Objective To examine the associations between season of birth and factors as age at menarche,age at menopause and reproductive span.Methods A total of 285 186 female from the China Kadoorie Biobank,with complete data on critical variables and had menarche at 9-18 years old,were included.A total of 132 373 female with natural menopause were included for the analysis on age at menopause and reproductive span.Multiple linear regression models were used to assess the associations of birth season and the age at menarche,menopause,and reproductive span.Subgroup analyses were performed on birth cohorts and urban/rural residence.Results Compared with the Spring-born (March,April,and May),participants who were born in Summer (June,July,and August),Autumn (September,October,and November),and Winter (December,January,and February)appeared late on both age at menarche and menopause.Multivariable-adjusted coefficients (95％ CI)appeared as 0.14 (95％CI:0.13-0.16),0.26(95％CI:0.24-0.27),0.10 (95％CI:0.08-0.12) for age at menarche respectively and 0.14 (95％CI:0.08-0.20),0.18 (95％CI:0.12-0.24),0.09 (95％CI:0.03-0.16) for age at menopause respectively.No statistically significant association was found between the season of birth and reproductive span.The association was consistent between urban and rural residents and across the birth cohorts.Conclusions female born in spring showed both earlier age on both menarche and menopause,compared to the ones born in other seasons.Our findings suggested that exposures in early life with some degree of seasonal variation might influence the development of female reproductive system.

Objective: To identify post-marketing active surveillance systems for vaccine safety around the world and understand their features and mechanisms, in order to provide guidance for vaccine administration activities in China. Methods: Following the steps of scoping review, literature about active surveillance system for vaccine safety and published by 30 June 2018 were identified by searching electronic databases, including PubMed, Scopus, and Cochrane Library. Grey literature were also sought by exploring relevant websites. Identified literature were screened according to eligibility criteria, and informative data from included literature were then charted. Framework Synthesis and Thematic Analysis were performed to integrate the charted data. Results: 97 pieces of literature were included for review, and 11 active surveillance systems for vaccine safety were identified, mostly located in developed countries. These systems were constructed by 3 types of organizations: administration departments, academic or research institutions, and health care providers. Their data sources included immunization registries, electronic medical records, claims data, case reports of adverse events following immunization electronic questionnaires, and epidemiologic study data. According to their operation procedures, these systems were grouped into 4 modes of active surveillance: Data Linkage, Investigator Network, Automatic Follow-up System, Studies Consortium. Conclusion Practice of active surveillance for vaccine safety greatly varies across countries, with different conditions and advantages. It is suggested that developing countries should choose suitable mode of active surveillance considering their local situations.