H Vo, B Smith, D Rubinow
H Vo, B Smith, D Rubinow. Effects of Caffeine Consumption on Premenstrual Syndrome: A Prospective Study. The Internet Journal of Endocrinology. 2010 Volume 6 Number 2.
Premenstrual syndrome (PMS) and the more severe premenstrual dysphoric disorder (PMDD) are debilitating illnesses of women in their reproductive years (1, 2) and have even been associated with suicidal behavior (3). Within the United States, studies show that 15% to 40% (1, 4, 5, 6) of women experience premenstrual syndrome. Considerable research shows that the severity of PMS symptoms is significantly impacted by dietary factors (7, 8, 9, 10, 11, 12, 13).
A potentially important dietary factor in PMS is caffeine. This powerful stimulant is the most widely consumed drug in the world (14), and its arousal properties are well-documented (15, 16), as is its toxicity (17). Moreover, caffeine has been reported to exacerbate PMS (7, 18, 19, 20, 21, 22). The authors of a more recent retrospective study also concluded that caffeine may exacerbate PMS symptoms, although they note that caffeine accounted for only a small proportion of the variance (23). Based primarily on the Rossignol studies, caffeine restriction is frequently recommended (24).
These studies, which employed self-administered questionnaires, showed that the risk of PMS was significantly elevated in college women who consumed more than four caffeinated drinks per day and increased further in those ingesting 8-10 drinks (19, 21, 22).
While the Rossignol studies suggested that caffeine intake is associated with PMS, Caan and colleagues failed to support this association (26). They diagnosed PMS retrospectively and then collected caffeine intake data for three consecutive days during both premenstrual and postmenstrual weeks via telephone interviews. The authors suggested that women with PMS were less likely to consume caffeinated coffee or tea, but were more likely to drink decaffeinated beverages (26).
As Halbreich and colleagues have recently pointed out, studies of PMS often suffer from methodological limitations (27), and those mentioned above are no exception to this observation. First, none of these studies diagnosed PMS according to the NIMH Workshop diagnostic guidelines (28). Specifically, data must be gathered for two complete cycles, in each of which must occur a 30% increase in symptoms during the luteal, as compared with the follicular, phase (29). Second, Rossiginol’s studies were cross-sectional and retrospective. While Caan and colleagues addressed the latter concern, their study was also cross-sectional. Third, previous studies did not report any screening of their participants for preexisting psychiatric conditions. And finally, the basis for determining the caffeine content of foods and beverages was not specified.
In order to address the methodological limitations seen in earlier work, the present study first implemented the NIMH diagnostic guidelines. Our diagnostic procedures were also consistent with those proposed by the recent consensus conference for inclusion in the next edition of the International Classification of Diseases (ICD-11) of the World Health Organization (30). Participants were then diagnosed with PMS only if they reported at least a 30% increase on at least one of either physical or emotional symptom scores 5 days before the onset of menses and symptom remission within 4 days of onset of menses. The Patient Health Questionnaire (PHQ, 31) was used to screen for current and previous psychiatric conditions, and participants who reported any psychiatric diagnoses within the past six months were excluded. Finally, caffeine values were adopted from Juliano & Griffiths (2005) and were consistent with those reported elsewhere (32).
The present study is the first to address the diagnostic limitations of prior studies examining the relationship between PMS and caffeine intake. Based on prior literature indicating a positive association between caffeine consumption and experience of PMS symptoms, we hypothesized that women with PMS would consume more caffeine than would controls across the entire menstrual cycle.
Subjects And Methods
The Participant Screening Form is a demographic questionnaire created by the researcher that elicits the following information: age, marital status, racial/ethnic identity, current medication regime, habitual smoking, and level of habitual caffeine intake. It was used to assess the representativeness and composition of the sample.
The Patient Health Questionnaire (PHQ; 31) is a tool provided to help primary care practitioners quickly diagnose mental disorders. The full PHQ is a four-page questionnaire derived from the Primary Care Evaluation of Mental Disorders (PRIME-MD; 31). The measure screens for common mental disorders (somatoform, mood, anxiety, eating, and alcohol) and functional impairment. It also includes questions about recent stressors and, for women, questions regarding menstruation, pregnancy, and childbirth. Clinicians often use only the first three pages, or some components, such as the 9-item depression module (PHQ-9; 31). The measure has good internal and test-retest reliability, with Cronbach’s alpha value of above 0.84 (35). Additionally, internal validity was 0.86 and validity of 0.70 and around that range for psychiatric diagnoses (e.g. depression and anxiety; 36).
The Caffeine Intake Form was used in the study to record daily caffeine consumption. Participants were asked to record their intake of foods and beverages daily. The response options for specified serving sizes were provided in the instruction. The relevant beverages included on the questionnaire and calculations of total caffeine intake were as recommended in Juliano and Griffiths (2005). It assesses the amount of consumption for various products containing caffeine (37). This form was included in the daily diaries.
The Self-Rating Scale for Premenstrual Tension Syndrome (PMTS-SR; 38) was used as part of the daily diary in order to record PMS symptoms. The correlation coefficients of the PMTS-SR and the Premenstrual Tension Scale for Others (PMTS-O) are 0.83 premenstrual and 0.84 postmenstrual as reported by Bergant and colleagues (2004). Reliability is 0.71 and 0.77 for the PMTS-O and PMTS-SR, respectively (39). In order to meet criteria for PMS, participants had to endorse at least a 30% increase in symptom severity during the luteal phase, as compared to the follicular phase, for 2 consecutive months. The PMTS-SR assessed for symptoms such as mood swings (sudden sadness or tearfulness), depression, anxiety (tension and nervousness), and irritability, avoidance of social activities, sensitivity, and loss of enjoyment or hopelessness. Percent increase was calculated using the difference between premenstrual and postmenstrual time periods.
For purposes of the data analysis, mean caffeine intake was computed for each participant for each phase of the cycle (caffeine values adopted from Juliano & Griffiths, 2005). Average caffeine intake was the average across both months of daily dairies. A goodness-of-fit (Chi Square) analysis was completed to control for possible demographic differences among groups. A mixed Analysis of Variance (ANOVA) compared caffeine consumption and symptoms of PMS. The between-subjects variable was Diagnosis [PMS (N = 34) and Control (N = 49)], and the within-subjects factor was menstrual cycle Phase (follicular vs. luteal).
Goodness-of-fit, Chi-Square test, analyses did not reveal group differences in age, [χ2 (7, N = 83) = 5.63;
Caffeine Consumption and PMS
Analysis of Variance (ANOVA) did not reveal any main effect of Diagnosis [
Two previous studies provide results contrary to those of the Rossignol group. In the first of these, PMS was diagnosed on a retrospective basis, and caffeine consumption was based on three days of daily caffeine intake data. Results showed no evidence that caffeine contributes to PMS symptoms (26). In the second, Gold and colleagues (43) employed retrospective, questionnaire data for both PMS and caffeine consumption. They also reported that caffeine had no significant effect on PMS symptomatology. Unfortunately, both studies also suffered from some of the same methodological concerns associated with the Rossignol studies.
The present study employed a design and methodology that addressed the issues raised concerning the prior work. In particular, this study used a prospective approach both for PMS diagnosis and for the assessment of caffeine intake. Specifically, data on both PMS symptoms and caffeine consumption were based on daily monitoring over the course of two complete menstrual cycles. In addition, psychiatric history was screened, and caffeine content was based on guidelines derived from prior research (38). This methodology provided for both a more accurate diagnosis of PMS and a more accurate assessment of caffeine consumption.
There were two principal findings in the present study. First, that caffeine intake is not associated with PMS symptoms (e.g. women with PMS were not more likely to consume caffeine than non-PMS sufferers). As noted above, this finding is consistent with those of two retrospective studies (26, 43). Present findings suggest that it is unlikely that caffeine consumption exacerbates PMS symptoms. The second major finding in the present study was that women, across groups, consumed more caffeine during the follicular than during the luteal phase. Thus the menstrual cycle phase difference in level of consumption appeared independent of diagnosis. In interpreting the findings of the present study, it is important to note that the college student sample, although they met inclusion criteria, may not consume as much caffeine as do older populations (44) and it was also unclear whether any participant(s) restricted caffeine use during the course of this study. A final consideration is that the PMS diagnostic criterion used here was a 30% increase in symptomatology, as recommended by NIMH guidelines, and thus level of impairment could not be determined (45). Nonetheless, self-ratings of impairment have been shown to be highly correlated with symptom self-ratings in women with PMS (32).
Media and internet sites often suggest that caffeine exacerbates PMS symptoms (25, 46-48). The current data does not provide evidence to support these recommendations. Data suggests that caffeine intake decreased during the luteal phase across women with and without PMS. The present study has demonstrated the value of longitudinal methods of data collection, in order to facilitate our understanding of how the menstrual cycle interacts with caffeine consumption, and it recommended that similar methods be applied to future research. In addition, future research might address the effects of caffeine withdrawal symptoms in relation to PMS, since there are some overlapping symptoms (49). Finally, further research should be more clearly guided by knowledge of underlying mechanisms and by theoretical models of caffeine-adenosine effects that integrate those mechanisms.