Accepted Article
Received Date : 27-Dec-2013 Revised Date : 07-Aug-2014 Accepted Date : 06-Oct-2014 Article type : Research Article
Prevalence and awareness of diabetes mellitus among a rural population in China: results from Liaoning Province
Short title/Authors running head: Prevalence of diabetes in rural China • X. Zhou et al.
X. Zhou1, H. Guan2, L. Zheng3, Z. Li1, X. Guo1, H. Yang1, S.Yu1, G. Sun1, W. Li1, W. Hu1, L. Guo1, G. Pan4, L. Xing4, Y. Zhang5 and Y. Sun1
1
Department of Cardiology, First Hospital of China Medical University, Shenyang, Liaoning,
2
Department of Endocrinology and Metabolism, Endocrine Institute and Liaoning Provincial Key
Laboratory of Endocrine Diseases, First Hospital of China Medical University, Shenyang, Liaoning, 3
Department of Clinical Epidemiology, Shenjing Hospital of China Medical University, Shenyang,
Liaoning, 4Department of Prevention of Chronic Non-Communicable Diseases, Centre for Disease Prevention and Control of Liaoning Province, Shenyang, Liaoning, and 5Department of Epidemiology, School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu, China
Correspondence to: Yingxian Sun. E-mail: [email protected]
This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/dme.12599 This article is protected by copyright. All rights reserved.
Accepted Article
What's new? •
Two nationwide epidemiological surveys of diabetes in China show that the prevalence of diabetes has increased from 9.7% in 2010 to 11.6% in 2013. The prevalence of cardiovascular disease and hypertension in rural northeastern China has been found to be much higher than in other regions, despite lower economic development in this region. These findings are confirmed by the present study.
•
The findings mean that the health issue of diabetes cannot be ignored, even in rural areas with less economic development.
•
The national average prevalence of diabetes should not be assumed to represent the prevalence at local regional level. The present findings highlight the considerable importance of addressing the health problem of diabetes across China.
Abstract Aim To clarify the diabetes prevalence trends among the rural population in northern China. Methods All eligible permanent residents aged ≥35 years in selected rural villages of Liaoning province were invited to participate in the study. A total of 11 600 people completed all questionnaires and were included in the study. The response rate was 85.3%. Fasting plasma glucose levels were measured after at least 12 h of fasting and diabetes was diagnosed according to WHO criteria, i.e. fasting plasma glucose ≥7 mmol/l and/or being on treatment for diabetes. Impaired fasting glucose was defined according to the 1997 and the 2010 American Diabetes Association (ADA) criteria (6.1–6.9 and 5.6–6.9 mmol/l, respectively). Previous diagnoses of diabetes were assessed on the basis of self-reports. Results The prevalence of diabetes among adults in the rural population was 10.6% (10.0% in men and 11.1% in women). The prevalence of impaired fasting glucose was 13.0 and 36.1% according to the 1997 and the 2010 ADA criteria, respectively. The prevalence of previously diagnosed diabetes was 4.3% among the whole population (3.3% in men and 5.1% in women). The prevalence of previously diagnosed diabetes was 34.8% in men and 50.2% in women. Only 29.6% of men and 42%
This article is protected by copyright. All rights reserved.
Accepted Article
of women with diabetes had taken oral hypoglycaemic agents or insulin to lower their blood sugar. In multivariate analysis, age, drinking habits, BMI, dyslipidaemia and family history of diabetes were identified as independent risk factors for diabetes, and occupational physical activity, smoking and lean meat intake were identified as independent protective factors for diabetes. Conclusions The prevalence of diabetes and impaired fasting glucose were found to be high in this rural population. Although the rate of treatment of people with diabetes has increased, the glycaemic control rate was still at a low level.
Introduction Diabetes is a worldwide public health issue. It has been estimated that the global prevalence of diabetes will be 7.7% (552 million people) by 2030 [1]. Because of the continent’s high population density, a larger number of people with diabetes is expected to be found in Asia than elsewhere in the world. Over the last two decades, the medical community has observed the Asian diabetes epidemic as it has unfolded and evolved. Ever since the reform and opening up of China, socio-economic development, lifestyle changes and aging of the population have turned diabetes into an urgent health issue. A national survey in 1994 showed the prevalence of diabetes to be 2.5% in 25–64 year-olds in China [2]. In 2003, Gu [3] reported that the prevalence of diabetes was 5.5% among 35–74 year olds, and the prevalence was higher in women than in men. Yang et al. [4] investigated 46 239 residents aged >20 years in 14 provinces from 2007 to 2008, and the results showed the age-standardized prevalence of diabetes in the general population to be 9.7% in 2007 and 8.2% in 2008 in rural areas. The latest data show that the prevalence of diabetes in China has reached 11.6% among women and 10.3% among men in the rural population which was far higher than estimated [5]. These findings highlight the grim situation regarding the prevalence of diabetes in China.
Two nationwide epidemiological surveys of diabetes mellitus in China have reported the worsening diabetes situation in the overall Chinese population [4, 5]; however, there are enormous differences in the different regions because of the vast boundaries and large population of China.
This article is protected by copyright. All rights reserved.
Accepted Article
These differences include geographical features, ethnic differences, dietary habits, economic status, and the presence of other chronic diseases. For example, there are many differences between Liaoning province, which is located in northern China and Guangdong Province, which is located in southern China; the total gross domestic product of the former is ranked eighth while the latter is ranked second among 34 provinces in China, which reflects the difference in economic level. Meanwhile, dietary habits were also different, the per capita intake of salt in Liaoning province was ~16 g/day, far higher than in Guangdong (9.1 g/day). In addition, the average temperature is much lower in the northeast than in the south. The incidence of hypertension, often accompanying diabetes [6–8]), was also higher in Liaoning province than the national average. The various differences between Liaoning province and other regions may have led to a higher incidence of cardiovascular disease and hypertension. The population in China accounts for approximately one fifth of the world population, and more than half of the Chinese population lives in rural areas. Although diabetes is an important risk factor for cardiovascular disease, few studies on the diabetes epidemic have been performed in rural populations in northern China. More epidemiological investigations are needed in rural communities. These would provide reliable information useful for the prevention and control of diabetes in China.
In the present study, the diabetes situation was examined in several rural communities in Liaoning province. Liaoning is located in northeastern China. It has an average population density of 297 people per km2, and the majority of the population lives in rural areas, engages in heavy physical labour, and is susceptible to hypertension [9]. The aim of the present study was to examine the prevalence, awareness and rates of treatment of diabetes and associated metabolic risk factors in adults living in Liaoning province.
Methods Study population From January 2012 to August 2013, a representative sample of the general population of Liaoning province aged ≥35 years was selected in order to examine the prevalence, incidence and
This article is protected by copyright. All rights reserved.
Accepted Article
natural history of cardiovascular risk factors in the rural parts of the province. The study adopted a multistage, stratified, random cluster-sampling scheme. The sampling process was stratified by geographic region (north, south, east and west). The first stage of sampling, in which cities were selected from geographic regions and counties were selected from cities, was not random. Three counties (Liaoyang in Liaoyang City, Zhangwu in Funxin City and Dawa in Panjin City) were selected to represent north, south and east. In the second stage, one township was randomly selected from each county and 8–10 rural villages were selected randomly from each township. In total, 26 rural villages were finally included. All eligible permanent residents aged ≥35 years from each village were invited to participate in the study (a total of 14 016 participants). Of these, 11 956 participants agreed and completed the present study, giving a response rate of 85.3%. Participants who were pregnant or had malignant tumours or mental illness were excluded from the study. The study was approved by the Ethics Committee of China Medical University (Shenyang, China). All procedures were performed in accordance with ethical standards. Written consent was obtained from all participants after they had been informed of the objectives, benefits, medical issues and treatment of personal information. If the participants were illiterate, written informed consent was obtained from their proxies.
Data collection and measurements At a single visit to the clinic by the patient, data were collected by cardiologists and trained nurses using a standard questionnaire delivered by face-to-face interview. Before the survey was performed, all eligible investigators were required to attend the organized training. Candidate investigators were briefed on the purpose of the study, how to administer the questionnaire, the standard method of measurement, the importance of standardization and the study procedures. There was a central steering committee with a subcommittee for quality control. A stringent quality assurance and quality control programme was implemented to ensure the validity and reliability of study data. A strict test was performed after investigator training, and only those who scored perfectly were allowed to collect data. During data collection, inspectors received further instructions and support.
This article is protected by copyright. All rights reserved.
Accepted Article
Data regarding demographic characteristics, lifestyle risk factors, dietary habits, annual family income, education level and family history of diabetes were collected. Information regarding drug use in the past two weeks was also collected. Current smoking was defined as currently smoking cigarettes, current alcohol consumption was defined as alcohol intake more than twice per week for 1 year or more.
According to the American Heart Association protocol, blood pressure was measured three times at 2-min intervals after at least 5 min of rest using a standardized automatic electronic sphygmomanometer (HEM-907; Omron, Kyoto, Japan). The calibration of the device was checked using a standard mercury sphygmomanometer every month by two doctors according to the British Hypertension Society protocol [10]. The mean of three blood pressure measurements was calculated and used in all analyses.
Weight and height were measured to the nearest 0.1 kg and 0.1 cm, respectively, with the participants barefoot in lightweight clothing. Waist circumference was measured at the umbilicus at the end of normal expiration using a non-elastic tape (to the nearest 0.1 cm), with the participants standing [11]. BMI was calculated as weight in kilograms divided by the square of the height in meters (kg/m2).
Fasting blood samples were collected in the morning after at least 12 h of fasting for all participants. Blood samples were obtained from an antecubital vein into Vacutainer tubes (Becton Dickinson, Franklin Lakes, NJ, USA) containing EDTA. They were centrifuged on site within 2 h of collection. Plasma glucose was measured locally using glucose oxidase or hexokinase methods within 24 h. Fasting plasma glucose, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and other routine blood biochemical indexes were analysed enzymatically on an Olympus AU640 autoanalyzer (Olympus, Kobe, Japan). All laboratory equipment was calibrated and blinded duplicate samples were used.
This article is protected by copyright. All rights reserved.
Accepted Article
Definitions According to a JNC-7 report, hypertension was defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg and use of anti-hypertensive medications [12]. BMI was categorized into three groups: normal (BMI
Received Date : 27-Dec-2013 Revised Date : 07-Aug-2014 Accepted Date : 06-Oct-2014 Article type : Research Article
Prevalence and awareness of diabetes mellitus among a rural population in China: results from Liaoning Province
Short title/Authors running head: Prevalence of diabetes in rural China • X. Zhou et al.
X. Zhou1, H. Guan2, L. Zheng3, Z. Li1, X. Guo1, H. Yang1, S.Yu1, G. Sun1, W. Li1, W. Hu1, L. Guo1, G. Pan4, L. Xing4, Y. Zhang5 and Y. Sun1
1
Department of Cardiology, First Hospital of China Medical University, Shenyang, Liaoning,
2
Department of Endocrinology and Metabolism, Endocrine Institute and Liaoning Provincial Key
Laboratory of Endocrine Diseases, First Hospital of China Medical University, Shenyang, Liaoning, 3
Department of Clinical Epidemiology, Shenjing Hospital of China Medical University, Shenyang,
Liaoning, 4Department of Prevention of Chronic Non-Communicable Diseases, Centre for Disease Prevention and Control of Liaoning Province, Shenyang, Liaoning, and 5Department of Epidemiology, School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu, China
Correspondence to: Yingxian Sun. E-mail: [email protected]
This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/dme.12599 This article is protected by copyright. All rights reserved.
Accepted Article
What's new? •
Two nationwide epidemiological surveys of diabetes in China show that the prevalence of diabetes has increased from 9.7% in 2010 to 11.6% in 2013. The prevalence of cardiovascular disease and hypertension in rural northeastern China has been found to be much higher than in other regions, despite lower economic development in this region. These findings are confirmed by the present study.
•
The findings mean that the health issue of diabetes cannot be ignored, even in rural areas with less economic development.
•
The national average prevalence of diabetes should not be assumed to represent the prevalence at local regional level. The present findings highlight the considerable importance of addressing the health problem of diabetes across China.
Abstract Aim To clarify the diabetes prevalence trends among the rural population in northern China. Methods All eligible permanent residents aged ≥35 years in selected rural villages of Liaoning province were invited to participate in the study. A total of 11 600 people completed all questionnaires and were included in the study. The response rate was 85.3%. Fasting plasma glucose levels were measured after at least 12 h of fasting and diabetes was diagnosed according to WHO criteria, i.e. fasting plasma glucose ≥7 mmol/l and/or being on treatment for diabetes. Impaired fasting glucose was defined according to the 1997 and the 2010 American Diabetes Association (ADA) criteria (6.1–6.9 and 5.6–6.9 mmol/l, respectively). Previous diagnoses of diabetes were assessed on the basis of self-reports. Results The prevalence of diabetes among adults in the rural population was 10.6% (10.0% in men and 11.1% in women). The prevalence of impaired fasting glucose was 13.0 and 36.1% according to the 1997 and the 2010 ADA criteria, respectively. The prevalence of previously diagnosed diabetes was 4.3% among the whole population (3.3% in men and 5.1% in women). The prevalence of previously diagnosed diabetes was 34.8% in men and 50.2% in women. Only 29.6% of men and 42%
This article is protected by copyright. All rights reserved.
Accepted Article
of women with diabetes had taken oral hypoglycaemic agents or insulin to lower their blood sugar. In multivariate analysis, age, drinking habits, BMI, dyslipidaemia and family history of diabetes were identified as independent risk factors for diabetes, and occupational physical activity, smoking and lean meat intake were identified as independent protective factors for diabetes. Conclusions The prevalence of diabetes and impaired fasting glucose were found to be high in this rural population. Although the rate of treatment of people with diabetes has increased, the glycaemic control rate was still at a low level.
Introduction Diabetes is a worldwide public health issue. It has been estimated that the global prevalence of diabetes will be 7.7% (552 million people) by 2030 [1]. Because of the continent’s high population density, a larger number of people with diabetes is expected to be found in Asia than elsewhere in the world. Over the last two decades, the medical community has observed the Asian diabetes epidemic as it has unfolded and evolved. Ever since the reform and opening up of China, socio-economic development, lifestyle changes and aging of the population have turned diabetes into an urgent health issue. A national survey in 1994 showed the prevalence of diabetes to be 2.5% in 25–64 year-olds in China [2]. In 2003, Gu [3] reported that the prevalence of diabetes was 5.5% among 35–74 year olds, and the prevalence was higher in women than in men. Yang et al. [4] investigated 46 239 residents aged >20 years in 14 provinces from 2007 to 2008, and the results showed the age-standardized prevalence of diabetes in the general population to be 9.7% in 2007 and 8.2% in 2008 in rural areas. The latest data show that the prevalence of diabetes in China has reached 11.6% among women and 10.3% among men in the rural population which was far higher than estimated [5]. These findings highlight the grim situation regarding the prevalence of diabetes in China.
Two nationwide epidemiological surveys of diabetes mellitus in China have reported the worsening diabetes situation in the overall Chinese population [4, 5]; however, there are enormous differences in the different regions because of the vast boundaries and large population of China.
This article is protected by copyright. All rights reserved.
Accepted Article
These differences include geographical features, ethnic differences, dietary habits, economic status, and the presence of other chronic diseases. For example, there are many differences between Liaoning province, which is located in northern China and Guangdong Province, which is located in southern China; the total gross domestic product of the former is ranked eighth while the latter is ranked second among 34 provinces in China, which reflects the difference in economic level. Meanwhile, dietary habits were also different, the per capita intake of salt in Liaoning province was ~16 g/day, far higher than in Guangdong (9.1 g/day). In addition, the average temperature is much lower in the northeast than in the south. The incidence of hypertension, often accompanying diabetes [6–8]), was also higher in Liaoning province than the national average. The various differences between Liaoning province and other regions may have led to a higher incidence of cardiovascular disease and hypertension. The population in China accounts for approximately one fifth of the world population, and more than half of the Chinese population lives in rural areas. Although diabetes is an important risk factor for cardiovascular disease, few studies on the diabetes epidemic have been performed in rural populations in northern China. More epidemiological investigations are needed in rural communities. These would provide reliable information useful for the prevention and control of diabetes in China.
In the present study, the diabetes situation was examined in several rural communities in Liaoning province. Liaoning is located in northeastern China. It has an average population density of 297 people per km2, and the majority of the population lives in rural areas, engages in heavy physical labour, and is susceptible to hypertension [9]. The aim of the present study was to examine the prevalence, awareness and rates of treatment of diabetes and associated metabolic risk factors in adults living in Liaoning province.
Methods Study population From January 2012 to August 2013, a representative sample of the general population of Liaoning province aged ≥35 years was selected in order to examine the prevalence, incidence and
This article is protected by copyright. All rights reserved.
Accepted Article
natural history of cardiovascular risk factors in the rural parts of the province. The study adopted a multistage, stratified, random cluster-sampling scheme. The sampling process was stratified by geographic region (north, south, east and west). The first stage of sampling, in which cities were selected from geographic regions and counties were selected from cities, was not random. Three counties (Liaoyang in Liaoyang City, Zhangwu in Funxin City and Dawa in Panjin City) were selected to represent north, south and east. In the second stage, one township was randomly selected from each county and 8–10 rural villages were selected randomly from each township. In total, 26 rural villages were finally included. All eligible permanent residents aged ≥35 years from each village were invited to participate in the study (a total of 14 016 participants). Of these, 11 956 participants agreed and completed the present study, giving a response rate of 85.3%. Participants who were pregnant or had malignant tumours or mental illness were excluded from the study. The study was approved by the Ethics Committee of China Medical University (Shenyang, China). All procedures were performed in accordance with ethical standards. Written consent was obtained from all participants after they had been informed of the objectives, benefits, medical issues and treatment of personal information. If the participants were illiterate, written informed consent was obtained from their proxies.
Data collection and measurements At a single visit to the clinic by the patient, data were collected by cardiologists and trained nurses using a standard questionnaire delivered by face-to-face interview. Before the survey was performed, all eligible investigators were required to attend the organized training. Candidate investigators were briefed on the purpose of the study, how to administer the questionnaire, the standard method of measurement, the importance of standardization and the study procedures. There was a central steering committee with a subcommittee for quality control. A stringent quality assurance and quality control programme was implemented to ensure the validity and reliability of study data. A strict test was performed after investigator training, and only those who scored perfectly were allowed to collect data. During data collection, inspectors received further instructions and support.
This article is protected by copyright. All rights reserved.
Accepted Article
Data regarding demographic characteristics, lifestyle risk factors, dietary habits, annual family income, education level and family history of diabetes were collected. Information regarding drug use in the past two weeks was also collected. Current smoking was defined as currently smoking cigarettes, current alcohol consumption was defined as alcohol intake more than twice per week for 1 year or more.
According to the American Heart Association protocol, blood pressure was measured three times at 2-min intervals after at least 5 min of rest using a standardized automatic electronic sphygmomanometer (HEM-907; Omron, Kyoto, Japan). The calibration of the device was checked using a standard mercury sphygmomanometer every month by two doctors according to the British Hypertension Society protocol [10]. The mean of three blood pressure measurements was calculated and used in all analyses.
Weight and height were measured to the nearest 0.1 kg and 0.1 cm, respectively, with the participants barefoot in lightweight clothing. Waist circumference was measured at the umbilicus at the end of normal expiration using a non-elastic tape (to the nearest 0.1 cm), with the participants standing [11]. BMI was calculated as weight in kilograms divided by the square of the height in meters (kg/m2).
Fasting blood samples were collected in the morning after at least 12 h of fasting for all participants. Blood samples were obtained from an antecubital vein into Vacutainer tubes (Becton Dickinson, Franklin Lakes, NJ, USA) containing EDTA. They were centrifuged on site within 2 h of collection. Plasma glucose was measured locally using glucose oxidase or hexokinase methods within 24 h. Fasting plasma glucose, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and other routine blood biochemical indexes were analysed enzymatically on an Olympus AU640 autoanalyzer (Olympus, Kobe, Japan). All laboratory equipment was calibrated and blinded duplicate samples were used.
This article is protected by copyright. All rights reserved.
Accepted Article
Definitions According to a JNC-7 report, hypertension was defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg and use of anti-hypertensive medications [12]. BMI was categorized into three groups: normal (BMI
