The results of this study can be divided into two levels. Firstly, without stratification, we founded that there was no association between alcohol consumption and dysmenorrhea among university students in North China. However, our findings showed there was a negative association between alcohol consumption and dysmenorrhea stratified by AAM (13 years).
In our study, alcohol consumption is not related to dysmenorrhea without stratification. It has been reported that alcohol use was not associated with any type of gynecological pain, which is lined with our findings. Another research identified that dysmenorrhea is not significantly associated with consumption of salt, tea, coffee, or alcohol use among 488 health school students. Alcohol consumption did not influence the prevalence of dysmenorrhea. However, the findings of relationship between alcohol consumption and dysmenorrhea among students were inconsistent. Dysmenorrhea, heavy menstrual flow, and premenstrual discomfort increased with drinking level and were particularly strongly associated with reported consumption of 6 or more drinks a day at least once a week.
The average age of menarche is 12.27 years (95% CI, 12.16-12.39) in China, and the average age of menarche in this study is 13.42 ±1.30 years, so we divided female college students into two groups stratified by AAM 13 based on a priori hypotheses. Interestingly, we founded that there is a significant relationship between alcohol consumption and dysmenorrhea among participants with AAM ≥13 years. There is a study that may explain the association between alcohol consumption among participants with AAM ≥13 years. Firstly, a dose of alcohol affected the serum concentrations of allopregnanolone throughout the menstrual cycle, which might affect the occurrence of severe premenstrual syndrome and dysmenorrhea. Secondly, for participants older than 13 years of AAM, the function of the adrenal and hypothalamic pituitary-gonadal axis (HPG) may mature later. In this condition, alcohol consumption might disrupt the unstable maturation process, which may lead to many of the physical and hormonal changes and even dysmenorrhea. We observed that alcohol use was not related to the prevalence of dysmenorrhea among participants with AAM before age 13. Several studies can explain the possible mechanisms responsible for this phenomenon. Among female university students with AAM before age 13, dysmenorrhea may be due to higher levels of estrogen caused by hormone patterns in the early stages of sexual maturity. Furthermore, a longitudinal study reported that women with an earlier age at menarche were more likely to have longer and more painful episodes. Also, frequent alcohol consumption increased duration and severity among women with menstrual pain. Thus, participants with AAM before age 13 might reduce alcohol use and alcohol consumption.
Our study still has several limitations. The main limitation of our study is a cross-sectional design so that statistical associations can be determined, but no causal inferences can be made. In the future, it is necessary to conduct a longitudinal study. Also, we collect the questionnaire information from a large government-owned and operated public university located in North China. We can’t generalize the results to the whole college students because of selection bias. Our research only showed that the association between alcohol use and the prevalence of dysmenorrhea was consistently stronger among participants with AAM ≥13 years than among participants with AAM <13 years. However, it does not explain the underlying mechanism. Further research was needed to confirm our findings and clarify the potential specific mechanisms. In our study, alcohol consumption and dysmenorrhea were evaluated through a retrospective questionnaire, which might be subject to recall bias. Accurate responses from the study participants were crucial for the study validity. Several underlying factors that could affect the magnitude of dysmenorrhea were not sufficiently investigated, including age at first alcohol use, the disease which could cause dysmenorrhea, lifestyle, drug abuse, exercise, and genotypic variation. Future studies including these additional factors are needed. One additional limitation that should be noted is that non-standard questions were used for assessing passive smoke exposure and alcohol use and consumption, which may make the results not comparable to those of prior studies that have used standardized instruments. Finally, the questionnaire did not query about the occurrence of dysmenorrhea before the start of alcohol use, which may have a confounding effect on the association of alcohol consumption with dysmenorrhea, due to the participants with dysmenorrhea may tend to avoid using alcohol or reduce alcohol consumption. It is important to use standard questions and reduce information bias in further research.