The secondary research process involved comprehensive analysis of regulatory databases, industry publications, consumer health journals, and authoritative health organizations. Key sources included the US Food & Drug Administration (FDA), European Medicines Agency (EMA), Health Canada, American Podiatric Medical Association (APMA.org), American Diabetes Association (ADA), International Diabetes Federation (IDF), National Institutes of Health (NIH), National Center for Biotechnology Information (NCBI/PubMed), Centers for Disease Control and Prevention (CDC) National Center for Health Statistics, World Health Organization (WHO) Global Health Observatory, EU Eurostat Health Database, US Bureau of Labor Statistics Consumer Expenditure Survey, National Retail Federation (NRF), Euromonitor International, Mintel Global New Products Database, NielsenIQ Retail Measurement Services, and national health ministry reports from key markets including China National Health Commission, India Ministry of Health and Family Welfare, and Brazilian Health Regulatory Agency (ANVISA). These sources were used to collect consumer expenditure data, regulatory approval data for therapeutic foot care products, clinical safety studies on active ingredients (urea, salicylic acid, tea tree oil), demographic trends in diabetes and aging populations, retail sales tracking, and market landscape analysis for creams, gels, sprays, ointments, patches, and specialized foot care devices.
Additional industry-specific sources included Personal Care Products Council (PCPC), Cosmetics Europe, International Association for the Study of Pain (IASP), Podiatry Management Magazine, Journal of the American Podiatric Medical Association, Journal of Foot and Ankle Research, International Federation of Podiatrists (FIP), American Orthopaedic Foot & Ankle Society (AOFAS), Society for Vascular Surgery, and World Diabetes Foundation reports. E-commerce and retail data were sourced from Statista Digital Market Outlook, eMarketer/Insider Intelligence, Amazon Retail Analytics (where publicly available), and Census Bureau Annual Retail Trade Survey.