Measurement Modalities and Number of Vasomotor Symptoms
Measurement Modalities and Number of Vasomotor Symptoms
The primary aim of this study was to examine the accuracy of end-of-day and morning VMS recall by comparing them with prospective report and physiological detection of VMS. We found that the women in this study had a tendency to underestimate the number of VMS at the end of the day compared with those prospectively reported or physiologically measured throughout the day. The tendency to underestimate daytime VMS was especially pronounced among African-American women and, contrary to our expectations, more anxious women. For overnight VMS, women overestimated the number of overnight VMS upon waking as compared with those prospectively reported or physiologically detected during the night. This pattern was particularly pronounced among women with poorer sleep (more wakefulness during the night). Racial/ethnic differences pointed to a pattern of African-American women being most likely to underestimate VMS and a pattern of white women being most likely to overestimate VMS, particularly in the context of negative affect or poor sleep.
This study is one of the few studies to investigate the degree of correspondence between VMS assessed through retrospective recall, prospective report, and physiological detection. This study is important given that findings in studies using VMS diaries completed prospectively or retrospectively are often treated interchangeably. However, daytime VMS may be systematically underestimated, and overnight VMS may be systematically overestimated. Moreover, recalled VMS are subject to the additional influence of affect and sleep. These findings underscore the potential importance of using prospective VMS reports.
Other symptom literatures, such as those related to pain, have previously described individuals' difficulty in precisely recalling these symptoms. Notably, research in the pain literature shows greater accuracy for recall of novel acute pain than for recall of chronic or repeated episodic pain, such as the VMS experienced here. Memory for pain is also influenced by the mood at the time of recall. For example, negative affect, particularly anxiety, impacts both symptom reporting and memory for pain across a range of physical conditions. For VMS, anxiety plays an important role in VMS reporting. However, negative affect is typically associated with overestimation of symptoms. Why anxiety was related to underestimation of VMS in our study is not entirely clear. A possible theory is that anxiety plays differential roles in prospective and retrospective symptom reporting, as some research shows that anxiety is associated with elevated prospective symptom reports, but not symptom recall. It is also notable that the greater underestimation associated with higher negative affect was most apparent among African-American women. Prior work has not considered that the relation between affect and VMS reporting may vary by race; our findings suggest the potential importance of considering racial/ethnic differences.
Overestimation of nighttime VMS upon waking compared with those prospectively reported or physiologically measured during the night is in accordance with our previous work showing moderate to no correlation between prospectively reported or physiological VMS and morning-diary-recalled VMS, respectively. Consistent with links between poor sleep and VMS, women overestimated VMS upon waking if they had poorer sleep (ie, more sleep disruptions). Measuring nighttime VMS via self-report is a challenge, given that women are typically sleeping; thereby, physiological monitoring can be useful in obtaining overnight VMS estimates. However, physiological monitoring is often not feasible for large studies; thus, the accuracy of morning reports becomes paramount. Consistent with our prior work, the present findings indicate that these morning reports may be somewhat inflated if a woman has had a poor night of sleep.
Consistent with previous reports, African-American women prospectively reported more VMS and experienced more physiological VMS than white women. Greater underestimation of daytime VMS at the end of the day versus prospective measures was also more apparent among African-American women. The reason for this racial/ethnic difference is not entirely clear and should be interpreted with caution, given the small numbers of women in these stratified models. We considered whether the racial/ethnic differences in BMI might have played a role, but BMI was adjusted for in all models and was generally not associated with the reporting difference scores. Other demographic factors (eg, age, employment status, marital status, living arrangements) were also considered but were not related to VMS reporting outcomes, nor did they account for these racial/ethnic differences (data not shown). Other works show variations by race/ethnicity in both VMS and pain reporting. The present findings highlight the potential importance of considering racial/ethnic differences in patterns of VMS reporting.
Several limitations of this study should be mentioned. The small size of our sample may have limited the power to detect associations, especially for interactions and stratified models. Interpretation of racial/ethnic differences, in particular, requires caution. Moreover, given the inclusion of only African-American and white women, we cannot draw conclusions about other racial/ethnic groups.
This study has numerous strengths. This is the first study to examine the concordance/discordance of three different VMS measurement modalities: retrospective daily diary, prospective report, and physiological detection. We compared both subjective versus objective measures of VMS and retrospective versus prospective assessments of VMS. This study also evaluated daily diaries similar to those used in recent studies of VMS treatments. In addition, as mentioned above, we provided three different ways to prospectively report VMS events and monitored women in the home setting. Finally, this study included a well-characterized sample of African-American and white women in approximately equal numbers.
Discussion
The primary aim of this study was to examine the accuracy of end-of-day and morning VMS recall by comparing them with prospective report and physiological detection of VMS. We found that the women in this study had a tendency to underestimate the number of VMS at the end of the day compared with those prospectively reported or physiologically measured throughout the day. The tendency to underestimate daytime VMS was especially pronounced among African-American women and, contrary to our expectations, more anxious women. For overnight VMS, women overestimated the number of overnight VMS upon waking as compared with those prospectively reported or physiologically detected during the night. This pattern was particularly pronounced among women with poorer sleep (more wakefulness during the night). Racial/ethnic differences pointed to a pattern of African-American women being most likely to underestimate VMS and a pattern of white women being most likely to overestimate VMS, particularly in the context of negative affect or poor sleep.
This study is one of the few studies to investigate the degree of correspondence between VMS assessed through retrospective recall, prospective report, and physiological detection. This study is important given that findings in studies using VMS diaries completed prospectively or retrospectively are often treated interchangeably. However, daytime VMS may be systematically underestimated, and overnight VMS may be systematically overestimated. Moreover, recalled VMS are subject to the additional influence of affect and sleep. These findings underscore the potential importance of using prospective VMS reports.
Other symptom literatures, such as those related to pain, have previously described individuals' difficulty in precisely recalling these symptoms. Notably, research in the pain literature shows greater accuracy for recall of novel acute pain than for recall of chronic or repeated episodic pain, such as the VMS experienced here. Memory for pain is also influenced by the mood at the time of recall. For example, negative affect, particularly anxiety, impacts both symptom reporting and memory for pain across a range of physical conditions. For VMS, anxiety plays an important role in VMS reporting. However, negative affect is typically associated with overestimation of symptoms. Why anxiety was related to underestimation of VMS in our study is not entirely clear. A possible theory is that anxiety plays differential roles in prospective and retrospective symptom reporting, as some research shows that anxiety is associated with elevated prospective symptom reports, but not symptom recall. It is also notable that the greater underestimation associated with higher negative affect was most apparent among African-American women. Prior work has not considered that the relation between affect and VMS reporting may vary by race; our findings suggest the potential importance of considering racial/ethnic differences.
Overestimation of nighttime VMS upon waking compared with those prospectively reported or physiologically measured during the night is in accordance with our previous work showing moderate to no correlation between prospectively reported or physiological VMS and morning-diary-recalled VMS, respectively. Consistent with links between poor sleep and VMS, women overestimated VMS upon waking if they had poorer sleep (ie, more sleep disruptions). Measuring nighttime VMS via self-report is a challenge, given that women are typically sleeping; thereby, physiological monitoring can be useful in obtaining overnight VMS estimates. However, physiological monitoring is often not feasible for large studies; thus, the accuracy of morning reports becomes paramount. Consistent with our prior work, the present findings indicate that these morning reports may be somewhat inflated if a woman has had a poor night of sleep.
Consistent with previous reports, African-American women prospectively reported more VMS and experienced more physiological VMS than white women. Greater underestimation of daytime VMS at the end of the day versus prospective measures was also more apparent among African-American women. The reason for this racial/ethnic difference is not entirely clear and should be interpreted with caution, given the small numbers of women in these stratified models. We considered whether the racial/ethnic differences in BMI might have played a role, but BMI was adjusted for in all models and was generally not associated with the reporting difference scores. Other demographic factors (eg, age, employment status, marital status, living arrangements) were also considered but were not related to VMS reporting outcomes, nor did they account for these racial/ethnic differences (data not shown). Other works show variations by race/ethnicity in both VMS and pain reporting. The present findings highlight the potential importance of considering racial/ethnic differences in patterns of VMS reporting.
Several limitations of this study should be mentioned. The small size of our sample may have limited the power to detect associations, especially for interactions and stratified models. Interpretation of racial/ethnic differences, in particular, requires caution. Moreover, given the inclusion of only African-American and white women, we cannot draw conclusions about other racial/ethnic groups.
This study has numerous strengths. This is the first study to examine the concordance/discordance of three different VMS measurement modalities: retrospective daily diary, prospective report, and physiological detection. We compared both subjective versus objective measures of VMS and retrospective versus prospective assessments of VMS. This study also evaluated daily diaries similar to those used in recent studies of VMS treatments. In addition, as mentioned above, we provided three different ways to prospectively report VMS events and monitored women in the home setting. Finally, this study included a well-characterized sample of African-American and white women in approximately equal numbers.