An evaluation of the impact of the folate and neural tube defects health claim pilot

Transcription

1 An evaluation of the impact of the folate and neural tube defects health claim pilot Maxwell Watson and Lyndsey Watson Abstract Objective: To evaluate the impact of the pilot folate and neural tube defect health claim instituted by the Australia New Zealand Food Authority (ANZFA). Design: Analysis of data, provided by ANZFA, from: 1. crosssectional population-based telephone surveys conducted in 1998 prior to, and in 1999 after the implementation of, the pilot claim; 2. food industry data on implementation of the claim from the same time period; and 3. contemporaneous retail sales data. Subjects: 2324 women of child-bearing age. Setting: Australian population. Main outcome measures: Changes in knowledge and attitudes to folate, uptake of the pilot health food claim and changes in consumption of foods over the period of the claim. Statistical analyses: For survey data, binary and multinomial logistic regression was used to estimate odds ratios after adjustment for variations in socio-demographic characteristics and survey source. Results: Over the survey period there was an increase in the proportion of women who had heard of folate (82% to 89%) and were aware of the association between folate and birth defects (33% to 41%), P < Knowledge about foods containing folate increased for leafy green vegetables (40% to 52%), and for cereals (26% to 49%), P =0.001 and P < respectively. Although there was uptake of the claim by the food industry, there was no evidence for change in purchase of foods with folate messages. Conclusions: This evaluation has shown that although there were increases in knowledge about folate over time, these may not be due solely to the folate health claim. (Aust J Nutr Diet 2001;58: ) Introduction The evidence is strong that folate is important to maternal and child health, as an adequate intake of folate periconceptionally can reduce the risk of neural tube defects (NTDs) by about two-thirds (1). The substantiation for a health claim derives from an earlier review of folate fortification in Australia (2). The three primary prevention strategies to reduce risk of NTDs by increasing folate intake are: increased intake of supplements; increased consumption of foods naturally high in folate; and fortification (voluntary or mandatory) of staple foods. There are particular features relating to health promotion with respect to knowledge of periconceptional folate. The neural tube develops before many women know they are pregnant and about 40% of pregnancies are unplanned (3), so that a population approach with health promotion activities directed at all women of child-bearing age is appropriate. While increasing the levels of knowledge in women is critical, it is apparent that other public health responses are also necessary. Because the consumption of foods rich in folate has been low in Australia (4), environmental strategies such as the addition of folate to foods have been implemented. In common with international trends, the 1995 National Health and Medical Research Council report recommended voluntary fortification of folate to staple foods (2). Manufacturers of breakfast cereals responded following revision of Standard A9 of the Australian Food Standards Code (5). Health claims are an innovation in food regulation that enables elaboration of the nutrition message on a label attached to a food to include a link to a named disease. This is seen as more specific than a simple nutrition message and theoretically provides impetus for the food industry to produce and promote products likely to deliver a public health nutrition benefit (6). Under Australian and New Zealand food regulations, the use of health claims about foods on product labels and associated advertising has previously been prohibited. The Australia New Zealand Food Authority (ANZFA) granted approval for the folate and NTD health claim (P170) as a pilot in a wider review of health claims in November 1998 (ANZFA Proposal P153). A key element was an evaluation of the impact of the pilot claim so that, in the event that ANZFA proceeded and permitted health claims, their implementation could be better informed. Relative to the introduction of comparable food regulation elsewhere, the conduct by ANZFA of a pilot of a specific health claim prior to implementation of health claims in general, is unique. This paper is concerned with the monitoring and evaluation of the impact of this pilot claim in females of child-bearing age from Australian data only, by measuring the proportion who had heard of folate, were aware of the association between folate and NTDs, and had knowledge of food sources of folate. Also measured were an estimated effect of the health claim on the food supply and sales of foods with health claims. Methods Organisation of the claim The pilot claim was managed by ANZFA in partnership with the Australian Food and Grocery Council, the fresh food industry, individual food companies, the Common- This study was funded by the Australia New Zealand Food Authority. Department of Perinatal Medicine, Royal Women s Hospital, Melbourne, Victoria M. Watson, PhD, RPH Nutr, Research Officer Centre for the Study of Mothers and Children s Health, La Trobe University, Melbourne, Victoria L. Watson, MSc, Senior Research Fellow Correspondence: M. Watson, Centre for Adolescent Health, 2 Gatehouse St, Parkville, Vic watsonm@cryptic.rch.unimelb.edu.au 236 Australian Journal of Nutrition and Dietetics (2001) 58:4

2 wealth Department of Health and Aged Care, and health and community organisations. Implementation of the claim Applications for products to make a folate and NTD claim were solicited from November Uptake was assessed in June 1999 and January The statement for the claim recommended by ANZFA was: This food contains folate. A diet rich in folate may help prevent birth defects like spina bifida. ANZFA produced a logo which read ANZFA endorsed folate health claim. Survey methods In planning for the evaluation of the health claim pilot, provision was made for baseline estimates of these relevant impact measures to be determined prior to the implementation of the pilot, with follow-up estimates after implementation. The proposed time frames for the collection of survey data were from November 1998 to November To generate information cost effectively, where possible, ANZFA sought cooperation from other groups to include appropriate questions in surveys already planned. This report includes two state-based surveys and one national survey from: the South Australian Health Monitor of 1998 to 1999; the Eat Well Tasmania Survey of 1998 to 1999; and the Australian Supermarket Institute Consumer Monitor Survey of 1998 to All these surveys were population-based surveys the Tasmanian surveys were telephone-based interviews and the others were computer-assisted telephone interviews. Choosing South Australia and Tasmania allowed comparisons between states that had had considerable and little health promotion about folate prior to the survey period respectively. The target group for the Australian Supermarket Institute survey was the main grocery buyer in households and all states and territories were included. The format of questions relevant to folate knowledge was the same in the South Australian and Tasmanian surveys. The Australian Supermarket Institute survey had a different order of questions and some changes in the wording (7). Response rates for the South Australian surveys were 77% in 1998 and 79% in This information was not available for the Tasmanian surveys. The Australian Supermarket Institute surveys were based on quota sampling. Analyses of survey data The combined file for all survey respondents contained over 7000 unit records. The data used in the analysis for women of child-bearing age comprised in total 2324 records: in 1998, 542, 243 and 416, for the South Australian, Tasmanian and Australian Supermarket Institute surveys respectively and correspondingly 476, 250 and 397 in Thus residents of South Australia and Tasmania had higher representation in the sample than other states. As there were some differences between the Australian Supermarket Institute survey and the others, some comparisons were restricted to particular surveys. Statistical analyses, using the Stata statistical software package (STATA Corp, College Station, TX, Release 6.0, 1999) were made using binary and multinomial logistic regression to adjust for variations in socio-demographic characteristics (age group, education level, marital status, income level) and survey source. This method was used in preference to adjustment by sample survey weighting. Odds ratios (OR), 95% confidence intervals (CI) and P- values were calculated. Estimates of sales of products with health claims Retail sales data in tonnes based on scan data were available for some processed ready-to-eat breakfast cereals and fresh foods (vegetables and fruit) participating in the pilot claim. Data for breakfast cereals comprised sales in individual states in consecutive four-week periods between late March 1998 and late November 1999 in all major supermarkets for 15 products that had implemented a claim as well as total sales for all breakfast cereals. The corresponding data for vegetables and fruit were from a single but large supermarket chain for March 1998 and 1999 and October 1998 and 1999 for 14 products in all states. Estimates were made of the percentage of market share of products with claims, of the total sales for the product group in question. Changes in the market share ratio for sentinel periods in 1999 were compared with 1998 in consecutive four-week periods in March to April and September to October, thus accounting for seasonal variation. Results Implementation of the claim In June 1999, ANZFA had approved 28 primary foods and 76 processed foods to make a folate and NTD claim. In January 2000 this had increased to 41 primary foods and 81 processed foods. In January 2000, more than threequarters of the approved processed foods were bread and breakfast cereals, although all these had been registered by June Some breakfast cereals increased their folate content to comply with the health claim; virtually all breakfast cereals in Australia would now (in 2001) meet the requirements (40 µg per serve). Fewer foods, 29 in total (see Methods section above), actually implemented the claim. The ANZFA logo was extensively used in promotional material including pamphlets distributed by ANZFA and at the point of sale for fresh products and in the retail sector, but was not widely adopted by processed food manufacturers. Survey results Women who had heard of folate and who were aware of the link between folate and birth defect The survey results for women who had heard of folate and who were aware of its link to birth defects before and after implementation of the claim are shown for individual states in Table 1. Overall, the proportion who had heard of folate initially was high (82%) and increased significantly to 89% during 1999 (OR 1.81, 95% CI , P < after adjusting for differences between state baselines). There were significant differences between states in regard to those who had heard of folate at baseline: South Australia and Western Australia being higher than NSW and ACT (OR 1.62, 95% CI , P = 0.01 and OR 2.85, 95% CI , P = 0.03) while Tasmania was lower (OR 0.67, 95% CI , P = 0.04). However, the change over time in regard to Australian Journal of Nutrition and Dietetics (2001) 58:4 237

3 those who had heard of folate was not significantly different between states (χ 2 4 = 8.8, P =0.08). A smaller proportion of women of child-bearing age were aware of folate and the association with birth defects than had heard of folate, but again the proportion who were aware of folate increased significantly during 1999 (OR 1.31, 95% CI , P = 0.004). Compared to the reference (NSW and ACT), Tasmania had a lower folate awareness at baseline, (OR 0.43, 95% CI , P < 0.001). The change over time in folate awareness was not significantly different between states (χ 2 5 =10.8, P =0.06). Having heard of folate and an awareness of its link to birth defects were both influenced by socio-demographic variables in a similar manner. The final model included adjustment for state of residence, age and education (both variables increasing with increasing age and education level). Income level (data were not collected in the Tasmanian survey) was also related, but it was correlated with age and was not included in the model. Women aged 25 years or over were more likely to have heard of folate (OR 1.40, 95% CI , P = 0.04) and were more likely to be aware of folate (OR 1.65, 95% CI , P = 0.001) than younger women. With each increasing level of education 1. secondary education only, 2. trade qualification, certificate or diploma, 3. university education women were more likely to have heard of folate (OR trend 1.58, 95% CI , P < 0.001) and to be aware of folate (OR trend 1.32, 95% CI , P < 0.001). In both years, about 20% of women who had heard of folate gave vague, imprecise or inaccurate reasons for folate s importance with respect to prevention of NTDs, citing reasons such as anaemia and related disorders and requirement for bones. In 1998, 29% of women who had heard of folate did not know why it was important compared with 23% in 1999 (OR 0.79, 95% CI , P =0.03). Sources of information about folate The results for sources of information about folate are shown in Table 2. The most common responses were written material including newspapers, books and pamphlets (35%), followed by doctors (29%), television (21%) and families and friends (13%) (see Table 2). None of these changed significantly during the survey period: only a small proportion (8%) indicated food labelling as a source of information in the two surveys. Women who indicated that information about folate had encouraged them to eat foods containing folate were asked to rank the influence of this material. There was a strong preference for educational material (75% most influential) compared with advertising in supermarkets and messages on food labels (Table 2), with no evidence of any change over the study period. With respect to the source of messages about folate on food labels and detail recollected in the three surveys, many women recalled seeing no information and of those who recalled seeing information, many could not name a specific food. More women had seen messages about folate on foods, particularly cereal foods in 1999 (Table 2). There was also an increase (from a low level) in the number citing labels on tablets or supplements as a source of information about folate in Vegetables and fruit were cited only rarely in both surveys. Knowledge about foods containing folate and health messages Based on the Australian Supermarket Institute survey only, there were increases in 1999 in the proportion of respondents citing leafy green vegetables (from 40% to 52%) and cereals (from 26% to 49%) as good food sources of folate (see Table 3). There were significant increases in the recall of messages over time (Table 3) including having seen the health claim message (from 11% to 29%). Some respondents thought they had seen the health claim prior to it having been introduced. Almost half the women (45% in 1998 and 49% in 1999) stated that the health claim message would influence their purchase of foods (see Table 3). In 1998, in the South Australian and Tasmanian surveys combined, 22% of women indicated that information about folate had encouraged them to eat foods containing folate, compared with 23% in However, considering the states individually, in South Australia this intention decreased significantly over the study period (26% to Table 1. Number and percentage of women of child-bearing age who had heard of folate and were aware of folate and birth defects by state and year of survey (n = 1201 in 1998 and 1123 in 1999) Heard of folate Aware of folate and birth defects State n % n % P-value (a) OR (95% CI) (b) n % n % P-value OR (95% CI) NSW and ACT ( ) ( ) Victoria ( ) ( ) Queensland ( ) ( ) South Australia ( ) ( ) Western Australia nd (c) ( ) Tasmania < ( ) ( ) Total < ( ) < ( ) (a) P-values adjusted by logistic regression for variations in socio-demographic characteristics and survey source and compared across time periods within states only. (b) OR, odds ratio; CI, confidence interval. (c) nd, not defined as model predicts perfectly; estimate is rejected (33 observations not used). 238 Australian Journal of Nutrition and Dietetics (2001) 58:4

4 21%, OR 0.74, 95% CI , P = 0.05), but increased significantly in Tasmania (12% to 29%, OR 2.98, 95% CI , P < 0.001). Estimates of sales of products with health claims The market share of breakfast cereals with health claims (expressed as a percentage of total breakfast cereals sales) was consistent across the states (data not presented) and comprised slightly more than one-third of the total weight of ready to eat breakfast cereals sold. Sales were slightly lower following the introduction of the health claim, the proportion of sales decreasing to about 95% of the 1998 breakfast cereals sales. The sales of vegetable and fruit products with health claims was 16% of the weight of all fresh vegetable and fruit products. These products were a smaller proportion Table 2. Reported sources of information about folate by women of child-bearing age in 1998 and 1999 (a) n % n % P-value OR (95% CI) (b) Important information sources (multiple sources permitted) South Australia and Tasmania only (n = 650 in 1998 and 642 in 1999) Written material ( ) Doctors ( ) Television ( ) Family and friends ( ) Food labels ( ) Preferred information sources (n = 171 in 1998 and 170 in 1999) (c) Education material (d) Advertisements ( ) (e) Food labelling ( ) (e) Messages seen about folate (n = 987 in 1998 and 998 in 1999) Folate in foods < ( ) Cereals < ( ) Vegetables and fruit (f) Incorrect (f) Tablets or supplements ( ) (a) Based on respondents who had heard of folate. (b) OR, odds ratio; CI, confidence interval; 1999 compared with (c) Based on respondents who answered the question. (d) Education material (any of pamphlet, magazine, poster, doctor, chemist, radio or school mentioned). (e) Change in advertising and food labelling compared with educational material. (f) No statistical comparisons. Table 3. Knowledge about foods containing folate and health messages in women of child-bearing age comparing 1999 with P-value OR (95% CI) (a) n % n % Food source of folate Leafy green vegetables (b) ( ) Cereals (b) < ( ) Both leafy green vegetables and cereals (b) < ( ) Message recalled Needed for normal growth (b) < ( ) Contains folate (b) < ( ) Had seen health claim (b) < ( ) Able to specify foods with health claims (c) < ( ) Correct 0/ / (Not tested) Health claim messages would increase purchase (b) ( ) (a) OR, odds ratio; CI, confidence interval. (b) Based on respondents who had heard of folate, Australian Supermarket Institute survey only, n = 337 in 1998 and 356 in (c) Based on those who stated that they had seen the health claim, n = 987 in 1998 and 998 in 1999, see also Table 2. Australian Journal of Nutrition and Dietetics (2001) 58:4 239

5 of the market share following the introduction of the health claim, in 1999 being 97% of that in There was no evidence of a seasonal effect in this proportion (Table 4). Discussion A full report of the outcome evaluation of the folate and neural tube defect health claim pilot is presented in the ANZFA final report (7). Fewer women were aware of the link between folate and birth defects than had heard of folate. Comparable findings have been found in other studies. For example, in women attending an antenatal clinic in Ireland in 1997, 76% of respondents had heard of folic acid while only 43% knew of the role of folate in the prevention of birth defects (8). Awareness of this link is the specific knowledge required by women of child-bearing age to enact appropriate behaviour change. State of residence was a significant factor. South Australia and Western Australia (9,10), have both had active folate awareness campaigns prior to the implementation of the pilot, and respondents from these states were more likely than respondents from other states to have heard of folate. More respondents indicated they had heard of folate and were aware of folate and birth defects in states such as Tasmania that previously had little promotion prior to, or during the survey period (J Seal, Tasmanian Department of Health and Human Services, Hobart, 2000, personal communication). In contrast, in South Australia there was no change in knowledge about folate during the survey period. Considering the ongoing promotion since 1992 (10), the large increase in awareness of folate and birth defects recorded in 1999 in Western Australia is surprising and may be a reflection of the small sample size or of sampling bias. While there were positive outcomes with respect to knowledge, the extent to which these changes can be attributed solely to the folate health claim per se is uncertain, as other health promotion activities external to the health claim pilot are likely to have contributed to the increased knowledge about folate. Table 4. Market share of ready to eat breakfast cereals and vegetable and fruit products with implemented use of health claims in 1998 and 1999 September to March to April June to July October Percentage market share Ready to eat breakfast cereals with health claims Market share ratio 1999: Vegetable and fruit products with health claims Percentage market share Market share ratio 1999: However in Victoria, the increase in acquisition of knowledge about folate between 1998 and 2000 (including the period of the health claim) was higher compared to before 1998 (prior to the health claim) (11). Whether or not the folate health claim can produce a measurable public health outcome (that is, a reduction in the incidence of NTDs) can only be determined over a longer time frame than the survey period. In addition to the surveys described, a national postal survey was conducted by CSIRO in October 1998 and repeated in June and July 1999 and these included questions on folate. Generally the results of the CSIRO surveys were comparable with those of the surveys reported in this paper, but there was a smaller increase in awareness of the association between folate and birth defects in the CSIRO surveys, possibly due to the earlier follow-up (7). As has been established previously (12), women learn about folate from a variety of sources, principally written material, doctors, television and personal contacts. Food labels were also a source of information, but there were no changes in any of the sources as reported by respondents over the survey period. There was a strong preference for educational material compared with advertising or food labels with no evidence of any change over the study period. This may indicate some ambivalence towards health claims on food labels it being seen as a form of advertising. This may diminish in an environment in which consumers become more familiar with the intent of nutrition-related food labelling, but in our view support ing the notion that its effectiveness will be improved if it is accompanied by independent public health nutrition education. More women recalled food labels with folate information following the introduction of the health claim. Cereals (type unspecified by respondents) and breakfast cereals were predominant as foods for sources of this information; other foods scarcely contributed to this knowledge at either baseline or follow-up. In particular, the promotion of fresh vegetables and fruit with a health claim appears to have had a lesser impact on knowledge than the promotion of breakfast cereals had during the survey period. This is not surprising given the emphasis on folate in breakfast cereals, in both packaging and promotion, compared with other foods. Much of the activity with respect to health claims and fresh vegetables and fruit was point-of-sale information rather than specific information on labels. Nonetheless, while this pilot claim showed that there was a large increase in recognition of breakfast cereals as a source of folate, it also showed that there was a significant increase in identification of leafy green vegetables as a folate source and it remained the most commonly recalled source. The increased proportion of women aware that both breakfast cereals and leafy green vegetables are good sources of folate is an important beneficial outcome. These findings suggest that consumers understood the importance of natural folate sources as well as fortified sources and interpreted the health claim appropriately. At baseline prior to their formal introduction, 11% of women claimed to have seen information on food packaging related to a folate health claim. This is indicative that consumers do not make a distinction about the content of 240 Australian Journal of Nutrition and Dietetics (2001) 58:4

6 nutrient related messages, perceiving a variety of nutrition messages as health claims. The estimates of sales based on scan data provide robust estimates of purchasing patterns of breakfast cereals and vegetables and fruit not subject to respondent bias and are likely to reflect any changes in consumption behaviour of the total population. Such estimates are also potentially useful, as some consumers may not be able to provide information on specific breakfast cereals. Many women (a majority of women aged 25 to 34 years) who had seen the health claim message reported they would increase their purchases of foods with this food label. However, during this time there was no indication of any increase in the retail sales of foods that used the health claim message in their promotion. Thus, there may be an inconsistency between intention and action. Equally, the small increase in purchase intentions in the study period in a part of the population means that it may be unrealistic to expect measurable change in the broader population in the purchase of foods with health claims. Conclusions As there is widespread unfamiliarity with the role of periconceptional folate, there is a clear need for consumer education (13). A health claim about folate and NTD has a role in informing women, and does appear to have encouraged initiatives in the food supply to increase the availability of products with folate and appropriately labelled to provide nutrition education. Nonetheless, because of the complexities of minimising risk of NTDs, it is unrealistic to expect that brief health claim messages alone can adequately address the need for consumer education. For example, the folate health claim per se does not provide the critical detail on the specific timing for folate periconceptionally, although occasionally it may be present in accompanying information. The folate and NTD pilot claim is a useful model and provides helpful indicators with respect to the implementation of other claims. However the folate and NTD health claim is very specific, and the extent to which the findings of this pilot health claim can be generalised to other claims, especially those more generic in nature is debatable. Willett has described the many distinct features of the association between folate and NTD and commented that these are unlikely to be easily generalisable to associations between other nutrients and diseases (14). Health claims need to be implemented on a case-by-case basis. Studies in the Netherlands indicate that, while media campaigns were effective in informing women about folate, they were less effective in achieving the use of folate by women in the periconceptional period (15). Most associations between diet and health are complex and health claims do not usually contain the depth of information required to understand fully both the nutritional requirements and the disease whose risk is reduced. Therefore, if health claims are introduced, it is important that their limited potential to impact on the food supply is recognised, that the complexities of improving dietary behaviour are not underestimated, and that they are accompanied by adequately publicly resourced nutrition education and health promotion programs. Acknowledgments ANZFA and ANZFA staff provided critical assistance by commissioning the surveys and arranging for provision of sales data by ACNielsen and Coles Supermarkets. References 1. Lumley J, Watson L, Watson M, Bower C. Periconceptional supplementation with folate and/or multivitamins for preventing neural tube defects (Cochrane Review). In: The Cochrane Library 1998, issue 4, update 2001, issue 3. Oxford: Update Software; National Health and Medical Research Council. Folate fortification. Canberra: Australian Government Publishing Service; Marsack C, Alsop C, Kurinczuk J, Bower C. Prepregnancy counselling for the primary prevention of birth defects: rubella vaccination and folate intake. Med J Aust 1995;162: Australian Bureau of Statistics. National nutrition survey: nutrient intakes and physical measurements Australia 1995, catalogue No Canberra: ABS; Australia New Zealand Food Authority. Food standards code. Canberra: ANZFA; Australia New Zealand Food Authority. Proposal P153 full assessment report. Canberra: ANZFA; Watson M, Watson L. Outcome evaluation of the folate-neural tube defect health claim pilot, final report, part 3 evaluating the folateneural tube defect health claim pilot. Canberra: Australia New Zealand Food Authority; McDonnell R, Johnson Z, Doyle A, Sayers G. Determinants of folic acid knowledge and use among antenatal women. J Pub Health Med 1999;21: Chan A, Pickering J, Haan E, Netting M, Burford A, Johnson A, et al. Folate before pregnancy: the impact on women and health professionals of a population-based health promotion campaign in South Australia. Med J Aust 2001;174: Bower C, Blum L, O Daly K, Higgins C, Loutsky F, Kosky C. Promotion of folate for the prevention of neural tube defects: knowledge and use of periconceptional folic acid supplements in Western Australia, 1992 to Aust N Z J Public Health 1997;21:716 21, erratum in 1998;22: Watson M, Watson L, Bell R, Halliday J. The increasing knowledge of the role of periconceptional folate in Victorian women of childbearing age: Follow-up of a randomised community intervention trial. Aust N Z J Public Health 2001;25: Watson M, Watson L, Bell R, Halliday J, Burford N, Brennecke S. A randomized community intervention trial to increase awareness and knowledge of periconceptional folate in women of childbearing age. Health Expectations 1999;2: Bower C, Werler M. Folate before pregnancy: are we doing enough? Med J Aust 2001;174: Willett W. Folic acid and neural tube defects. In: Willett WC, editor. Nutritional epidemiology, 2nd ed. Monographs in epidemiology and biostatistics, volume 30. New York and Oxford: Oxford University Press; de Jong-van den Berg L, de Walle H, van der Pal-de Bruin K, Buitendijk S, Cornel M. Increasing awareness of and behaviour towards periconceptional folic acid consumption in The Netherlands from 1994 to Eur J Clin Pharm 1998;54: Australian Journal of Nutrition and Dietetics (2001) 58:4 241