Social Marketing Improved the Consumption of Iron-fortified Soy Sauce among Women in China

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1 RESEARCH ARTICLE Social Marketing Improved the Consumption of Iron-fortified Soy Sauce among Women in China Continuing Education Questionnaire available at Meets Learning Need Codes for RDs and DTRs 4010, 4100, and Xinying Sun, PhD 1 ; Prof. Yan Guo, MPH 1 ; Sisun Wang, MPH 2 ; Jing Sun, MD 3 ABSTRACT Objective: To test the feasibility and effectiveness of social marketing on the improvement of women s knowledge, attitudes, and behaviors regarding iron-fortified soy sauce (FeSS). Design: A community-based intervention was conducted among 4 groups, experimental rural (E R ), control rural (C R ), experimental urban (E U ), and control urban (C U ). Setting: Urban and rural areas in Guizhou province, China. Participants: Women 19 to 70 years old (n 193 in rural areas and n 179 in urban areas). Intervention: A mass-media campaign to promote use of FeSS was conducted throughout Guizhou province. In the intervention areas, social marketing strategies using integrated 6 Ps (product, price, place, promotion, policy, and partnership) were implemented from December 2004 to February Main Outcome Measures: Knowledge of FeSS; benefits, barriers, and intention to purchase; availability of FeSS; behaviors regarding purchase and use of FeSS. Analysis: Analysis of covariance, paired T test and cross-tabulations were used. The level was set at.05. Results: Compared with the baseline, perceived benefits of FeSS, barriers (BARRI) and intention to buy (INTEN) significantly improved within both experimental groups (P.01 or.001). The only improvement in control groups was for BARRI in C R (P.001). Availability of FeSS increased in all areas. Purchase and use of FeSS in rural and urban intervention groups increased by nearly 30% more than those in control groups. Conclusion and Implication: Social marketing of FeSS is feasible and effective to improve knowledge, perception (perceived benefits and overcoming barriers), intention to purchase, and consumption of FeSS among women in Guizhou, China. Key Words: iron deficiency, iron-fortified soy sauce, social marketing, Theory of Planned Behavior, Health Belief Model (J Nutr Educ Behav. 2007;39: ) CPE Continuing Professional Education INTRODUCTION 1 School of Public Health, Peking University Health Science Center, Beijing, P. R. China 2 Institute of Hygienic Monitoring and Inspection, Guizhou Provincial Center for Disease Control and Prevention, Guizhou, P. R. China 3 Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, P. R. China The authors have no conflicts of interest or financial interest in the sales of NaFeEDTA-fortified soy sauce. This study was funded by a grant to the Chinese Center for Disease Control and Prevention from the Global Alliance for Improved Nutrition (GAIN), Geneva, Switzerland. Address for correspondence: Xinying Sun, PhD, Department of Social Medicine and Health Education, School of Public Health, Peking University Health Science Center, 38, Xueyuan Road, Haidian District, Beijing , P.R.China; Tel. & Fax: ; xysun@bjmu.edu.cn 2007 SOCIETY FOR NUTRITION EDUCATION doi: /j.jneb Iron deficiency anemia (IDA) is the most common nutritional problem in the world. The World Health Organization estimates that approximately 48.1% of children, 42.3% of women and 30.0% of men are affected by IDA in developing countries. 1 The China Nutrition and Health Survey in 2002 indicated that the anemia prevalence of the Chinese population was 20.1% (15.8% of males and 23.3% of females), and the rates reached 30% in children ( 2 years) and the elderly ( 60 years). 2 Guizhou, an economically depressed province, is one of the most affected areas; the IDA rate in Guizhou was 58.0% among children in the year Food fortification is the most feasible, costeffective, and sustainable way to improve iron status of people in such poor areas. As a popular condiment, soy sauce was selected as the food vehicle to improve iron deficiency (ID) and IDA, through sodium iron ethylenediaminetraacetic acid (NaFeEDTA) fortification, in China s National Nutrition Improvement Program: Iron-Fortified Soy Sauce (FeSS)

2 Journal of Nutrition Education and Behavior Volume 39, Number 6, November/December Project (Project for short). A double-blind controlled randomized intervention in Guizhou clearly proved that FeSS was significantly effective in controlling ID, reducing the prevalence of IDA and improving physical growth of children. Also, the results showed that FeSS was well accepted by local residents on its taste, color, and odor. 4 Social marketing is the application of commercial marketing technologies to the analysis, planning, execution, and evaluation of programs designed to influence the voluntary behavior of target audiences in order to improve their personal welfare and that of their society. 5 The unique characteristics of social marketing include that (1) it holds behavior change as its bottom line (ie, behavior change is the benchmark used to design and evaluate interventions); (2) therefore it is customerdriven (eg, to understand target audiences needs through audience research and then design products); and (3) it emphasizes creating attractive exchanges that encourage behavior. In addition, social marketing campaigns usually use 4 Ps of the traditional marketing mix. That is, social marketing creates attractive benefit packages (products) while minimizing costs (price) wherever possible, making the exchange convenient and easy (place) and communicating powerful messages through media relevant to and preferred by target audiences (promotion). 6 Social marketing has been used to improve knowledge, attitude, behavior, and use of a variety of foods or nutrition supplements, including fruits and vegetables, 7 red palm oil, 8 vitamin A-rich foods, 9 ironfolic acid supplements, and multivitamin and mineral supplements. 16 The investigators conducted formative research based on the Theory of Planned Behavior (TPB) 17 and the Health Belief Model (HBM) 18 to understand women s needs. The results of the study showed that women s behavioral intention to buy FeSS was directly or indirectly impacted by FeSS knowledge, health value, perception of IDA, behavior identity, attitudes toward behavior, barriers, and control beliefs. 19 Meanwhile, the formative research explored some information related to the 4 Ps elements of social marketing. The results showed that women in Guizhou knew little about the characteristics and benefits of FeSS; rural families mostly cared for taste and price when buying soy sauce, whereas urban families cared for taste and brand. The average price paid by rural families for ordinary soy sauce was 0.83 Yuan (RMB, $0.10)/ half a kilogram, and urban families paid 1.37 Yuan (RMB, $0.17). Rural families often bought ordinary soy sauce at small stores, groceries, and booths in markets, and urban families purchased it at stores and supermarkets. It was quite inconvenient for both rural and urban families to buy FeSS. In both rural and urban areas, television and doctors were the most important sources of information about nutrition. 19 The present research further tested the hypothesis that social marketing improves women s knowledge and attitudes regarding FeSS, as well as availability of FeSS and purchase and use of FeSS through the strategies of the 6 Ps (product, price, place, promotion, policy, and partnership). Although social marketing has proven successful in prior nutrition-related programs, this study represents the first attempt to promote a fortified condiment in a poor area in China. METHODS Study Design, Subjects, and Procedure A community-based intervention trial was implemented using a stratified sampling to select subjects from 2 districts (urban communities) in Kaili city and 2 villages (rural communities) in Huishui County in Guizhou Province. At district or village level, the communities were randomly divided into intervention and control groups. The sample areas ranked medium economically in the province and had FeSS available. The poorest areas were not chosen, because many families there ate only salt and did not eat soy sauce because they could not afford it, and there was almost no FeSS supply in these poorest areas when the Project was begun. At baseline, the percentage of FeSS-buying behavior was expected to be about 1%. It was determined that a sample size of 135 women was needed to detect an increase of 9 percentage points in women s purchase of FeSS (.05,.1). Meantime, a sample size of 131 women was needed to detect a difference of 6% between 2 groups on numerical variables such as perceived barriers, attitudes toward behavior, and intention (.05,.1). The attrition rate was controlled at about 10%. So it was determined that the sample size needed was 145 for each group. In addition, because women s names and their ID numbers were registered in surveys, paired-sample analysis was feasible with a smaller sample size. Baseline and follow-up questionnaire surveys were conducted from July to December of 2004 and in March and April of 2006, respectively. At baseline, about 140 subjects took part in the survey in each project area; the experimental group (E R ) and the control group (C R ) in rural areas, and the experimental (E U ) and control group (C U )in urban areas. Women who were responsible for cooking and buying household commodities in their families and had no hearing disorder were eligible to volunteer for the survey. Age range was not restricted, because prior research indicted that age was not an important factor influencing women s perception of FeSS, attitude, intention, purchase behavior, and source of information. 19 The first 140 women who met the requirements in each area entered the study. When doing the follow-up survey, as many people as possible from the baseline survey were followed, but the attrition rate reached to 20% to 40%. So the subjects who completed both the baseline and the follow-up survey were analyzed. There were 113, 80, 97, and 83 women in E R,C R, E U, and C U, respectively. Investigators were medical workers from provincial, civic, and prefectural centers of disease control and preven-

3 304 Sun et al/iron-fortified SOY SAUCE CONSUMPTION IN CHINA tion in Guizhou. All were appropriately trained to administer the questionnaire and familiar with the handbook of instructions. Community organizations, a committee of residents, or a primary clinic took responsibility for recruiting and organizing the subjects. In villages, the educational level of subjects was low, so investigators interviewed the subjects individually and recorded their answers on the questionnaire. In cities, the questionnaire was filled out by subjects themselves if they had received a high school education or above and could understand the questionnaire; otherwise, the investigator helped to fill it out. The study protocol was approved by the Ethics Committee of Peking University Health Science Center, and all subjects gave informed consent. Measures The questionnaire was designed based on HBM and TPB using Likert-type scales (Table 1). We assessed the following: knowledge of FeSS (KIRON), attitudes toward behavior of consuming FeSS (ATB, calculated by perceived benefits of FeSS [BENE] multiplied by evaluation of behavioral outcome, perceived barriers (BARRI), health behavior identity (IDEN), intentions to buy FeSS (INTEN), availability of FeSS, behaviors regarding purchase and use of FeSS, and sociodemographic variables (age, education, family size, income, etc). For the variable BARRI, a higher score indicated fewer barriers and therefore may lead to more consumption. Hence for all variables, higher scores implied higher endorsement. Prior to data collection, a pilot study was conducted in which an initial draft of the questionnaire was administered to a sample of 10 women in rural areas in Guizhou. The women were instructed to identify any words or items that were difficult to understand. Modifications to the questionnaire were made, then the modified questionnaire was administered to 120 residents in Guizhou to test internal consistency and construct validity. The reliability of the questionnaire was good, and the Cronbach coefficient of variables was at least 0.87 (Table 1). The validity was also good, with 10 factors explaining 70% of variance of the questionnaire accumulatively. 19 Intervention Integrated 6 Ps strategies were applied in the social marketing campaign: product (the taste, quality and safety of FeSS), price (suitable pricing to ensure the affordability for local families), place (increasing supply as much as possible), promotion (mass media and interpersonal communication), policy (policy support from government), and partnership (cooperation of stakeholders). Product, price and place. Guiyang Weichunyuan Foods (Group), Ltd. in Guiyang City, Guizhou Province, was one of the first 11 enterprises producing FeSS in China. As the largest condiment enterprise in western China, its soy sauce covered 80% of areas of Guizhou province. Its FeSS was 1.8 Yuan (RMB, $0.23)/bag (450 g) which is an acceptable cost in the urban areas, but it was more expensive than the families in the rural areas could afford. In Table 1. Internal Consistency of Questionnaire on Iron-fortified Soy Sauce (FeSS) Variable Items Range Item example Score KIRON Iron in FeSS can be well 1 true, 0 false/don t know absorbed. BENE Eating FeSS can make 1 strongly disagree, 5 strongly agree children stronger. ATB Eating FeSS can make children stronger: a. To what extent do you agree a, 1 strongly disagree, 5 strongly agree; b, 1 very unimportant, 5 very important with this statement? b. To you, is it important? BARRI I m afraid that FeSS will 1 very afraid, 5 not at all afraid affect the taste of dishes. IDEN To buy FeSS is one of the 1 strongly disagree, 5 strongly agree best things that I can do for my family members. INTEN Suppose that there is FeSS to buy now, what is the possibility that you will buy it the next time? 1 absolutely not, 5 absolutely KIRON indicates knowledge of FeSS; BENE, perceived benefits of FeSS; ATB, attitudes toward behavior; BARRI, perceived barriers to buy FeSS; IDEN, health behavior identity; INTEN, intention to buy FeSS.

4 Journal of Nutrition Education and Behavior Volume 39, Number 6, November/December Table 2. Comparability between the Experiment Group and the Control Group at Baseline Women in Rural Areas Women in Urban Areas Variable E R C R t/ 2 E U C U t/ 2 Age (y) * Education (y) * Family size Nationality Han 64.6% 65.0% % 22.9% Minority 35.4% 35.0% 87.5% 77.1% E R /C R indicates the experimental group or the control group in rural areas; E U /C U, the experimental group or the control group in urban areas. *P.001 Nationality was compared with 2 test; other variables were compared using the t test. 2004, the Project tried to introduce FeSS from another province (Hebei province in northern China), but it was not acceptable because of its northern-style salty taste. So the Project extended to the second-largest local enterprise, Guizhou Qianweitianjiale Foods, Ltd. to produce FeSS especially for rural areas. After nearly one year, the FeSS came off the product line in the autumn of 2005 with a price of 1.0 Yuan (RMB, $0.13)/bag (450 g). By early 2006, it had been sold in 60 counties in Guizhou. In this study, the FeSS supply and price were not different between the intervention site and the control site in urban areas. The FeSS supply was a little better in the intervention rural area than in the control rural area, but the prices were the same. Promotion. Mass-media intervention activities were carried out all over the province, mainly by news or short reports in various newspapers, 30-second public service advertisements of Have iron, have power on television, and fixed ad columns in communities. In the rural areas, 14% of subjects in the intervention areas and 8% in the control areas had watched programs or public service advertisements on TV regarding FeSS, whereas the percentages in E U and C U were 36% and 26%, respectively. In addition to the mass-media campaign, interpersonal educational activities were also conducted at the intervention sites. For example, nutrition and health lectures focusing on improving iron deficiency and anemia, supplementing iron, and benefits of FeSS, were given to women. Health consultations on similar topics were provided. Specially designed calendars were distributed with FeSS information during holidays and at periodic markets where the farmers visited. During holidays and periodic market activities, FeSS (2800 bags) was given as gifts to farmers in the rural intervention areas. These FeSS samples gave the villagers a chance to try and become familiar with it. The periodic market activity, called Gan Chang locally, was held every 6 days among villages alternatively. Policy. The Chinese Food and Nutrition Development Program ( ), promulgated by the General Office of the State Council in 2001, emphasized that the food processing industry should speed up work on food fortification and focus on promotion of nutrition fortification of staple foods to improve the lack of nutrients. 20 The Report on Improving Physical Quality and Health of Children and Adolescents, submitted to the State Council by the Ministry of Health, the Ministry of Education, the Ministry of Agriculture, and the General Administration of Sport in 2000 referred to FeSS more particularly. 21 The Action Plan of the Implementation of the Iron-Fortified Soy Sauce Project, distributed by the Ministry of Health in September 2004, and The Notice on Promoting the Iron- Fortified Soy Sauce for the Prevention of Iron Deficiency Anemia, delivered by the Department of Disease Control, Ministry of Health, provided powerful policy support for the FeSS intervention. Partnership. Social marketing involved the stakeholders. Steering committees responsible for the planning, implementation, evaluation, and coordination of the project were established at state and province levels. The following stakeholders or organizations worked together during the social marketing intervention procedure: the Guizhou Provincial Center for Disease Control and Prevention and Institute of Sanitation Inspection, organizations of health education and health promotion, China Condiment Industry Association, local condiment and business associations, local food or condiment factories, mass media (TV, newspaper, etc.), and organizations of local communities. The strong partnership and collaboration among these organizations made it possible to conduct the interventions. Statistical analysis. Data was processed by EpiData (Version 3.02, The EpiData Association, Odense, Denmark, 2003). Analysis of covariance was employed to assess changes over time in knowledge, attitudes, and intention to purchase FeSS among groups. Cross-tabulations 2 was used to assess changes in knowledge of characteristics of FeSS, availability of FeSS, and purchase and use behaviors. Statistics were processed by Statistical Package for the Social

5 306 Sun et al/iron-fortified SOY SAUCE CONSUMPTION IN CHINA Table 3. Changes and Comparison of Knowledge of Characteristics of Iron-fortified Soy Sauce (FeSS) among Women in Rural or Urban areas on Baseline and Follow-up Surveys (%) Women in Rural Areas E R (%) C R (%) Women in Urban Areas E U (%) C U (%) Characteristics of FeSS Pre- Post- Pre- Post- 2 (Pre-/Post-) Pre- Post- Pre- Post- 2 (Pre-/Post-) Iron in FeSS can be well absorbed /15.513** /2.197 FeSS does not change the taste of the soy sauce /12.694** /1.074 FeSS does not change the color of the soy sauce /16.037** /0.765 FeSS is good for health /13.420** /8.770* FeSS has preventive effect to iron deficiency anemia /17.701** /7.888* E R /C R indicates the experimental group or the control group in rural areas; E U /C U, the experimental group or the control group in urban areas; Pre-, baseline survey; Post-, follow-up survey. *P.01 **P.001 Sciences (SPSS, Version 10.0, Chicago, Ill, 2001). A simple random sample was assumed in the analysis. The level was set at.05. RESULTS Characteristics and Comparability Between the Experimental Group and the Control Group Attrition happened in the follow-up survey in the 4 groups, but there were no significant differences at baseline between the followed subjects and the lost subjects in age, education, family size, income, and their knowledge of FeSS, attitudes, and intention to buy FeSS. Only the data from subjects who completed both the baseline and follow-up surveys were analyzed. There were 113, 80, 97, and 83 women in E R,C R,E U and C U, respectively. The comparability between the experimental group and the control group in urban areas was better than in rural areas (Table 2). There was no significant difference in the economic situation between E R and C R ; of these families, 26.5% in E R and 32.5% in C R lived below China s standard of poverty level (annual per capita income less than $80), 60.2% in E R and 52.5% in C R dressed warmly and ate their fill, and 13.3% in E R and 15.0% in C R lived on the edge of the poverty line. The economic situation of urban families was generally better than that of rural families, and there were no significant differences between E U and C U. The monthly per capita income in 47.8% of families in E U and 46.8% in C U was less than $35 (about RMB 300 Yuan). Knowledge of the Characteristics of FeSS There were no significant differences regarding knowledge of the characteristics of FeSS between E R and C R, and between E U and C U at baseline. After the intervention, the percentage of subjects who were aware of FeSS characteristics in E R was significantly higher than C R (P.001). In the urban areas, the percentage of awareness of FeSS is good for health and FeSS has a preventive effect on IDA was significantly higher than those in C U (P.01) at follow-up (Table 3). Scores of Perception, Attitude, and Intention Because of the difference in age and education between E R and C R and the influence of baseline score on follow-up score, analysis of covariance was used to eliminate these effects. The original means, the corrected means, difference of the latter between groups, and increase rates are shown in Table 4. Compared with the baseline, BENE, BARRI, and INTEN significantly improved within both E R and E U (P.01 or.001). In the control groups, none of the variables improved except for BARRI in C R (P.001). Net increase rates are the difference between the experiment groups and the control groups on the posttest and reflect the effectiveness of interpersonal communication. Net increase rates were 8.2% for BENE (P.01), 10.4% for ATB (P.01), 5.9% for IDEN (P.05), and 12.8% for INTEN (P.001) among rural women. Among urban women, significant net increase rates were 17.0% for BARRI (P.05) and 19.8% for INTEN (P.001). Availability of FeSS FeSS was generally unavailable to the rural residents at baseline (about 3% of women said FeSS was available to buy in general ). The women s perceptions regarding avail-

6 Journal of Nutrition Education and Behavior Volume 39, Number 6, November/December Table 4. Attitude Scores at Baseline and at Follow-up for Women in Control and Experimental Groups and Corrected Means for Follow-up Survey through Analysis of Covariance Area Rural areas Urban areas Increase Original Mean 95% Covariate Net Corrected Standard Confidence Estimate Increase Variable Group Pre- Post- P Mean Error Interval Value P Rate (%) Rate (%) BENE E R ** ** C R ATB E R * C R * BARRI E R *** C R *** IDEN E R * C R INTEN E R *** *** C R BENE E U ** C U ATB E U C U BARRI E U ** * C U IDEN E U C U INTEN E U *** ( ) *** C U *** ( ) 4.1 E R /C R indicates the experimental group or the control group in rural areas; E U /C U, the experimental group or the control group in urban areas; Pre-, baseline survey; Post-, follow-up survey; BENE, perceived benefits of FeSS; BARRI, perceived barriers to buy FeSS; IDEN, health behavior identity; ATB, attitudes toward behavior; INTEN, intention to buy FeSS. *P.05 **P.01 ***P.001 The corrected means were estimated with covariate variables evaluated at the following values: age 38.8 (yrs), education 5.6 (yrs). P values were from paired-sample T test. P values were from analysis of covariance. There was a significant effect of the INTEN (pre) -covariate on INTEN (post) in the urban group, P.05. ability improved at follow-up. The proportion of rural women choosing the available to buy in general response reached 46.2% in the intervention area and 15.8% in the control area; the proportion responding available/easily available was 8.5% in E R and 2.3% in C R. Availability in urban areas improved much more than in the rural areas, with the proportion responding available/easily available at 70% in E U and 40% in C U (Table 5). Behaviors: Purchase and Use of FeSS Compared with the baseline survey, the rates of eating and purchasing FeSS increased significantly in both rural areas and urban areas in the follow-up survey. The increases in the 2 experimental groups were significantly higher than those of the 2 control groups (Table 6). The rate of eating was almost the same with that of purchase in urban areas, whereas the former was higher than the latter in rural areas, because FeSS had been given as a gift during the social marketing intervention in the rural areas. Diffusion of FeSS Purchases According to Everett M. Rogers s definition, diffusion is the process in which an innovation is communicated through certain channels over time among the members of a social system. 22 Considering the diffusion characteristics of FeSS were similar between city and village, rural and urban data were combined to reflect the diffusion characteristic of FeSS in Guizhou (Figure 1). From 1999 to March 2005, the cumulative purchase rate of FeSS was in a slow upward trend. From April to December in 2005, the pace of increase gradually accelerated, which was related to gradual expansion of the social marketing campaign of FeSS. The purchase rate was highest in February and March 2006, the time when the second local FeSS in Guizhou became

7 308 Sun et al/iron-fortified SOY SAUCE CONSUMPTION IN CHINA Table 5. Perception Regarding Availability of Iron-fortified Soy Sauce (FeSS) among Women in Rural or Urban Areas on Baseline and Follow-up Surveys (%) Women in Rural Areas Women in Urban Areas E R (%) C R (%) E U (%) C U (%) Availability Pre- Post- Pre- Post- 2 (Pre-/Post-) Pre- Post- Pre- Post- 2 (Pre-/Post-) Not available /15.488** */19.478*** Available but not easily Available Easily available Don t know/not noticed E R /C R indicates the experimental group or the control group in rural areas; E U /C U, the experimental group or the control group in urban areas; Pre-, baseline survey; Post-, follow-up survey. *P.05 **P.01 ***P.001 Available and Easily available were combined in 2 tests. Table 6. Changes and Comparison of Eating and Purchase Behaviors of Iron-fortified Soy Sauce (FeSS) among Women in Rural or Urban Areas on Baseline and Follow-up Surveys (%) Women in Rural Areas E R (%) C R (%) Women in Urban Areas E U (%) C U (%) Behavior Pre- Post- Pre- Post- 2 (Pre-/Post-) Pre- Post- Pre- Post- 2 (Pre-/Post-) Have eaten FeSS /11.335* /30.362* Have bought FeSS /23.233* /22.787* E R /C R indicates the experimental group or the control group in rural areas; E U /C U, the experimental group or the control group in urban areas; Pre-, baseline survey; Post-, follow-up survey *P.001 available. Diffusion speed of the intervention group was a little faster than that of the control group, thus it can be seen that the effect of interpersonal communication and mass-media interventions is superior to that of mass media only. DISCUSSION The multiphase social marketing campaign was deemed successful because it resulted in: (1) increased knowledge regarding characteristics of iron-fortified soy sauce; (2) improved perception of FeSS (perceived benefits and overcoming barriers); and (3) increased purchase and use of FeSS. Mass-marketing campaigns were conducted throughout Guizhou province, China. Portions of the mass-media campaign, such as newspaper and television, were not applicable for some villages owing to educational, economic, and signal transmission reasons. Thus, the exposure rate of TV and newspaper advertisements in rural areas was lower than that in urban areas. However, at the periodic market there was relatively frequent communication between people in the intervention and control rural areas; thus, people in control rural areas also had opportunities to learn about and obtain FeSS. In a comparison of their pretest and posttest responses, control group participants from both urban and rural areas had increased awareness of FeSS characteristics and an increased number reported purchases of FeSS. The intervention groups participated in a more intense intervention than the control groups. In addition to the mass-media communications, interpersonal communication which included nutrition and health lectures and health consultations regarding iron deficiency, calendars with FeSS information, and gift bags of FeSS occurred in the intervention areas. Compared to the rural control group, the rural intervention group had increased knowledge of the characteristics of FeSS, greater awareness of the benefits of using FeSS, and enhanced behavioral intention to purchase FeSS. Compared to the urban control group, the urban intervention group reported diminished worries about FeSS (overcoming barriers to purchase). Surprisingly (and perhaps a reflection of the periodic market personal interactions), the rural control group had a significant improvement in their posttest score related to overcoming barriers to buying FeSS, and there was no significant difference between the rural control and intervention groups on the posttest barrier score. Compared to the pretest results, the percentages of

8 Journal of Nutrition Education and Behavior Volume 39, Number 6, November/December Figure 1. Diffusion of purchase of iron-fortified soy sauce (FeSS) among intervention and control groups in Guizhou, China. participants in rural and urban control groups who reported use and purchase of FeSS was significantly higher at posttest, indicating that the mass-media campaign was sufficient to result in behavior change for some people. The addition of interpersonal communications to the mass-marketing campaign resulted in a significant improvement in adoption of the desired behavior, since the percentage of both rural and urban intervention participants reporting they had purchased FeSS was more than 30% greater than was reported by the control groups. These findings confirm previous research findings that social marketing is an effective way to improve knowledge, attitudes, and behaviors for a variety of food or nutrition products. Smitasiri et al reported that social marketing of vitamin A-rich foods in Thailand significantly improved knowledge, attitudes, and reported behavior of women with respect to vitamin A-rich foods and daily intake of vitamin A of pregnant and lactating women and preschool children in the intervention areas. Cases of night blindness among schoolchildren decreased significantly. 9 Warnick et al reported that a social marketing campaign increased women s awareness and use of multiple supplements. 16 Paulino et al reported that a social marketing and social mobilization campaign successfully improved knowledge and the practice of buying and regularly taking iron-folic acid supplements by women of reproductive age in the Philippines. The percentage of women taking supplements increased from less than 10% at the beginning to 95% by the fourth survey (1 year after the beginning of the intervention). 15 Limitations. A limitation of this study is that it was not possible to observe the loyalty to FeSS through long-term tracking of participants. Those who tried FeSS during the social marketing campaign may not persist in the use and purchase of FeSS after the social marketing project ends. Thus, regular long-term monitoring is needed to track people s behavior. The overall goal of the Iron-fortified Soy Sauce Project is to reduce the prevalence of IDA in the entire population, including women, children, and elderly. However, the present research aimed only at promoting women s purchase behavior through a social marketing campaign. Without physiological testing (eg, hemoglobin), the impact on IDA could not be evaluated. As the Project goes on, its effectiveness in decreasing IDA and improving iron status will emerge. Another limitation of this study is that higher attrition happened at the follow-up survey than expected. We attribute this result to the following reasons. Some of the subjects did not leave an accurate address (unwilling to give to investigators or address not clear) or telephone number (unwilling to give out or did not have a telephone), or they gave unclear registration information. Some of the rural subjects migrated to cities to seek employment. Others moved or were lost for other reasons. Because of the decrease of the sample size, the power of tests decreased to some extent. When the difference between groups was compared, however, application of paired analysis enabled the authors to resolve this problem to a large extent. Finally, the study findings can be extrapolated only to areas with similar conditions, because random sampling was not used to recruit the subjects, and the project was not implemented in the most economically disadvantaged areas. IMPLICATIONS FOR RESEARCH AND PRACTICE Doctors in the intervention areas conducted interpersonal communication about IDA and the benefits of iron-fortified soy sauce. The success of this intervention indicates the valuable role of interpersonal communication led by doctors as the chief practitioners. Because people generally regard doctors as trustworthy health authorities, doctors should continue to play their roles in future promotions. Poor, rural areas should be given special attention in future programs. The FeSS supply needs to be improved in these areas. In order to reach a broad segment of the poor, rural population, mass-media accessibility also needs improvement. The strategy to give gifts of FeSS in the rural areas likely played an important role in overcoming barriers and promoting purchase behavior. Rural women in both the experimental group and the control group diminished their worries (BARRI) about FeSS, and the main reason may be that the gift of FeSS gave them a chance to try it, alleviating their worries about side-effects, taste, and quality of FeSS. Moreover, the purchase rates in rural areas were higher than those in urban areas (E R vs. E U,C R vs. C U ), though the availability of FeSS in rural areas was lower than in urban areas. Therefore, the strategy of giving out free FeSS should be continued in rural areas and should also be extended to urban areas in future programs. The com-

9 310 Sun et al/iron-fortified SOY SAUCE CONSUMPTION IN CHINA panies that make iron-fortified soy sauce could give FeSS gifts to consumers at stores and supermarkets in commercial promotion activities, and the health sector or nongovernment organizations could give community residents FeSS gifts during education activities conducted for the Iron- Fortified Soy Sauce Project. ACKNOWLEDGMENT We would like to acknowledge Prof. Junshi Chen, Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, for his support and valuable comments. We would also like to thank all health care workers in Guizhou province for their help in data collection. This study was funded by a grant to the Chinese Center for Disease Control and Prevention from the Global Alliance for Improved Nutrition (GAIN), Geneva, Switzerland. REFERENCES 1. United Nations Children s Fund, United Nations University, World Health Organization. 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