This study was to conducted investigate the incidence of dysmenorrhea and socioeconomic factors affecting the dysmenorrhea occurrence in Vietnam women of childbearing age. Various factors were found to be significantly related with the incidence of dysmenorrhea. Age, age at menarche, menstrual period, and menstrual volume were correlated with dysmenorrhea, and a history of obstetric factors, such as pregnancy experience, full-term delivery and breastfeeding, as well as socioeconomic factors including resident region, education and religion, were significantly correlated with dysmenorrhea. BMI, menstrual period, average monthly gross income, and residence period in Korea did not show a clear association.
Various studies have investigated the current prevalence of dysmenorrhea. In a study of adolescents between 13 and 18 years, Wong discovered that one out of six experienced dysmenorrhea [13
]. Banikarim et al. [14
] reported an 85% prevalence of dysmenorrhea in Latin American women, and Sundell et al. [7
] found an incidence of 72% in 19-year-old and 67% in 24-year-old Swedish women. Jamieson and Steege [15
] reported 90% in 18-year-old to 45-year-old American women, and Lu [16
] reported 51.3% in 15-year-old to 54-year-old Taiwan women [8
]. This study was the first to determine the prevalence of dysmenorrhea in domestic Vietnamese marriage immigrants and Vietnamese resident women; the dysmenorrhea prevalence of Vietnamese women was similar (58.8%) with Turkish women of the same age (55.5% to 58.2%) [12,17
In 1988, the dysmenorrhea prevalence amongst Korean high school girls was 77.8%, and it had fallen to 73.9% in 1998 [18
]. This incidence was still higher than this study's finding of 58.8%, which might have been caused by the age difference. This study's participants had an average age of 25.5 ± 4.4 years. When we reanalyzed our data to include only 17-year-old and 18-year-old women in this study, the prevalence of dysmenorrhea was 78.3%, which confirmed that there was no difference between same-aged Korean high school girls and this study's result (data not shown).
The average age of women who experienced dysmenorrhea was lower compared to women without dysmenorrhea. When logistic regression analysis was done, the result was consistent that the risk of dysmenorrhea was 0.97 times lower as age increased (P
<0.006). Therefore, it may be worthwhile to review the relationship between age at menarche and dysmenorrhea. In this study, the average age at menarche of the group who experienced dysmenorrhea was 14.7 ± 1.8 years old, which was significantly lower than the group who had no dysmenorrhea (14.9 ± 1.6 years old) (P
=0.001). It might be inferred that early menarche produces more prevalent dysmenorrhea, which matches with the study of Andersch and Milsom [8
] with Swedish women and Tangchai et al. [19
] study with Thai adolescents. Another study reported that delayed menarche showed a high dysmenorrhea occurrence [20
]. The association with early age at menarche and dysmenorrhea was thought to result from the fact that women who matured earlier showed similar hormone patterns with adults, and slower-maturing women had only a half ovulation efficiency.
The menstrual period was significantly longer in the dysmenorrhea group (P
<0.05), but the correlation of menstrual cycle length and dysmenorrhea was not significant. This finding agrees with the study that showed no correlation between menstrual period regularity and dysmenorrhea [21
], but it did not match up with the study that found women with irregular menstrual cycles, massive menstrual volumes and long menstrual cycles showed high incidences of dysmenorrhea [22
]. The result was consistent with an existing report that revealed high menstrual volumes were significantly correlated with dysmenorrhea [8
The correlation between weight and dysmenorrhea was somewhat contradictory; women who were underweight showed a high incidence of dysmenorrhea in our study, and another study found that dysmenorrhea of sub-standard weight women was 1.5 times higher than overweight or obese women [19,23
]. However, a different study reported higher complaints of dysmenorrhea in obese participants [8
]. BMI and dysmenorrhea had no significant correlation in this study, which was consistent with local study results among adolescents [21
Pregnancy and breastfeeding experience was associated with a low frequency of dysmenorrhea. Our findings matched with other reports that showed a significantly lower incidence of dysmenorrhea in women who had a delivery history [7,8
]. Our results also disagreed with another report that found miscarriages did not decrease the frequency of dysmenorrhea [8
]. No report has investigated the correlation between breastfeeding and dysmenorrhea. Therefore, to uncover the existence of an association among obstetrics history, menstrual history and dysmenorrhea frequency, further research is required for miscarriage experience, delivery method, breastfeeding period, etc.
Socioeconomic factors, resident region and dysmenorrhea frequency were associated, but there was no correlation with the average monthly gross income. Place of residence also affected the frequency of dysmenorrhea; 68.3% of domestic marriage immigrants reported dysmenorrhea, while 65.2% of southern Vietnam residents and 43.3% of northern Vietnamese residents complained of the same symptoms. Similarly, our regression analysis result showed a lower risk of dysmenorrhea in northern and southern residents (0.411 and 0.459, respectively) compared to the Vietnamese domestic marriage immigrants; Vietnamese northern residents were at the lowest risk. The average monthly gross income was highest in Korea, and residents of the southern Vietnam region earned more income than those in the northern region. Therefore, these results could imply that socioeconomic status in each residence as well as resident region were correlated. However, the incidence of dysmenorrhea was not correlated with average monthly gross income (P
=0.298), which agreed with the existing report [6
] that showed no correlation between the incidence of dysmenorrhea and income but disagreed with the report [18
] that indicated women with higher monthly gross incomes had a higher dysmenorrhea incidence than those making a lower monthly gross income. The association between dysmenorrhea and economic factors will need further research.
The limitations of this study were that we did not distinguish between primary dysmenorrhea and secondary dysmenorrhea, and mental types of socioeconomic factors, such as depression, stress, social isolation, etc., were also not considered. In addition, as the problem of co-linearity among various socioeconomic factors could not be ruled out, independent factors affecting the incidence of dysmenorrhea should be revealed through further analysis. Since the participants filled out the questionnaires independently, the possibility of recall bias and difficulty making an objective dysmenorrhea assessment cannot be ruled out completely. In further research on dysmenorrhea in different races, the dysmenorrhea prevalence could be surveyed with Korean women living in the same area compared to this study's Vietnamese marriage immigrant women.
In conclusion, this study showed that the incidence of dysmenorrhea was significantly correlated with age, menstrual history and obstetric history as well as socioeconomic factors, such as resident region, education and religion.