Association Between ABO Blood Groups and Big Five Personality Traits in Healthy Young Adults: A Cross-sectional Study

Introduction: The pursuit of optimal health is a universal human aspiration. This ideal state can be conceptualised as a harmonious interplay between external and internal health. While numerous factors contribute to an individual’s health profile, the potential influence of blood type on these aspects remains a topic of ongoing exploration. The present research project delves into this question, aimed to elucidate the relationship between the ABO blood group system and personality traits in healthy young adults. Aim: To categorise young adults aged between 18 and 25 years according to ABO blood groups and to analyse the association between personality traits and varying blood groups. Materials and Methods: The present cross-sectional study was carried out on 187 healthy young medical students of both genders aged between 18 and 25 years at Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, between June 2024 and May 2025. Subjects were categorised into different groups based on their ABO blood grouping using the slide agglutination method, while personality traits were assessed using the Big Five Personality Questionnaire. Comparisons were made between blood group, personality traits, and gender. Statistical analysis was performed using the Chi-square test in Statistical Package for the Social Sciences (SPSS) version 22. Results: The study population had a mean age of 20.05±1.08 years. In terms of gender distribution, females and males constituted 128 (68.4%) and 59 (31.6%) participants, respectively. Both genders showed a higher association with the openness personality type, while females exhibited a wider variation in personality traits (p=0.042). Analysis of ABO blood grouping revealed that most subjects belonged to the O blood group. A statistically significant association was observed between ABO blood group and personality type (p=0.038), with individuals having A, B, and O blood groups predominantly exhibiting the openness personality type, while those with the AB blood group tended to show the agreeableness personality type. Conclusion: The current body of research presents mixed findings regarding the relationship between blood groups and personality traits. Further studies with larger sample sizes and more rigorous methodologies are needed to clarify these associations.