Objectives To investigate the association between tea drinking and dysmenorrhoea among women of reproductive age.
Design A cross-sectional study based on Shanghai Birth Cohort Study.
Setting Two preconceptional care clinics in Shanghai, China.
Participants 1183 women of reproductive age who sought preconceptional care were recruited from August 2013 to April 2015.
Primary and secondary outcome measures Participants were asked if they had pelvic pain associated with menstrual bleeding during the past 12 months and to further grade the intensity of menstrual cramp as mild, moderate and severe. Multinomial logistic regression was performed to assess the association of tea drinking and dysmenorrhoea. Other information, such as demographic and lifestyle factors, was also collected and assessed in relation to dysmenorrhoea.
Results The prevalence of dysmenorrhoea was 57.8%, among whom 10.4% and 3.5% had moderate and severe dysmenorrhoea, respectively. Tea drinking was associated with a lower prevalence of dysmenorrhoea (adjusted OR [aOR]=0.68, 95% CI 0.50 to 0.93 for mild dysmenorrhoea; aOR=0.59 (95% CI 0.32 to 1.04) for moderate-to-severe dysmenorrhoea). Green tea and oolong tea appeared to have most reduction in the prevalence of dysmenorrhoea (for mild dysmenorrhoea: green tea: aOR=0.63 (95% CI 0.44 to 0.90) and oolong tea: aOR=0.60 (95% CI 0.35 to 1.03); for moderate-to-severe dysmenorrhoea: green tea: aOR=0.42 (95% CI 0.20 to 0.85) and oolong tea: aOR=0.34 (95% CI 0.11 to 1.09)).
Conclusions Consumptions of green tea and possibly oolong tea were associated with a lower prevalence of dysmenorrhoea.
- reproductive age
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Contributors JZ, PZ and YT contributed to study conception and design, and contributed to acquisition of data. XZ, DC and RH contributed to analysis and interpretation of data. XZ and RZ contributed to drafting article. JZ, and PZ contributed to revising the article critically. All authors reviewed the final version of the manuscript and gave final approval of the version to be published.
Funding This work was supported by the National Basic Science Research Program Ministry of Science and Technology of China (2014CB943300; 2014DFG31460); the Shanghai Municipal Commission of Health and Family Planning (GWIII-26; 2017ZZ02026); Shanghai Jiao Tong University 985 Fund and the National Human Genetic Resources Sharing Service Platform (2005DKA21300).
Competing interests None declared.
Ethics approval This study is based on the Shanghai Birth Cohort which was approved by the Institutional Review Board of Xinhua Hospital affiliated to the Shanghai Jiao Tong University School of Medicine, and no additional review was needed for this analysis.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Currently, the Shanghai Birth Cohort data are not yet open to public due to the confidentiality agreement. Data used in this analysis and computing programs are available from the corresponding author on request.
Patient consent for publication Not required.
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