Participants
vomiting 2, bleeding, endometriosis, pain, adenomyosis
BLEEDING, ENDOMETRIOSIS, PAINFUL PERIODS, STRESSFUL EVENTS, DISEASE, ADENOMYOSIS, SECONDARY DYSMENORRHEA, VITAMIN D DEFICIENCY
Participants were healthy, Iranian, and single female college students. The inclusion criteria included: age 18 to 25 years old, BMI ≤ 30 (kg/m2), regular menstrual cycles of 21–35 days with menstrual period of 3–7 days, experience at least four consecutive painful periods in the past six months with the pain starting a few hours before or just after the onset of bleeding, vitamin D deficiency (25[OH]D serum level ≤ 30 ng/mL), normal serum calcium (8.6–10.3 mg/dL), no one of the following conditions: a history of underlying disease causing secondary dysmenorrhea (e.g. endometriosis or and adenomyosis), undertaking regular exercise, exposure to recent stressful events (past 3 months), using oral contraceptives and/or hormonal drugs (past 3 months), using any medications containing or interacting with calcium and/or vitamin D (past 6 months), special dietary (e.g. vegetarian), smoking or engaging in alcohol consumption. Participants were excluded if they had no menstruation during the intervention period, used oral contraceptives and/or other hormonal drugs along with non-pharmacological methods or pain relief supplements, smoking or engaging in alcohol consumption through the duration of the intervention period, vomiting 2 h after supplement consumption, or unwillingness to continue the study.