In the current study, we identified the patterns of PMS by factor analysis. We found three types of premenstrual symptoms: affective, mixed, and somatic. Furthermore, we revealed associations for each type. There were some positive associations between affective type and SDS score, mixed and physical activity, and somatic type and physical activity. There was a negative association between the somatic type and some nutrients (manganese, folic acid, vitamin C, and dietary fiber). Our new idea about the patterning of overlapping premenstrual symptoms may enable further understanding of PMS and be useful in developing strategies for its management.
The SDS score had a marginally positive association with the affective type, with the higher score correlated with the higher possibility of severe affective type symptoms. This type includes anxiety, confusion, depression, social withdrawal, anger outbursts, and skin problems. These psychological symptoms are similar to the symptoms of depression. In fact, SDS has evaluation items such as confusion and depression . The SDS index of the affective type was 45.2 ± 6.7 points. In Japan, the mean SDS index of depressed patients is 61.9 ± 6.9 points, while that of normal controls is 36.5 ± 12.2 points . The SDS index of this type is lower than that of depressed patients but higher than that of normal controls in Japan. Hence, the participants with this type might be not diagnosed as depressed. However, they have a higher level of depression than normal participants. Many reports recommend the use of SSRIs as the first-line treatment for PMS with predominantly emotional symptoms . For the women suffering from affective symptoms, psychotherapy may be useful.
It is interesting that the symptoms of the mixed type show only the mixed symptoms between the affective and somatic types, while the affective type shows precisely the psychogenic symptoms. However, in the mixed type, “Poor motivation,” “Fatigability,” and “Drowsiness” show a low intention of activity, expressing the physical symptoms. “Abdominal bloating” and “Swelling of hands or feet” seem to be the autonomic symptoms. In the somatic type, the symptoms (breast tenderness or pain, abdominal pain, and headache) are the physical symptoms predominating for pain. “Low back pain” is patterned in the mixed type, but the factor 3 score is 0.38 and the factor 1 score “Irritability” is 0.42. The associated factors seem to be similar between mixed and somatic types. For instance, physical activity is significantly positively associated with the mixed and somatic types. Moderate exercise, which is not strenuous, has been proposed as the first-line therapy for PMS [39, 40]. Additionally, female college athletes have a high prevalence of PMS due to the intense workload and severe physical stress . As an example to explain this, the hypothalamic dysfunction associated with strenuous exercise can affect the female reproductive system . Briefly, high and excessive physical activity is related to a high prevalence of PMS. Likewise, in this study, we observed that excessive exercise was associated with a high prevalence of these two types. In contrast, regular exercise improves PMS compared with the sedentary lifestyle . PMS rates were reported to be higher in women with either low or high daily physical activity levels than in those with normal physical activity levels . These results suggest that appropriate exercise may be needed. Women suffering from these two types may have to self-reevaluate their activities.
Although the associated factors are similar between the mixed and somatic types, there is a clear difference between them concerning nutrition. Some nutrients such as manganese, folic acid, vitamin C, and dietary fiber were significantly negatively associated with the somatic type. The average intake of these nutrients in this type was lower than those of the other types (Supplemental Table 2). Particularly considering manganese, vitamin C, and dietary fiber, the intake in this type is lower than the dietary reference intakes of Japanese women . Thus, deficiencies of these nutrients may influence the somatic type of PMS. Regarding manganese, a study reported that lower dietary manganese increased pain symptoms of PMS , which is consistent with our results. Folic acid has a hematopoiesis function . Vitamin C improves endothelial function, resulting in improvement of blood flow . Hence, these two nutrients play a role in controlling blood flow. In addition, a relationship between the occurrence of headache and low blood flow has been reported . Therefore, deficiency of folic acid and vitamin C might reduce blood volume and flow, resulting in painful symptoms. Dietary fiber is effective for constipation . Therefore, we could presume that the deficiency of dietary fiber tends to increase constipation. One of the symptoms of constipation is abdominal pain . In addition, constipation occurs around the menstrual cycle . These might accelerate symptoms of the painful type. Thus, we assume that the function of these nutrients causes painful symptoms. However, the underlying mechanism is unclear and further examination is needed to reveal the relationship between PMS and these nutrients.
There were several limitations to this study. First, the symptoms investigated in the current study were selected because they were the main symptoms, although over 200 symptoms have been reported [4, 13], and others remain under discussion. Moreover, the assessment for PMS was conducted retrospectively, although prospective assessment is recommended . Thus, further studies using recommended diagnostic criteria and investigating various symptoms are required to support the results of this study. Second, participation was limited to medical collegiate women with the medium age of 18.9; therefore, it may not be widely representative and we could not analyze the effect of alcohol. Simultaneously, we examined the relationship between various nutrition and each PMS pattern, although the sample size was smaller to detect them. Thus, larger studies expanding the sample range and sample size is required to support the results of the current study and reveal the detail relationships between the nutrition factors and PMS patterns. Third, the menstruation phase was not controlled, although the information was collected by self-report. Additionally, some of the participants who reported a normal menstrual cycle might have taken some management such as using contraceptives or diets. The possibility of affect by these menstrual cycle or management cannot be denied. Fourth, nutrition and physical activity information was collected via questionnaires and not through actual measurements. The cause and effect correlation between PMS and SDS score, physical activity, and each nutrient is unknown since this was a cross-sectional study. Hence, treatment strategies such as recommended nutrient intake cannot be suggested from the results of this study.
Despite these limitations, the following purposes in order to simplify the PMS treatment were accomplished. At first, it was revealed that various premenstrual symptoms can be classified into three patterns. In addition, the association between each PMS pattern and some factors which were related to daily life were revealed. It can be said that the patterning of a wide variety of PMS symptoms is useful for understanding the complicated PMS symptoms, and analyzing the factors associated with each pattern is useful in developing strategies for the management of PMS in the clinical field.