premenstrual syndrome ( pms ) is a set of somatic and psychological symptoms which occur during the luteal phase of the menstrual cycle ( 1 ) . up to 85% of women of reproductive age report experiencing one or more of the symptoms of pms ( 2 ) and approximately 5% suffer from a severe form of pms called premenstrual dysphoric disorder ( pmdd ) ( 3 ) . the exact cause of pms still remains unclear and many factors are supposed to contribute to the condition ; therefore , it has been proposed that pms is a multicausal problem ( 4 ) . according to the neurobiological data on the subject , the activities of the neurotransmitter system are mainly affected by gonadal steroids . through this process , estrogens , progestins , and androgens may be indirectly implicit in the development of depression ( 5 , 6 ) . although several studies have focused on the hormone and lipid profiles of women with pms , they report findings that are controversial . for example , several studies that have assessed the connection between pms and testosterone levels , present findings that conflict ( 7 , 8) . similarly , there is also disagreement over the association between prolactin ( prl ) levels and pms ; while benedek - jaszmann and hearn - sturtevant reported higher levels of prl in women with pms ( 9 ) , backstrom and aakvaag failed to find any association ( 10 ) . there are also conflicting data on the mean concentration of cholesterol among women with and without pms ( 11 ) . by conducting epidemiological and clinical studies , many researchers have uncovered conflicting results regarding the association between estradiol ( e2 ) , follicle - stimulating hormone ( fsh ) , testosterone ( t ) , dehydroepiandrosterone ( dhea ) , and dehydroepiandrosterone sulfate ( dhea - s ) levels and depression ( 12 - 15 ) . to date , few studies have evaluated the association between hormonal and metabolic factors and pms . most of the results were restricted by their small sample size , inappropriate inclusion criteria for women with pms , and by their comparison of a limited number of variables between the two groups of women , both with and without pms ( 10 , 16 ) . as a result , in the present study we aimed to investigate the association of hormonal and metabolic factors with pms among iranian women of reproductive age . the subjects of this study were selected from among the participants in the iranian pcos prevalence study which was a community based cross - sectional study of 1026 women , aged 18 - 45 years , conducted between 2009 - 2010 ( 17 ) . the eligible women were invited to participate in a comprehensive interview and their blood pressure , anthropometric , hormonal , and metabolic measurements were documented . data were completed for all but 97 women who did not come to the clinics and 19 participants whose hormonal and metabolic profiles were unavailable . we also excluded women who were using antidepressants ( n = 34 ) , oral contraceptive pills ( n = 151 ) , or taking hormonal medication for irregular menses . furthermore , those women who were pregnant at the time of the study ( n = 43 ) and menopausal women ( n = 37 ) were also excluded . finally , after the exclusion of the women who did not meet our inclusion criteria , 656 women were enrolled in the study . the american college of obstetricians and gynecologists ( acog ) criteria were used to diagnose pms . according to these criteria , the women needed to experience at least one of each of the following affective symptoms ( depression , angry outbursts , irritability , anxiety , confusion , social withdrawal ) and one somatic symptom ( breast tenderness , abdominal bloating , headache , swelling of extremities ) during the five days before menses in order to be diagnosed as having pms . each symptom must appear in three consecutive menstrual cycles and be scored on a scale of 1 ( low intensity ) , 2 ( moderate intensity ) and 3 ( severe intensity ) . the sum of the pms score ranges from 2 to 30 . using these criteria , our study participants were categorized into two groups : women with pms ( n = 354 ) and those without pms ( n = 302 ) . all the participants underwent clinical examinations , where their body weight , height , waist and hip circumferences , and blood pressure were measured by trained staff . height and weight were also measured with the subjects wearing light clothes but without shoes , using standard apparatus . height and waist circumferences ( wc ) were measured to the nearest 0.5 cm using a measuring tape . the waist was measured midway between the lower rib margin and the iliac crest , after a gentle expiration . body mass index ( bmi ) was calculated by dividing a participant s weight in kilograms by their height in meters squared ( kg / m ) . a blood sample that was used to determine biochemical measurements was taken from each subject on the second or third day of their menstrual cycle , after 12 hours of overnight fasting . blood samples were collected in edta treated test tubes . written informed consent was obtained from all participants before study entry . 17-hydroxyprogesterone ( 17oh - p ) , total testosterone ( tt ) and androstenedione ( a4 ) were measured by enzyme immunoassay ( eia ) , ( diagnostics biochem canada inc . , ontario , canada ) . sex hormone - binding globulin ( shbg ) was measured by immunoenzymometric assay ( iema ) , ( mercodia , uppsala , sweden ) . all elisa tests were performed using a sunrise elisa reader ( tecan co. , salzburg , austria ) . luteinizing hormone ( lh ) , follicle stimulating hormone ( fsh ) , prolactin ( prl ) , and thyroid stimulating hormone ( tsh ) were measured by immunoradiometric assay ( irma ) ( izotop , budapest , hungary ) using a gamma counter ( wallac wizard , turku , finland ) . it has been shown that in women , the free androgen index ( fai ) has a good correlation with free testosterone measured by a physical separation method ( 18 ) ; therefore , in this study the fai was calculated by using the formula : the intra- and inter - assay coefficients of variation for tt were 5.6% and 6.6% ; for shbg , 1.2% and 5.7% ; for a4 , 2.2% and 3.5% ; for lh , 3% and 5.8% ; for fsh , 3.5% and 4% ; for tsh , 1.7% and 3.4% , and for prl , they were 2.1% and 4.1% , respectively . according to the acog practice guidelines for the diagnosis of pms , one or more of the disturbing affective or somatic symptoms must have occurred in the five days before menses in each of three previous menstrual cycles . metabolic syndrome , based on the joint interim statement ( jis ) definition , was considered to be the presence of any three of the following five risk factors ( 19 ) : wc  95 ( country - specific cutoff point for iranians ( 20 ) , hdl < 50 , sbp  130 or dbp  85 , tg  150 and fbs  100 . according to the sixth report of the joint national committee ( jnc - vi ) criteria , hypertension or high bp was defined as mean sbp _ 140 mmhg , mean dbp _ 90 mmhg , or applied to a person undergoing current treatment for hypertension with prescription medication ( 21 ) . based on the american diabetes association s ( ada ) definition of diabetes , participants who met the following criteria were considered to be diabetic : 1 ) using anti - diabetic drugs or with fasting blood sugar ( fbs ) of _ 7 mmol / l or 2-h plasma glucose ( 2hpg ) _ 11.1 mmol / l ; 2 ) those with 2hpg between 7.77 and 11.1 mmol / l were defined as igt , and ; 3 ) fbs between 5.6 - 6.9 mmol / l was defined as impaired fasting plasma glucose ( ifg ) ( 10 , 22 ) . based on atp ii , dyslipidemia was defined as tc _ 240 mg / dl or ldl _ 160 mg / dl or tg _ 200 mg / dl or hdl < 35 mg / dl ( 23 ) . biochemical hyperandrogenism was detected by fai and/or a4 levels above the upper 95 percentile for the 362 women studied who were not on any hormonal medication and had no clinical evidence of hyperandrogenism , anovu , or pco . specifically , the upper normal limits for total t were = 0.88 ng / ml , a4 = 2.3 ng / ml , and fai = 5.47 . continuous variables were checked for normality using the one - sample kolmogorov - smirnov test , and expressed as mean , standard deviation , and/or median ( iq : 25 - 75 ) , as appropriate . linear regression ( forward method ) was used to identify the association between pms scores and metabolic disorders ( dependent variable ) after adjustment for age and bmi . the data analysis was performed using the spss 15.0 pc package ( spss inc . , the subjects of this study were selected from among the participants in the iranian pcos prevalence study which was a community based cross - sectional study of 1026 women , aged 18 - 45 years , conducted between 2009 - 2010 ( 17 ) . the eligible women were invited to participate in a comprehensive interview and their blood pressure , anthropometric , hormonal , and metabolic measurements were documented . data were completed for all but 97 women who did not come to the clinics and 19 participants whose hormonal and metabolic profiles were unavailable . we also excluded women who were using antidepressants ( n = 34 ) , oral contraceptive pills ( n = 151 ) , or taking hormonal medication for irregular menses . furthermore , those women who were pregnant at the time of the study ( n = 43 ) and menopausal women ( n = 37 ) were also excluded . finally , after the exclusion of the women who did not meet our inclusion criteria , 656 women were enrolled in the study . the american college of obstetricians and gynecologists ( acog ) criteria were used to diagnose pms . according to these criteria , the women needed to experience at least one of each of the following affective symptoms ( depression , angry outbursts , irritability , anxiety , confusion , social withdrawal ) and one somatic symptom ( breast tenderness , abdominal bloating , headache , swelling of extremities ) during the five days before menses in order to be diagnosed as having pms . each symptom must appear in three consecutive menstrual cycles and be scored on a scale of 1 ( low intensity ) , 2 ( moderate intensity ) and 3 ( severe intensity ) . the sum of the pms score ranges from 2 to 30 . using these criteria , our study participants were categorized into two groups : women with pms ( n = 354 ) and those without pms ( n = 302 ) . all the participants underwent clinical examinations , where their body weight , height , waist and hip circumferences , and blood pressure were measured by trained staff . height and weight were also measured with the subjects wearing light clothes but without shoes , using standard apparatus . height and waist circumferences ( wc ) were measured to the nearest 0.5 cm using a measuring tape . the waist was measured midway between the lower rib margin and the iliac crest , after a gentle expiration . body mass index ( bmi ) was calculated by dividing a participant s weight in kilograms by their height in meters squared ( kg / m ) . a blood sample that was used to determine biochemical measurements was taken from each subject on the second or third day of their menstrual cycle , after 12 hours of overnight fasting . blood samples were collected in edta treated test tubes . written informed consent was obtained from all participants before study entry . 17-hydroxyprogesterone ( 17oh - p ) , total testosterone ( tt ) and androstenedione ( a4 ) were measured by enzyme immunoassay ( eia ) , ( diagnostics biochem canada inc . , ontario , canada ) . sex hormone - binding globulin ( shbg ) was measured by immunoenzymometric assay ( iema ) , ( mercodia , uppsala , sweden ) . all elisa tests were performed using a sunrise elisa reader ( tecan co. , salzburg , austria ) . luteinizing hormone ( lh ) , follicle stimulating hormone ( fsh ) , prolactin ( prl ) , and thyroid stimulating hormone ( tsh ) were measured by immunoradiometric assay ( irma ) ( izotop , budapest , hungary ) using a gamma counter ( wallac wizard , turku , finland ) . it has been shown that in women , the free androgen index ( fai ) has a good correlation with free testosterone measured by a physical separation method ( 18 ) ; therefore , in this study the fai was calculated by using the formula : the intra- and inter - assay coefficients of variation for tt were 5.6% and 6.6% ; for shbg , 1.2% and 5.7% ; for a4 , 2.2% and 3.5% ; for lh , 3% and 5.8% ; for fsh , 3.5% and 4% ; for tsh , 1.7% and 3.4% , and for prl , they were 2.1% and 4.1% , respectively . according to the acog practice guidelines for the diagnosis of pms , one or more of the disturbing affective or somatic symptoms must have occurred in the five days before menses in each of three previous menstrual cycles . metabolic syndrome , based on the joint interim statement ( jis ) definition , was considered to be the presence of any three of the following five risk factors ( 19 ) : wc  95 ( country - specific cutoff point for iranians ( 20 ) , hdl < 50 , sbp  130 or dbp  85 , tg  150 and fbs  100 . according to the sixth report of the joint national committee ( jnc - vi ) criteria , hypertension or high bp was defined as mean sbp _ 140 mmhg , mean dbp _ 90 mmhg , or applied to a person undergoing current treatment for hypertension with prescription medication ( 21 ) . based on the american diabetes association s ( ada ) definition of diabetes , participants who met the following criteria were considered to be diabetic : 1 ) using anti - diabetic drugs or with fasting blood sugar ( fbs ) of _ 7 mmol / l or 2-h plasma glucose ( 2hpg ) _ 11.1 mmol / l ; 2 ) those with 2hpg between 7.77 and 11.1 mmol / l were defined as igt , and ; 3 ) fbs between 5.6 - 6.9 mmol / l was defined as impaired fasting plasma glucose ( ifg ) ( 10 , 22 ) . based on atp ii , dyslipidemia was defined as tc _ 240 mg / dl or ldl _ 160 mg / dl or tg _ 200 mg / dl or hdl < 35 mg / dl ( 23 ) . biochemical hyperandrogenism was detected by fai and/or a4 levels above the upper 95 percentile for the 362 women studied who were not on any hormonal medication and had no clinical evidence of hyperandrogenism , anovu , or pco . specifically , the upper normal limits for total t were = 0.88 ng / ml , a4 = 2.3 ng / ml , and fai = 5.47 . continuous variables were checked for normality using the one - sample kolmogorov - smirnov test , and expressed as mean , standard deviation , and/or median ( iq : 25 - 75 ) , as appropriate . correlations between hormone concentrations and premenstrual syndrome scores were checked using the pearson correlation . linear regression ( forward method ) was used to identify the association between pms scores and metabolic disorders ( dependent variable ) after adjustment for age and bmi . the data analysis was performed using the spss 15.0 pc package ( spss inc . , the demographic characteristics of the women who did not complete the questionnaire or those without hormonal measurements available did not significantly differ from those who completed the study procedure ( data has not been presented ) . according to our findings , the education levels in women with pms were significantly higher than those without the condition . table 1 demonstrates some of the demographic , reproductive , and anthropometric characteristics of the studied women , as divided into two groups , i.e. women with pms and those without it . the values are expressed as mean  sd except income , marital and job statuses that are presented as % . comparison carried out using t - tests or  tests for continuous and categorical variables , respectively . table 2 shows a comparison of the hormonal , metabolic , and lipid profiles of women with and without pms . our results suggest that there was a significant increase in prl and tg among women with pms , whereas tes , hdl and 17oh - p were significantly decreased when compared to women without pms . mean prl and tes for women with pms were 18.5 and 0.58 , respectively , whereas for the controls these values were 16.3 and 0.67 , respectively ( p < 0.05 ) . the mean serum levels of tg , hdl and 17oh - p for women with and without pms were 147.3 , 44.2 , and 1.8 versus 128.2 , 46.3 , and 2 , respectively . using ancova , we compared all the above variables between the two groups in order to adjust for age and bmi ; the results of the t - test analysis were not significantly different . the results of the pearson correlation analysis showed that t4 , prl , tes , and 17oh - p had significant correlations with pms scores among the affected women ( p < 0.05 ) . other variants , including serum levels of tsh , lh , shbg , hdl , tg , insulin , fbs , ldl , chl , systolic bp , diastolic bp , lh / fsh , fai , and a4 were not significantly correlated with pms . after adjusting for age and bmi , using partial correlation after adjusting for age and bmi , a linear regression analysis demonstrated a significant association between pms scores and the prevalence of metabolic syndrome ( p = 0.033 ) . according to our findings , for every one unit increase in pms score there was a 12% increase in the probability of having metabolic syndrome . using a linear regression analysis we found a non - significant association between pms scores and other metabolic disorders , such as diabetes , hyperandrogenism , dyslipidemia , hypertension , and hypothyroidism ( table 3 ) . abbreviations : bmi , body mass index ; ci , confidence interval ; pms , premenstrual syndrome . in the present study , we assessed a wide range of hormones and metabolites in order to establish their associations with pms . the association found between lower tt levels and pms in the present study contradicts the findings of bloch et al.s study ( 7 ) which indicated significantly lower tt and free t levels in women with pms . however , eriksson et al . ( 16 ) and backstrom and aakvaag ( 10 ) discussed the contrary . it has been found that low testosterone in women can cause a number of physical and emotional symptoms , including depression , loss of sexual desire , and declining libido ( 24 - 26 ) . despite there being a limited number of studies concerning the effects of testosterone on mood , the results show that testosterone treatment per se , or with estrogen , improves mood in women ( 27 ) . we observed significantly lower 17-ohp levels among women with pms which are findings that contradict those of eriksson et al . ( 16 ) who assessed women with pms during the luteal phase and reported higher 17-ohp levels when compared to age - matched controls ; these differences may be explained by the difference in the age of the subjects and the effects of age on hormone levels . the present study demonstrated that the serum prl level is significantly higher in women with pms , which is a finding that is in line with previous studies ( 9 , 28 ) . by contrast , another study ( 10 ) reported that the mean plasma prolactin level among 15 women affected with pms was not significantly different from that of the 17 women in the control group ; it appears that because of the small sample size , the researchers found no association between prl and pms . prolactin plays an indirect role in premenstrual syndrome and may cause renal retention of water , sodium , and potassium , and it interacts with lithium . prolactin can also interact with ovarian hormones to cause symptoms of depression , anxiety , or irritable hostility ( 29 ) . the data report higher levels of total cholesterol in women with pms with no significant alteration in tg and hdl ( 11 ) ; conversely , our data showed higher tg and lower hdl levels . to our knowledge , this is the first study examining the association of metabolic disorders in iranian women with pms . several studies have demonstrated that depression is significantly associated with metabolic syndrome ; for example , raikkonen et al . ( 30 ) also suggest that there is an association between metabolic syndrome and higher rates of depression . since depression is one of the main criteria of diagnosing pms , it can be speculated that pms and metabolic syndrome are associated . according to the data produced by this study , there was no significant association between insulin levels and pms , which is a consonant result with that of zarei et al . eriksson et al . ( 16 ) found no significant difference between pms cases and controls in shbg levels , which was also consistent with our findings . one of the strengths of our study was the large cross - sectional community based sample that it used . since most similar studies have focused on the small number of variants that contribute to pms disorders , we were able to investigate a broad range of anthropometric parameters and hormone levels in order to determine the independent association between endogenous hormones and metabolic parameters in multivariate analyses . however , a potential limitation that must be recognized is that we used homa - ir as a surrogate marker for assessing insulin resistance ( ir ) ; in spite of the good correlation between homa - ir and gold standard clamp methods , it might be inaccurate in women with pcos . moreover , we did not measure free testosterone due to our inability to access a proper method for its measurement . however , we calculated the fai using equation 1 it has been shown that fai correlates with free testosterone as measured by the physical separation method in women , which is the same as calculated free testosterone ( 17 ) . in conclusion , we found a significant association between pms scores and the prevalence of metabolic syndrome . moreover , we observed higher levels of prl and lower levels of tes , ohp-17 , tg , and hdl among women with pms , when compared to women without the syndrome . further studies are needed to confirm and validate the relationships between lipid profile abnormalities and metabolic disorders with pms .