Shufa Du

Cohort Profile: The China Health and Nutrition Survey—monitoring and understanding socio-economic and health change in China, 1989–2011

This research journal article presents a detailed overview of a cohort profile of the China Health and Nutrition Survey (CHNS) which allows for the monitoring and understanding of socio-economic and health change in China from 1989-2011. The author discusses the history and development of the CHNS as a result of the countrys transformations since Chinas reform and open policy. The CHNS was established with the goal to develop a multipurpose longitudinal survey that would allow the research group to examine a series of economic sociological demographic and health questions. The article describes the design of the survey to include in-depth coverage at the individual household and community levels though it was not designed to be representative of China but to be randomly selected and capture a range of economic and demographic circumstances. It provides data randomly from eight different provinces and rounds have been completed nearly every three years since 1989. Though they are very complex to determine with the survey response rates and attrition are assessed along with descriptions of changes in lost-to-follow-up rates. The article describes key finds and publications to be numerous including links to obesity from occupation and transportation; nutrition and chronic disease; and important policy results for agriculture and poverty reduction programs. Lastly the author provides a summary of the CHNSs strengths and weaknesses and recommendations for accessing the data and further information.

A new stage of the nutrition transition in China

OBJECTIVE To fully explore the long-term shifts in the nutrition transition and the full implications of these changes in the Chinese diet. DESIGN A descriptive, population-based study. SETTING Data come from nationally representative surveys: the China Health and Nutrition Survey (1989-1997), the China National Nutrition Survey (1982 and 1992), the annual household consumption surveys of the State Statistical Bureau, and the Annual Death Report of China. RESULTS During the first part of the major economic transformation in China (before 1985), cereal intake increased but decreased thereafter. There was also a long-term reduction of vegetable consumption that has now stabilised. Intake of animal foods increased slowly before 1979 and more quickly after the economic reforms occurred. While the total energy intake of residents has decreased, as has energy expenditure, large changes in the composition of energy have occurred. The overall proportion of energy from fat increased quickly, reaching an overall average of 27.3% and 32.8% for urban residents in 1997. Over a third of all Chinese adults and 60.1% of those in urban areas consumed over 30% of their energy from fat in 1997. Large shifts towards increased inactivity at work and leisure occurred. These changes are linked with rapid increases of overweight, obesity and diet-related non-communicable diseases (DR-NCDs) as well as total mortality for urban residents. CONCLUSIONS The long-term trend is a shift towards a high-fat, high-energy-density and low-fibre diet. The Chinese have entered a new stage of the nutrition transition.

Measuring the full economic costs of diet, physical activity and obesity-related chronic diseases

Most studies that have focused on the costs of obesity have ignored the direct effects of obesity‐related patterns of diet and physical activity. This study reviews the full effects of each component – poor dietary and physical activity patterns and obesity – on morbidity, mortality and productivity. The direct healthcare costs are based on a review of the effects of these factors on key diseases and the related medical care costs of each disease. The indirect costs on reduced disability, mortality and sickness during the period of active labour force participation prior to retirement are also examined. A case study is prepared for China to provide some guidance in the utilization of this review for economic analysis of obesity. The case study shows that the indirect costs are often far more important than the direct medical care costs. The Chinese case study found that the indirect effects of obesity and obesity‐related dietary and physical activity patterns range between 3.58% and 8.73% of gross national product (GNP) in 2000 and 2025 respectively.

Dynamics of the Nutrition Transition toward the Animal Foods Sector in China and its Implications: A Worried Perspective

Many changes in diet and in physical activity are occurring simultaneously in the developing world. These diet shifts include large increases in energy density, in the proportion of the population consuming a high fat diet and in animal product intake. Animal source foods (ASF) play a major role in these diet shifts. This article documents the large shifts in the composition of diets and obesity across the developing world and notes that these changes are accelerating. Using China as a case study, evidence of the speeding up of this process is presented in descriptive and more rigorous dynamic longitudinal analysis. The implications of these changes for dietary and obesity patterns and cardiovascular disease are great. Indeed, developing countries are at a point where the prevalence of obesity is greater than that of undernutrition and concerns related to intake of saturated fat and energy imbalance must be considered more seriously by the agriculture sector. Current agriculture development policy in many developing countries focuses on livestock promotion and does not consider the potential adverse health consequences of this strategy. Although linkages between ASF intake and obesity cannot be established as clearly as they are for high ASF intakes, heart disease and cancer, the potential adverse health effects linked with an increased ASF intake should no longer be ignored.

Prospective study on nutrition transition in China.

The aim of the prospective study reported here was to examine the effects of social and economic transformation on dietary patterns and nutritional status in China. The study began in 1989 and continued with follow-ups in 1991, 1993, 1997, 2000, and 2004. A total of 5000 subjects aged 18-45 years from 4280 households in nine provinces were included. Weighed records and three consecutive 24-h recalls were used. Over the study period, average consumption of all animal foods except milk increased, while cereal intake decreased. The proportion of animal protein and fat as a percentage of energy also increased. However, vitamin A and calcium intake did not increase and remained low. Child height and weight increased while undernutrition decreased and overweight increased. The results indicate that rapid changes in dietary pattern are associated with economic reforms in China.

Dynamics of the Chinese diet and the role of urbanicity, 1991-2011.

Chinas food consumption patterns and eating and cooking behaviours changed dramatically between 1991 and 2011. Macronutrient composition has shifted towards fats, and protein and sodium intakes remain high and potassium intake low. The rapid decline in intake of coarse grains and, later, of refined grains and increases in intake of edible oils and animal‐source foods accompanied by major eating and cooking behaviour shifts are leading to what might be characterized as an unhealthy Western type of diet, often based on traditional recipes with major additions and changes. The most popular animal‐source food is pork, and consumption of poultry and eggs is increasing. The changes in cooking and eating styles include a decrease in the proportion of food steamed, baked, or boiled, and an increase in snacking and eating away from home. Prior to the last decade, there was essentially no snacking in China except for hot water or green tea. Most recently, the intake of foods high in added sugar has increased. The dietary shifts are affected greatly by the countrys urbanization. The future, as exemplified by the diet of the three mega cities, promises major growth in consumption of processed foods and beverages.

Physical activity and inactivity in Chinese school-aged youth: the China Health and Nutrition Survey.

OBJECTIVE: To describe physical activity (PA) and inactivity levels and patterns in Chinese school children (aged 6–18 y).DESIGN: PA and inactivity were assessed in a youth cohort enrolled in the China Health and Nutrition Survey (CHNS) in 1997.SUBJECTS: A total of 1423 males (11.5±3.2 y) and 1252 females (11.5±3.3 y).MEASUREMENTS: PA and inactivity were assessed by self-reported usual activity (questionnaire). Children under 10 y were assisted by parents.RESULTS: Approximately 84% of Chinese youth actively commute to school for a median of 100–150 min/week. A total of 72% engage in in-school moderate/vigorous (MOD/VIG) PA for a median of 90–110 min/week. Relatively few children (≈8%) participate in any MOD/VIG PA outside of school. A total of 72% engage in study-related activities outside of school for a median of 420 min/week. Only 8% of Chinese school children, regardless of gender, watch television ≥2 h/day; less than 1% watch ≥4 h/day. Chores related to housework are not a part of life for Chinese school children; fewer than 20% performed these tasks.CONCLUSION: Chinese youth are unique compared to those in other developing countries because they do not perform household chores. Instead, they are under pressure to achieve scholastically. Participation in MOD/VIG PA outside of school is almost nonexistent. Current television watching habits are relatively low compared to developed countries and walking/biking is a common form of commuting. The descriptive analysis herein represents the foundation upon which future longitudinal studies of PA in this population will be based.

The expanding burden of cardiometabolic risk in China: the China Health and Nutrition Survey.

China faces a major increase in cardiovascular disease, yet there is limited population‐based data on risk factors, particularly in children. Fasting blood samples, anthropometry and blood pressure were collected on 9,244 children and adults aged ≥7 years in late 2009 as part of the national China Health and Nutrition Survey. Prevalent overweight, elevated blood pressure, and cardiometabolic risk factors: glucose, HbA1c, triglycerides (TG), total cholesterol (TC), high‐ and low‐density lipoprotein cholesterol (HDL‐C and LDL‐C), and C‐reactive protein (CRP) are presented. We found that 11% of Chinese children and 30% of Chinese adults are overweight. Rates of diabetes, dyslipidaemia, hypertension and inflammation are high and increased with age and were associated with urbanization. Approximately 42% of children have at least one of the following: pre‐diabetes or diabetes, hypertension, high TC, LDL‐C, TG, and CRP and low HDL‐C, as do 70% men and 60% women aged 18–40 years and >90% of men and women ≥60 years. In sum, the HbA1c findings suggest that as many as 27.7 million Chinese children and 334 million Chinese adults may be pre‐diabetic or diabetic. The high prevalence in less urban areas and across all income levels suggests that cardiometabolic risk is pervasive across rural and urban China.

The China Health and Nutrition Survey, 1989–2011

The China Health and Nutrition Survey (CHNS) began in 1989 with the goal of creating a multilevel method of data collection from individuals and households and their communities to understand how the wide‐ranging social and economic changes in China affect a wide array of nutrition and health‐related outcomes. Initiated with a partial sample in 1989, the full survey runs from 1991 to 2011, and this issue documents the CHNS history. The CHNS cohort includes new household formation and replacement communities and households; all household members are studied. Furthermore, in‐depth community data are collected. The sample began with eight provinces and added a ninth, Heilongjiang, in 1997 and three autonomous cities, Beijing, Shanghai, and Chongqing, in 2011. The in‐depth community contextual measures have allowed us to create a unique measure of urbanicity that captures major dimensions of modernization across all 288 communities currently in the CHNS sample. The standardized, validated urbanicity measure captures the changes in 12 dimensions: population density; economic activity; traditional markets; modern markets; transportation infrastructure; sanitation; communications; housing; education; diversity; health infrastructure; and social services. Each is based on numerous measures applicable to each dimension. They are used jointly and separately in hundreds of studies.

Understanding the patterns and trends of sodium intake, potassium intake, and sodium to potassium ratio and their effect on hypertension in China

BACKGROUND Recent studies have shown inconsistent effects of sodium reduction, potassium intake, and the ratio of sodium to potassium (Na/K ratio) on hypertension and other cardiovascular diseases. Major gaps exist in knowledge regarding these issues in China. OBJECTIVE We analyzed the patterns and trends of dietary sodium intake, potassium intake, and the Na/K ratio and their relations with incident hypertension in China. DESIGN The China Health and Nutrition Survey cohort includes 16,869 adults aged 20-60 y from 1991 to 2009. Three consecutive 24-h dietary recalls and condiment and food weights provided detailed dietary data. Multinomial logistic regression models determined trends and patterns of sodium and potassium intake and the Na/K ratio. Models for survival-time data estimated the hazard of incident hypertension. RESULTS Sodium intake is decreasing but remains double the Institute of Medicine recommendations. Most sodium comes from added condiments. Adults in the central provinces have the highest sodium intake and the most rapid increase in hypertension. Potassium intake has increased slightly but is below half of the recommended amount. The Na/K ratio is significantly higher than the recommended amounts. Recent measurements of high sodium intake, low potassium intake, and high Na/K ratio have strong independent dose-response associations with incident hypertension. CONCLUSIONS Reducing sodium in processed foods, the major public health strategy in Western countries, may be less effective in China, where salt intake remains high. Replacing sodium with potassium in salt to control and prevent hypertension in China should be considered along with other public health and clinical prevention options.