Diabetes Care Publish Ahead of Print, published online August 12, 2009 Diet and glucose tolerance abnormalities Dietary patterns and glucose tolerance abnormalities in Chinese adults Short running head: Diet and glucose tolerance abnormalities Yuna He1,2 MPH, Guansheng Ma1 PHD, Fengying Zhai1 MPH, Yanping Li1 PHD, Yisong Hu3 PHD, Edith JM Feskens2 PHD , Xiaoguang Yang1 PHD 1National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention 2Division of Human Nutrition, Wageningen University, The Netherlands 3 Public Health Surveillance and Information Service Center, Chinese Center for Disease Control and Prevention Corresponding address: Yuna He Email:[email protected] Additional information for this article can be found in an online appendix at http://care.diabetesjournals.org Submitted 14 April 2009 and accepted 27 July 2009 This is an uncopyedited electronic version of an article accepted for publication in Diabetes Care. The American Diabetes Association, publisher of Diabetes Care, is not responsible for any errors or omissions in this version of the manuscript or any version derived from it by third parties. The definitive publisher-authenticated version will be available in a future issue of Diabetes Care in print and online at http://care.diabetesjournals.org. Copyright American Diabetes Association, Inc., 2009 Diet and glucose tolerance abnormalities Objective: To investigate the association of the dietary pattern with the presence of newly diagnosed glucose tolerance abnormalities among Chinese adults. Research Design and Methods: A total of 20,210 adults aged 45-69 yrs from the 2002 China National Nutrition and Health Survey were included. Information on dietary intake was collected using a validated food frequency questionnaire. Factor analysis and cluster analysis were used to identify the food factors and dietary pattern clusters. Results: Four dietary pattern clusters were identified (“Green Water”, “Yellow Earth”, “Western Adopter”, and “New Affluence”). The prevalence of glucose tolerance abnormalities ranged from 3.9% in the (Green Water) to 8.0% in the (New Affluence). After adjustment for area, age, sex, current smoking and physical activity, subjects in the Yellow Earth cluster (PR 1.22, CI: 1.04-1.43) and New Affluence cluster (PR 2.05 CI: 1.76-2.37) had significantly higher prevalence rates compared with the Green Water. After further adjustment for BMI and waist to height ratio, the elevated risk in the New Affluence remained statistically significant Conclusions: Dietary patterns and food factors are associated with the presence of glucose tolerance abnormalities in China, even independent of obesity. A New Affluence diet are important modifiable risk factors which need attention from the prevention point of view. 2 Diet and glucose tolerance abnormalities he prevalence of type 2 diabetes is Study population: The 2002 China increasing rapidly worldwide (1). The National Nutrition and Health Survey T 2002 China National Nutrition and (CNNHS) is a national representative Health Survey showed that 2.6% of the adults cross-sectional study on diet and chronic have diabetes, translating to more than 20 diseaseIt covered all 31 provinces, million people (2). Behavior and lifestyle autonomous regions, and municipalities factors, such as eating habits and physical directly under the central government activity, are recognized to play an important throughout China (except Taiwan, Hong role in the development of diabetes. The Kong, and Macao). Participants were traditional approach to investigate recruited by use of a stratified multistage diet-disease associations focuses on single cluster sampling design. The country was dietary components, such as single nutrients divided into six strata: large cities, small to or foods (3-8). However, people eat meals medium cities, class 1 rural areas, class 2 instead of foods or nutrients, making it more rural areas, class 3 rural areas, and class 4 difficult to separate the effect of individual rural areas, according to their economic dietary components. The effect of the overall characteristics and social development. The diet can be studied with dietary pattern first stage of sampling involved the random analyses. This approach is used increasingly selection of 22 districts (urban) or counties in studies on the relationship between diet (rural) from each of the six strata. The second and diabetes among Western populations. stage involved the random selection of three Some studies suggest that the adoption of a neighborhoods (urban) or townships (rural) western dietary pattern, characterized by red from each of the selected districts/counties. meat, processed meat, French fries, high-fat From each of the neighborhoods or dairy products, refined grains, sweets, and townships, two residential committees (urban) desserts, may be associated with increased or villages (rural) were randomly selected; 90 incidence of type 2 diabetes (9-12). households were randomly sampled from Little work however has been done to each village. A total of 795 residential investigate Asian dietary patterns, and in committees or villages and 68,828 families particular the Chinese diet. Recently four were sampled. About 1/3 households were Chinese dietary patterns were identified in a selected to participate in the dietary survey. to study on dietary habits and obesity among All participants aged 15 years and older Chinese adults (13). The identified dietary completed an interview with a structured patterns were considered to be highly food frequency questionnaire. All family realistic within the nutrition transition members of these dietary survey participants, framework in China. In the present study, we provided being above 2 years old, were used these four dietary patterns to investigate invited for the measurement of fasting blood the association with the presence of newly glucose. An oral glucose tolerance test diagnosed glucose tolerance abnormalities in (OGTT) was undertaken in subjects whose China. fasting glucose was ≥5.5 mmol/l. RESEARCH DESIGN AND METHODS 3 Diet and glucose tolerance abnormalities Once the village/neighbourhood Appendix 1 for the factor loading matrix. It committee decided to participate, the can be found at individual response rate was always more http://care.diabetesjournals.org.). than ninety percent. Of the 68925 subjects Subsequently, we used the obtained who attended the dietary survey, 60158 factor scores in cluster analysis, using a participated in the fasting glucose two-step approach. Firstly, hierarchical measurement, a response rate of 87%. cluster analysis by randomly filtering 1% of Among the 5887 subjects whose fasting the total number of participants was used, to glucose level was above 5.5 mmol/l and who help identify the number of clusters and to should therefore have participated in the oral determine the initial cluster centers for the glucose tolerance test (OGTT), 1818 subjects subsequent K-means cluster analysis;. A plot did (response rate 31%). Among the subjects of the agglomeration coefficients in the who finalized the food frequency successive steps revealed an elbow at the questionnaire, 6% was excluded because of 4-cluster solution. We then saved the means extreme values including daily energy intake of the 4 clusters as initial cluster centers for above 5000 kcal. Further details of this the K-mean cluster. By using the output from survey have been published elsewhere (2). the hierarchical clustering, K-means cluster For the present study, we used data of method was used to calibrate the solution for 20,866 subjects aged 45-69 years who had a all cases. In the end, all cases were assigned completed a food frequency questionnaire to each of the four clusters (Appendix 2). We and underwent fasting blood sampling for calculated the average food consumption of analysis of blood glucose. All subjects who different diet patterns as the average amount were known with diabetes before the survey (g) per reference men per day, a men being an were excluded from the analyses (n=656), 18 yrs old man with light physical activity because they may have changed their dietary level, whose reference energy intake is 2400 habits. The final study population comprised kcal. Mean values of individual amounts in 20,210 persons. reference men among each group were then Dietary Assessment: An validated calculated.. According to these characteristic semi-quantitative food frequency of food intake, the four dietary patterns were questionnaire was used to investigate the labeled as “Green Water” (like the rice area usual diet in the previous one year of the in the South-East), “Yellow Earth” (their study (14). A previous paper described the food is mainly produced on the dry and hilly construction of dietary patterns by using land, like the mountain area in the factor analysis combined with cluster North-West), “New affluence” (well-to-do analysis in (56,442) men and women aged people mainly) and “Western adopter” above18 years old in the 2002 CNNHS for (young people mainly, a more whom dietary data were complete (13). In Western-oriented food style) respectively. short, four factors were identified by Ascertainment of Glucose Tolerance applying the principal components method Abnormality: Fasting blood glucose level with oblique rotation based on the quartiles were measured by trained technicians, and an of the consumption quantity. (See online oral glucose test (OGTT) was taken from 4 Diet and glucose tolerance abnormalities