LAUSR

INTRODUCTION Most Indian studies on menstruation include only girls/women as participants, making it a 'women's' topic. This exclusion of adolescent boys fails to understand menstruation as a social epidemiological entity with existing gender inequalities. For engaging boys to play a meaningful role in improving women's health, studying their knowledge, beliefs regarding topics such as menstruation and socioeconomic characteristics influencing their menstruation-related experiences need attention. Addressing this is an essential step for reducing gender disparities in adolescent health. Thus, we explore boys' knowledge, beliefs and attitudes regarding menstruation and the impact of social determinants on their menstruation-related experiences. METHODS A sequential mixed-methods study comprising 21 semi-structured interviews, 5 Focus Group Discussions and 12 key respondent interviews; followed by a cross-sectional survey of 744 boys from Nashik district, India was conducted. We employed thematic analysis for qualitative data and multivariable regression to model risk ratios for outcomes. RESULTS An amalgam of curiosity and awkwardness regarding menstruation was observed. Many lacked accurate knowledge and possessed misinformation. Social and individual-level determinants influenced boys' menstruation related experiences. Fully adjusted models revealed that being admitted in private unaided schools; having mothers with at least a college education; and comfort with teacher positively influenced boys'knowledge, attitudes and beliefs (incidence rate ratios at 95% CI: 2.67 [1.02, 6.95], p < 0 0.05; 3.16 [1.35, 7.38], p < .05 and 1.92 [1.24, 2.99],p < .01, respectively). CONCLUSION Our study highlights the need of improving Indian boys' understanding and beliefs about menstruation by addressing the social determinants that influence their menstruation-related experiences.