Dietary habit profile in European communities with different risk of myocardial infarction: The impact of migration as a model of gene/environment interaction
Risk factors influenced by both nutrition and genetic polymorphisms were studied in 3 European communities by general practitioner's networks. The IMMIDIET project has produced an enormous amount of data that have contradicted several common believes and should have a strong impact on national and European public health policies. First of all, the so-called “North-South” gradient of risk and probably mortality for cardiovascular disease is disappearing. England that was considered the country at highest risk of cardiovascular disease, is improving successfully its situation, at least in some of its regions. Although not representative of the whole country situation, these data demonstrate that by modifying life style, such as dietary habits, smoking habits, physical activity and so on, it is possible to stop and even revert the increase in the risk of cardiovascular disease. Particularly worrying is the observation on blood pressure and sodium clearance. There is a clear-cut trend for blood pressure to increase from England to Belgium to Italy. This is more evident amongst women but is present also in men, at least for systolic blood pressure. In men and women combined there is also a clear-cut trend for urinary sodium excretion (marker of salt intake) to increase from England to Belgium to Italy. This trend is evident amongst women. In men, however, Italians have much greater salt intake than both northern European countries. A positive ecological association was found between levels of salt intake and blood pressure that suggests that the higher level of blood pressure in Italians is dependent on the high salt intake with the diet. These factors may be significant contributors to an increased risk of stroke in Italy. Recent data of the “Progetto Cuore” show an increase in the incidence of stroke in the Italian population and in particular in Southern Italy women (131). Several campaigns against elevated salt intake have been conducted in England in the past 20 years with the results to have lowered salt intake and consequently the levels of blood pressure. Similar action should be taken in Italy and implemented in Belgium on the basis of the IMMIDIET results. Contrary to what we expected, the differences in dietary intake among groups were not so large, which could be interpreted as a trend toward homogenisation of the European populations in terms of nutrition. In other words, English and Italians did not behave so different by which can be seen in parallel with the trend toward less difference among countries in presence of cardiovascular risk factors and in the incidence of the disease. However, while this is”good news” for England or Belgium, the situation is really worrying in Italy. Italians are loosing their protection and are acquiring detrimental life habits. This is especially true for women. The high prevalence of smokers, the lowest levels of physical activity, the high level of salt intake have all been observed in Italians. Moreover, dietary habits are slowly loosing the characteristics of the Mediterranean diet. Secondly, the results of this study have assigned a weaker role of genetics in determining the risk of population. Although genetic factors are very important in the regulation of metabolic pathways and their study cannot be omitted in understanding the physiology and pathology of metabolic mechanisms, the role of environment is overcoming in determining the risk. Therefore genetics cannot be ever studied without taking simultaneously into consideration the environment. Migration and integration have really created a new improved culture from the health point of view. Mixed couples have the better risk profile. In particular they smoke less, drink less, have a good level of physical activity and maintain the great food habits of both cultures. Through the Immidiet study, local and international GP networks have been established and strengthened and are in place in preparation for future research. This successful example lends further support to the idea that the EU should continue – and perhaps increase – the level of commitment to funding primary care-based clinical research to allow such research to remain independent from the likely influence of the pharmaceutical industry. The project has created an anonymous database containing information on 2050 subjects respectively from eligible It/It, Be/Be, UK/UK and IT/Be couples and the database is available for further studies. The project has also launched the Immidiet web-site (http://www.moli-sani.org/progetti/immidiet_site) to keep in touch with researchers and let them exchange data in real time and to, in an area devoted to general public, to contribute to present activities and achievements of the network and to disseminate healthy lifestyles among visitors. A four-page full colour publication (IMMIDIET newsletter) has been published in different languages (Italian, English and Flemish). Immidiet News has been conceived keeping in mind the “double soul” of the project: science and real time prevention. For this reason, it reached scientists, GPs and Immidiet volunteers (In Italy, Great Britain and Belgium), as well as medical institutions and local and national policymakers. A Food Frequency Questionnaire validated for the Belgian population was not available before the IMIDIET project validated one. Now a new instrument is available for the whole scientific community for further study on dietary habits and risk of disease on this population. In addition, a multilanguage integrated dietary questionnaire was developed. This well standardised integrated questionnaire could be used as a model in all the dietary studied in multicultural society. The project also developed a Biological Bank of DNA, plasma, serum and urine samples of 2050 subjects respectively from eligible It/It, Be/Be, UK/UK and It/Be couples. This bank is available primarily for the IMMIDIET consortium. External scientist can apply for the biobank use and their proposal should be approved by all the IMMIDIET participants.