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. 2019 Mar 26;21(3):e11726. doi: 10.2196/11726

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©Pedro Oliveira, Leid Zejnilovic, Salomé Azevedo, Ana Maria Rodrigues, Helena Canhão. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 26.03.2019.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.

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Flowchart of the population-based study named Epidemiology of Chronic Diseases (EpiDoC). The first wave (2011-2013) is entitled EpiDoC 1 - Epidemiology of rheumatic diseases study (EpiReumaPt). The second wage (2013-2015) is entitled EpiDoc 2 - Cohort of rheumatic diseases (CoReumaPt).