Understanding age at menarche: Environmental and demographic influences over a quarter century in India.

This study investigates the factors influencing the age of menarche in various Indian states over a quarter century from 1992 to 2019, with the aim of understanding how climate change and demographic factors have shaped menarche timing. Data from the Indian Demographic and Health Survey (DHS) for 1992-93 and 2019-21, along with climate data from NASA's POWER project, were analyzed using a cross-sectional study design, including 23,083 respondents from 1992 and 45,329 from 2019. Across most states, a slight decrease in age at menarche was observed, with the exception of Maharashtra, which showed an increase. Higher specific humidity was associated with earlier onset of menarche, whereas higher temperatures correlated with delayed onset. Improvements in educational attainment, particularly higher education levels, were strongly linked to earlier menarche, indicating that demographic changes had a significant influence. The findings highlight the need for public health interventions that improve nutrition, healthcare access, and educational programs to promote health awareness. Ongoing monitoring of climatic impacts on health is essential for understanding and mitigating the effects of environmental changes on menarche timing.