Abstract
Objectives: The PROtein-enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing in older adults (PROMED-COG) is a European project that investigates the role of nutritional status on neurocognitive ageing. This methodological paper describes the harmonization process of dietary data from four Italian observational studies (Pro.V.A., ILSA, BEST-FU, and NutBrain). Methods: Portion sizes and food frequency consumption within different food frequency questionnaires were retrospectively harmonized across the datasets on daily food frequency, initially analyzing raw data using the original codebook and establishing a uniform food categorization system. Individual foods were then aggregated into 27 common food groups. Results: The pooled cohort consisted of 9326 individuals (40-101 years, 52.4% female). BEST-FU recruited younger participants who were more often smokers and less physically active than those of the other studies. Dietary instruments varied across the studies differing in the number of items and time intervals assessed, but all collected dietary intake through face-to-face interviews with a common subset of items. The average daily intakes of the 27 food groups across studies varied, with BEST-FU participants generally consuming more fruits, vegetables, red meat, and fish than the other studies. Conclusions: Harmonization of dietary data presents challenges but allows for the integration of information from diverse studies, leading to a more robust and statistically powerful dataset. The study highlights the feasibility and benefits of data harmonization, despite inherent limitations, and sets the stage for future research into the effects of diet on cognitive health and aging.
Keywords:
dietary data; observational studies; pooled dataset; population-based studies; retrospective data harmonization.
MeSH terms
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Adult
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Aged
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Aged, 80 and over
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Aging / physiology
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Cognitive Aging
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Cohort Studies
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Diet / statistics & numerical data
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Diet, Mediterranean*
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Feeding Behavior
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Female
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Humans
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Italy
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Male
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Middle Aged
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Nutritional Status
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Portion Size
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Retrospective Studies
Grants and funding
This PROMED-COG project received funding from the UK Research and Innovation (UKRI): Biotechnology and Biological Sciences Research Council (BBSRC) and Medical Research Council (MRC), from the Italian Ministry of Universities and Research (MUR) (National Research Council and University of Padova), and Health Research Board (2021 R546) under the umbrella of the European Joint Programming Initiative “A Healthy Diet for a Healthy Life” (JPI HDHL) and of the ERA-NET Cofund ERA-HDHL (GA N°696295 of the EU Horizon 2020 Research and Innovation Programme). The ILSA project was supported by the Italian National Research Council from 1991 to 1998 as part of the Progetto Finalizzato Invecchiamento. Since 1999, the Italian National Research Council, the “Biology of Aging” Strategic Project and the Ministero della Sanità, through the program “Epidemiology of the Elderly” of the Istituto Superiore di Sanità and the “Estimates of Health Needs of the Elderly” Special Programme of the Tuscany Region have been supporting the ILSA. BEST-FU was supported by the research programme grant funding from the CNR-targeted project “Prevention and Control of Disease Factors—FATMA”. The data collection phase of the PRO.V.A. study was supported by the Fondazione Cassa di Risparmio di Padova e Rovigo; the University of Padova; Veneto Region’s Local Health and Social Care Services No. 15 and No. 18 (Azienda Unità Locale Socio Sanitaria 15 and 18); and a grant from the Veneto Regional Authority (Ricerca Sanitaria Finalizzata n.156/03). The data analysis phase was financed by a grant from the “Ricerca Sanitaria Finalizzata Bando 2017, Regione Veneto” (RSF-2017-00000533, deliberazione n. 490 17.04.2018). NutBrain was supported by the Italian Ministry of Health (GR-2016-02361730730). The studies’ funders had no involvement in the design and conduct of the study, collection, management, analysis and interpretation of data; preparation, review, or approval of the manuscript; and the decision to submit the manuscript for publication.