Background & objectives: Primary dysmenorrhea is one of the most common menstrual disorders in young girls. Given the impact of physical activity and diet on prevention and control of Primary dysmenorrhea and consequently on the quality of life, this study aimed to investigate the association of diet and physical activity with the severity of primary menstrual pain in girls.

Methods: This descriptive cross-sectional study was carried out in Tabriz University of Medical Sciences in 2014.Using convenience sampling method, 124 university students with moderate to severe PD participated in the study. A demographic information form and the Food Frequency Questionnaire (FFQ), International Physical Activity Questionnaire (IPAQ) and pain visual analogue scale (VAS) were used for data gathering. Univariate and multivariate linear regression tests were used for statistical analyses.

Results: Univariate (β= -0.2, p=0.02) and multivariate (β=-0.2, p=0.04) linear regression test showed significant association between fat intake and severity of pain. After adjusting for confounding variables, one unit increase in fat intake was correlated with 0.2 unit decrease in VAS score. In other words, fat intake had negative correlation with severity of menstrual pain.

Conclusion: This study found inverse correlation between fat intake and severity of menstrual pain. However, quantitative dietary assessment with larger sample in different population age groups and social classes for more accurate results is needed.