OBJECTIVES We aimed to test whether birth season is associated with age at menarche in the sub-tropical climate of Central India where temperature and photoperiod differences between seasons are very small. METHODS Date of birth and age at menarche were collected for 330 female students of Central University, Sagar. The impact of birth month and birth season on age at menarche was analyzed using ANOVA and time-to-event analysis with the use of the Kaplan-Meier curve. RESULTS ANOVA, Kaplan-Meier estimation and Cox Proportional Hazard did not show statistically significant differences in age at menarche according to birth month and birth season. CONCLUSIONS Constant sun exposure during the whole year, related to a stable vitamin D amount and to equal access to fruits and vegetables, may translate into a lack of association between seasons and age at menarche.

中文翻译：

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印度中部年轻成年人的出生季节与初潮年龄无关。

目的我们的目的是测试印度中部亚热带气候中出生和初潮的年龄是否与年龄相关，该季节之间的温度和光周期差异很小。方法收集萨加尔中央大学的330名女学生初潮的出生日期和年龄。使用ANOVA和使用Kaplan-Meier曲线进行事件发生时间分析，分析了出生月和出生季节对初潮年龄的影响。结果方差分析，Kaplan-Meier估计和Cox比例危害未显示根据出生月份和出生季节不同的初潮年龄差异。结论全年恒定的日照时间与稳定的维生素D量和平等获取水果和蔬菜有关，