobacco Survey reported data for 16,416 U.S. students aged 1315 years, of whom 23.1% are currently using any tobacco product (28). In the PDAY study (4), a 44.0% prevalence of smoking in subjects aged 1534 was calculated. The Behavioral Risk Factor Surveillance System in the U.S. indicated that the prevalence of smoking among adults with diabetes was 23.6% in 1990 and 23.2% in 2001. Among participants without diabetes, the prevalence was similar, showing 24.2% in 1990 and 23.2% in 2001 (29). All these studies show a similar prevalence of smokers compared with our data. Taking into account the occurrence of at least one abnormality among the lipid variables we analyzed, the number of patients with any dyslipidemia increased significantly from 22.3% in age-group 1 to 34.3% in age-group 3. Total cholesterol values >200 mg/dl (>5.2 mmol/l) emerged in about 26% of all patients, LDL cholesterol >130 mg/dl (>3.4 mmol/l) in about 11%, and LDL cholesterol >160 mg/dl (>4.1 mmol/l) in about 5.3%. Insulin deficiency is associated with reduced activity of LDL receptors, and glycation of LDL particles reduces their receptor affinity, thereby impairing the clearance of LDL cholesterol and increasing their susceptibility to oxidation. Longer diabetes duration, hyperglycemia, albuminuria, hypertriglyceridemia, and lower HDL cholesterol are associated with elevated levels of small dense LDL particles that are extremely atherogenic (30,31). The risk factor profiles of our patients vary according to sex. Raised blood pressure and current smoking were lower in female than in male subjects, whereas increased A1C, total cholesterol, LDL cholesterol, and BMI values emerged in female subjects. It is known that women with type 1 diabetes have an increased risk of developing CVD and, therefore, equalizing the sex difference seen in the general population (32). In addition to the risk factors discussed here, several variables are related to CVD in women such as age, fasting triglyceride levels, albumin excretion rate, retinopathy, fat distribution, and depressive symptomatology (15,33). With regard to the management of additional atherogenic risk factors, there is a considerable discrepancy in juvenile type 1 diabetic patients between the high risk for future cardiovascular morbidity and the low treatment rate of modifiable risk factors such as hypertension and dyslipidemia. The main reason may be the lack of drugs that are generally recognized as safe and effective for long-term use in diabetic children and adolescents. Besides regular risk factor testing, it is also necessary to draw therapeutic conclusions from abnormal findings to continuously improve quality of diabetes care long term. In a recently published retrospective cohort study, 1,765 adult patients with type 1 or type 2 diabetes were included if they had at least two visits within 24 months. The authors found that despite a high rate of annual A1C, blood pressure, and cholesterol measurements, rates of required medication initiation and dose adjustment were comparatively low (34). Although vascular complications are normally subclinical during childhood and adolescence, cardiovascular risk factors should be given our full attention to reduce risk by optimal metabolic control and lifestyle modification (35,36). Only if these efforts are insufficient is pharmacotherapy a reasonable form of treatment, but it must be individualized based on the number of atherogenic risk factors, family history, and existing complications. Hypertension in children and adolescents with type 1 diabetes may primarily be treated early with ACE inhibitors, as was the case in 83% of our patients. These agents have antihypertensive effects and reduce the incidence of microalbuminuria and nephropathy (37). Besides hypertension, dyslipidemia is a common concomitant disease in patients with diabetes. Moderate hypertriglyceridemia, lower HDL cholesterol levels, and hypercholesterolemia with elevated levels of LDL cholesterol and small, dense LDL particles can be seen in type 1 diabetes (5,38). The American Diabetes Association strongly recommends lipid-lowering pharmacotherapy for patients with LDL >160 mg/dl (>4.1 mmol/l) but for LDL cholesterol values between 130 and 159 mg/dl (3.4 and 4.1 mmol/l, respectively) only if nutrition therapy and lifestyle changes fail. In any case, the treatment target is LDL cholesterol <100 mg/dl (<2.6 mmol/l) (15). In adults with diabetes, fibrates are recommended for hypertriglyceridemia with lower HDL cholesterol (11% in our study) and statins for reducing total and LDL cholesterol (54% in our study) (39). So far, in a limited number of children with familial and severe hypercholesterolemia, statins showed good LDL cholesterol-lowering efficacy and a low rate of side effects (40). Beyond these effects, statins improve endothelial dysfunction and have antioxidant, antithrombotic, and anti-inflammatory properties that may contribute to their antiatherogenic efficacy (41,42). In conclusion, this representative analysis demonstrates the high age-dependent frequency of atherogenic risk factors in children and adolescents with type 1 diabetes and underlines the importance of an early search for these risk factors. Significant sex differences were computed for most of the risk factors. The discrepancy between a high prevalence of cardiovascular risk factors and the low rate of antihypertensive and lipid-lowering treatment deserves special consideration.
The DPV program was supported by Novo Nordisk Germany, the Dr. Bürger-Büsing Foundation, the German Diabetes Foundation, and the German Ministry of Health. We thank all investigators who participated in the DPV initiative. The following institutions contributed data to this analysis: Aachen, Uni-Kinderklinik RWTH; Ahlen, St. Franziskus Kinderklinik; Aue, Helios Kinderklinik; Augsburg, Innere; Augsburg, Kinderklinik, Zentralklinikum; Aurich, Kinderklinik; Bad Driburg/Bad Hermannsborn, Innere; Bad Hersfeld, Kinderklinik; Bad Kreuznach-St. Marienwörth, Innere; Bad Kösen, Kinder-Rehaklinik; Bad Lauterberg, Diabeteszentrum, Innere; Bad Oeynhausen, Diabetesfachklinik; Berlin, Kinderklinik Lindenhof; Berlin, Klinik St. Hedwig, Innere; Berlin, Schlosspark-Klinik, Innere; Berlin, Virchow-Kinderklinik; Berlin-Hellersdorf, Innere; Bielefeld, Kinderklinik Gilead; Bocholt, Innere Medizin; Bonn, Uni-Kinderklinik; Bottrop Kinderklinik; Bottrop, Knappschaftskrankenhaus, Innere; Bremen, Kinderklinik Nord; Bremen, Kinderklinik St. Jürgenstrasse; Bremen, Epidemiologieprojekt; Bremerhaven, Kinderklinik; Bruckmühl, Internist. Praxis; Celle, Kinderklinik; Chemnitz, Kinderklinik; Coesfeld, Kinderklinik; Darmstadt, Kinderklinik Prinz. Margareth; Datteln, Vestische Kinderklinik; Deggendorf, Kinderarztpraxis; Deggendorf, Kinderklinik; Deggendorf, Medizinische Klinik II; Delmenhorst, Kinderklinik; Detmold, Kinderklinik; Dortmund, Kinderklinik; Dortmund, St. Josefshospital, Innere; Dresden, Uni-Kinderklinik; Düren-Birkesdorf, Kinderklinik; Düsseldorf, Uni-Kinderklinik; Erfurt, Kinderklinik; Erlangen, Uni-Kinderklinik; Essen, Uni-Kinderklinik; Esslingen, Städtische Kinderklinik; Eutin, Kinderklinik; Eutin, St.-Elisabeth, Innere; Frankfurt, Uni-Klinik, Innere; Freiburg, Uni-Kinderklinik; Friedberg, Innere Klinik; Friedrichshafen, Kinderklinik; Fulda, Innere Medizin; Fulda, Kinderklinik; Fürth, Kinderklinik; Gaissach, Kinder-Fachklinik; Garmisch-Partenkirchen, Kinderklinik; Gelnhausen, Kinderklinik; Gelsenkirchen, Kinderklinik Marienhospital; Gießen, Uni-Kinderklinik; Göppingen, Kinderklinik am Eichert; Görlitz, Städtische Kinderklinik; Göttingen, Uni-Kinderklinik; Hachenburg, Kinderpraxis; Hagen, Kinderklinik; Halle, Uni-Kinderklinik; Halle-Dölau, Städtische Kinderklinik; Hamburg, Altonaer Kinderklinik; Hamburg, Kinderklinik Wilhelmstift; Hamburg-Nord, Kinderklinik Heidberg; Hamm, Kinderklinik; Hanau, Kinderklinik; Hanau, St. Vincenz, Innere; Hannover, Henriettenstift, Innere; Hannover, Kinderklinik MHH; Hannover, Kinderklinik auf der Bult; Heidelberg, Uni-Kinderklinik; Heidenheim, Kinderklinik; Heilbronn, Innere Klinik; Herdecke, Kinderklinik; Herford, Kinderklinik; Heringsdorf, Inselklinik; Hermeskeil, Kinderpraxis; Herten, St. Elisabeth, Innere Medizin; Herzberg, Kreiskrankenhaus, Innere; Hildesheim, Innere; Hildesheim, Kinderarztpraxis; Hildesheim, Kinderklinik; Hinrichsegen-Bruckmühl, Diabetikerjugendhaus; Homburg, Uni-Kinderklinik Saarland; Idar, Oberstein, Innere; Innsbruck, Universitätskinderklinik; Itzehoe, Kinderklinik; Jena, Uni-Kinderklinik; Kaiserslautern, Westpfalzklinikum, Kinderklinik; Karlsburg, Diabetesfachklinik; Karlsruhe, Städtische Kinderklinik; Kassel, Kinderklinik Park Schönfeld; Kassel, Städtische Kinderklinik; Kaufbeuren, Innere Medizin; Kempen, Heilig Geist, Innere; Kiel, Städtische Kinderklinik; Koblenz, Kemperhof, 1. Med. Klinik; Koblenz, Kinderklinik Kemperhof; Konstanz, Innere Klinik; Krefeld, Innere Klinik; Köln, Uni-Kinderklinik; Landshut, Kinderklinik; Leipzig, Uni-Kinderklinik; Lingen, Kinderklinik St. Bonifatius; Lippstadt, Evangelische Kinderklinik; Ludwigsburg, Innere Medizin; Ludwigsburg, Kinderklinik; Ludwigshafen, Kinderklinik St. Anna-Stift; Lübeck, Uni-Kinderklinik; Lübeck, Uni-Klinik, Innere Medizin; Lüdenscheid, Kinderklinik; Magdeburg, Uni-Kinderklinik; Mannheim, Innere; Mannheim, Uni-Kinderklinik; Marburg, Uni, Innere; Marburg, Uni-Kinderklinik; Mechernich, Kinderklinik; Memmingen, Kinderklinik; Minden, Kinderklinik; Moers, Kinderklinik; Mutterstadt, Kinderarztpraxis; Mönchengladbach, Kinderklinik; Rheydt, Elisabethkrankenhaus; München, von Haunersche Kinderklinik; München-Harlaching, Kinderklinik; München-Schwabing, Kinderklinik; Münster, Kinderarztpraxis; Münster, Uni-Kinderklinik; Nagold, Kreiskrankenhaus, Innere; Neuburg, Kinderklinik; Neunkirchen, Kinderklinik Kohlhof; Neuss, Lukaskrankenhaus, Kinderklinik; Neuwied, Kinderklinik Elisabeth; Nürnberg, Cnopfsche Kinderklinik; Nürnberg, Kinderklinik, Klinikum Süd; Oberhausen, Innere; Oberhausen, Kinderklinik; Oberhausen, Kinderpraxis Bachran; Offenbach/Main, Kinderklinik; Oldenburg, Kinderklinik; Osnabrück, Kinderklinik; Paderborn, St. Vincenz, Kinderklinik; Passau, Kinderarztpraxis Handwerker; Passau, Kinderklinik; Pforzheim, Kinderklinik; Rastatt, Gemeinschaftspraxis; Rastatt, Kreiskrankenhaus, Innere; Ravensburg, Kinderklink St. Nikolaus; Recklinghausen, Dialysezentrum, Innere; Regensburg, Kinderklinik St. Hedwig; Remscheid, Kinderklinik; Rendsburg, Kinderklinik; Rheine, Kinderklinik; Rosenheim, Innere Medizin; Rosenheim, Kinderklinik; Rostock, Universität, Innere Medizin; Rotenburg/Wümme, Kinderklinik; Saaldorf-Surheim, Diabetespraxis; Saalfeld, Thüringenklinik, Kinderklinik; Saarbrücken, Kinderklinik Winterberg; Saarlouis, Kinderklinik; Scheidegg, Reha-Kinderklinik Maximilian; Schw. Gmünd, Margaritenhospital, Kinderklinik; Schweinfurt, Kinderklinik; Schwerin, Kinderklinik; Siegen, Kinderklinik; Singen, Hegauklinik, Kinderklinik; Sinsheim, Innere; Spaichingen, Innere; Stade, Kinderklinik; Stolberg, Kinderklinik; Stuttgart, Olgahospital, Kinderklinik; Suhl, Kinderklinik; Sylt, Rehaklinik; Trier, Kinderklinik der Borromäerinnen; Tübingen, Uni-Kinderklinik; Ulm, Uni-Kinderklinik; Vechta, Kinderklinik; Viersen, Kinderklinik; Waiblingen, Kinderklinik; Waldshut, Kinderpraxis Biberbau; Weiden, Kinderklinik; Weingarten, Kinderarztpraxis; Wetzlar, Praxis Klewer/Teichner; Wetzlar/Braunfels, Innere; Wien, Uni-Kinderklinik; Wiesbaden, Horst-Schmidt-Kinderkliniken; Wiesbaden, Kinderklinik DKD; Worms, Kinderklinik; Wuppertal, Kinderklinik.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. Received for publication April 25, 2005. Accepted for publication October 20, 2005.
This article has been cited by other articles:
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||