Mtr/u,i/o.c. 14 (1992) 157-l 60 Elacvier Scientific
MAT
I.57
Publishers Ireland
Lrd
00665
Longitudinal
studies: comparative J.G. Greene”
conclusions
and A.Ph. Visserb
Introduction The four studies described in this issue of Muturitas have all shed light on a number of key issues currently exercising the minds of those with an interest in the study of the menopause (l-41. What they have in common, as longitudinal studies, is that they followed the same groups of women over a critical period of time during their passage through the climacteric transition [5]. This made it possible, firstly, to time and monitor critical changes, phases and events almost as they happened and, secondly, to determine those variables which predict women’s responses during the peri- and postmenopause. Within the context of the longitudinal design each of the authors addressed different issues depending on their interests and orientation and adopted different research strategies to deal with these. For example, there is a clear difference in the approach of Kaufert [4] and McKinlay [l] whose background is sociology, and that of Holte and Hunter, whose background is psychology [2,3]. The purpose of this editorial comment is to draw together some of the main pointers that have emerged from these similar yet different studies. Methods of Analysis One of the most absorbing and fundamental features of these longitudinal studies is the particular way in which the researchers handled the analysis of their complex data - complex because prospective studies, by their very nature, must perforce deal with repeated measures. Hunter probably had the easiest task in this respect, in that, having two measures to contend with, she was able to use the well-established technique of paired statistical tests [2]. Holte and Kaufert, who had to deal with five measures, chose to ‘collapse’ these [3,4]. Holte used a relatively untried method, known as the summary measurement procedure, which he adapted to enable him to relate health complaints at several Corre,spondencr to: J.G. Greene, Gartnavel
Royal Hospital,
Department
U.K.
037%5122/92/%05.00
0
1992 Elsevier Scientific Publishers Ireland
Printed and Published in Ireland
Ltd.
of Clinical Psychology, Glasgow.
time-points to menopausal status [3]. This involved summating scores taken at time points both before and after the menopause was reached. Rather than regarding the information from each 6-monthly interview as an independent data set, Kaufert’s solution was to treat all changes in menopausal status as if dealing with a single period of 6 months, separated by two time points, referred to as Time 1 and Time 2 [4]. By doing so, she was able, for example, to look at changes in depression as a woman makes the transition from one menopausal status to another. This technique also allowed her to calculate the adjusted relative odds for those independent variables related to depression, using multiple logistic regression. McKinlay’s approach was to utilize a number of different and varied analytic strategies depending on the type of data set and the problem being investigated [ 11. These included the use of logit analysis to estimate median age at the inception of the perimenopause, logistic regression to investigate factors associated with the transition to and duration of the perimenopause, and a stepwise loglinear model to determine whether the number of perimenopausal contacts varied with some of these factors. This approach reflected McKinlay’s objective in that particular paper to use her large sample to establish some basic menopause parameters and the strength of factors influencing these. Age at menopause With her large sample and repeated measures, McKinlay would appear to have definitively confirmed the median age of menopause as the first part of the 52nd year [l]. This concurs with the estimates derived from three other large-sample, crosssectional surveys involving Dutch women. These were the seminal study by Jaszmann (1967) the study by Brand (1977) and that by Oldenhave (1987) in which the median age at menopause was calculated to be 5 1.4, 5 1.5 and 5 1.1 years, respectively [6-81. McKinlay also reports the median length of the perimenopause transition to be almost 4 years and that a major factor in bringing forward age at menopause and shortening the perimenopausal transition is the habit of smoking [ 11. There is, however, a cultural limitation as regards the findings of the four present studies, since they relate to Europe and North America. Nevertheless a crosssectional survey in seven Far-East countries, reported similar findings as to age at menopause [lo]. Menopause criteria Holte’s data suggest that as short a period of amenorrhoea as 6 months could be used to define postmenopausal status [3]. This is clearly contrary to most current practice, where a period of 1 year is generally applied, although this is very much an ad hoc criterion. [9] It would obviously greatly ease the difficulties involved in the comparison and replication of studies if uniform criteria could be agreed. Longitudinal studies ought now to facilitate such an agreement.
Symptomatology
at the menopause
Not unexpectedly, all three studies reporting data on vasomotor symptoms found a marked and significant increase in these. Nevertheless, vasomotor symptoms were not uncommon during the premenopause and Hunter further implicated earlier premenstrual tension as a factor predicting the severity of vasomotor symptoms in the perimenopause [2]. Insomnia was also found to be associated with vasomotor symptoms, as it was in McKinlay’s study [l]. In only one study (that of Hunter) was there any clear evidence of an increase in symptoms other than vasomotor ones with the onset of the climacteric [2]. This was confined, however, to just one of her factor scales, namely depression, and was of modest proportion. Hunter found no significant change in any of her other symptom measures, such as anxiety, sexual problems and somatic symptoms. McKinlay reported a transitory increase in ‘combined’ symptomatology at the perimenopause, but a closer examination of her data (see Fig. 2 of Ref. 1) suggests that this apparent increase in combined symptoms was probably due to an increase in vasomotor symptoms at the perimenopause among women already experiencing other symptoms, the latter in themselves showing very little increase [I]. In Kaufert’s study, no change in clinical depression, as measured by the CES-D Scale, was noted as women moved through the transition from being pre- to peri- to postmenopausal in the case of natural menopause [4]. Finally, among all Holte’s many measures, the only psychological one showing any increase with the onset of the climacteric was a measure of social dysfunction: he attributed the increase largely to severity of vasomotor symptoms [3]. He also made the interesting observation that a substantial number of women in this study reported an improvement in well-being following menopause. Aetiology of symptoms at the menopause
Hunter’s was the only study to find an association between depression and the menopause [2]. Nevertheless, on the basis of her data, she rejected the possible explanations that depression was either a result of hormone deficiency or a reaction to severe vasomotor symptoms, since she saw no empirical association between these and depressed mood in her sample. Rather, she found considerable evidence than psychological factors such as negative stereotype, employment status and socioeconomic status account for more of the variation in depressed mood that menopausal status. Furthermore, women themselves were more likely to attribute their depressed mood to family problems, bereavements, ill health, work and financial problems rather than hormonal changes. Hunter’s conclusions find confirmation in those of Kaufert, to the effect that poor interpersonal relations, particularly family ones, contribute to the onset of clinical depression as women’s menopausal status changes [4]. She also implicates poor physical health both in causing the onset of depression and in maintaining it, making the valid point that greater consideration must be given to general health problems in the evaluation of the impact of the menopause on women. Her findings indicating
that psychological factors play a major role in the aetiology of psychological complaints at the time of the menopause are clearly consistent with those from crosssectional studies. Conclusion
The publication in a single issue of some of the findings emerging from current longitudinal studies of the climacteric transition has the advantage of facilitating their contrast and comparison in regard to both method and outcome. So far, these generally seem to confirm and complement findings from cross-sectional studies. Nevertheless. these studies go beyond merely confirming and complementing earlier findings, since they not only give such findings greater precision and authority, but also change the status of putative relationships between variables from being mere associations to being predictive and causal. That must be seen as an important development in the scientific study of the menopause. The future will no doubt the publication of more data from these studies and a consequent advancement our knowledge and understanding of this important phase of women’s lives.
see of
References McKinlay SM. Brambilla DJ. Posncr 103-I 15. Hunter M. The South-East England Maturitas 1992; 14: 117-126.
JG. The normal longitudinal
mcnopausc
study
transition.
of the climacteric
Maturitas
1092: 14:
and postmenopau~.
Holte A. Influences of natural menopause on health complaints: a prospective study of healthy Norwegian women. Maturitas 1992: 14: 127-141. Kaufert PA. Gilbert P. Tate R. The Manitoba project: A re-examination of the link between menopause and depression. Maturitas 1991: 14: l43- 155. Greene JG. The cross-sectional legacy: an introduction to longitudinal atudica of the climacteric. Maturitas 1992; 14: 95-101. Jaszmann L, Van Lith ND, Zaat JCA. The age at the menopause in the Netherlands: the statistical analysis of a survey. Med Gynecol Sot 1969; 4: 256-277. Brand PC, Lehert PH. A new way of looking at environmental variables that may affect the age at menopause. Maturitas 1978; 1: 12l- 132. Oldenhave A, Jaszmann LJB. The climacteric: absence or presence of hot flushes and their relation to other complaints. In: Schonbaum E. ed. The climacteric hot flush. Basel: Karger. 1990 Vol. 6, 6-39. Vankeep P, Kellerhals J. The aging women. Aging and estrogens. Front Horm Res Basel: Karger. 1973. Vol. 2, 160-173. Lehert P. Factors affecting age at natural menopause in Far-East countries. Results of a crosssectional survey in seven countries. Paper presented at Sixth International Congress on the Menopause, Bangkok. Thailand. 29 October-2 November, 1990. Abstracts. Carnforth: Parthenon Publishing. 1990; p. 24.
MAT
I.57
Publishers Ireland
Lrd
00665
Longitudinal
studies: comparative J.G. Greene”
conclusions
and A.Ph. Visserb
Introduction The four studies described in this issue of Muturitas have all shed light on a number of key issues currently exercising the minds of those with an interest in the study of the menopause (l-41. What they have in common, as longitudinal studies, is that they followed the same groups of women over a critical period of time during their passage through the climacteric transition [5]. This made it possible, firstly, to time and monitor critical changes, phases and events almost as they happened and, secondly, to determine those variables which predict women’s responses during the peri- and postmenopause. Within the context of the longitudinal design each of the authors addressed different issues depending on their interests and orientation and adopted different research strategies to deal with these. For example, there is a clear difference in the approach of Kaufert [4] and McKinlay [l] whose background is sociology, and that of Holte and Hunter, whose background is psychology [2,3]. The purpose of this editorial comment is to draw together some of the main pointers that have emerged from these similar yet different studies. Methods of Analysis One of the most absorbing and fundamental features of these longitudinal studies is the particular way in which the researchers handled the analysis of their complex data - complex because prospective studies, by their very nature, must perforce deal with repeated measures. Hunter probably had the easiest task in this respect, in that, having two measures to contend with, she was able to use the well-established technique of paired statistical tests [2]. Holte and Kaufert, who had to deal with five measures, chose to ‘collapse’ these [3,4]. Holte used a relatively untried method, known as the summary measurement procedure, which he adapted to enable him to relate health complaints at several Corre,spondencr to: J.G. Greene, Gartnavel
Royal Hospital,
Department
U.K.
037%5122/92/%05.00
0
1992 Elsevier Scientific Publishers Ireland
Printed and Published in Ireland
Ltd.
of Clinical Psychology, Glasgow.
time-points to menopausal status [3]. This involved summating scores taken at time points both before and after the menopause was reached. Rather than regarding the information from each 6-monthly interview as an independent data set, Kaufert’s solution was to treat all changes in menopausal status as if dealing with a single period of 6 months, separated by two time points, referred to as Time 1 and Time 2 [4]. By doing so, she was able, for example, to look at changes in depression as a woman makes the transition from one menopausal status to another. This technique also allowed her to calculate the adjusted relative odds for those independent variables related to depression, using multiple logistic regression. McKinlay’s approach was to utilize a number of different and varied analytic strategies depending on the type of data set and the problem being investigated [ 11. These included the use of logit analysis to estimate median age at the inception of the perimenopause, logistic regression to investigate factors associated with the transition to and duration of the perimenopause, and a stepwise loglinear model to determine whether the number of perimenopausal contacts varied with some of these factors. This approach reflected McKinlay’s objective in that particular paper to use her large sample to establish some basic menopause parameters and the strength of factors influencing these. Age at menopause With her large sample and repeated measures, McKinlay would appear to have definitively confirmed the median age of menopause as the first part of the 52nd year [l]. This concurs with the estimates derived from three other large-sample, crosssectional surveys involving Dutch women. These were the seminal study by Jaszmann (1967) the study by Brand (1977) and that by Oldenhave (1987) in which the median age at menopause was calculated to be 5 1.4, 5 1.5 and 5 1.1 years, respectively [6-81. McKinlay also reports the median length of the perimenopause transition to be almost 4 years and that a major factor in bringing forward age at menopause and shortening the perimenopausal transition is the habit of smoking [ 11. There is, however, a cultural limitation as regards the findings of the four present studies, since they relate to Europe and North America. Nevertheless a crosssectional survey in seven Far-East countries, reported similar findings as to age at menopause [lo]. Menopause criteria Holte’s data suggest that as short a period of amenorrhoea as 6 months could be used to define postmenopausal status [3]. This is clearly contrary to most current practice, where a period of 1 year is generally applied, although this is very much an ad hoc criterion. [9] It would obviously greatly ease the difficulties involved in the comparison and replication of studies if uniform criteria could be agreed. Longitudinal studies ought now to facilitate such an agreement.
Symptomatology
at the menopause
Not unexpectedly, all three studies reporting data on vasomotor symptoms found a marked and significant increase in these. Nevertheless, vasomotor symptoms were not uncommon during the premenopause and Hunter further implicated earlier premenstrual tension as a factor predicting the severity of vasomotor symptoms in the perimenopause [2]. Insomnia was also found to be associated with vasomotor symptoms, as it was in McKinlay’s study [l]. In only one study (that of Hunter) was there any clear evidence of an increase in symptoms other than vasomotor ones with the onset of the climacteric [2]. This was confined, however, to just one of her factor scales, namely depression, and was of modest proportion. Hunter found no significant change in any of her other symptom measures, such as anxiety, sexual problems and somatic symptoms. McKinlay reported a transitory increase in ‘combined’ symptomatology at the perimenopause, but a closer examination of her data (see Fig. 2 of Ref. 1) suggests that this apparent increase in combined symptoms was probably due to an increase in vasomotor symptoms at the perimenopause among women already experiencing other symptoms, the latter in themselves showing very little increase [I]. In Kaufert’s study, no change in clinical depression, as measured by the CES-D Scale, was noted as women moved through the transition from being pre- to peri- to postmenopausal in the case of natural menopause [4]. Finally, among all Holte’s many measures, the only psychological one showing any increase with the onset of the climacteric was a measure of social dysfunction: he attributed the increase largely to severity of vasomotor symptoms [3]. He also made the interesting observation that a substantial number of women in this study reported an improvement in well-being following menopause. Aetiology of symptoms at the menopause
Hunter’s was the only study to find an association between depression and the menopause [2]. Nevertheless, on the basis of her data, she rejected the possible explanations that depression was either a result of hormone deficiency or a reaction to severe vasomotor symptoms, since she saw no empirical association between these and depressed mood in her sample. Rather, she found considerable evidence than psychological factors such as negative stereotype, employment status and socioeconomic status account for more of the variation in depressed mood that menopausal status. Furthermore, women themselves were more likely to attribute their depressed mood to family problems, bereavements, ill health, work and financial problems rather than hormonal changes. Hunter’s conclusions find confirmation in those of Kaufert, to the effect that poor interpersonal relations, particularly family ones, contribute to the onset of clinical depression as women’s menopausal status changes [4]. She also implicates poor physical health both in causing the onset of depression and in maintaining it, making the valid point that greater consideration must be given to general health problems in the evaluation of the impact of the menopause on women. Her findings indicating
that psychological factors play a major role in the aetiology of psychological complaints at the time of the menopause are clearly consistent with those from crosssectional studies. Conclusion
The publication in a single issue of some of the findings emerging from current longitudinal studies of the climacteric transition has the advantage of facilitating their contrast and comparison in regard to both method and outcome. So far, these generally seem to confirm and complement findings from cross-sectional studies. Nevertheless. these studies go beyond merely confirming and complementing earlier findings, since they not only give such findings greater precision and authority, but also change the status of putative relationships between variables from being mere associations to being predictive and causal. That must be seen as an important development in the scientific study of the menopause. The future will no doubt the publication of more data from these studies and a consequent advancement our knowledge and understanding of this important phase of women’s lives.
see of
References McKinlay SM. Brambilla DJ. Posncr 103-I 15. Hunter M. The South-East England Maturitas 1992; 14: 117-126.
JG. The normal longitudinal
mcnopausc
study
transition.
of the climacteric
Maturitas
1092: 14:
and postmenopau~.
Holte A. Influences of natural menopause on health complaints: a prospective study of healthy Norwegian women. Maturitas 1992: 14: 127-141. Kaufert PA. Gilbert P. Tate R. The Manitoba project: A re-examination of the link between menopause and depression. Maturitas 1991: 14: l43- 155. Greene JG. The cross-sectional legacy: an introduction to longitudinal atudica of the climacteric. Maturitas 1992; 14: 95-101. Jaszmann L, Van Lith ND, Zaat JCA. The age at the menopause in the Netherlands: the statistical analysis of a survey. Med Gynecol Sot 1969; 4: 256-277. Brand PC, Lehert PH. A new way of looking at environmental variables that may affect the age at menopause. Maturitas 1978; 1: 12l- 132. Oldenhave A, Jaszmann LJB. The climacteric: absence or presence of hot flushes and their relation to other complaints. In: Schonbaum E. ed. The climacteric hot flush. Basel: Karger. 1990 Vol. 6, 6-39. Vankeep P, Kellerhals J. The aging women. Aging and estrogens. Front Horm Res Basel: Karger. 1973. Vol. 2, 160-173. Lehert P. Factors affecting age at natural menopause in Far-East countries. Results of a crosssectional survey in seven countries. Paper presented at Sixth International Congress on the Menopause, Bangkok. Thailand. 29 October-2 November, 1990. Abstracts. Carnforth: Parthenon Publishing. 1990; p. 24.
